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A Petroiogical Investigation of the
Copper Cliff Ernbayment Structure
Sudbury. Ontario
P. Clayton Capes
A thesis suhitted in confmity with the requirements
for the degree MSc.
Graduate Department of Geo togy
University of Toronto
Copyright by P.Claflm Capes 2001
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A Petrological Investigation of the Copper Cliff Embayment Structure, Sudbury, Ontario MSc. Departmait of Geology P. Claytm Capes University of Toronto 200 1
The Copper Cliff embayment structure is located in the South Range of the Sudbury lgneous Cornplex (SIC). The
embayment is composecl predorn inan tl y of coarse-grain& gabbronorite mesocurnulates which grade outward into a
fine-grained quartz monzogabbrmorite orthocurnulate diaracterized by large blue quartz crystal S. nie outermost
region of the embayment is occupied by a thin discontinuous rind of diabasic textured quartz rnonzodiorite, which
has traditionally been called quartz diorite.
The contact relatimships with in the em bayment coupled with the geochem ical data suggest that the quartz
monzodiaite is a quenched liquid and the quar& monzogabbronorite and gabbronorite are cumulates derived fiom
the residual. In addition, it appears that there are two distinct groups of rocks with in the em bayment; a high Al-0,
group and a low A120; group, with the division occurring at approxirnately 15 wtO/o. The low Al values are found in
rocks that tend to have higher than average inclusim numbers, and sulphide content.
Aclrsowkdgcmcmb
1 would Iike to thank Jim Mun@ and Jacob Hanley at the University of Toronto for al1 their assistance
with this project. 1 would also like to thank Gord Monisori and Ctuis Davies at iNCO Exploratiori Sudbury for their
advice and MC0 Ltd for both their financiai and tachnical support. 1 would also like to acknowledge the work of
Peter Lightfooî et al. 1997a IWb, bom whid a large amount of data for various O- and rocks fiom the SIC was
obtained. Finally 1 would like to thank Sara Benjamin for her patience and attention during numerous discussions
pertaining to the nature of the SIC.
List of Tables List of Plates List of Figures List of Appendices
v vi vii ix
1 . 1 Introduction 1.2 l'wpose
2 Reviais Work 3 Regional Geology of Sudbury Area
3.1 Main Mass 3.2 Sublayer
4 Geology of O f f k t Dikes and Em bayments 4.1 Geology of the Oaet Dikes 4.2 Geology of the Copper Cliff O s e t 4.3 Geology of the Copper Cliff Embaymmt
5 Methods 5.1 Sam pl ing Rogram 5 -2 Sample Reparaticm 5.3 Cmtarnination 5.4 Sample Analysis 5.5 Data Validation
6 Microprobe Analysis 6.1 Ordiopyoxene 6.2 Blue Quam
7 Gdemistry 7.1 Major Oxide Geochemistry of the Copper Cliff Embayment Rocks and SIC 7.2 Trace Element Geochemisby for Copper Cliff Embayment Rocks 7.3 REE Geoctiemistry fm Copper Cliff Embayment Rocks 7.4 Major Oxide Geochemisby for Sudbury O f k t Environmats
8 Discussion 8.1 Relaticmsbip between QMD, QMGN , GN of Copper Cliff Embayment 8.2 Relationship between O f i e t Dikes and Em bayments 8.3 Relationship between Copper Cliff and the Main M a s 8.4 Copper Cliff Embayment and Dike Formath Mode1
9 Summary of Findmgs l O Future Work I 1 References
12 Table Captions Tables
13 Plate Captions Plates
14 Figure Captions Figures
15 A p p d i x Data Set
List of Taides
1. Reproducibility (error) on XRF on I O consecutive samples
2. Error and precision of data analyzed on fused bead XRF at McGill University
3. INAA data precision check using UTB2 for samples nm at University of Toronto
4. Standard values for QMD/QMGN/GN c m pared to international rock standards
5. Orthopyroxene data by Electron Microprobe at University of Toronto
6. Table of average rack values for Copper Cliff rocks and selected SIC racks
List of pI.bcs
Quartz Monzodiorite in Handsample
Quartz Mcmzodiorite in Th in Section
Contact of QMD with Country Rocks, Creightm Granite Pod in QMD Maîrix
Quartz Monzogabbrmorite in Hand Sample
QMGN in Thin Section
GN in Hand Sample
GN in Thin Section
High relief inclusions with gossan
High relief inclusions
Low relief inclusions
Low relief inclusions
Contact between inclusion rich and inclusion poor GN
Pod o f Elsie Mtn. Fm in QMGN mairix -inclusions are sericitized staurolite
Pod o f coarse grained QMD in QMGN
Pod o f cuarse grained QMD in QMGN
Band of pyroxenite pods in QMGN matrix
Gossan/Inclusion rich outcrop
Gossan/inclusim rich outcrop
List of Figures
1)
2)
3 )
4)
5 )
6 1
7)
8 1
9)
10)
11)
1 2a)
12b)
1 2c)
1 5d)
1 2e)
1 3a)
13b)
13c)
14a)
14b)
1 Sa)
! 5b)
1 Sc)
16)
1 7a)
Map showing the regional location of the SIC at the bounthy between the Ardiean and Roterozoic
provinces
Map showing SIC and the location of ofçets and embayments
Map of Copper Cl i ff Dike, Project Study Area, rock standards collection sites
Stratigraphie Colurnn of SIC
Diagram showing stmchne of an O- dike
Geology basemap of Copper Cli ff embymen t
Map showing inclusion population in Copper Cliff embayment
Air Photo of Copper Cliff Embayment showing Fault Structure
Map showing sulphide occurrence in the Copper Cliff embayment
Station Location Map for Copper Cliff embayment
Triple plot for OPX classification
AI2O3 VS. Mg0 for surhce and underground samples for the Copper Cli ff Embayment
AI203 variation with distance h m East to West across the Copper Cliff Embayment
False colour SURFER image showing Al2@ variatim for the entire Copper Cliff Embayment
A1203 variation with distance for the Murray Mine Traverse
A1203 vs. Mg0 for Copper Clic the Main Mass of the SIC, Inclusions and Country Rocks
Mg0 vafiat ion with distance fiom East to West aaoss the Copper Cliff Embaymm t
False colour SURFER image showing M g 0 variatim for the entue Copper Cliff Embayment
Mg0 variation for the Murray Mine Traverse
Si02 vs. Mg0 for surfkce and underground samples for the Copper Cliff Embayment
Si% vs. Mg0 for the Copper ClifTenvironmait and major rock types of the SIC
Fe20, vs. Mg0 for surîàce and drill m e samples for the Copper Cliff Embayment
Fe203 variath with distance 6orn East to West aaoss the Copper CIiff Embayment
FezQ vatiaticm for the Murray Mine Traverse
Ca0 vs. M g 0 for surface and &il l m e samples for the Copper CIiE Em bayment
Na20 vs. Mg0 for surfkce and drill core samples for the Copper Cliff Embayment
vii
1%) F a k colour image showing Na20 variation for the entire Copper Cliff Embayment
K20 variation with distance h m East to West aaoss the Copper Cliff Embayment
False colour image showing K20 variaticm for the entire Copper Cliff Embayment
Ti@ vs. MgO for surlàce and drill core samples for the Copper Cli ff Embayment
TiO? variation with distance fim East to West across the Copper Cliff Embayment
False colout image showing TiOz variation for the entire Copper Cliff Embayment
TiQ variation for the Murray Mine Traverse
P2O5 VS. !VI@ fm swîkce and drill m e samples fot the Copper Cliff Embayment
P20!i variation with distance fiom East to West across the Copper Cliff Embayment
False colour image showing -O5 variation for the entire Coppa Cliff Embayment
&O5 variation for the Murray Mine Traverse
S vs. Mg0 for underground and surfàce samples h m the Copper Cliff Embayment
S variation with distance for the entire Copper Cliff Embayment shown by false colour image
S variation with distance for îhe Murray Mine Traverse
Zr vs. Mg0 for surfàce and underground samples fiom the Copper Cl iff Em bayment
Y vs. M g 0 for surfàce and underground samples fiom the Copper Cliff Embayment
Y vs. Zr for surfâce and drill core samples for the Copper Cliff Embayment
False colour image showing Y variation for the entire Copper Cliff Embayment
Lu vs. Zr for surface samples fot the Copper Cliff Embayment
Lu variation with distance fiom East to West across the Copper Cliff Embayment
Lu variation for the Murray Mine Traverse
CI Normalid REE Spider Plot of Copper Cliff Rocks
A1203 vs. Mg0 variation for the O f k t Dikes and Embayments fiom the aitire Sudbury region
Si@ vs. Mg0 variation for the 0- Dikes and Embayments kom the mtire Sudbury regim
Diagrams afier Morrison (1984) of slump terraces h i c h may help explain the formation and genesis of the Copper Cliff Embayment. Diagrams showing a possible scenario for the formation of the Copper Cliff Embayment and Dike.
List of Appediccs
1 ) Appendix 1 Table of entire data set. Included are major elements, trace elements, and REE
1 lntnductioa
The 1.85 Ga year old Sudbury Igneous Complex (SIC) is located at the main contact between die Early
Proterozoic suprauusîal Huronian rocks of the Souehem Rovince and the Archean age plutonic rocks of the
Superior Rovince (Figure 1). lt is now generally believed to be the folded remnant of a 200-km wide meteorite
impact crater which outcrops t&y as 60-km long, 27-km widz elliptical ring with its long axis striking
northeast. The SIC has been of major importance fot almost 150 years, since the first copper discovery in the
area in 1856 by a govemment surveyor named Salter. &es of the Sudbury district are estimated to contain
1648 x 1 o6 tonnes of Ni, and comparably large amounts of copper, cobalt, gold, silver and approximately 10"
grams of PGE (Giblin, 1984).
The mineralization in Sudbury occurs in three genetal f m s ; umtact-type deposits, footwall-type deposits,
and ofEet type deposits. Cantact-type deposits tend to occur as disseminated or massive sulphide bodies at or
very near the contact of the SIC with the basement (Archean or Roterozoic) rocks. The Footwall-type deposits
occur as veins, vein-stockworks, or sheet-like M i e s of massive sulphide within breccia zones up to two km
fiom the contact of the SIC with the basement rocks. The final mineralizaîion type known as O--type, occurs
as massive to disseminated sulphide bodies within ofkt dikes and embayments whidi e.xtend either radially or
concentrically out fiom the SIC as fàr as 65 kilometers into the basement rocks.
Radial o f k t dikes such as the Foy, Worthington, Whistle or Copper Cliff dikes extend ouîward at hi&
angles to the contact of the Sudbury lgneous Complex with the basment rocks. They begin as large funnel
shaped embayments and narrow quickly to thin, o h discontinuous dikes. Concentric o î k t dikes such as the
Manchester, Frood-Stobie. or Vermilion ofiet dike, tend to strike parallel to the tower contact of the SIC and
may be either continuous or discontinuous and do not initiate as embayments (Figure 2).
The Copper Cliff offiet dike located in the South Range of the SIC begins as a 1.6 km wide fiumel-shaped
embayment where the SIC mets the basement Roterozoic rocks. nie embayment extends south approximately
one km where it narrows to l e s than 100 m and forms the Copper Cliff dike (Figure 3). The dike extends for
another 19 km to the south at widths varying &om 25-75 m and finally cornes to its terminus south of Kelly
Lake. Mieralization at the Copper Cliff ofki dike was first disçovered in 1884, and îhe Coppet Cliff Mine
was brought into production two years later.
The Copper Cliff Mine was the first underground mine at Sudbury but was shat lived as interest sbifled to
more easily attainable deposits elsewhere in the district.
Furtfier explmation by iNCO in the 1950's brougtit the Clarabelle Open Pit into production by 1960 and the
Copper Cliff North and South Mines into production by 1968 and 1969 respectively. The Clarabelle Open Pit
ceased production in 1977 but the North and South mines remain two of MCO's four bckbme in Sudbury as it
is estimated that the Copper Cliff dike contains 15% (by weight) of the Cu-Ni mineralization in the Sudbury
District. Despite the almost 120 years of mining and explmation of the Capper Cliff dike, no study of the
Copper Cliff embayment has never been undertaken beyond surface mapping and thin section petrography
(Slaught, 195 1).
1.2 Purwac of S t d y
The purpose of th is project is fourfold; i) To study the relationship between the di fferent rock types
within the Copper Cliff embayment, ii) to study the relationships between the rocks of the Copper Cliff
embayment and the Copper Cliff dike, iii) to compare the Copper Cliff embayment with the rest of the o f k t
and embayment mvironments in Sudbury* and iv) to study the relationships between the rocks of the Copper
Cliff embayment and the rest of the Sudbury lgneous Complex. The investigation of these four points should
provide a better understanding of the structure and composition of the embayment structures as well as better
understanding of the processes involved in the formation of both the offset dikes and the em bayments. The ore
deposits and sulphide occurrences of the Copper Cliff environment were n d the prime focus of this
investigation. A îüll account of the ore and ore-hosting environment of the ofiets can be found in papers by
Cochrane (1984) and by Grant and Bite (lYû4).
The objectives of this study have been achieved by collecting and analyzing a large number of sarnples
fiom the Copper Cliff embayment since such a task had never been done before. The development of a large
database of geochemical &ta, especially for such a historically signifiant are* can only serve to help complete
the puule of the formation and genesis of the SIC.
2 Previous Work oa the Cwmr Cüff Dike and Embrvment
Coleman (1903, 19 13) was the first to study the Copper Cliff dike extensively, and was the first person
to use the term "ofiet" to describe the nature of the intrusion. Coleman was also the first to use the term
-fiinnef" to desciibe the nature of the contact relaticmships of the dike with the Sudbury Igneous Complex. The
tenn h e l has since becorne synonymous with the term embayment, and can be applied to al1 of the radial
dikes in Sudbury.
Collins (1937) was the first to describe the rocks of the Copper Cliff' offset as quartz diode, as
opposed to norite as Coleman had. Collins recognized the distinct diffaence between the main mas norite and
the material within the dike and embayments. Further work on the dike was dme by Yates ( 1938), Slaught
(1 95 1 ), Souch et al. (1969). Their wwk fwused on the grnetic links between the dike and the rest of the SIC, as
well as the ore bodies of the Copper Cliff dike and their relationship to the Sublayer. Pattison (1979) suggested
that the ore deposits of the ofltset dikes were a result of the injection of sulphide-rich liquid outward into the
basement rocks as a result of a meteorite impact.
More recently, Cochrane (1984) studied the ore deposits of the dike, choosing not to fwus on the
spatial and geochemiçal relationships between the dike mataial and the rest of the Sudbury Igneous Cornplex.
Cochrane idcntified two different ore deposit types within the dike; a disseminated zone near the core of the
dike ( 1 20 orebody) and a disseminated zone wi th addit icmal string- type m ineralization near the eastern contact
of the dyke (8 1 0 orebody). Cochrane discussed format ion mdels for both types of ore Mies represented in
the dike.
Grant and Bite (1984) discussed not only the Copper Cliff offset but also the other significant offsets in
the Sudbury region. Grant and Bite, as did Cochrane, gave little attention to the Copper Cliff ernbayment and
instead focused on the off se^. Grant and Bite did however suggest a genetic cmnectim of the dike to the SIC,
and believed that the quartz diurite is sligtitly younger than the basal norite of the main mas as ev idend by
the presence of inclusions of quartz diorite in basal naite. They also indicated that there has been a signifiant
contribution fiom the country rocks to the geochemisûy of the quartz diorite, and that thae are zones of
severel y con taminaîed quartz diorite.
The map of the Sudbury Basin compiled by Dressler (1984) indicates that the Copper Cliff embayment
is c m posed en tirely of sublayer material, and that there is no change Ui rock type moving fiom the di ke in to the
embayment.
The most recent investigation of the Copper Cliff dike was by Lightfoot et al. (1997a,b), who
discussed the geochemistry of the main mas, sublayer, inclusicris and the offset dikes of the SIC. They
investigated in great detail the relationships between al1 of the above. Some of the more significant
observations that emerged fiom this shidy are that there are two distinct phases of quartz dion'te in al1 of the
ofltSet dikes; the dikes of the North and South range can be distinguished fiom eacb other geochemically, and
finally that the quartz diorite is very similar to the felsic norite of the main m a s of the SIC, suggesting a
common magma source for the two rock types.
Not a single m e of the studies listed above addresses the Copper Cliff embayment in any great detail,
the main focus k i n g the Copper Cliff dike.
3 Re~hnaI Ccoiopv of the Sudborv Area
The Sudbury Structure is composed of three parts; the 1.85 Ga old ring-shaped Sudbury igneous
Complex (SIC), the Whitewater group which fills the basin fonneà by the SIC and the beccias in the Archean
and Roterozoic foohvall rocks of the SIC. The SIC is located at the main contact between Early Proterozoic
supracmstal rocks of the Southern Province (Hurm ian Supergroup) and Archean pluton ic and m igmatit ic rocks
of the Superior Province. The SIC is composeci chiefly of norite, quartz gabbro, granophyre and a complex unit
called the sublayer which hosts a significant proportion of the Cu-Ni deposits in Sudbury. The Whitewater
group is composed of breccia, mudstone, siltstone and wacke. The Whitewater group and the breccias of the
footwall rocks will not be discussed any fiyther here.
The Sudbury igneuus Complex is generally separated into the North, South, and East Ranges. The East
and Na th Ranges are geodiemically similar but are both difkent h m the South Range (Lightfod et al.,
1997a). Because of their similarities, the North and East Ranges will simply be refmed to as the North Range
for purposes of this report The most sign i ficant di f fmces are between the North and South Range, at least in
part because the South Range has a strong metama-phic overprint while the North Range is largely unaltered.
The SIC, once separated into North Range and South Range can then be M e r be subdivided into the main
mas and the sublayer. 7he main m a s is made up of the lower zone, middle zone and upper zone and makes up
the largest volume of rocks in the SIC. The lower zone consists of the mafic and felsic norites of the North
Range, and die south range naite and quartz-nch norite of the South Range (Figure 4). Golightly (1994)
estimateci that the norites of the main m a s make up 27% by weight of the total Sudbury Igneous Cornplex. The
middle zme and upper zme consist of quartz gabbro and granophyre tespectively, both of which are found
thraighout the SIC. The Sublayer is the rock unit that hosts most of the ore in the Sudbury district and is
generally found below the lower Zme of the main m a s , at the contact between the SIC and the f-Il or
basement rocks. The following rock descriptions are primarily taken fiorn Naldrett et al. ( I W O ) and Lightfoot
et al. ( 1997% 1997b).
3.1 Main Miss
Lower Zone
Quartz Ricb Noritc (QRNR)
The QRNR is the stratigraphical ly lowest member of the SIC. Like the south range norite (below) it
consists of cumulus plagioclase and hypersthaie with intacumulus quartz, K-feldspar, augite, magnetite and
ilmenite. It is generally relatively fine-grained and does not display any igneous kbric. The QRNR contains up
to 20% quartz and 25% biotite, and commonly contains pockets of quartz-K-feldspar granophyre whose
abundance inaeases towards the lower contact. The most striking characteristic ofthe QRNR is the presence of
large blue quartz crystals, which do not occur in the south range norite. Mafic minerals in the QRNR are almost
ubiquitously uralitized .
South Range Noritc (SRNR)
Stratigraphically upward fkom the QRNR is the SRNR lt is a medium to coarse graine4 black rock
consisting of cumulus plagioclase and hypersthene with intercumdus quare augite, magnetite and ilmenite.
The SRNR ofien displays hypidiomorphic granula texture and a planar lamination defined by paraflelisrn of the
plagioclase grains (Naldretî and Hewins, 1984). The SRNR is black in its unaltaed state but more often
appears dark green due to the abundance of hornblende, which replaces both hypersthene and augite. The blue
quartz that is so prevalent in the QRNR is not present in the SRNR Moving upwards there is a gadational
contact into the quartz gabbro of the midde zone, marked by a decrease in hypersthene content, and an increase
in augite, quartz, magnetite, ilmenite, and apatite.
M a f ~ Norite
The poikilitic textured mafic norite occurs as the basal unit of the SIC in the North Range. It has 40-60
modal % cumulate orthopyroxene, with 20-40% intercumulus plagioclase, 20-25% intacumulus quartz and
miaographic intergrowth and 4 4 modal % intercumulus augite (Naldretî et a1.,1970, Hewins, 1971). The
mafic norite is sornetimes referred to as melanorite (see below).
Mcîanorite
This is andher rock type described by Lightfmt et al in the OGS report 5959. The melanorite is the
dominant inclusion type in the suiphide rich portions of the Parkin, Foy, and Ministic ofiets and is very
comrnon in the Whistle embayrnent. The melanorite occurs most oflen as either fine-grained a as coarse-
grained fksh pods or bodies. The fine-grain4 melanorite is characterized by intercumulus plagioclase, augite
and biotite and a 2mm grain size. The coarse grained melanorite is characterized by intacumulus plagioclase,
biotite and a 2 cm grain size. The melanorite will be usai almgside the igneous-textured sublayer matrix
(below) in cornparison to the Copper Cliff embayment rocks.
Felsic Norite
The hypidiomorphic granular-textured felsic norite occurs mainly in the North Range but may be
found as discontinuais pods elsewhere in the SIC (Naldrett et al., 1970). It is a medium to coarse-grained rock
that contains 40-55% plagioclase and <15% uralitized pyroxene as the cumulus phases. Augite ( 520%) and
quartz showing miuographic intagrowths with K-feldspar (2030%) are the main intacumulus phases with
minor amounts of biotite, pyrite, apatite and ilmenite as accessory phases. The cumulus plagioclase is ofien
zoned. The felsic norite lies stratigraphically above the mafic norite.
Middk Zoae
Qwrtz Gabbro
The quartz gabbro is gaierally found as a layer les than lOOm thick and tends to be îâirly oxide rich.
The cumulus m inerals are plagioclase, augite, ulvospinel, and apatite with intercum ulus m iaographic quartz-K-
feldspar intagrowth. Uralitized pyroxene makes up 25% of the rock. Textural evidence suggests that it was
al1 cumulus augite before alteration. This unit shows a gaieml inaease upward in quartz., augite, magnetite,
ilmenite and apatite. The granophyre amtent inmeases upwards as die gradaiional cmtact with the uppa zone
is approached. Plagioclase is zoned and often cloudy with sericitic alteration.
Uppcr Zone
G nmopbyrc
The granophyre maka up the geatest percentage of rocks in the Sudbury district; Golightly (1994)
estimated that it rnakes up 73% by weight of the SIC. This would account for 10 053 km' of the inferred total
13 900 km' preserved volume of the SIC. Naldrett and Hewins (1 984) indicate that the granophyre is generally
a medium to coarse grained rock with granodioritic to quartz mmzonitic composition with well developed
tabular plagioclase (23%) distributcd in a rnatrix of micrographie intergrowth (65%). Biotite and combined
mafic minerais make up the remaining 12% of the rock.
3.2 Sublrvcr
Pattison (1974) fùst used the t m sublayer to describe the fine to medium-grained quartz dioritic to
noritic unit that hosts most of the Cu-Ni oces in Sudbury. The sublayer has a gradational contact with the
overlying norite of the main mass and a gmerally sharp contact with the underlying footwall rocks. The
sublayer is generally recognized by low malal quartz content, abundant pyroxenes and an mcrease in the
amount of inclusims. niere is no rock type in the South Range thai can be described as the quivalait to the
sublayer h m the North Range, There is not even a cocicise definitim of what mstitutes die sublayer in the
South Range. The orehosting phase of the South Range is dominantly quartz diorite and acmdingly Cu-Ni
deposits in the South Range hosted in quartz diaite are often described as king hosted by the sublayer.
Following Lightfoot et al (1997a) 1 will consider the sublayer to include "igneous-textured inclusion-rich
sulphide-bearing subpoikilitic to nm-poikilitic textured naitic-gabbroic and melanocitic-melagabbroic rocks at
the base of the SIC' and will not include the quartz diaite of the offsets and embayments.
Igatous Tcxturcd Sublrycr Matrix
Lightfoot et al (1997a) describe a rock graip in the Whistle embayment called the igneous-textured
sublayer matxix (lTSM) whicti includes norites, gabbronorites, and gabbros with porphyritic to non-poikilitic
texture, which aiso occurs in most of the other embayment envirmments. The ITSM has an elevated sulphide
content whicti m u r s as disseminations, blebs and pods of massive sulphide. The inclusion content is variable,
ranging tiom 1% to W h . The 1TSM rocks are used in a later section in cornparison to the rocks of the Copper
Cliff dike and embaymeiit.
Quartz k r i t c
According to Grant and Bite (1984) there are three main types of quartz diorite. The first is
hypersthene quartz diœite, which is a medium to coarse-grained rock. it corisists of acicular hypersthene,
plagioclase lattis with interstitial quartz potassium feldspar and granophyre. Biotite, apatite. titanite, ilmenite
and leucoxene are accessoiy phases. The second type is known as twepyroxene quartz diorite. It is very
similar to the hypersthene quartz diode except that there is a significant proportion of clinopyroxene. It is also
fin= grained and has an overall higher mafic content than the hypersthene quartz diotite. The final and most
abundant type of quartz diorite is known as amphibole-biotite quartz diorite. it is characterized by abundant
amphibole as both primary minaals and as pseudomorphs afier pyroxene. n i e amphibole-biotite quartz diorite
is the most common ore-hosting phase of the radial o f k t dikes.
4 Gcohy of the Olkct Dikcs r i d Embvuuits
In general. al1 of the o f k t dikes and ernbayrnents have the sarne structure and composition.
They are primarily composeci of what has been traditicmaliy called quartz diorite. As Grant and Bite (1984)
pointed out the quartz diorite of both the North and South Ranges have approximately 20-35% normative
orthdase making than, according to Streckeisen's (1976) system of classification, quartz monzodiaites.
The quartz diorite occurs in the dikes as two seprate and distinct phases; an i m a disccnitinuous core
of inclusion-rich, sulphide-rich, coarser-graineci mataial (IQD) and an outer rind of inclusion-poor, sulphide-
poor, fine-pined to quench-textured mataial (QD) (Figure 5). The IQD has long been an exploration target
because of its elevated sulphide content, and is generally the ore-hosting phase of the offkt dikes and
embayments. 'Ihere is a gradational transition 60m one phase of QD to another, but the transition h m QD to
basement rocks is sharp and well defineci. There are often clearly definable chil1 margins, sphenilitic texture
and knife sharp boundrvies indicating that hot dike materiat was injected into the relatively cold basement rocks
and rapidly cooled after injection.
The inclusions withm the IQD tmd to differ fiom dike to dike but they are always related to the
basement rocks into which the dike material was injected. in genaal, the inclusions are of granite, amphibolite,
melanarite, diabase, metasediment and metavolcanics, with occasional exotic clasts and sometimes hgments of
what appears to be an older gaieration of QD and basal main mas norite.
Although the ofki dikes appear simitar thae are significant geochemical differenœs between
individual oeets. b e e n the offset dike material and the embayment material, and between offsets on the
South Range and North Range. This will be discussed in a later section. Figure 2 is a diagram showing the
locations of al1 of the offsets and embayments that will be discussed in the following section.
4.1.0 FOY Ofhct
The Foy radial o f k t dike is located in the North Range of the SIC in Bowell Township. It begins as a
400-m wide embayment and extaids north for 28km to Tyrone Township, which was until recently believed to
be the terminus. The dike continues nordi hm Tyrone Township fot approximately 65 km and has a width of
15-30 m at its terminus. The Foy offset has two brandies. The first (radial) strikes NNE into Tyrone Township
and the second (concentric) strikes WSW through Leinster, Harty and Hess Townships. Pattism ( 1 979) f m d
that the QD is fine grained at the margins of the dike and gradually coarsens towards the m e , which is
discmtinuously inclusion and sulphide rich. Thae is no quartz diorite wiîhin the Foy embayment, which is
composed chiefly of norites and quartz gabbros. The first occurrence of QD is located a signifiant distance
fiom the embayrnent within the O-.
4.1.1 Maackster O f k t
The 12 -30 m wide Mandiester offset dike is Iocated Siun south of the South Range main mass in
Falconùridge Township (Thompson 1957). lt strikes continuously for 5 h at 050-055 and dips at 60-65. It
then continues for a m e r two km as disumtinuous poâs within Sudbury Breccia. The dike has distinctive
sphemlitic texture almg rnargins with an inuease in grain size towards the centa, although in g a i m l the dike
remains fine-grained overall (Bite, 1974 and Grant and Bite, 1984). The mineralized zones tend to have greater
development of granophyre and as a whole, the dike is inclusion k, in distinct contrast to ail of the other
offsets in Sudbury.
The Parkin o@et is located north of the Whistle embayment and it is generally believed that the two
were once connecteci. The embayment is 350 wide at the contact with the SIC and narrows over 1.5 km where
it is offset 2km io the NW. The dike extends for a fivther 3.5 km as smaller branches, which combine over
1 Oûû m to form a single 15-m wide branch. The single branch narrows to 1 m in width over 200 m where the
QD then pinches out. It reappears to the north and extends for an additional 10 km. The dike is composed of
pyroxene-rkh quartz diorite and m the most southern portions occurs in sheets of variable thickness. The
Whistle embayment is cornposecl of what Lightfoot et al. (1997a) cal1 ITSM. The core of the Whistle
embayment is predominantly mafic, opx rich, gabbronorites and gabbros Mile the edges of the ernbaymmt
tend to be les mafic. opx poor gabbronorite cumulates. The inclusion content of the ITSM in the Whistle
embayment is highly variable ranging fiom 1% to 90%. The dominant inclusion types are melanorite, diabase,
anorthosi te, troctolite, gabbro, and occasionall y pyroxen ite.
4 3 FrodStobic m t
The Frood-Stobie concentn'c of%& dike is located 2km çouth of the main mas in the South Range of
the SIC. It extends for approximatety 3000 m as discontinuais elliptical pods of quartz diorite in Sudbury
Breclia.
4.1.4 Wortbiiintoa 0-t
The Worthuigton radial ofkt dike extaids SW 6m the SW edge of the SIC in Denison Township to
L m e Township. The dike splits into an eastm and a western lim b. The eastem lim b tapers for 1 500 m then
broadens with depth. The western limb extends southwest for 1 5 Cn with a uniform thickness of 70 m. The
contacts of the dike are knife-sharp and the QD gets ber grained towards them.
Like most of the O-, the Worthington has both an inclusion-rich and an inclusim-poor zone.
Pekeski et. al (1994, 1995) noted that the inclusion-ri& phase of QD within the core of the dike contains
inclusions of inclusion fiee QD which resembles die marginal QD. They also noted inclusions, which appeared
to be the basal quartz rich norite of the main mas . The core of the dike tends to be medium grain& amphibole-
biotite quartz diaite, whereas the rnargins tend to be pyroxene-amphibole quartz diaite.
4.1.5 Vermiüoh 0-t
The Vermillion ofiket is located in Denison Township and is detached fiom the main mass of the SIC
by a 2km gap. It is a 200-m lmg NW trading dike of discontinuous ellipsoidal pods of amphibole-biotite
quartz diorite. The QD pods are medium grain4 m their m e and progressively finer grained towards the edges
where there is ofien sphaulitic texture. According to Grant and Bite ( 1 984) thae are OcCwTences of a
medium -graineci amphibole-biotite QD as inclusions within the finer grainai amphibole biotite QD which is
the m m o n phase at the VermiIlicm o W .
4.1.6 Mimistic OCISct
The Ministic o s e t which is located in Cascaden Township West of the SIC has not been studied in
very much detail. Farrell et. al (1995) found ihat die dike has fine to medium grain& amphibole-biotite QD in
the mineralized zones and a hypersthene-rich QD m the unminaalized zones. They also found what may have
been a small embayment structure which is devoid of QD.
4.1.7 Kirkwad and McCoiiei l 0-l
The McConnell ofEet is approximately 1 2 0 m laig and lies SE of the Kirkwood ofiet. which is 1500
rn in length and strikes East-West. The two ofiets lie 600 m swth of the main mass of the SIC in the South
Range. They are both approximatel y 60 m wide and occur as discontinuous elliptical pods of amph ibole-biotite
quartz diorite in Sudbury Brecçia. The pods have a medium gained core and a fine-grained edge. Grant and
Bite (1984) indicate that based on field relations within the dike that the dike was emplaced as a liquid after the
brecciation event.
The Creighton ernbayment extends approximately 3km into the footwall rocks of the South Range
(Pattison, 1979). He describes it as king filled with sulphide and inclusicm rich quartz lnvptive norite (QRNR,
basal norite). Sublayer (quartz mcmz~di~ te ) occupies the margins between the quartz rich norite and the
footwall rocks. n i e relationship between the quartz dimite and the quartz rich naite is ambiguais but it
appeared to Pattison that the quartz diorite was em placeci before the bulk of the em bayment aystallized.
4.1.9 Trill Embavmcnt
Little has been written on the Trill embayment. It occurs as a 45 plunging trwgh just south of the
Ministic ofiet cm the North Range of the SIC (Naldreît et al., 1999). The Triil embayment, much Iike many of
the other embayments has sublayer norite af îhe base which grades upwards into mafic norite and felsic norite.
Sulphide occurs prirnarily in the sublayer naite.
4.2 Cwmr Clin O f k t Dikc
nie Copper Cliff o f k t dike show in Figure 3, begins as a 1.6-km wide lùnnel-shaped
embayment where the Sudbury Igneous Cornplex contacts the Roterozoic-aged footwall rocks. The
ernbayment extends south for approximately 1.5 km where it narrows to 100 m in width and becornes the dike
proper. The dike then continues south for an additimal 17.5 km at an average widtfi of 40 m. The Copper Cliff
dike is several times over its 19km laigth by east west trendhg fâults. The fùst beak occurs at the
Creighton Fault just south of the original Copper Cliff Mine, whae the dike is displaceci 20 m l a td ly . A
second o f k t occurs south of Kelly Lake at the Murray Fault system. The dike extends for a t'urther 10 km
south at an average width of less than 10 m. The portion of the dike south of Kelly Lake is known as the dista1
portim of the Copper Cliff oflket. The distal portion is geachemically, mineralogically and texturally much
different 6m the proximal and embeyment @ans of die Copper Cliff dike. The distal quartz diotite has
signifiant arnounts of lathy blue-green amphibole pseudomorphs after pyroxene, altered smdiy coloured
plagioclase and abundant (-1%) granophyric intergrowth. Chlorite, epidote and carbonate are minor
secondary minerals while bidite is not present (Grant and Bite, 1984).
The proximal porticm of the Copper Cliff dike is stnicturally the same as the rest of the o f k t dikes in
the Sudbury district. It has an outer rind of inclusion-fiee, sulphide-poor, fine-grained quartz diorite and an
inner core of discontinuous coarse-grained, inclusion-ri&, sulphide-rich quartz diorite. The proximal quartz
diorite tends to be the amphibole-bide variety, containing 3545% plagioclase, 25-30% amphibole, 10-15%
quartz, and IO-20% bidite with minor amounts of granophyre, apatite and sphene (Cahrane, 1984).
The discontinuous inclusion-rich core of the Copper Cliff dike contains two groups of inclusions. Most
of the maIl inclusions (< two cm in size) are amphibolites, metasedimentary rocks, anorthosites and quartzites.
The larger uiclusiais (> two cm in size) are genmlly gabbros, metapyroxenites, naites, quartz diorites and
exotic rnataial. n i e smaller inclusions arc associated with zones with mina sulphides wtiereas the larger
inclusions are associated with zones wirh significantly more sulphides.
The Copper Cliff dike intmdes into the Creighton and Murray Plutons as well as the Elsie Mm Fm
marginal to the SIC, and the sedimentary rocks of the Huronian Supggroup fiutha to the south. The Creighton
Pluton which lies to the West of the Copper Cliff ofltSet is a mass of granitic rock six km wide, 2 1 km long and
2200 Ma year old (Dutch, 1977). The Murray Pluton is believed once to have been connected to the Creighton
Pluton, but at the present aosional level of the Sudbury district there is no direct connecticm. The Elsie Mtn Fm
which lies directly east of the Copper Cliff embayrnent is c m p d chiefly of metavolcanics and
mctasediments. In the area of the Co~per Cliff dike, it is composed of mostly massive to pillowed metabasait
and to a lesser extent mecagreywacke. The portions of the Copper Cliff dike south of the embayrnent go
through several different formations. in ader fiom north to south, the dike passes through the Stobie Fm
(massive to pillowed metabasalt, rnafic pyroclastic rocks), the Copper Cliff Fm (rhyolite, dacite), the McKim
Fm. (wacke, silty mudstone), Nipissing Intrusives (gabbro) and south of Kelly Lake the dike continues through
the Ramsey Lake Fm. (conglomerate) and finally the Pecors Fm (wacke).
The contacts of the Copper Cliff ofiet are well defined and the host rocks are ofien brecciated,
althaigh the arnount of breccia decreases toward the south. The highest concentraticri of breccia occurs where
the dike is o s e t , and adjacent to ore bodies. The distal pmtims of the dike are in direct contact with the
unbrecciated country rocks and display prominent chilled margins and spherulitic texture indicative of rapid
cool ing.
4.3 Ceolopy of tbe Cwmr Cliff Embaymcat
There is a long history of mining and geology in Sudbury and because of that and the sheer number of
people who have worked in the region, there is a large and confiising systern of naming for the al1 of the rocks
related to the SIC. There is commonly more than one name for a single rock type, and some names have
entaed comrnon usage despite their failure to adhae to accepteci nomenclature. For this reason, 1 have decided
to forego any use of the traditional rock names for the Copper Ciiff embayment rocks and instead use
Streckeisen's (1976) system of classification for plutonic rocks. The three major narne changes 1 introduce in
this report are to change quartz diorite (QD) to quartz mcmzodiorite (QMD), quartz rich norite (basal naite or
QRNR) to quartz mmzogabbronorite (QMGN), and finally South Range norite (SRNR) to gabbronorite (GN).
These changes are discussed tùlly in a later section. The area of study for this report was restricted to the
Copper Cliff embayment. The study area (Figure 3) extended south 6om the southem shore of Pump Lake to
wtiere the Copper Cliff embayment narrows and becornes the o f k t proper. The eastern and western
boundaries of the shidy area were the east and west contacts of the Copper Cliff em bayment with the footwall
rocks. Since there was not a detailed geological base map of the Copper Cliff embayment, this was a priority of
this study. The map produced over two field seascms is reproduced as Figure 6.
Qua* Monzodiorite (QMD)
nie QMD, shown in purple in Figure 6, is highly variable in grain size but tends to be fine grained
overalt and commmly displays diabasic texture. It consists of 45 modal % plagioclase, 25% amphibole afier
pyroxene, 15% quartz and granophyric intergrowth, 5% K-feldspar (usually microcline or orthoclase) 15%
biotite and variable arnounts of titanite, chlorite and epidde depending on how akered the sample is (Plates 1,
2). The quartz is a dark smdcey colour in hand sample and is ofien found as quartz/K-feldspar granophyric
intagrowths. The amount of granophyric intergrowth is highly variable fkom sample to sample. It always
occurs as small grains between larger quartz grains. Am phi bole is generall y deep green coloured h m blende or
actinolite and can occur both as prirnary crystals and as sxmdary pseudomorphs afier pyroxene. Unaltered
pyroxene is uncornmon and the few intact grains are clinoenstatite showing little compositional zonation 6om
c m to rim (See microprobe analyses, section 6.1). Biotite occurs as fîne disseminatims throughout the matrix
commmly associated with minor sulphides. Plagioclase shows oscillatory zoning and is generdly sericitized
and altered with rniaoinclusions of epidote. The QMD is dominantiy inclusim fhx amphibole-biotite quartz
monzodiaite, much like the proximal portions of the Copper Cliff dike.
The published compilation map of the Sudbury area shows the QMD as a thick (>100rn) unit along the
contacts of the Copper Cliff embayment, which projects 250 m up into the embayment fiom a point in the N W
contact. My work shows (Figure6) thaî not only is the spike mapped over an area in which there is no outcrop,
but the QMD in general is a thin (<Som) discmtinuous unit that often pinches out, and then reappears as
isolated pods or outcrops. nie most eastem and n a t h a n extent of the QMD murs just east and south of the
intersection between the road and railroad tracks in the norîheastern corna of the map area. Here the QMD is a
small isolated pod in direct contact with rnetabasalt of the Elsie Mtn Formation. There is well-developed
t h m a l breccia with pods of basalt in a fine grained quartz diaite matrix. The western part of this outaop was
removed by constnictim so it is unknown whetha ttiere was a connecticri to the embayment a whedia tbis is
an isolated pod.
In the norbiwestern portion of the map area, the outcrop is poor and determining continuity between
outcrops is difficult. in this area there are several isolated occurrences of QMD with the final series of outçrops
parallehg the contact berween the SIC and the basement rocks West ofthe westem shore of Pump Lake. In this
area the QMD grades into QMGN and then GN over 10 m with no visible contacts between the QMD, QMGN
and GN despite relatively fiesh outaop.
The contacts of the quartz mmzodiorite with the country rocks (Creightai Granite and Elsie Mtn Fm
are generaliy well defined and commonly are igneous breccias. The breccia is composed of large clasts of
granitic (on the westem side of the embayment) or m e t a s e d i m e n ~ / m ~ v o l m i c material in a maîrix of fine
grallied quartz monzodiorite (Plate 3). As well as k i n g brecciated, the country rocks show extensive thermal
alteration near h e u conîacts with îhe QMD. Chilled margins are not visible, nor is the spherulitic texture
described by Cochrane ( 1984) in the more distal portions of the Coppa Cliff dike. The contact between the
quartz monzodiorite and the quartz monzogabbronorite is gradational over several meters.
There are several instances of QMD intdngering with the QMGN. As well, there is one k h
outcrop wtiere there is a large (two meters in diameter) pod of coarse-grained QMD in a QMGN matrix. The
edges of the pod are ragged and partially resorbed. The relationship between the QMD and the QMGN is ofien
confiing. The quartz monzodiorite grades upsection to a mesocumulate-textured quartz monzogabbronorite
(QMGN) but tracing the contacts by simply lodting at the weathered surfàce was found to be impossible. The
thick (often 5- 10 cm) weathering rind on the surface of nearly al1 outcrops made mapping extremely di fficult.
The determination ofwhere the contacts between the embayment rocks lay required extensive sampling. It was
ofien impossible to collect fiesh sarnples and as such the contact of the QMD with the QMGN is not exact.
Bearing this in min& the instances of QMD interfingering with the QMGN m u r in at least three separate areas
of the embayment apart fiom the single outcrop, which comptetely encloses the QMD pod. It is possible that
the apparent interfingering of the QMD with the QMGN is in fact a prduct of the poor exposure and that there
are large rafts or pods of QMD completely enclosed within the QMGN. The interfingering or rafting of the
QMD with the QMGN seems to imply a complicated crystallization history, which will be addressed fully in a
later section.
Quartz Monzogabbromoritc
The QMGN shown in green in Figure 6, tends to be coarser grained than the QMD, displays obvious
cumulate texture, and contains on average less quartz and granoph yre han the QMD though in some cases these
may reach up to 20%. The QMGN consists of about 4045% cumulate plagioclase, 25-35% amphibole
(including amphibole afler cumulate pyroxene) 5-20% intercumulus quartz, 10% biotite, 5% granophyric
intergrowth, and variable but m i n a K-feldspar. ikpending on the degree of alteraîion there may be varying
arnwnts of chlorite, and epidote (Plates 4,5).
The quartz in the QMGN tends to be either a datk smoky grey colour or a distinctive blue colour. The
plagioclase is also very dark in appearance with nunterous microinclusions. nie rock is lait an overall dark
green to black colour due to the presence of amphibole. The amphibole is either a dark green honiblende or
actïnolite. In most cases biotite makes up about 1û% of the rock, but it is highly variable with some samples
having as mu& as 25%. It occurs as large dots rathm than the fine disseminations found in the QMD and is
probably mostly seumdary biotitc developed fiom the alteratim of amphibole. The pyroxene is always altered
and for the most part has been replaced by amphibole (uralizatim). Miaoprobe analysis of the most unaltered
pyroxenes indicates that they are clinoenstatites, much like those found in the QMD. There are many
occurrences of pseudornorphic amphibole afier augite. The amount of alteration in the samples makes it
difficult to determine the proportion of CPX to OPX, hence the use of the narne quartz morizogabbronorite (and
gabbronorite in the following section). The most distinctive feature of this unit is the presence of btue quartz
ranging h m zero to 8% of die total quartz content. The blue quartz is occasionally found in very minor
amounts (cl%) in the transition zone between the QMGN and the GN as well as the transition zone between the
QMGN and the QMD. The blue quariz is corn pletely absent with in meters of the contact in these other units.
As was menticmed above the contact b e e n the QMD and the QMGN is gradational over several
meters, as is the contact betwm die QMGN and the overlying GN. As was found with the QMD, the QMGN
is interfingered ~4th the GN. There are marked inaeases in grain size item the QMD to the QMGN and again
into the GN, whidi seems to indicate a large-scale temperature gradient fiom the cool country rocks to the
relatively h d core of the embayment. The QMGN is petrologically vety similar to the QRNR or basal naite of
the SIC. They have the sarne minaal proportims, texture and the sarne characteristic blue quartz Essentially
the two appear to be the same rock unit, however becaux 1 have decided to forgo any use of the traditional
tenns for the SIC in the Copper Cliff embayment it would not be appropriate to refer to the QMGN as the
QWR
Gabbroaorite (GN)
The central mass of the embayment is composed of coiuse-grahed mesoçumulate-textured
gabbronorite, wtiich has traditimally been referred to as the South Range n d t e and is shown in blue in Figure
6. It consists of 55% cumulus plagioclase, 25% amphibole afier pyroxene, 15% biotite and generally much less
than 5% quartz (Plates 6, 7). The differences between the QMGN and the GN are that the GN does not contain
blue quartz, has much less quartz overall, does not contain granophyre, and is slightly more coarse grained The
GN is a very dark looking rodc with a significantly higher prmm of mafic mherals than the quartz
monzodiorite. Amphibole occurs as either dark green homblende or adnoli te and occurs as both primary
mtercurnulus grains and as pseudomorphs a i l a pyroxene. Plagioclase is commonly sericitized, zmed and
contains numaous hclusions. Fresh plagioclase is most often a dark srndry colour in handsample. The GN
tends to be highly altered with chlorite and epidote ofien making up to 20% of the rock. Biotite occurs most
ofien as fine disseminations throughout the rock and there is a strcmg affiliation of the biotite with sulphide.
Sulphide always occurs with biotite, which commmly completely encloses the sulphide grains. Quartz is most
often a dark srnm colour and near the contacts with QMGN, there is some blue quartz (less than 1 %), which is
absent M e r towards the center of the embayment structure.
The GN is the most inclusion rich unit of the embayment as will be discussed below. There are
numerous outcrops that are both inclusion rich and contain a higher proportion of sulphides. These outcrops
can easily be distinguished fiom the surrounding sulphide poor rocks by the msty gossan appearance in the
highest sulphide areas or by the uumbly irai rich nature of those outcrops somewhat poorer in sulphide. These
samples were difficult to identiQ as GN or QMGN based on field observations. The Fe staining was pervasive
and cmly thin section and geochernistry clearly indicated the rock type. Like the QMGN, this unit is the direct
equivalent of the SRNR but that traditicmal name reveals Iittle about the bue nature of the rock without furtha
reading of Sudbury literature.
laclusions
The greatest number of inclusions occurs almg a n d d southwest trendmg belt, which spans the
entire breadîh of the embayment, and in snaller zones in the soudieast and northwestem cornas of the
embayment. Figure 7 shows the distribdon of inclusions for the Copper ClifFernbayment. The inclusions take
two forms, either hi& weathaing relief (Plates 8a, 8b) or low weathering relief (Plates 9a, 9b). The low relief
inclusions taid to be almost exclusively amphibolite or pyroxenite, whereas the hi& weaîhering relief
inclusions are generaily more hetaogeneais k i n g metasediments, metavolcanics, anodosites, granites and
unidentified lithologies. The inclusions range in size fiom < 1 cm in diameter to rafts that are nearly 20 rn
long and tend to occur as either subrounded or as lath shapes. ïkere are many inclusions with a gossanous
weathered swhce, which appear to be fine-grained mafic/ultramafics. n i e low relief amphibolites and most of
the laminated metasedimentary inclusions are completely sulphide fi-ee. The thick weathaing rind and
advanceci state of decomposition of al1 the inclusions, especially the ones with abundant sulphide grains made
identification extremely difficult.
The inclusions occur in zcmes and a high inclusicm population zme (>30% of the rock) can be in direct
contact with a zme with no inclusions (Plate 10). There is no apparat difference either geochernically or
mineralogically between the two zones other than the presence of inclusions. This zone is located at the
western end of the NW-SE trending ridge that runs across the embayment.
Within the major northeast-southwest trending belt of inclusion rich rock, there is a large raft of
metasediment possibly fiom the Elsie Mtn Fm. The margins of this raft are sîrongly sheared and it is adjacent
to a tàult that spans the entire width of the embayment and offsets the igneous units in the northeastern corner.
The raft is exposed in three outcrops the largest k ing 20 m long and the smallest less than two m long (Figure
6). A n d e r large poâ of what may be McKim Fm metasediment was found in the throat of the embayment
(Plate 11). The pod, which has sharp contacts with the GN matrix, is several meters in laigth and is
chbicterized by sericitized staurol ite much like what was observed by Dressler ( 1 984).
Tire inclusion ridi zone which occurs in the NW corner of the study ara consists almost exclusively of
bright green amphibolite pais ranging in size fiorn 5 cm to greater than 5 meters in length hosted in a coarse-
grained QMGN matrix. The pods occur in thick band, which nms fiom the contact of the embayment wiîh the
Creighton Pluton to the shoreline of Pump Lake where it disappears. The band ranges fiom 10 rneters across to
l e s than 1 meter and is variable in widtti along its entire lOemeter length (Plate 13). The band may continue
north of Pump Lake but it is intemipted by an east-west trtmdmg late stage diabase dike on the shoreline and
ttiere is virtually no outcrop north of the lake. These pods are found in several other locations in the
embayment, but they are always isolated pods or clusters of pods.
There are also several examples of coarse &ed amphibole-biotite quartz rnonzodiorite pods
c m pletel y enclosed in quartz moruogabbronorite (Plates 1 2% 1 2b). The quartz monzodiorite pods have ragged
contacts with the quartz monzogabbronon'te matrix.
Disconirot Structures
The fàult rnentioned in the previous section nms h m the northeast mer of the Copper Cliff
embayment thraigh the core and ends at the western contact of the embayrnent rocks with the Creightm Plutm.
The structure can be seen un air photos of the embaynent as a large trough with a ridge running parallet to it on
the north side (Figure 8). The fàult may also continue t'urther to the south-west into the Creighton Pluton. This
structure was mapped a s a fàult on the original gmlogy map of the Copper Cliff embayrnent (Author unhoun ,
date unknown, scale 1 :26 000) which was used as a base map for this projed. There is no indicaticm of diis
structure at depth fiom drill core data or fiom modeling of the embayment. I believe ihat the erroneous large
spike of QMD shown on the published map (Dressler, 1984) follows this structure. The structure is best
observed in the northeast m e r of the embayment at the contact of the embayment with the country rocks
wher2 the structure offsets the umtact by approximately 20 metas. T h a e is no foliatim or lineaîiai of the
adjacent rocks, but the o f h t is accompanied by a higher than average number of quartz veins and inclusions.
The o f k t affects not cmiy the embayment rocks but also the granite of the Creighton Pluton (a small mass
occurs on the east side of the embayment). Further SW along the structure are the three large outcrops of
metasediment. There is a strong foliation in the GN outcrop, which is north (CCS-1) of the raftai metasediment.
(See Figure 10 for station locations). Ttie strike and dip of the foliation in the GN is 26g0/Steep to die SE. This
foliation could be a ârag effect of the raft k i n g transporteci, but that is pure speculation at this point. There has
been some significant amount of folding of the largest rafted pod (CC7- 1 ) as evidenced by several folded quartz
veins with the shortenhg direction papaidicular to the trmd of the structure. There is no more evidence of the
raAed metasediments as fragments, foliation, or otfierwise either nath or south of the structure beyond the SW
tip of station CC7-1. To the southwest of CC7- 1 a large ridge occurs on the north side of the structure. This
ndge carries the most significant number of inclusions for the aitire Copper Cliff ernbayment. Most of these
inclusions are laminateci metasedirnaits anorthosites, mafiduhrarnafic hgments, and metavolcanics. The
structure appears as a large trou& south of the large ridge, and t h a e are very fëw outcrops within the trough.
The southem side of the structure has much l e s relief than the nordiem side. The outcrops are
generally flat, but still contain a high percentage of inclusions, especially gossanous inclusions and low
weathering relief inclusions. The mostly unidentified, low weathering relief, inclusions do n a contain
sulphides. The inclusion rich zone ends abruptly at station CC 150-1 and starts again at station CC1 50-2. The
contact between the inclusion poor part (SW) of the outcrop and the inclusion ri& part (NE) of the outcrop is
h i f e sharp and trends perpendicular (126O/Steep to the SW) to the large hult structure (Plate 10). The zone of
inclusion rich material is mly 2.5 meters wide and has a second area of uiclusiar fiee material on the extreme
NE edge of the outcrop. There is no evidence either ta the north or to the south of CC 150 of the contact.
Further to the SW the ridge ends and the trough widens. There is no outcrop in the trwgh fiom the end of the
ridge to the edge of the Copper Cliff embayment. The inclusim population drops off drarnatically fiom the end
of the ridge as well. SWsingly, there is no ofEîet apparent on the western side of the embayment and there is
no evidence of QMD along the contacts. However, there is a prominent lineament in the Creighton Granite
along strike. The QMD appears to pinch out just south of the fàult structure and reappears again just to the
north of the structure. If the structure were a simple sinisnal strike slip fàult as it appears to be on the east side
of the fwinel thm thae should be a similar ofiet paam on the west side of the embayment. Thae is no QMD
and an average thickness of QMGN to the nuth of the stnicture and a thinner than normal QMGN to the south
of the structure. The QMD south of the structure forks into two thin branches, one of which narrows towards
the contact and the Creighton Pluton. The secorid trends almost exactly north and pindies out 20 meters before
the edge of the trough. The second branch ends at statim CC83- 1, which is fine-grained QMGN. There is no
discemible contact or change in the hcst rocks, but the QMD simply thinned out over two meterr (Figure 6).
Sulphide Occurrences
Sulphide is present to sorne degree in al1 of the rock types witbin the embapent as either blebs or fine
disseminations throughout the matrix. The amount and mode of sulphide occurrence is vastly different both
fkom rock type to rock type and often fiom sarnple to sample of the same rock type. Figure 9 is a map of the
sulphide distribution as eitfier gossanais (sulphide nch wtaops) andlor inclusions with gossan. in al1 cases,
there is a strong associatim of sulphide with bidite. Most often dark brown biotite surrounds sulphide grains.
In the quartz monzodiorite, biotite occurs as large clusters with large chlcopyrite grains, whereas in the quartz
monzogabbronorite and gabbronarite biotite is more often found as fine disseminations with the sulphide
throughout the rock. The highest occurrence of sulphide is found in association with a relatively hi& density of
inclusions. In several locations, thae is a thick gossan and p a t e r than 300/0 inclusions (Plates 14a, 14b). In
several other locations the inclusions themselves are sulphide rich and display a gossan where they are exposed
at the outaop surface. The greatest occwence of both sulphide and inclusions occurs to the south and east of
the large fàult thraigh the embayment, while the nœth and west side of the fàult (excepting directly adjacent to
the fàult) is relatively fiee of bah.
Opaque Miacnlogy
Accordhg to Cochrane (1984), the sutphide minaalogy of the Copper Cliff dike ore zones is
dominantly pyrrtiotite, pmtlandite and chalcopyrite with the chalcopyrite being slightly more abundant than
pyrrhotite. The Copper Cliff embayment sulphide mineralogy is slightly different with chalcopyrite and pyrite
being the two dominant minera1 species. Sulphide contait of the anbayment rocks rarely reaches 3% and in
most cases is less than t %. Magnetite and ilmenite are the most m m m accessory opaque phases. A more
complete and thorough description of the sulphide minaalogy can be found in Cochrane (1984).
5 Methods
5.1 SImnlian Propnm
Samples were collectecl fiom surfàce at the Copper Cliff embayment as shown in Figure 10.
Surtàce samples were selected to be as unweathered and unaltered as possible. Great care was also taken to
ensure that eacb sample was representative by taking multiple samples fiom each locatim. A total of 345
samples were col l d e d fiom the surfiice at the Copper Cliff ernbayment. Of those samples, 308 were samples
of the three major rock types and 37 were sarnples of inclusions. Of the surfàce sarnples taken tiom the Copper
Cliff ern bayment there are 28 sarnples fiom two traverses, which ran fiom the contact of the Creighton Granite
with the western side of the embayment. Ebth traverses rqesent the transition from the granite footwall rocks,
through the quartz r n d i o r i t e at the contact and into quartz rncmzogabbrmorite, towards the cote of the
embayment. Traverse # 1 was a 30 m traverse with samples taken every meter and Traverse #2 (Figure 10,
detail) was a 75 meter traverse with samples taken every 5 meters.
Additional samples of quartz diorite, quartz rich norite and south range naite were collected fiom the
Sudbury Igneom Complex as show in Figure 3 to be used as rock standards in the petrological and
geochemical classification of the Copper Cliff embayment rocks. The quartz diarite standards were collected
tiom the Copper Cliff dike north of the Creighton Fault, and north of Hwy 17, but south of the tamination of
the Copper Cliff mbayment. Several 0th- sarnples were taken fiom just south of the terminus of the
embayment for cornparison to the quartz diaite standards taken hrîher south. The quartz rich norite and Souîh
Range norite standards were taken fiom beside the CNR tracks h i d e the Murray Mine Historical Site (Figure
3). A 483 meter traverse was done at this location and sarnples were collected every 25 m. A sample was
collected at 8 metas fiom the first sample because it marked the transition fiom QMD to QRNR (QMGN). A
sample was not collected at 333 m e t a s due to a lack of outcrop; the next sarnple was taken at 358 meters. This
traverse represents the complete transiticm fiom footwall rocks to the basal norite and through to the muth range
norite.
Samples of Creightm Granite, as well as sarnples 6m the Elsie Mtn Fm (metavolcartics and
metasedirnents) were collected both proximal to the contact of the Copper Cliff embayment as well as distally
as shown in Figure 3.
A total of six drill holes were sarnpled. Three were fiom a tàn of exploration drill holes (holes 102-
622, 102-623, 102-624) radiating out underground fiorn the 2000 foot level, 19 1 footwaIl drift into the 19 1
o r M y h m the Copper Cliff North mine. This orebody sits to the west of the Copper Cliff North Mine shafi
under the embayment at depth. These three holes represent the transitim fiom the eastem limb of the Creightm
Pluton at depth into QMD and into the granite of the western Iimb of the Creighton pluton. The depth fiom
which these three holes were ciritlecl fiom is at the point where the Copper Cliff embayment narrows and
becornes the Copper Cliff dike. n i e drill holes pas fiom relatively unmineralized inclusion -fie amphibole-
bioti te QMD to inclusion -fi&, sulphide rich QMD. There are 0.3 meter long sections throughout the holes diat
are massive sulphide in a fine grained inclusion rich QMD matrix.
The remaining three holes (holes 97 1 7 1, 97 1 72, and 97 1 73) were collared at surfàce on the shore of
Pump Lake and passed through the embayment to the f m l l contact. Holes 971 71. and 97 1 72 were collared
on the north shae of Pump Lake, h i l e hole 971 73 was mllared ai die south sbae. mese three holes
represent the transition fiom metasediment of the footwall rocks to a thin rind of quartz monzodiorite and quartz
monzoga bbtonorite to gabbronorite. Large sections starting at approximately f 400 fm fiom surkce of a 1 1 three
holes were removed by WC0 for analysis. The missing sections span tiom 1400 feet deep to approximately
3200 feet deep and are ri& in sulphide and inclusicms. The sulphides fiom these sections are hosted in
primarily gabbronorite. The bottom of the holes end in Creighton Granite.
Samples were collected every 10 meters and additional samples were taken at contacts and any d e r
important transitions in the holes.
A total o f 27 1 satnples, m g h g tiom 0.5 - 2 kg, were analyzed by X-Ray Fluorescence (XRF) on
W bead and presseci powder, and by Instrumental Neutron Activation Analysis (NUI). The sarnples were
hitially cut to eliminate any remaining weathering rind and to separate inclusims fiom the matrix in those
sarnples containhg inclusions greata than one cm in diameter. The sarnples were thai cut into cubes
approximately two cm x îwo cm x four cm and crushed in a flat sofl steel jaw mill. The crushed sample were
then powdered in a 99.85% pure alumina puck miIl for three-five minutes to less than 200 mesh in size.
The samples were then made into pressed powder pellets for XRF using approximately four grams of
material, N A A pellets using 0.2 g r a m of material, and fked beads using four grams of material. nie
remaining material was then stored or used to make duplicates to ensure accwate results. Of the 271 samples
analyzed 122 were fiom the surfice of the Copper Cliff ern bayment (QMD, QMGN, GN samples), 106 were
fiom drill core through the Coppet Cliff embayment, 19 were QRNR and SRNR fiom the Murray Mine
Historical Site. 6 were fiom the Creightai Pluton, 5 were fiom the Elsie Mtn. Fm, 5 were fiom the Copper Cliff
oflket, and 8 were inclusions from the Copper Cliff embayment.
5.3 Coaîamination
Samples were thoroughly cleaned witb water aiter cuîting and dried with compressed air both aiter
cleaning and before they were d e d Contamination aAer aushing was tracked by nmning 99.85% pure silica
sand thrwgh the jaw cnisher and alumina mil1 a i l a every sixth sample.
5.4 S p m ~ k Andvsis
AI1 major oxides as well as Ni, Co, and Cu were analyzed at McGill University by XRF on fused bead.
Samples were also analyzed on a Phillips PW24û4 X-ray Fluorescence Spectrometer with a Rhodium X-ray
tube and a PW2510 Automated Sampler at the University of Toronto for the elements Ba, Ni, Co, Cy Zn, F, CI.
Br, S, Nb, Zr, V, Sr, Rb, Cr and Y. Sarnplts were MI for i 8 minutes for everything except the halogens which
were ntn for 4 minutes.
Samples were also analyzed for Cr, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Th, U, Cs, Hf, Ta. Sb, Mo, Sc, W.
Au, and As by N A A at the University of Toronto. The samples were sent to the SLOWPOKE II reactor at the
Royal Military Coilege in Kingston, Ontario to be irradiated and were then analyzed using an Aptec Coaxial
Germanium Crystal Detector at U of T for a minimum of 10 000 seconds at times 7 and 40 days afier
irradiation.
Microprobe analysis of orthopyroxene was perforrned on three sarnples using a Cameca SX-50
Electron Microprobe with TAP. LIF, and PET wavelength dispasive spectrometa, at the Universiîy of
Toronto.
5.5 Data Validation
Several sarnples selected at random were made into 10 pellets each and analyzed on the XRF at the
University of Toronto and the values agree very well tiom me sample to the next. The results for one of these
tests are shown in Table 1. The largest discrepancy in reproducibility for this test was for Ba, Zr, and Cr with
1 9.45 ppm and 9.06 ppm and 6.40 ppn at two standard deviatims. The machine er ra therefore is very good
fw the trace elements on the XRF at the University of Toronto.
lncluded in each batch sent to McGill University were duplicates of samples within a single batdi, as
well as a duplicate flom a previous batch to ensure that data within the set and between two different sets were
comparable. Also included were examples of in-house standards UTB2, UTG 1, and UTAI. The dam
reproducibility is excellent for the more reliable UTB2 and UTAlbut less satishctory for üTG 1, whicb is
known to suffer fiom inhomogeneities (M. Gocton, 2000 persona1 cornmunicatiai). The results are shown in
Table 2. The composition of UTGl is not h o w n with as much precision as UTB2 and UTAl and
consequently the data show much geater -or. There is 62% error in the results for Mm, 13.33% for Mn0
and 17.78% for &O5 for UTG 1. The highest m o r s for UTAl are for Mn0 with 15.71% and Mg0 with 9.57%.
However, the UTB2 values for Mg0 have less than 4% error which equates to 0.2% at 2 standard deviations.
The error for Mn0 is l e s than 5% mur and less than 7% aror for Na20. The rest of the elemaits show
excellent reproducibility and accuracy, except for Ni, Co, and Cu which are poor and as su& these values will
not be used for diis study. The erra for these trace elements is most likely due to the srnall amount of material
used to f m the beads and fiom the process of making the fiised beads which requires that the sample be
diluted several times.
Samples of UTB2 were included in each run for iNAA and indicate very little deviation between
sample sets (Table 3). The highest errm is for Hf with 17% and a correspoiiding two standard deviatims of
6.98 ppm. The mly other elements with any signifiant error fiom accepted values would be Nd, which has
les than IOO/o mot (16.75 ppm at two standard deviations) and W has 22.85 ppm at two standard deviations.
6.1 O rt bo~vroxenes
Intact and unaltaed pyroxenes are uncommon in the rocks fiom the Copper Cliff embayment, ln most
cases the pyroxenes are urditized or now exist as amphibole pseudomorphs after pyroxene. Because of this
pervasive alteratim of the pyroxenes it is exîremely difiicult to determine their original composition. Three
samples out of the 1 O6 that had been made into thin sections contained fieh pyroxene and were selected for
andysis on the electron miaoprobe at the University of Toronto. Five pyroxene grains per sarnple were
analyzed at three points representing a path kom the coce to the rim. Thae was little variation ôetween the
points in the core and the points at the rims of the grains. There was also little variation between samples,
including samples taken kom exploration drill cote and surface samples. Table 5 shows the results of the
microprobe analysis. In al1 cases, the pyroxene was a clinoenstatite, a low Fe, high Mg type of pyroxene,
(Figure 1 1) with an average Mg# (atomic Mg/(Mg +Fe)) of 0.5473.
6.2 Blue Quartz
Microprobe analysis was also used to try to determine the source of the distinct blue colour that is so
prevalait in the quartz of the QMGN or basal norite of the main m a s of the SIC. Silva (1996) investigated biue
quartz fiom the Antequera-Olivera Ophite in Spain and determinel the source of the colour to be
microinclusions of aerinite (a zeolite-facies hydrothermal silicate-carbonate). The blue quartz fiom Silva's
study appears blue in both reflected and transmitted light, which is not the case with the blue quartz fiom
Sudbury. The blue quartz fiom Sudbury only appears blue in reflected ligh?, in transmitted Iight the quartz
appears colourless and indistinguishable 6orn colairless or smokey quartz. Another study by Zolensky et al.
(1988) on blue quartz in Llano hyolite from Texas found ihat the blue colour originated fiorn microinclusims
o f ilmenite. Theu work found these microinc1usions produced the blue colair by Rayleigh scattaing and that
the blue quartz had elevated Fe and Ti contents compared to colourless quartz. n i e microprobe analysis of the
blue quartz fiom Copper Cliff did not indicate an elevated Fe or Ti level, nor were any miaoinclusions
identifid that were without question ilmenite. A third possibility is that the quartz may have been deformed
and due to the skewing of the uystal lanice, the quartz appears blue (G. Henderson, 2000. personal
communication). Thin section analysis did not reveal any major d e f m a t i m in the quartz so the ptobability
that the blue colour was deformation induced is low. A fourth possibility is that the blue colour is because of
submicroscopic inclusions of rutile (Fronde], 1 %2). The blue colour (often referred to as the "Tyndall effect")
is only visible in reflected light and in transmitted light, the quartz appears slightly pinkish. Since there was no
evidence indicating an elevated Ti content in the quartz and thae was no evidence of a pinkish hue to the quartz
in transrnitted light, the colour at Copper Cliff is not likely to be a result o f rutile. Miaoprobe analysis o f the
blue quartz was not conclusive in terms of composition, but the anaiysis did show a high level of
miaoinclusions in al1 of the quartz There are also elevated levels of T i G in the QMGN compared to the GN
and so ttie most likely case is that there are microinclusions of either ilmenite or rutile within the quartq but at
such a s a l e as to make microprobe analysis inconclusive.
7 Gcoc bcmist ry
The purpose of the sampling pograrn was to determine what relatimships, if any, exist between the
rock types within the embayment, but also to determine the relationships b e e n the Copper Cliff embayment
and the &a offset enviraimentsi as well as the rest of the SIC. Because the rocks of the Copper Cliff
ern bayment rnay also have been contaminated by a number of soucces including the country rocks surrounding
the embayment, and by the large inclusion populatiai found throughout the embyment a number of samples
were taken fiom both of these groups. The country rocks are predominantly granites of the Creighton Granite
to the West of the embayment and the metasedimen& and the basal& of the Elsie Mtn. Fm to the east of the
embayment. The inclusions are a mix of hgmaits fiom the country rocks, amphibolites, pods of QMD. and a
large set of unidemtifiable mafic inclusims. Tnie data used for the following analyses coma fiom surface
samples, drill core sarnples and fiom several traverses.
Synthetic Traverses # I and #2 were constnicted using data fiom outcrops fiom the Copper Cliff
embayment. These two traverses span a west to east transect aaoss the embayment ûom QMD through QMGN
and GN and back to QMGN and GMD again. î l e outcrops are as evenly spaced and in a straight line as
surhce exposure wwld allow. The QD, QRNR, and SRNR colIected in the Murray Mine Traverse are the
equivalent to the QMD, QMGN and GN of the Copper Cli ff em bayment. Traverses were used to determ ine if
there was a definable transition fiom one rock type to another within the embayment, and if that transition was
present for the equivalent rocks at the Murray Mine site.
7.1 M i io r Oxide Gcocbemistry of t k Cwmr Clin Embayment iad the SIC
The following section de& with major elernent variatims for the Copper Cliff embayrnent rocks, the
country rocks sunoundhg the embayment and the inclusion population from embayment rocks. The Copper
Cliff rocks have also been plotted in cornparison to the rest of the major rock types in the SIC as well as in
corn parison to the rest of the offset dikes and em bayments in the Sudbury area. The data have been plotted as
major oxides vs. MgO, as major oxide variatiai for two synthetic traverses fiom east to West across the
ern bayment, and as làlse colour elemmt variation images for the entue em bayment.
The major oxide data were plotted against Mg0 instead of S i 0 because Mg is compatible in OPX and
consequently is a good indicator of crystal hctionation. The Si02 content ofthe major rock types in this study
is too similar to be of much value in distinguishing between them.
As a amparison, the &ta fiom the Murray Mîne traverse have been includeâ to represent the
mposi t ional transition that occvs in the lower zone of the SIC. The data have been plotted as major oxide
variation with distance fiom the footwall rocks. A meter scale traverse tiom the western side of the embayment
has also been used to detamine wherher any large-scale trends w l d also be found on a small scafe. The small
s a l e traverse (Traverse #2, See Figure 10) will not be graphically reprodud here since ttiere is very little
correlat iut between the large s a l e trends discussed klow and the small s a l e trends observeci for Traverse #2.
Alr03
The relationship of Al& to Mg0 is shown in Figure 12a. The QMD tiom the Copper CEE
ernbayment is plotted as diarnmds. 7he data for al1 the igneous rocks belmging to the SIC in my dataset show
a clear separatim into hivo distinct populations on this diagram. One goup is characterized by relatively hi&
M g 0 and A1,03 < 15% whereas the other has generally Iowa Mg0 and AII03 > 15%. On the basis of this
division, 1 have coded the symbols such thaî in this and al1 subsequent variation diagrams, the hi& Mg0
populatim is represented by open syrnbols and the low Mg0 populaticm is represented by filled symbols.
Because al1 significant concentrations of sulphide in the ernbayment and of& are hosted by rocks in the low
Al2% group, al1 rnembers ofthis group will be referred toas the " low AI " group or simply low Al samples in
the following discussion. This grmp includes many sarnples that do not have any significant amount of
sulphide visible. The other group are the " hi& Al " samples which are samples associated with outcrops with
very few inclusions and l e s than the average amount of sulphide. Diamonds represent sarnples of QMD,
squares represent QMGN and triangles represent GN. There is a tight cluster for the high Al sarnpies of QMD
centered on 4.5 wt?? M g 0 and 16 wi?h Al2@. The low Al QMD samples are centaed around 5 wt?h Mg0 and
14 Wioh AIIa and tend to be more widely scatîered. niere is a significant amount of overlap between the
QMGN samples and the QMD samples. The high Al QMGN is tightly centered on 5 Wt.6 M g 0 and 16 wt?A
AIZ03 whereas the low AI QMGN has much more scatter and centers on 7 wt?A M g 0 and 14 wt% A1203. The
high Al GN samples cluster tightly on 6.5wtoA Mg0 and have an average Al2@ value of 17.5W?, which is
higtier than eidia the QMD or die QMGN. The low Al sarnples of GN have a large scatter with respect to both
Mg0 and A1203. n i e M g 0 values on average range tiom 9 to 1 1 &/O and the AII03 values range fiom 1 O to
15.5 wt??. Also plotted on this graph are samples of inclusions fiom within the Copper Cliff embayment
(shown as open cucles), samples of Creightm Granite (shown as maIl x's), samples of metasedimait and
basah fiom the Elsie Mm Fm (shown as stars), the composition of OPX, plagioclase and K-feldspar (shown as
solid circles), and a crystallizatim model generated by MELTS (Ghiorso and Sack 1995) (shown as large X's).
These symbols wiil be used in al1 subsequent graçibs. MELTS is software that allows models of different
crystallizatim histories to be created which are dependait m different initial conditions such as temperature,
pressure,n2 and magma compositions. The trendline produced by MELTS takes the initial composition (in
this case least alter& Onaping glass) and models uie resulting composition with respect to equilibrium
thaimation and aystal accumulation as tempaahne decreases.
A tie line between the composition of plagioclase and the composition of OPX represmts an idealized
crystal accumulation trend. Both MELTS and petrographic observation show that the principal cumulus phases
6m the Sudbury magmas were OPX and plagioclase, so that any pure adcumulate assemblage must plot
m e w h e r e almg this line. Both the low AI group data and the hi& Al data trend in the direction of this tie
line. The QMD tends to have much less OPX than the GN and this is most likely what prduces the trend fiom
low M g 0 in the QMD to high M g 0 in the GN. The low Al samples tend to have even geater amounts of OPX,
especially the low AI GN. If the QMD represents an initial liquid composition as the petrology seems to
support that the QMGN and GN (m-adcumulates) çould have formed by a mbination of ûactional
crystallization and aystal accumulation fiom the residiial liquid lefl after the uystallizatim of QMD.
The MELTS trendline was created using data fiom the least altered g Iass fiom the Onaping Fm (Ames,
1999) as the initial composition. The model simulated equilibrium fkactimation at an oxygen fugacity buffered
to the assemblage Fayalite-Mapetite-Qwtz The trend shows crystallization of only OPX until
approximately 85% Iiquid remains, at which point the trend line curves with the onset of plagioclase
crystaltization. There is a second bend in the trendline wtiere K-feldspar begins to crystallize, but this bend is
not discemible in many of the major oxide plots. The MELTS model is not well constrained at such low
temperatures and felsic magma compositions, and the final bend is not reliable. nie initial composition of the
Iiquid fiom the Onaping g l a s is close to uiat of the QMD. Thae is however a distinct compositional diffmce
between the low Al and high Al QMD. This seems to indicate that there are two distinct starting compositions
for the QMD.
The spatial variatim in A12a for the Copper Cliff em bayment is shown in Figure 1 2b. n i a e are two
different synthetic traverses plotted, which span the emhyment fiom east to west. Synthetic Traverse #I is
represented by a dashed l ine and diamond shaped points and Synthetic Traverse #2 is represen ted by a sol id Iine
and square points. The east side of üie each traverse starts in QMD for the first two locations. The next two
outcrops are QMGN, which are then followed by six GN outcrops in the core of the enibayment. The western
side of the iraverse ends in QMGN (two locations) and QMD (final location). Thae is no clear trend in either
traverse, alhough it dws appear that tfiere are slightly elevated AI2O3values in the GN (core) cornpared to the
QMD (margins). This is most likely because the QMD and QMGN for both traverses is the high Al type
whereas the GN is for the most part in the low AI group. nie GN samples, wtiether low Al or not, tend to have
higha A S 4 than eitha the QMGN or QMD. If the synthetic traverses were through al1 hi& Al samples or al1
low AI sarnpies there might be a more noticeable trend aaoss the Copper Cliff embaymen t. The overail spatial
variation of AI2O3 for the Copper Cliff embayrnent is shown in Figure 12c, which is a SURFER FaIse colour
image of the embayment. The image was produced tiom 105 sarnple sites fiom the embayment and by using
krïging to interpolate between the points. The lower AI2Q values are s h o w in blue while the higher values are
shown in purple and red. The division between rock types is again n d distinct, but the difference between the
low AI and high Al samples is. niere is a large area in the care of the embayment, which has depleted &O3
values. There are also several smaller areas with low A&. The exiges of the emtwyment show elevated
AI2O3. The lowest A12Q value sites amespond with the locatims with the highest inclusim populations and
higher levels of sulphide. This same relationship is observable in the data collected fhm the Murray Mine
Traverse, which is shown in Figure i 2 6 This graph shows the variation in A1203 over the 483 m traverse
disdance, whidi spans the transitim fiom QD (QMD) to QRNR (QMGN) to SRNR (GN). The QD samples are
generally inclusion fiee and sulphide poor and have a high Al f i content ranging 6i.om 16 to 16.5wtOA. The
QRNR, wtiich is often heavily mineralixed, has low AI2O3 values, ranging fiom 12.8wtOh to 14wtOh. The
SRNR, which occurs at the end of the traverse, tends to have high A1203 values, which reflect the lack of -. inclusions and sulphide poor nature of the rock. The data f h n the Murray Mine Traverse corresponds well
with the observation of two distinct rock groups one related to m indizatiori and m e related to high AI rocks.
The dependence of A1203 on M g 0 for most of the major rock types of the SIC as well as the Copper
Cliff rocks is show in Figure 12e. In addition to the rock types Iisted fOr Figure 12% there are several other
significant rock types, which are included in this plot The data for these rock types has been takm fiom the
OGS Open File Report 5959 (Lightfbot et al, I997a). The volurnetrically dominant granophyre simples are
shown by Iight coloured solid squares with dark borders and are mtered ai 3wt4A M g 0 and 13wtOh A1103.
The g.anophyre field 0ccupie.s the same region as the end of the MELTS @end where both plagioclase and K-
fèldspar are uystaliizing with OPX and CPX There is a compositional gap between the granophyre and the
QMD 60m the Copper Cliff embayment and dike. The gap ranges fiom three to five wt?! M e , and ends at the
QMD, or at the initial composition of the MELTS mode1 (Onaping glas). Overlapping the high Al samples
fiom the Copper Cliff ernbayrnent are siunples of febic norite shown as black x's on a light colwred square.
The felsic node generally has higher than 15wtOh A I 2 a and between 5 and 8 wt?! MgO. There are two groups
of igneuus ttxtured sublayer matrix (ITSM) which are shown by light coloured solid circles with a dark border.
The first overlaps with the high Al samples tiom the Copper Cliff embayment. The second group overlaps the
composition of the low Al GN. There is a large amount of scatter within the ITSM and there is no clear
distinction h e m the two groups as Uiere is fot the Copper Cliff rocks. The sublayer norite s h o w by open
circles occur near the end of the overall aystallization trend The sublayer norite has low Alz@ and hi& Mg0
averaging 7wt% and 14wt?/o respectiveiy. The mafic norite shown by short Ihes occupies the gap in between
the GN of Copper Cliff and the sublayer norite. Finaliy, the melanorite shown by small stars spans a wide range
of compositions. It overlaps fiom the low Al QMGN to beyond the sublayer norite at the end of the trend The
melanorite samples are tom several ditférent locatims around the SIC wtiich may account in part for the large
range in compositions.
The overall trend of the SIC rocks parallels the ideal aystal accumulation trendline fiom QMD toward
the tieline connecting OPX to plagioclase. The SIC rocks plot along a tie line fiom the composition of the
unaltereû Chaping glasses to the composition of OPX. The exception to this is the high Al samples fiom
Copper CliK which plot slightly higher than the MELTS projected crystallization trend. The high Al samples
also trend at an angle to the rest of the SIC rocks. The data for the inclusion population of the Copper Cliff
embayment plots high on the ideal trendline fiom plagioclase to orthopyroxene and could be a major factor in
the composition of the Copper Cliff rodcs. The rocks belonging to the hi& Al group may have been formed by
a combination of contamination and crystal accumulation of both OPX and plagioclase whereas the low Al
samples may have had l e s contamination and were formed as a result of aystal accumulation of primarily
OPX.
Mg0
Mg0 is an excellent indicator in these rocks on the amount of hctimation and aystal sorting that has
occurred since it partitions p.imarily into OPX. The quenched QMD of the Copper Cliff embayment tends to
have M e OPX while the mew-adcumulate QMGN and GN tend to have a signifiant proportion. The spatial
distribution of Mg0 in the Copper Cliff rocks is indicated by the synthetic traverses across the embayment
shown in Figure 13a. The QMD at the margins on both the east and west sides of the ernbayment have low
Mg0 consistent with their low OPX content, whaeas the core of GN and QMGN have elevated Mg0 values.
Both the low Al and the high Al QMD samples have low Mg0 values whereas the QMGN and GN have high
M g 0 values. The low Al QMD has 445.5% MgO, the QMGN has 6-8% M g 0 and the GN has between 8.5 and
13% Mg0 (Figure 123). The high AI samples have a much narrower range of values with the QMD ranging
fiom 44% the QMGN fiom 456% and îhe GN fiom 5 5 7 % MgO.
The overall Mg0 variation is shown by the fàlse colour image of the Copper Cliff embayment in
Figure 13b. There is a distinct inaease in Mg0 in the core of the embayment and in the north west corner of
the study are. towards the lower units on the Main Mass of the SIC. The lowest Mg0 values occupy a thin rind
almg the edges of the emhyment, correspondhg to the occurrence of diabasic-textured QMD. which contains
no textural evidence of OPX accumulation.
The data fiom the Murray Mine Traverse shown in Figure 13c indicates a trend that i s the opposite of
the Copper Cliff embayment trend The SRNR ha. lower Mg0 values than the QRNR w the QD. The QRNR
has the highest Mg0 values. This may be related indirectly to the amount of sulphide in the QRNR çompared
to the QD and SRNR in this traverse. The low Al samples tend to have higher Mg0 values than the high Al
and so the opposing trend for Mg0 observeci at the Murray Mine niay be a product of this association. The QD
and SRNR are both high Al and as expected have comparativefy low Mg0 values. The QD has the lowest
Mg0 values for this traverse averaging l e s than 5wt?/&, whereas the SRNR samples average 6WA. If the
QRNR fiom this location had been hi& Al then there may have been a m a e recognizable trend fiom low
Mg0 in the QD through the QRNR to high values in the SRNR
sio*
The relaticmship between Si(& and M g 0 for îhe Copper Cliff embayment rocks is show in Figure
14a. As is the case with al1 of the Sudbury rocks the Copper Cliff embayment rocks al1 display elevated levels
of SiOl compared to similar mafic rock types hm other locations. Nœite and a quartz diorite worldwide in
tenns of silica content are nonnally quite distinct, with norite having approximaîely 52% OJlM-N) whereas
quartz diorites (SKD- 1 ) have 60% (Govindaraja, 1994). in the SIC there is g e n d l y les than a one to five
percent difference, whidi makes Si% content difficult to use in distinguishing h e m rock types.
There are however, several trends show in Figure 14a, which need to be a d d r d . The first is the
relaticmship between the QMD, QMGN and the GN of the Copper Cliff ernbayment, in general, there is l e s
silica in the GN than in the QMGN and QMD. The distinction between the rock types is minor in tenns of
silica but there is a difference. n i e mesocumulate to adcumulate textured GN which contain both the lowest
SiOt and highest Mg0 may be explaineci in t m s of the aystal accumulation trend s h o w by the tie-line
between plagioclase and OPX. The G N has significantly more accumulatd OPX and much l e s quartz than the
other rock types. The fiactional crystallization and accumulatim of OPX allowed Iittle intastitial space for tbe
fmaticm of quartz ûom trapped melt- The QMGN in contrast has much l e s OPX and significantly more
interstitial quartz, while still k ing a cumulate. The QMD however is not a cumulate rock but still plots very
close to the composition of both the QMGN and GN in terms of S i 0 and M g 0 content. This is consistent with
derivation of the GN and QMGN fiom an initial liquid composition very similar to the QMD.
A second trend that is important is the major distinction between the low Al and the high Al rocks. The
low Al and high Al sarnples are represented by open and solid symbols respectively as was described above.
The low Al sarnples generally contain 6 5 % SiOz whereas the high Al samples contain >55% although there is
not as clear a distinction with Sis- as there was with Al&. There is a significant arnount of overlap between
the samples especiaily the low Al samples, which show a large amount of scatter.
The third trend which may help explain the scatter in the low Al samples and the tight clustering of the
high Al samples is îhe trend of the low AI samples towards the composition of the inchision population and
country rocks surrounding the embayment. In most cases, the inclusicms (except granites) show by solid
circles have significantly les SiG dian the embayment rocks. The samples of Elsie Mtn Fm melasediment and
basalt shown by stars also have very low Si02 values compared to the embsyment rocks. The low Al samples
tend to also be the sarnples with the highest number of inclusions and so a possible cause of the large scatter in
the low Al samples rnay be that they are severely contarninated. The trend towards the inclusion population
seems to support this hypothesis sinœ the scatter can not easily be explained in t m s of simple a y s b l
accumulation or hctionation involving plagioclase and OPX in a liquid similar to the Onaping glasses. The
samples of Creightcm Granite fiom the West side of the embayment plot much higher than any of the Copper
Cliff rocks and may have had much less impact ai the SIC magma composition than the Elsie Mtn Fm rocks or
the inclusions. This will be discussed mare fiiliy in a later section.
The relaticmship between S i 0 and Mg0 for the major rock types of the SIC is show in Figure t4b.
The data show a curved trend extending fiorn the grtuiophyre (hi@ SiOzAow MgO) to the sublayer and
melanaite (Iow Si@/high MgO). The major trend Iine moves fiom the granophyre to the QMD of the Copper
Cliff embayment and dike. There is however a major compositional gap between the granophyre and the QMD
fkom approximately 63wtOh SiO, to 60wt?/o Si@ and between 4 wt% Mg0 and 2 WtOA MgO. The MELTS
model tmdline initiates at the 63wtOh Si- and 4.5 wt?h Mg0 at least partially spanning the cornpositional gap.
When this is coupled with the contamination trend is considered the gap is narrowed. The amount of
contaminatim that has occurred in the QMD fkom Copper Cliff may account fm the silica depletion and
elevation in MgO. The overall Mg-enrichment trend of the mafic members of the SIC continues through the
QMGN and GN of the Copper Cliff embayment and into the ITSM, low Al GN rocks ftorn Copper Cliff, and
the mafic norite of the n& range. The trend passes through the sublayer norite and ends at the more rnafic
samples of melanarite. Thae tends to be a signifiant amount of overlap beniveen the ITSM and the low Al GN
and QMGN rocks fiom Capper Cliff
The dependence of Fez03 on Mg0 for the Copper Cliff ernbayment rocks is show in Figure 15a.
There is little correlation between the crystal accumulation trend between OPX and plagioclase and the overall
trend tiom QMD to GN. Ttiere are two di fferent trends for the Copper Cliff rocks, both of wh ich are at an angle
to the accumulation trend The hi& Al samples tend to have decreasing Fe2% values with inueasing MgO,
whereas the low AI sarnples have increasing Fe!& values with haeasing MgO. These observations are
consistent with the presence of abundant Fe-rich OPX in the cumulates of the low Al trend, and the relative
importance of iron-fiee plagioclase in the high Al cumulates. Addition of Fe fiom sulphide is unlikely to affect
visibl y the total amount of Fe& present in the analyses because few of the rocks analyzed contain more than a
hcticm of a percent of sulphide. In general, the QMD has higher values than both the QMGN and the GN
whether in low Al group or not. The low Al QMD averages 10-14% , wtiereas both the QMGN and
GN average 8- 10% Fe203. The h igh Al QMD averages 8- 1 0% F e 0 3 as does the QMGN, whereas the GN has
between 7 and 8% Fe. The Fe& data has more scatter fot the low At rocks than the high Al.
Unlike Al2@ and Si@ the Fe2@ data for the high Al rocks cluster tightly araund the unalterd
Onaping g l a s composition at Swt?? M g 0 and 9wt% Fe20;. The low Al QMD samples scatter to higher Fe.03
compositions in the direction of a large number of inclusions fiom the Copper Cliff embayrnent and the samples
of Elsie Min Fm metasediment and basalt. The low AI QMGN and GN foliow a tie line linking the initial
composition of the MELTS trend and the composition of OPX. This suggests thaî the initial Iiquid fiom which
the low Al samples are derived was crystallizing almost exclusively OPX, since plagioclase accumulation
would defled the trend toward the origin. The high Al QMD sarnples which plot at the same composition as
the Onaping glass trmd at angle fiom the low Al group towards lower F e @ values. The angle and direction of
the hi& Al sample trmd may indicate that the initial liquid composition was wystallizing ôath OPX and
plagioclase. There are also several iran poor inclusicms, as well as the Creighton Granite samples that plot well
below the Copper Cliff rocks fiom one to six wt?? Fe03. The high Al samples could have fomed fiom a
process of crysbl accumulation of plagioclase and OPX, pasibly with a signifiant contaminant mtributiun
6m the iron poor inclusions and country rocks. The low Al samples may have f m e d h m a similar
proçess of crystal accumulation of primarily OPX, and a significant contaminant contribution 6om the irai rich
inclusions and Elsie Mtn Fm rocks. This could account in part for the differing trendlines for the low Al and
hi& Al samples.
The spatial distnbutim of Fez@ in the Copper Cliff embyment is show by Figure 1 Sb, showing the
two E-W traverses. There is marked decrease in Fe203 û-om the east to the West perhaps because the western
side of the ernbayrnent is in contact with iron poor Creighton Granite while the east side is in contact with the
relatively iron rich Elsie Mtn Fm melasediments and rnetavolcanics. n i e spatial relaîionship of Fe& with
distance at the Murray Mine traverse is show in Figure 1 Sc. The FezQ in die QD is low, the QRNR is hi&
and the SRNR is lower than either of the other two rock types. The elevated levels of Fe203 in the low Al
QRNR are consistent with the trend observed at Copper Cliff where al1 of the low Al samples had elevated Fe
compared to the high Al. Again, this seems to imply the existaice of two separate magma batches with
differing initial liquid compositions.
Ca0
The dependence of Ca0 on M g 0 fot the Copper Cl iff em bayment rocks is shown in Figure 16. There
is a large arnount of scatter for al1 of the Copper Cliff data, although the low Al samples tend to have a greater
range dian the high Al. The C a 0 content increases fiom the hi& Al QMD through QMGN and GN ranging
fiom 6 to 8wto5. The low Al rocks have the opposite trend and Ca content decreases fiom the QMD through the
GN. The low AI QMD ranges h m 5-8&! Ca0 whereas the QMGN ranges fkom 6-7wt4h and the GN fiom 4-
6Wh. The low Al samples follow the crystal accumulation trendline toward OPX but the high AI trend is at an
angle to it. All of the Copper CIiRQMD samples have a 3 Wto! higher C a 0 content compared to the Chaping
g l a s used as the initial composition for the MELTS model. The inclusion population and Elsie Mtn Fm rocks
al1 have C a 0 contents of between 8 and 1 2 wt??. Cmtamination o f the Copper Cliff rocks by these high Ca
inclusions could elevate the entire data set fiom the 3wî% Ca0 level of the Onaping g l a s to die observed
concmtrations around 6 wt%.
The QD fiom the Murray Mine Traverse has low Ca, but the QRNR has low to medium Ca0 levels.
The SRNR is relatively quite rich in Ca, which is consistent with k i n g in the high Al group of rocks.
Na20
The relationship between Na-O and M g 0 is shown in Figure 17a. In general, the QMD has elevated
NazO in cornparison to the QMGN and GN of the Copper Cliff ernbayment. The QMD tends to have values
greater than 3 wt % while the QMGN and GN range Ç m the 2 to 3 &/o. T h a e is also a significant divisiar
b e e n the low Al samples and the high AI sarnplm. The low Al outcrops tend to have depleted Na20 and
more scatter in the data set than die high Al samples which have elevated NazO and cluster more tightly.
Within the two groups of rocks, QMD always occupies the field of higtiest Na20 values whereas the GN
occupies the lowest values. The QMD o f the low AI group has 3% Na, the QMGN 2.5% and the GN Ph. The
high Al QMD has 3.25% Na, the QMGN 3%, and the GN 2.75%. This is consistent with whaî is oôsewed for
the Murray Mine traverse where the hi& Al QD and SRNR are high and the low Al QRNR is low. All of the
Copper Cliff rocks follow a trend patallel to the tie-line fiom OPX tu plagioclase. The samples are however
much poorer in Na20 than die either the tie-line a the MELTS model. The sarnples fàll off the line in the
direction of some of the inclusions and the Elsie Mtn Fm rocks. The Creightm granite inclusions also have low
NazO and may have contributed to the deviation fiom the ideal crystallization trend. Some of the observed
NazO depietion might also be related to the greenschist hcies metamorphic overprint imposed during the
Penokean Orogeny.
Shown in Figure 1% is the spatial variation of Na20 fot the entire Copper Cliff embayment. This fàlse
colour image shows the GN core of the embayment and severai other mal1 areas as k i n g low in NafO wtiaeas
the margins are consistently one to two wt?? higher. The lowest NazO regions also correspond with the highest
incidences of inclusions and sulphide.
Overall Na10 content decreases with increasing M g 0 content for most of the rocks fiom the SIC
apparently reflecting dilution by cumulus OPX. This trend is followed by both the low AI and high Al rocks
6m Copper CliR The low Al GN samples fiom Copper Cliff plot in che same Mg0 and NazO range as ITSM
samples fiom the M c C r d y West and Frasier Mines.
K2O
The dependence of K 2 0 on Mg0 is show in Figure 1& The KzO values are consistently higher in
the QMD averaging 1.5-2 * O whereas the QMGN and GN samples average 0.5 to 1 % K20. There is little
difference in K20 content between the low Al and high Al samples although the high Al samples have K20
contents that decrease more steepiy with increasing Mg0 content trend than do those in the low Al samples.
Both the low Al and high Al QMD sampfes center around 5 wtO? M g 0 and 1.8 Wtoh &O. There is no clear
separation as there was in elements such as A1203. Since both low AI and high Al QMD samples have similar
KzO contents, it appears that the two initial liquid compositions also had similar KzO levels. The steeper
îrendline of the high Al sarnples is skewed in the direction of the low K20 (0.25 to 1.5 &/O) inclusion
population. The skewed trendlins can be explained by crystal accumulation of plagioclase and OPX into the
high Al suite, and dominantly OPX into die low Al suite.
In the E-W trending traverses aaoss the embayment shown in Figure 1 8b, the samples fiom the
western side of the embayment are eririched in KiO cornpared to the eastm side. The western side is in contact
with rocks of the Creightai Pluton. Local contaminatim of these rocks by K-ri& granite would produœ this
spatial distribution west to east. The effect does not penetrate very hr into the embayment.
The spatial variation of K20 for the entire Copper Cliff embayment is show in Figure 18c. which is a
tàlse wlour image, produced using SURFER The GN core has consistently lower K20 values than the QMD
margins. i l m e is a distinct transition generally within 100 m of the embayment contact fiom QMD to GN or
low &O material. This is consistent with what was found at the Murray Mine Traverse where the QMD was
high with >2% KzO, the QMGN had a strong decreasing trend tkorn 2.3% d o m to 1.1%. The SRNR averages
about 1.3% KzO.
TiO,
The relationship between Ti@ and Mg0 for the Copper Cliff embayment rocks is show in Figure
1 9a. In general, the QMD have T i 0 values in the range 0.75- 1 wt%. The QMGN samples fàl l between 0.5-
0.75% and the GN around 0.5%. Unlike the data for AIz03. the trend Iines of the low Al and hi& Al QMD,
QMGN and GN for Ti@ extend in the same direction. The high AI sample set however has a mu& steeper
trend line than the low Al sample set. The low Al data set follows an OPX accumulation trend whereas the hi&
Al follows a more plagioclase-rich assemblage and is skewed in the direction of a set of TiOz poor inclusions.
The obvious scatter in the low Al QMD samples may be caused by the assimilation of materials represented by
îhe suite of Ti% rich inclusions and rocks fiom the Elsie Mtn Fm. As with the data fot AI2O3 îhe data for T i 6
does not deviate too niuch h m the mode1 trendline produced by MELTS. The data set is higher overall than
the Onaping glas composition an& as mmtioned above, is skewed off the ideal trenâîine in the direction of the
inclusion and oountry rock &ta Forn the Copper Cliff embayment.
Shown in Figure 19b are the synthetic traverses, which refiect the spatial relationship of Ti@ in the
Copper Cliff embayment. Both traverses indicate that there are elevated TiOt levels in the QMD and relatively
depleted levels in the QMGN and GN. The mafgins of the embayment range tiom 0.8 to 1 Wta% Ti@ in the east
and 0.76 to 0.9 wt?! on the west side. The disparity between the two contacts may be due to the contamination
of the east side by high Ti@ rocks fkom the Elsie Mtn Fm. and dilutim on the West side by low Ti02 Creighton
Granite. The core of the embayment composed chiefly of GN average 0.5 wt% which grades upsecticm to the
QMGN at a Ti@ level of 0.5 to 0.8 wtO/o. The fàlse colour image of the Ti@ variation for the Copper Cliff
embayment is show in Figure 19c. Again, TiQ is low in the core of die embayment and inmeases toward the
QMD along the margins. In this case, the rind of QMD appears to be less than 100 m thick in most locations
and in several locations is disconthuous along the contact.
The Ti@ variation with distance for the M m y Mine Traverse shown in Figure 19d shows the same
general trend as the Copper Cliff rocks with high Ti values in the QD and low in the SRNR The low Al QRNR
has elevated Ti02 levels compared to the high AI QD and SRNR which is consistent with what was found at the
Copper Cliff embayment.
p2os
The dependence of P2O5 on Mg0 for the Copper Cliff embayment rocks is shown by Figure 20a. The
QMD has elevated levels of P205 averaging 0.20-0.25%, compared to the QMGN and GN which have relatively
low values, varying between 0.15-0.20D! and O. le0.15% respectively. Much like KzO and T i a the high Al
samples have a much steeper trmdline 6om QMD to GN than the low AI samples. There is a Id of overlap and
scatter for al1 the samples but more so for the low Al samples. AI1 of the QMD samples have elevated PiO5
compared to the initial composition of the Onaping g las from the MELTS trend.
The Elsie Min Fm rocks generally have higher PiOS han the Copper Cliff rocks, whereas almost all of
the inclusions have depleted Pz05 with values ranging tiom 0.04 to O. I wt?!. n i e scatter of the data may be a
result of contamination of the initial melt composition by these inclusions. The observed trend of decreasing
P1O5 content with inaeasing Mg0 is consistent with accumulation of OPX. The relationship between P2O5 and
distance for the Copper C li ff em bayment is shown in Figure 20b. Both of the synthet ic traverses show the same
trend. The QMD at the contacts of the emhyment have h igh PiO5 ranging h 0.2 to 0.3 wt%. The GN at the
core of embayment has low P averaging 0.14 wt?! which increases towards the contacts to approximately 0.17
wt% in the QMGN. A sirnilar relationship for the entire embayment is show by the FaIse colour variation
diagram in Figure 20c. The QMD at the margins forrns a thin, disumtinuous rind of high P while the QMGN
and GN form a core of low -O5.
In com parisai the variatim of Pz05 for the Murray Mine Traverse is shown in Figure 20d. There is an
overall trend h m hi& Pz05 in the QD to low P20S in the SRNR The low Al QRNR is elevated in P205 due to
the shallower trend towards low P205 with inueasing Mg0 values.
Suipbur
Shown in Figure 2 la is the relationship between S and Mg0 for the Copper Cliff rocks. There is a
tremendais amount of scatter and overlap for al1 of the sarnples. The QMD is plotted as diamonds, filled
diamonds indicate high Al sarnples while open diamonds indicate low Al samples. The high Al samples of
QMGN are shown by solid squares and the high Al sarnples of GN are shown by solid triangles. Similady, the
low Al QMGN and GN are s h o w by open squares and open triangles respectively. The low Al sample tend to
have much higher S dian the high Al samples afthough there are numerous sarnples that plot as a low Al
sample in t m s of A120j but do not have high S contents. The average low Al QMD contains I 1 91 1 ppm S,
while the high Al QMD contains mly 1 1 4 4 ppm. Thae is Iittle différence beniveen the high Al and low Al
QMGN samples, which average 1966 and 2 182 ppm S respectively. The low AI CiK siipies have an average
of 4024 ppm S wtiile the high Al contain mly 877 ppm. There is no othtr relationship discernible for S in the
Copper Cliff rocks other than the diffèrence between the low Al and hi& Al gï-wps. The spatial variation of S
for the entire Copper Cliff embayrnent is s h o w in Figure 21b. niere are several locations with high sulphur
content which correspond with the locations with the higtiest inclusion populations as well as the greatest
amount of gossan. The highest reading, at statim 70 (Figure I 1) also happens to be the thickest gossan (Plates
14a, 14b) found in the embayment as well as a location with greater than 1û?4 inclusions (Figures 8, 10). The
same can be said about stations 72- 1,72-2, 149,200,20 1, and 222. These stations al1 have high S, some degree
of gossan and higha ttian average inclusion populations. At many of the low Al outcrops, there was little
visible difference between them and the supposedly hi& Al outcrops. Not all "low Al" locations had visible
inclusions or a gossan. The greatest nurn ber of these locations occurred in the core of the embayment to the
south-east of the large f;ault. In addition the samples taken fiom drill core proximal to ore zones also plot in the
" low Al " citegory and have some of the highest S contents, while not appearing to have greater than average
sulphide contents when examined in hand specimeri.
The S variation with distance for îhe Murray Mine Traverse is shown in Figure 2 1c. The QD in this
case has low S, wtiile the low Al QRNR has a very high S content which Qops gradually with the
mesporiding deaease in suIphide away hm the f m l l contact. The SRNR averages less than 1000 ppn S,
much Iike the high AI GN flan the Copper Cli ff embayment. It should be noted that S was analyzed as a trace
element by presseû powder pellet at the University of Toronto and the high levels (94 000 ppm) may have
affected the quality of the data
7.2 Tncc Ekmeit Gcocbrrnistry of the C-r Cliff Emimymeit iii Rehtior to the Footnsll Rocks
Surroumdinp the Embayment and the lacfusion Pmulrtioa of the Embavmcnt
All of the trace elements analyted for were plotted using several different meiliods. Al1 elements were
plotted versus distance for the Copper Cliff ernbayment as well as for the samples taken near the Murray Mine
Historical Site. The elements were also platteci versus Zr to deiermine if th- were any majw trends relative to
the other rocks within the embayment as well as to other rocks fiom around the SIC. Finally, each element was
plotted using SURFER, which produces a i l s e colour map of the study area showing Uie concentration
distribution of each element. There was no t m d fond for As, Ba, Cs, Cu, Mo. Ni, Sb, Sc, Sr, U, V, W, and
Zn. The rest of the trace elements divided into those that were high in the QMD and low in the QMGN and GN
and thosci that were low in the QMD and high in the QMGN and GN. Rie elements that are high in the QMD
are F, Hf, Nb, Rb, Ta, Th, Y, and Zr. The elements that are low in the QMD compareci to the QMGN and GN
are CI, Co, and Cr. The CI, Co, Cr, and Hf trends are weak and will not be discussed here. n e trend in the
data that occurs for sudi elements as F, CI may or may not be related to the overall aystallization history of the
Copper Cliff embayment. These elements are extremely mobile during greenschist hcies metamoiphisrn and as
such the trends produceci fiom these elements are suspect. In the same respect, the lack of a trend for elemaits
such as Ba may also be the result of hydtahamal alteration and n d a reflection of the original crystallization
history of these r&.
In almost every graph of trace element versus Zr there is a generally linear trend moving fiom the
inclusions near the aigin through the GN, QMGN, QMD and towards the Creighton Granite samples. Thae is
generally large scatter within the rock types for Zr and in most cases large overlap. niere was no trace element
data available to produce a MELTS rnodel, n a was there trace element data for the Onaping g l a s to c m p a r e
initial compositions.
Z r
The relaîionship of Zr with Mg0 is shown in Figure 22. niere is tremendous scatter and overlap for
boùi groups but in general, the high Al QMD averages 100 ppm Zr while the low Al sarnples average 150 pprn.
The high Al GN samples average 75 p p Zr while the low Al samples average 100 ppm. The two groups
have parallel trends towards high M g 0 and low Zr. The decreasing Zr trend tiom QMD to GN is consistent
with crystal accumulation and tracticmation. The inclusion population s h o w by solid circles tends to have
variable Zr, but both the Elsie Mbi Fm rocks and the Creighton Granite sarnples have elevated Zr and could be
the cause of the large scatter in the data if they cmtam inated the Copper Cli ff rocks.
Y
Shown in Figure 23a is the dependence of Y on MgO. Y in the Copper Cliff rocks shows one of the
strcmgest trends moving fiom the high levels in the QMD to moderate and low levels in the QMGN and GN of
the core of the embayment. The QMD generally ranges fiom 20-35 ppm and may reach as hi@ as 65 ppm Y.
The QMGN and GN tend to have lower values, around 15-25 ppm and 10-1 8 ppm respectively. Unlike the
trend for Zr, the low Al and high Al rocks have trendlines for Y at an angle to each other. The high Al samples
have a steeper trend towards low Y and high MgO, whereas the trendline for the low Al rocks is flatter but
still t i d s towards low Y and high MgO. These trends again reflect accumulation of a more magnesian
assemblage in the low Al group.
The relationship between Y and Zr is s h o w in Figure 23b. Symbols follow fiom the previous gaph ,
but in addition to these are trendlines showing the composition of both the inclusion population and basalt fiom
the Elsie Mtn Fm. These trendlines bracket the Copper Cliff data set. Contamination of the Copper Cliff rocks
by these inclusions and country rocks could produce the scatta in the àaîa. The high Al samples have a
trendline that is much steeper than the low AI w h i d may reflect the difference in the contaminants. n i e
inclusion populatim was for the most part collecteci h m low Al outcrops and as such, it would be consistent to
have the low Al samples parallel the inclusim population trendline.
The FaIse colour image of the embayment shown in Figure 23c produced by using SURFER illusarates
the high Y ruid along the margins of the embayrnent and the Y poor core. nie rind of high Y values is ihin.
generally l e s than 1 0 0 m. There is an abrupt transition to low Y, which umesponds to the rnapped transitiai to
cumulate QMGN. There are several locations with much hi&= Y values than the surrounding rocks. These
samples were visibly contaminated with granite and metasediment.
Nb, Rb, Ta and Th al1 show very similar behaviour to Y. The inclusion populatiai and the Elsie Mtn
Fm rocks bradret the Copper Cliff samples. The high Al sampies have a steep trend possibly pulled by the
composition of the Elsie Mtn Fm rocks while the low Al samples have a flatter trend that is more like the
inclusion populaticm trendline.
7.3 REE
Of the REE mly Ce, Eu, La, Lu, Sm, Tb, and Yb were analyzed due to instrument limitations. These
elernents were plotted in the same manner as the trace elements (See above). Of the REE, only Ce did not have
any discemible trend. nie other six elements were al1 hi& in the QMD cornpared to the levels in the QMGN
and GN. Again data for REE was n d available for a MELTS m d e l or for Onaping g l a s
Lu
The relatimship between Lu and Zr is s h o w in Figure S4a This figure will be used to describe the
behaviour of al1 of the REE since they are al1 extremely similar. There is a significant amount of both scatter
and overlap of the data but in general, there are elevated levels of Lu in the QMD compared to the QMGN and
GN in the core of the embayment. The QMD ranges fiom 0.3 to 0.6 pprn Lu, h i l e the QMGN ranges hm 0.3
to 0.4 ppm. The GN, with the least amount of overlap with the Uthm samples ranges fiom 0.2 to 0.3 ppm Lu.
The inclusion population has low Lu and the Elsie Mtn Fm and Creigtitm Plutai rocks have high Lu; again
contamination by these rocks is a possible explmation for the scatter ofthe data.
Shown in Figure 24b is the Lu variatim with distance auoss the Copper Cliff embayment. Synthetic
Traverse #1 and #2 have Lu levels for the QMD of 0.4 ppm and 0.4- 1 ppm respectively. The QMGN and GN
for these two traverses range fiom 0.2 ppm to 0.6 ppm. The QMD sample at the western end of Synthetic
Traverse #2 (give station location) is greatly elevated compared to the otha samples and is most likely highly
contaminatecl by the relatively Lu ri& Creightai Granite.
A similar overall trend is shown in Figure 24c of the Murray Mine Traverse. The QD at the start of the
traverse has approximately 0.37 ppm Lu. There is a gradua1 drop in Lu levels thrwgh the low Al QRNR.
There is no apparent difference in tems of REE W e e n low Al and high Al samples. The SRNR has the
lowest average Lu levels.
REE a d Tncc Ekmest Spider Plot
When the REE and trace element data fot the Coppet- Cliff embayment are normalized to Cl Chondrite
(Sun and McDunough 1989) we find that al1 three rock types within the embayment are relatively enriched in
the LFSE and depleted in the HFSE (Figure 25). The average QMD, QMGN and GN al1 have parallel REE
patterns although the QMD data are ofiet to slightly higher averages than either the QMGN or GN, Aich most
likely reflects the accumulation of mafic minerals in the latter two.
There is a siightly steeper dope to the graph for the L E E , which becornes shallower and alrnost level
for the M E . This trend has been n o t d by numerous other authors. niere are also depleted levels of Rb, Nb,
and Ta for al1 the plotted rock types except for the average uppa trust. The depletim in Nb and Ta are most
likely the result of the contamination of the SIC by calc-alkaline rocks fiom the surrounding footwall rocks.
The Sr depletion in the ganophyre relative to the Copper Cliff rocks most likely represents the hctionation of
p tagioclase. The relative abundance of the rest of the REE in the granophyre is l ikely the proâuct of it king
formed fiom the residual liquid after the formation of the mafic cumulates. There is no Eu aomaly for al1 the
rocks except the granophyre, which has a slight negative anomaly and the GN, which has a slight positive
anomaly.
The QMD fiom the Copper CIiff ernbayment and the data fiom the Copper Cliff of&t are identical
dirough the LFSE but tend to have minor variations in the HFSE, pertiaps refleding the geater ease of
hmogenization of the relatively mobile LFSE. The Copper Cliff offset rocks tend to match the QMGN tiom
the embayment through the HFSE, although the variation 6m the Qh4D to the QMGN is minor.
The major oxide data for the entire set of offset dikes and embayments in the Sudbury area has a
significant amount of overlap and scatter. m l y Alz@ vs. M g 0 and SiO? vs. Mgû will be discussed in detail.
The remaining graphs are very similar to these two elements and can be summarized in relation to diem. In
general, the offset envircmments split into two overlapping but distinguishable groups. The first group includes
the South Range offset enviraiments: the Wotthington 0% Creightm embayment, Vermillion ofiet, and the
Copper Cliff o f k t and embayment, The second group cmsists of offSet enviruunaits fiom the North Range:
die Parkin of&%, Ministic offSet, the Foy o s e t and die Mandiester ofiet, which is die exception to rhe mie as
it is a South Range O-. The two groups are indistinguishable for A1203 but separate into a high silica goup
(hiordi Range) and a low silica group (South Range).
In addition to low silica. the South Range group is depleted in KzO. The South Range goup also has
elevated Fez@, Cao, Ti@ and P20S cunpared to the North range group. The plots for NazO and M n 0 were
much like that for Alz03 in that ttiere was no discernible relationship between the van'ous o f k t envuonments
The dependence of AI& CRI Mg0 for al1 of the dikes and embaynents fiom the Sudbury area is
shown in Figure 26. There is littie distinction between most of the ofExt dikes with respect to Alto3. However
the Copper Cliff data. both em bayment and dike, have higher AI2Q cmtents dian al1 die dher ofk t s . The high
Al Copper Cliff rocks genaal ly have greater than 1 5 wt, % A120j h i l e the &er offsets al1 have between 1 2.5
to 15 wt. %. The one striking observation is that the Copper Cliffdike mataial plots in the same regim as the
high Al QMD h m the Coppa Cliff embaymerit. The samples collected fiom the Copper Cliff dike were
taken fiom locations with litde sulphide and few inclusions.
The dependence of sitica on M g 0 for data representing the entire group of of%& dikes and
embayments in the SIC is shown in Figure 27. The o f k t dikes tend to split into two groups with respect to
Sioz. The high siiica group are predominantly ûcnn the N a t h Range and consists of the QD fiom the Parkin,
Mandiester, Ministic and Foy O* h i c h al1 have greater than 58 wt. % SiQ. The second group, al1 fiom
the South Range. consists of the Worthington, Creightm, Vermillion and the Copper Cliff o f k t dikes and the
Copper Cliff ernbayment A i c h al1 have les than 58 wt. % SiO2. The data ffm the Copper Cliff dike and the
rocks fiam the embayment ncû related to inclusion and gossan rich outcrops ail clusta beîween 55 and 58 %
Si@. The data h m drill m e and 6om g d m c l u s i m rich wtcrops at the srnface show large SC8tta and
tends to be silica depletai, even in cornparisai to the other QMD rocks fiom the Copper Cliff embayment.
8 Discussion
The major points to consider up to this point are h t the QMD appears to be a quenched liquid bath
fiom i ts diabasic texture and fiom its geodiemical compi t ion . 'Rie QMD is very similar to the Iiquid
composition determineci by Ames (2000) for the least altaed Onaping glass. The QMGN and GN appear to be
cumulates derived h m the residual melt tiom the aystallization of the QMD. This is based on their
mesocumulate to adcumulate texture and their geochemical relationship to the QMD. The QMGN and GN have
strong trendlines towwds the more mafic cumulates rucks of the SIC. This trend may be explained by
equilibrium ftactionation and crystal accumulation of orthopyroxene and plagioclase fiom the initial
composition of QMD.
There is considerable scatter in the compositions of the QMD. which is ms i s t en t with extensive local
contaminatim. The major trendlines mentioned above do not coc~espond exactly with a simple aystal
accumulation trend and the deviation tiom it cannot be easily explained except in t m s on contamination. The
trendlines are skewed in the direction on both the inclusion populations of the Copper Cliff ernbqment and die
country rocks that surround the embayment.
Possible the most intaest ing finding is that there appear to be two separate magmatic lineages derived
fiom two completely distinct starting liquids. nie first lineage referred to as the " low Al " group shows simple
opx accumulatian, whaeas the second lineage referred to as the "high AI" group shows opx-plag accumulation.
These major findings, their relevance and importance will be discussed fiirttier in the following sections.
8.1 R c l r t i d i n khveea OMD, OMCN. id C N nithin the Coppcr Cliff Embrymeit
The diabasic texture of the quartz mortzodiorite of the Copper Cliff embayment indicates that it is a
quenched liquid. Its extreme geochemical heterogeneity suggests that it has assimilaîed a considerable arnount
o f country rock. Ahernatively, it may be considered to be an incompletely homogenized impact melt. This is
best illustrated by the g h e m i c a l heterogeneity bîween samples within meters of each other within the sarne
outcrop. There is as much variability in the data for major oxides, trace elements or REE fiom the 75 m
Traverse #2 on the West side o f the embayment as t h a e is in the synthetic traverse a a o s s the entire embayment.
This the abundance of inclusions, and the complexly interfingered contact of the QMD with the brecciated
m t r y rock indicate that local contamination played a significant role in the composition of the embayment
rocks. The small-sale heterogeneity moving away fiom the contact and the gaieral lack of inclusions other
than the brecciated zones at the margins seems to also point to local contamination. Inclusions of country rock
may have been small enough and the heat in the system hi& enough to have completely digested the small
inclusions in the QMGN and GN.
The major geochemical haerogeneity for al1 elements that was found for Traverse #2 is n a evident in
hand specimen or at the outcrop s a l e between samples less than 1 nieter spart. Thae may have been large
inclusions suspended in the matrix that the thick weathering rind cm al1 the outcrop surfaces may have hidden.
The likelihood that any such large inclusions went undiscovered is low considering the nurnber of fi& pieces
investigated. It is more likely that there were many smalla inclusions that were completed assimilated by the
crystallizing QMGN and GN but that the magma was n d ttioroughly mixed aller this occurred.
n i e QMGN and GN appear to be cumulaie rocks derived tiom the residual Iiquid lefi afier the rapid
crystallization of the QMD almg the margins of the embayrnent. The very similar incompatible element tmds
displayed by the QMD, QMGN and GN despite the effects of local contaminah indicaie diat al1 three came
fiom the same magma source. Additimal evidence to support îhat die QMD, QMGN and GN are genetically
related is their similady petrologically. Their pyroxene composition, *ich varies less than a few w+!! fw al1
rock types, and the presence of blue quartz in the transitimal rocks b e e n the QMD and the QMGN and
between the QMGN and GN are both prime examples. The gradational: changes in gain size, quartz content,
and mafic minaals fiom the edge of the embayment to the m e without any abrupt intemipions or
discontinuities also seems to support the genetic Iink between the three rock types and argues againçt their
origin as separate batches of magmas.
The highty variable diickness and ofien discontinuous nature of the QMD rnay simply be the effects of
local variatims in temperature. nie zones where thae is little QMD proôably retained more heat and were
never tmly quenctied, allowing the development of cumulate-textured QMGN along the contacts rather than
QMD. The areas with a relatively thicker m a s of QMD were most likely the regions which çooled relatively
rapidly. ni is may be an effect of heterogeneous temperature distribution in the country rocks afier the Sudbury
Impact, or simply a h a i o n of the embaymmt amtact geunetry, where the pojecting nature of the contact
allowed the more rapid cooling of magma confineci in the embayment. There are several instances of extremely
irregular gradational contacts within the Embayment (Figure 6). Thae are large fingers of QMD in QMGN and
vice versa, as well as fingas of QMGN hto GN. These fingers are most likely attributable to the
hetaogeneous heat distribution within the residual melt during crysbllizatim. It may also possibly be the result
of more than one pulse of magma into the system or of erosion of early-forrned cumulates by magma
convection. This will be considered finther in the section c o n m i n g the f m a t i m and gaiesis of the Copper
Cliff dike and embayment. Considering the large variety in grain size and the geochemical signature within the
QMD (as well as die QMGN and GN) it is most likely that a combinatim of contact geometry and pods of
country rocks entrained in the melt contributed to the pcesent form of the QMD. Zones containing greater
amounts of country rock inclusions should tend to show the greatest heterogeneity as well as the thickest mass
of QMD because Iarger nurnbers of cold inclusions would promote fàster mling.
TextrPally rhe QMGN is a mesocumulate with plagioclase and opx forming the cumulus grains and
quartz plus accessory rninerals f m i n g the intercumulus material. whereas the GN is an orthocumulate with a
higher percentage of mafic m inerals and much lcss quartz. These rocks represent an increasing temperature
gradient fi-am the margins of the embayment to its core, which continues towards the cote of the SIC.
Although gaieticaily linked, the QMû is significantly different fiom the other rocks of the Copper
Cliff ernbayment. Since the QMD is a quenctied rock and the QMGN and GN are the result of crystal
accumulaîicm processes, there should be very noticeable distinction between them. The QMD tends to show
elevated SiO?, NazO, PzOs, K1O, al1 of the REE analyzed for, and the trace elements F, Hf, Nb, Rb, Ta, Th, Y,
and Zr. m e QMD tends to be depleted of the test of the major oxides, and CI, Co and Cr. n i e elevated silica
and sodium are most likely the result of the silica and plagioclase content of the QMD compared to ihe QMGN
and GN which have significantly higher arnounts of mafic rninerals. The increase in Mg0 and Fei03 fiom the
QMD to the GN in the m e most Iikely represents the same trend, Le. the decrease in plagioclase and quartz and
the incl-ease in mafic minaals. The REE and trace elements, which are elevated in the QMD, tend to be
incompatible elements rejected by crystalluing opx and plag and are most likely depleted in the QMGN and
GN relative to the QMD due to dilution by cumulus phases.
8.2 Relstiowbiv bttweea the Cwmr Cliff Emimymeat .id t k 0- Dika of t k SIC
There are clear sirnilarities becween the O- dikes o f the South Range of îhe SIC and îhose of the
North Range of the SIC. nie South Range ofExts which are geochernically similar include the Worthingtm,
Vermillion, Creighton embayment. and both the Copper ClifTdike and embayment. The Foy, WhistleParkin,
and Ministic o f k s , which al1 occur in the North Range resem ble the Manchester oset, hich occurs in the
South Range The South Range group, apart fiom Manchesta, have low SiQ and K 2 0 and high Fe& MnO,
Ti@, Cao. and MgO. The similarities in composition between the offSets in the South Range and their
difference in corn parison to those o f the North Range and the Manchester of iet may be the result of the nature
o f the country rocks into which they have intruded ( c f , Grant and Bite, 1984). With the exception of the
Manchester offsec, al1 o f the South Range of lk ts in- into the same country rocks; mainly mafic
me$avolcanic and metasdirnents of the Elliat Lake Group. nie Manchesta offset occurs in sedimmts of the
Quirke Lake Group. The N d range offsets intnide predominantly rnigmatites and felsic plutonic rocks except
for the Parkin o&et which intnides mafic metavolcanics, Nipissing intrusives and the same sediments of the
Quirke Lake group that the Manchester o&et occurs in.
The initial compositional d i fkence that the country rocks ntay have imparted beâween the North and
South range ofiets may have been hrther exaggerated by the metamorphic alteration of the entire South
Range. Assimilation of more mafic country rocks would be more difficult than assimilation of granitic country
rocks (Grant and Bite 1984) and consequently the amount of contamination may be a fûnction of the type of
country rock the ofEa intrudes into. The reascm that the Manchester ofl5et is so different fiom the other ofUets
may be that it is the m l y offset to have no inclusim-bearing QD. This may have something to do with its
distinction fiom the South Range omets in general and al1 of the o f f a in terms of Na20.
The low AI QMD rocks of the Copper Cliff em bayment are unlike most of the other QD rocks fiom
the otha oîEets. They tend to have lower SiQ, lower AI2Q, and h igha Mg0 and Fe203 than al1 of the 0 t h
0fExt.s except for sorne o f the Worthingtm o f k t rocks. This could be a product of contamination, sinœ most
of the low Al QMD sarnples occur closest to mafic metavolcanics which if they could be assimilated would
increase the M g 0 and Fe203 concentrations and reduœ the abundances of S i 6 and Na20.
N m e of the dher ofkt dike rocks in the Sudbury area are compositionally like the distai poctions of the
Copper Cliff dike. There are some similarities between the low Al QMD of the embayment and the distal part
of the ofiet but the simi larities are not very strong. niey both have depleted SiOt and elevated MgO, Cao, and
Fe303 (Table #7). The abundances are much different, suggesting a link between the two or any other rock in
the Copper Cliff embayment would be pure speculation.
Although there are no two offsets that have exactly the same composition, petrological, structural, and
geochern i d similarities between ofiets suggest a cornmon magma source for al1 of the dikes and em bayments.
The similarities in structure in that al1 (except the Manchester) have an inclusion rich core and a fine graineci
inclusion poor margin, indicate that al1 of the dikes were probably emplaced in a very similar manner. The
geochemical similarities between al1 of the ofi5et.s despite the difference in the host rocks that they intrude into
also suggest a common magma origin. The minor differences beîween the offsets may be explained by local
contaminaticm differences. The differences between the North Range and the South Range offsets can be
explained by the level of alteration in the South Range mpared to the North Range and again the difkences
in the type of rwks that the ofiets intnide into.
8.3 Rehtionsbi~ beîween the Cmwr Cliff Ernbrvment rocks and tbe Main Mass
The relationship behkreen the rock of the Copper Cliff ernbayment with the rest of the SIC is a
contentious one. Pattison (1 979) believed that the subla- ( o fk t filling material) was emplaced before the
crystallization of the SIC, whereas Souch et al ( 1969) contendeci that the o f k t material and the norites of the
SIC forrned simultaneously. The picture is complicated fkther by the possibility is that there is more than
phase of QMD (QD) within the ofiets. The first may represent the earliest aystallizing phase of the SIC and
the second would presumably represent the magma of the SIC at some later time in its crystallimtion histœy.
nie SIC rocks would then represent the rocks produced by crystat accumulation and crystal fiadimation fiorn
the residual liquid after the initial aystallization of the QMD. The evidence is sîrongly in hvor of the latter
scenario. This will be addressed fùrther in the final discussion section, which deals with possible models for the
f m a t i m of the Copper Cliff of&t and embayment-
The QMD fiom the Copper Cliff embayment when plotted with the d e r major roçks types of the SIC
always plots at or near the beginning of the crystal accumulaticm trend fiom plagioclase rich rocks (granophyre)
to the mare mafic opx rich rocks (mafic norite, melanorite). The QMD fits the trend very well although there is
probably a large contaminant influence on not mly the composition of the QMD but al1 of the rocks of the SIC.
The QMGN and GN of the Copper Cliff ernbayment are most closely related to the QRNR and SRNR of the
Main Mas. The major differences between the Copper Cliff QMGN and GN to the QRNR and SRNR are in
the trends for NalO, Fe2@, Ca0 and MgO. The Copper Cliff rocks show a definite irend for NaiO, Fe& and
C a 0 where the QMD has high va lue and the QMGN and GN have lower values. The Murray Mine Traverse
has hi& Na in the QD and the SRNR but low Na in the QRNR The Fe values are low in the QD and SRNR
but high in the QRNR The Ca values are low in the QD and high for both the QRNR and SRNR The QMD
fiom the Copper Cliff embayment has low M g 0 values while the QMGN and GN have higher values. The data
fiom the Murray Mine Traverse indicates that the QRNR has the highest M g 0 values while the QD has medium
levels and the SRNR has the lowest Mg0 vaiues. The explanarion for the differences for these trends is most
likely due to the QRNR 6om the Munay Mine Traverse k i n g low Al while bdh the QD and SRNR are not.
When the Murray Mine Traverse trends are mpared to the Copper Cli ff rmks in light of th is characteristic the
trends make sense since the low Al samples tend to have higha MgO, Fe103, C a 0 and lower Na20.
In al1 other trends, the Murray Mine rocks match the Copper Cliff rocks, and in most cases have the
same abundances. An average o f the Major Oxide abundances fw the Copper Cliff rocks and the QRNR and
SRNR are s h o w in Table 6. Thcre is little, if any difference b e e n the rock types in hand samples except
that the grain size for both the QMGN a d GN is slightly finer than for the corresponding main mass rocks.
The differences in the geochemical trends is most likely not a matter of contamination diffiences since both the
Copper Cliff embayment and the main mas rocks fiom the Murray Mine Historical Site occur near similar
rocks of the Elsie Min Fm.
The low Al GN fiom the Copper Cliff embayment is geochemically very similar to the JTSM fiom the
Whistle, McCreeûy West and Frasier Mines and to the less MgO-rich melanorites and mafk norites fiom the
North Range. The high Al QMGN and GN are very similar to the ITSM fiom the Creighton, Crean Hill and
Little Stobie Mines. However based on the parallel REE patterns of the SIC rocks and the Copper Cliff rocks
(Figure 25), the excellent geochemical correlation between the less mafic norites of the main mass and the
Copper Cliff norites (Figure 14b), and the petrological similarities between the QMGN and GN to the QRNR
and the SRNR. it is clear that there is a strong relationship between them. The Copper Cl= QMGN and GN
most likely formeci by crystal accumulation into strcmgly contarnuiated QMD magma alter the rapid
çrystallization of the QMD at the margins of the ernbeyment. This is seen most strongly by the trends for A&03
vs. MgO, Si@ vs. M g 0 and Fe203 vs. Mg0 shown in Figures 12% 14a and 1 Sa respectively. The di fference
then between the Copper Cliff nuites and the norites of the lower Main Mass in the South Range is probably
the degree of contaminatim undergone by the initial liquid and the amount of tirne available for aystallization
and crystal sorting processes. The Copper Cliff rocks were most likely more strmgly influenceci by
contaminants since they fotmed in a more confined environment. The Copper Cli ff rocks also probably cooled
much fàster than their main m a s cuuntaparts. again most likely due to the m f i n e d crystallizatim
enviraiment. The similarity of the Iow Al rocks fiom the Copper Cliff embayment to the lTSM associated
with dha sublayer deposits suggests that al1 were f m e d as a result of the operation of similar prtxesses.
The low Al and high Al samples fiom Copper ClifFappear to have been f m e d by two distinct magma
sources. This is evident in most of the major oxide plots, but most clearly in the plot of AlZ03 vs. M g 0 (Figure
12a). n iere is a clear gap between the low AI and high Al sarnples at approximatety 15 wt% AlI@. Neither the
low AI QMD nor the hi& Al QMD have compositions which match exactly that of the initial liquid
composition of the Onaping glass (Ames, 2000). The evidence for two separate initial magma compositions is
also apparent in plots of MgO, and NazO variation with distance for the Murray Mine Traverse.
The position of low Al samples directly adjacent to high AI sarnples with little visible petrological
difference is puzzling. Ttiere may have been more dian one pulse of magma into the embayment, which could
account for the geochemical differences but not the petrological similarities, A second possible cause is the
hydrothmal alteration of the already crystallized rocks. For example the higbly mobile alkalis, could have
been remobilized and concentrated during the grmschist metamorphisn of the area This would be consistent
with the lack of difference between the low AI and high Al rocks in t m s of the REE, and other immobile
elements. However, the relative immobility o f A1203 during metamorphism suggests that the differences are
largely p r i m q in origin. The remobilization of elements during metamorphism would not likely affect the
crystal accumulation trends that ere evident in the major oxide plots.
8.4 C o ~ ~ c r Cliff Ernbr~ment and Dike F o ~ t i o a Mode1
The crystallizatim histay and genesis of the offSet dikes and embayments is a subject that has
received considerable attentim (Pattison, 1979, Grant and Bite, 1984, Ixessler, 1984, M a r i s and Pay, 198 1,
Naldrett et al, 1984, Lightfoot et al 1997a,b). nie timing oftheir formation with respect to the rest of the SIC is
both complex and confûsing. There is evidence to support both an early and a late timing for the formation of
the ofEet environments (Pattison, 1979; Grant and Bite, 1984). n i e data regardhg the relatiiwiship between
the Capper Cliffembayment, dike and the main mas of the SIC in this report may help dari@ the sequence of
events that f m e d the Sudbury structure.
There are mly three possible scenarios for the formation of the Copper Cliff embayment. The first is
thaî the embayment and the dike f m e d simultaneously as a singie cooling unit. The second is that the dike
was formed afier the embayment magma was largely solidified, and the third is that the dike forrned before the
embayment. It seerns unlikely that the embayment was formed after the dike given the stratigraphie
relatimship between the QMD, QMGN and GN observed in the embayment. The sbongest evidence for this is
occurrence of QMGN pods in both the ernbayment and the dike. There is no other instance of QMGN in oEet
dikes. if the dike had formed fint then there would have to be another source for the QMGN pods. Il-e does
not appear to be any other source for these pods other for thern to have corne fiom the early crystallizing
embayment. The structure ofthe SIC would also make it dificult for the early formation and aystallization of
the dike before the fmatiiwi of the embayment, unles the two were unrelateai, which is clear that they are not.
We are thm lefi with two possible scenarios. in the first -*O, it is possible to consider the formation of
both the embayment and the dike as either a single pulse of magma, or as more than one pulse. In the second
scenario it is only possible to consider the formaticni of the embayment and the dike as more than one pulse,
since it wodd be very difficult to have more than one generation of QMD contained within the dike and the
embayment 6om a single pulse of magma
If the dike and embayment were f m e d simultaneously and filled by a single pulse of magma, then
there would be several characteristics that would be evident despite the metarnorphisrn that has occurred in the
South Range. The QMD within the dike and the embayment should be geoçhernically identical except for the
local variations caused by the assimilation and contamination of country rocks, which differ in type along the
length of ihe dike. Grant and Bite (1984) found that there were significant differences between the proximal
parts of the Copper Cliff Dike and the distal parts south of Kelly Lake that wuld not be attribut& to
contaminatim différences. They concluded that this implies that the more mafic distal part was formeci first and
hhat a m d pulse of magma f m e d the proximal part afterwatds.
In addition to this, the single pulse of magma would then have needed to carry the inclusions of QMD
and QMGN fiom a diffèrent location. There is no evidence for a second source of QMD and QMGN ihgments
other than the Copper Cliff embayment itself, Furthemore, in h e case of a single pulse of liquid, t h a e should
also be no evidence of any succession of pulses, or contacts between different phases of QMD either fiom
palemagnetic data, field evidence, or ffom geochemical data. The presence of two geochemiçally distinct
magna trends for the low Al and high Al rocks of the Copper CIiff embayment could represent two pulses of
magma The initial pulse of magma could be the hi* Al phase while die secorid one w l d be the low Al one,
which brought with it the rnajority of sulphide and inclusions. In light of this it seems more likely that the
Copper Cliff dike was formed by successive pulse of magma rather than just a single intrusive event. The
question remains whether the dike and embayment forrned simultaneaisly or whether they were f m e d as
separate events.
In the case where the dike and the embayment fonned simultaneously but fiom successive pulses of
magma we would expect to see a slightly different scenario than what has been describeci above for the
simultaneous formation fhm a single pulse. The initial pulse of magma would fi I l the embayment and dike and
be quenched by the cold country rocks. This would poduce the sphenilitic-textured, fine-grained marginal
QMD in the dike and the fine-grained QMD along the margin of the embayment. The inaease in heat moving
away fiom the contacts and towards the core of the embayment would allow the slower crystallization and
accumulaîim of the QMGN and GN cumulates. This first pulse may be the initial more mafic pulse emvisioned
by Grant and Bite, whidi would fiIl the entire length of the Copper Cliffdike. The lower M g 0 content of the
high Al group of rocks ti-orn the Copper Cliff embayment does not seem to fit with the more OPX rich QMD
noted by Grant and Bite in the distal portions of the Copper Cliff dike. It is possible that there has been more
than two pulses, one of which could have been this more mafic phase observeci south of Kelly Lake.
The amount of time available for crystallization would be dependent on how much time elapsed
between the first pulse and the second. The time available before the second pulse of magma wcnrld determine
the thickness' of the QMD and QMGN in the embayment. The second pulse wwld have to carry with it the
inclusions and fragments to form the dismtinuous core of inclusiai rich material within the dike. In order for
both QMD and QMGN to be available to be sampled by the second pulse of magma and form inclusions within
the dike, t-here would have to be a signi ficant amount of cytallization within the em bayment and consequently
a notable amount of time between the first and second pulses of magma The entry of the second pulse of
magma along the trend of the dike wibiout sharp crosscutting relations requires that the dike remained
incompletely crysîallizeâ almg its lengh. If thae were successive pulses afler the second m e they too would
follow the path of the first and second pulses. The low AI group of rocks fiom the Copper Cliff embayment
could represent this second pulse of magma since diey are associated with both high nwn bers of inclusions and
a higher than average sulphide (sulphur) content.
In the second scenario where the dike and the embayment are formed at different times fiom several
pulses of magma, the embayment would be the first feature to begin crystalliration. The embayment would
begin to aystallize before dher areas almg the contact of the SIC simply because of the distance it has intnided
into the country rocks. This relief: although in many cases relatively small, would be enough to fonn fine-
grain4 inclusion-fiee QMD along the margin of the umtact, This situation, wtiere the embayment and dike
begins as a shallow protnisim into the footwall rocks is best described by Morrison (1984) as a slurnp terraces
along the impact =ter wall. Essentially a large depression could form along the unstable crater walls by
coliapse of the undalying brecciated footwall rocks fiom the pressure of the overlying magma pool. As
Milkaeit et al (1994) most recently pointed out, seismic data fiom the south range shows the contact of the SIC
m t e r wall with the footwall rocks to be steeply dipping (45" or greater). The palemagnetic work of Morris
(1979) indicates that this present steep dip was not the condition during the formation and genesis of the SIC.
Instead, the walls of the crater were dipping at somewtiere fiom 5 to 20 degrees Figure 28a and 28b show a
modified version of Morrison's slump terraces both before and after the ratatim of the South Range contact
with the footwall rocks. Once the slump terraces of Morrison are rotated to the original 5-20 degees the down
and outward injection of the Iiquid, the crystal accumulation by gravity settling to form the norites of the main
mas, and the inclusion of large rafts of country rock in both the embayment and the dike make more sense
spatially. Afier the walls of the aater assumed theu present dip, and the present aosion level is reached the
surfàce expression of, the Copper Cliff dike and embayment also make more sense spatially.
The zones along the originally gently sloping contact with the footwall rocks would cool rapidiy
f m i n g the QMD, while the core of the ernbayment would crystallize and accwnulate the QMGN and
eventuaIly GN cumulates. After the initial crysbllization within the emkyment the dike would thai be formed.
This could be achieved by a ôreach in the embayrnent walls caused by an influx of magma, which would force
its way into the country rocks by fiacturing them and thus fom ing the dike. Grant and Bite ( 1984) describe a
situatim wfiere the slump terrace or embayment wall could be breacheû to allow the formation of the dike.
They postulate thaî such an injection of magma could be îriggaed by an increase in die confining pressure
within the embayment resulting tiom 'mt-cratering tectonic readjustment". In essence, the walls of the crater
would slump or cave causing an inaease in the pressure within theconfined space of the embayment. ln this
scenario, the initial influx of magma into the embayment cwld inject the distal mafic portim of the Copper
Cliff dike and the high Al2(&, group of rocks. A second pulse, possibly represmted by the low AI& I group of
rocks, canying partially crystalline QMD and QMGN could then be injected into the existing fiacture formeci
by the first pulse widening ir, The highest velocity zone within the core of the injecting liquid would cany and
deposit the inclusions in the core of the dike forming the IQD.
Whether the Copper Cliff dike and embayment f m e d simultaneously or hebier the embayment
formed first and then the dike is difficult to establish. A possible model for formation of the Copper Cliff
embayment is presented in Figures 29% 29b, 29c. In the first step, the Sudbury crater is formed by a large
metemite impact, which also brecciates the country rock. Dilatant fiactining under a slurnp terrace (Morrison
19W) lying on the Crater wall at an angle between 5 and 20 degrees allowed melt to inwude into the country
rocks. Some crystallization of QMD and QMGN occurs along the margins of the slump contact witti the
relatively cool country rocks. Large blocks of material, both hgments of brecciated country rock and partially-
crystalline QMD and QMGN, $11 fiom the upper portions of the slump feature. The magma injected into the
cauntry rocks cools rapidly at its margins and f m s the inclusion-k, quench textured QMD and the finthest
reaching magma f m s the distal, geochemically different, QMD south of Kelly Lake.
In the second step (Figure 29b) the slump feature is reactivated to permit m e r injection of iiquid out into
the country rocks. The liquid takes wiîh it the large blocks of country rock and fragments of the previously
crystallized QMD and QMGN in the core of the flow where the velocity is the highest. nie liquid reuses the
incmpletely solidified core of the initial pulse of liquid and widens it. In the third step shown in Figure 29c
(assuming m ly two pulses of magma) the inner core of inclusion-rich material aystallizes as a coarser grained
QMD. The slump or embayment continues to crystallize as the SIC çools and f m s more QMGN and GN by
crystal accumulation.
The evidence fiom the Copper CIiff environment to support this hypothesis is firstly the presence of
inclusions of an older grneration of QMI) and QMGN within the inclusim-rich zones of the dike and in
portiais of the embayment, Secmdly the difking composition of the distal portions of the Copper Cliff dike
canna be acwnted for by differing contaminants (Grant and Bite, 1984). Thirdly, the geochemical and
petrological similarities between the proximal QD of the Copper Cliff dike and the QMD fiom the Copper Cliff
embayment suggest that they crystallized fiom the sarne magma body. More work stiH needs to be dme in
order to determine with more confidence the sequerice of events that fomed the Copper Cliff dike and
em bayment.
9 Surnaurv of Fiadians
This investigation aithough primarily involved with the Copper Cliff embayment has had to address the
relatiaiships between the embayment rocks and the Copper Cliff oftSet, the rest of the o f k t dikes. and the
main m a s of the SIC. The major findings are as follows.
i)
i i)
iii)
iv)
v)
vi)
The Coppet Cliff embayment is cornposed of three recognizable rock types, which show gradational
contacts in the field; the quartz mmzdiarite, quartz morizogabbronorite and the gabbronorite.
The QMD f m s a thin disumtinuous rind a h g the margins of the Copper Cliff ernbayment, and is
most likely the product of a quenched liquid,
The QMGN and GN are cumulates derived fiom the QMD
The QMD tends to show elevated S i a , Na20, PZOS, KzO, al1 of the REE anaiyzed for, and for the
trace eiements F, Hf, Nb, Rb, Ta, Th, Y, and Zr. The QMD tends to be depleted of the rest of the
major oxides, and CI, Co and Cr.
There is a clear distinction betwm the major oxide composition of rocks that are related to
rnkeralitation and those that barrai. Rocks that are inclusion rich and sulphide rich or are fiom
underground drill çore proximal to ore have low Al2@ values and higher M g 0 values than rocks fiom
surfâce that are inclusion poor and sulphide poor.
The low Al and high Al QMD fiom the Copper ClitT embayment appear to have completely
distinct initial liquid compositions, an observation suppated by a simiiar trend fiom the Murray Mine
Traverse.
vi i)
viii)
ix)
x)
xi)
xii)
xiii)
xiv)
The rocks associated with mindization fiom the Copper Cliff embqment are similar to the lTSM
6om the Whistle embayment.
A simple mode1 to explain the gaiesis of the Copper ClitTenvironmait was developed. It appears that
the Copper Cliff embayment and the ofEet were f m e d simultaneously, but contain multiple pulses of
magma
The Iow Al and high Al groups of rocks hm the Copper Cliff Embayment m l d represent
multiple pulses of magma
Inclusions of QMD in QMGN within the embayment imply that there was a signifiant amount of
crystallimtion within the anbayrnent before the final formation and crystallization of the Copper Cliff
o f k t dike.
The Cqper Cliff ernbayment resembles geochernically the other South Range o e e t dikes and is
dissimilar geochemicatly to the North Range ofiets.
There appears to have been a massive arnount of local contamination of the Copper Cliff embayment
rocks, as evidenced by the small-scale geûchemical heterogeneity of the rocks.
The Copper Cliff rocks fit an overall crystallizatim trend for the entire Sudbury lgneous Corn plex.
They fit between the granophyre and the melanorite (mafic norite).
The Copper Cliff rocks have similar trace element abundances and REE patterns to those of the main
mass rocks indicating that they probably came fiom the sarne magma source.
10 Future Work
Although this was a comprehensive study of the Copper Cliff embayment. there are still many issues that
need to be addresseci before a clear picture of the genesis of the oftset environments is corn plete. The
relatiaiship between the distal portion of the Copper Cliff the inclusim-fiee quartz m o d i o r i t e and the
inclusion-rich quart. mmzodicwite of the proximal Copper CliiToflket and the Copper Cliff embgyment should
be fiirther investigated in fùll. This would requue a more complete analysis of both the distal and proximal
portions of the dike, which could then be combined wiîh the data tiom this report. Specifically the composition
of the hgments of QMD and QMGN within the QMD of the o f k t and anbeyment should be analyzed to
determine their origin.
More work should be done to determine if there is the same distinction between rocks with low Al2Oj.
large nurnbers of inclusims and higtier than average sdphide contait and rocks that have high Ai2@. and no
association with inclusion or sulphide as has been found in the Copper Cliff embayment, in other offset
environments. If this relationship should prove to be common to more than just the Copper Cliff embayment
then an attempt should be made to refine this tool fm possible use in explmation.
A closer look should be taken at the structural disamtinuity that runs NE-SW through the Copper Cliff
em bayment and its possible expression at d e p h The inclusion populatiai fiom adjacent to this stnicture should
also be l d e d at in more detail. If possible a larger sample set should be analyzed and their relationship to the
SIC and the Copper Cliff embayment detamined. Thae should also be an anempt to determine the amount of
contaminatim that has occurred in the Copper Cliff embayment. FLathennae, it is vital to know if that
contamination is primarily fiom the assimilaîim of country rocks or primarily 6om the inclusion population
some of which are not locally derived rocks.
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Reproducibility for the XRF at the University of Toronto. Tm pressed powder pellets fiom the same sarnple were run and the results indicate a good pecision.
Anal ysis of precision for data obtained by tiised glas disc at the University of McGill. The data represents hree groups of 100 samples each. The data within a group has good precision, as does the data between groups.
Measure of precision for lNAA at the University of Toronto. A sample of the in-house standard UTB2 was sent with every 10 samples for irradiation.
Results fiom analysis of rock standards, and their cornparison with international standards of the sarne rock type. The Sudbury samples al1 have elevated silica in cornpariscm to intenaticmal standards of the sarne rock type.
Geochemical analysis of oriliopyroxene h m the Copper Cliff em bayment by electron rn iaoprobe analysis. There is no indication of zaning within the OPX grains, and al1 analyses indicate clinoenstatite as the OPX species. MiNPET software was used to determine OPX species.
Table of average rock compositions fiom the Copper Cliff environmat and 6om several rock types fiom ttie main mas of the SIC.
* O - L U
Ni PC
ppm) 1 se.! 1 SB.? 15l3.s 158.1 1 SI.€ in.4 180.1 158.4 156.6
Ch& fa iccuncy and praddon of data ftom McGill Univardty, umpks inilyzad on fund bord by XRF 1 Dircriptlon 1 SI02 1 AI203 1 Mn0 1 Mgô
M Al Mn ma 1 F.B. ( F.O. 1 F.B. ( F.O.
CC582- UT 0-2 55.99 13.66 0.101 3.33 UTB-2 314 FBXRF C M 55.80 13.68 0.t82 3.30
Awtigo 68.95 1 3 M 0.18 3.32 1 Std, Dav 0,06 0.0 0.00 0.02 2 8td. D i v 0.13 0.0 0.001 0.04
I I 1 I
1 CC18-1 1 SRNR 1 57.351 17,241 0.1091 5.81 CC18-1 FBXRF Ch& 57.t31 17,07 0.111 5.N
wChntlC8 o0nl 0.17 0.00 0.01 1
Cn) Na20 K20 Ti02 P208 FdO3 LOI Total Ca M8 K Tl P Fo F.O. F.0. F.6. F.B. F.B. F.B. FBXRF (%) cn, cw, w, cw cw cw cx,
uon ~lirdrrdr W'lW I W C M UIL)2 I W C h c i l m 2 I W C k c L UT87 I W C M WB2 I W C k C k UTBI l W C M UTB? I W C M ma IWCW
I W C k c i h ~ n g l 1 W d h v awdv
WB2 Biirdard ~ n o r LWI
8717 8 1 7 0 W 8019 8 1 9
8905 9533 ooos 9 0 U am
12#1 LU
2472 2451 2 3 W 2487 2417 2482 2503 N W 2405 mn 07415
1 . 0 252 i l ,
5041 5 1 2
5527 5539 8 5527
67 3 MW 5377 ma 2 1 ~ 5
*n 5 a
2783 7 5 7 27 35 3182 2843 2 8 t 0 1829 2073 2831 r w 83751 irn
28 t . 1 ~
3 8 3 9 9 8 2 8 9 8 3 1 9 8 4 3 8 8340 8095 oou 5193 ru,
0 m t O.M 8 4
1 . 1 ~
1 7 2053 1785 1005 1933 1074 1 075 1811 1 3 % 1 . m
01935 O 1 8
.o.m
1001 08233 OW27
1118 07404 0 W b
1 045 OIMS OMO5 c.m
0 l l m am 108
4.0,
3 1 5 3271
3 18 3 1 1 1 3 1 1 3315
3 03 SUD 3204 n i
0 1 ~ 8 0 O.) 355 R
0443 04725 04005 0 4 W t 04892 0 W 2 04277 O W ~ O M M
o m , 0 ~ 1 9
O.Y 0 5 1 rnr
8335 8 1 8 344 8324 8 8 8 Ml 1 7 3 8 /54 aw,
0 3 ~ 3 O.U O8
4.-
1407 1911 l m 3 1 lm 5 1 138 1 llbl 1 . w
01332 o .n
5115 1100 4 5 W 4877 4215 1479 4413 zou 4932 r w i
34912 am 5 4
-11.m
09482 09309 08812 08330 09172 OW89 O M M OOTW 08827. am
00379 na 0 9 ta
007CU8 O M O 1 OOOlOl
01203 OWl74
00808 008542 0 ~ 7 2 7 004771.
o.su 0 0 1 ~
a#
07582 1570
O M M 2208 1175 1132 1 305 1503 1141 1 . m
OMM o . u
3095 3097 3 1 3037 3178 3131 31 33 3321 3053
ai.* 0 8 ~
1.w 32
LIW
9 1 8 8113 7842 7241 5070
138 6077 3037 7 9 8 1 mm
114240 tt.w
03117 O019
06440 0 M 2 8 00414 03813 08391 o a a 3 0726) a.w
0 ~ 1 8
Dr- CO
an* Dpnl
M 40 Y1 43 Y) a 00 111 tan
11 I 4 ? D )
, 1
1
l,
U m 441 8 M
Cu Cu Cu k h h W b t C l DI Cu1 CU al
rumt t CI D l
II* ut II* n u ml w mm m w ~WIJ mi
I I ? ! I l * 4 Li.?
4 4 s 8 1 F l ; ' a i .,';* 1 ;, ; i i
111'1 'i Il l f l t U', <
.*u * > l a I 1'rJ );?II ] I L I ! / r
80 ncn l m 0 1 1 an c m
Table 5
497 Un 2ü CC164 3 wnb
570 51 1 51 2
, Un 8 CC87 3 ponts 474 475 476
Un 11 C C S T S ~ ~ S 483 484 «15
Un 14 CC873panS, 492 483 4m
Cki 18 -7-2 504 5Q 508
Un 18 CC873pafib 5Q7 MB 5 0 ~
c. P 7 . -- --x ?a.. - : ,-.
4 -- - _ 2-z
-.-- -: .-.:.%-:m,r!5
. :. -.
2:- - .? .- . - - - - i . . -.x 2 =ci-:s
:>; -3: S .
, ," 45 :--.=- 7 - A - .?ci c.5
4 s?. ' gi 5 cT
LI- .- * - - - - - . -.x 2 X.?S
sr- 5-22 :,+7 - -
'5385X?&l 53BROL26
5lOZSdd 53 W751.5 5?6?5,?tS
53.92i345 53gtMB11 PB257BB
MM 54OM885 5376252
53.4132CY 53Z2BZû 53.28392
5386054 53713196 53857173
53- 53 501782
=y g - 5 % - - - . . .- .- -- .. ---- -- - . ---dLT
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Table #6 Aveiage Major Oxide Compositions for Copper Cliff and selected SIC Rocks
Copper 'Copper 'Copper Coppw Main Copper Copper Main Copper 7 Cliff Cliff Ciiff Cliff Mass Cliff Cliff Mass Cliff ,
Low Al. High Al Low Al. High Al Low Al. High Al Di ke QMD QMD QMGN QMGN QRNR GN GN ISRNR QD l
Cliff Distal
IQRNR. SRNR. Copper Cliff Dike. Copper Cliff Distal Values from Grant and Bite (1984) I
Handsample of Quartz Mmzodidte; Example of fine-grained diabasic-textured inclusion -ûee amphibole-biotite qiiattz mmzodiorite hm the rnargins of the Copper Cliff Embayment.
Thin Section of Quartz Monzoûiorite showing fine grained diabasic texture. All pyroxene has been altered to green amphibole, prirnarily hmblende. Opaques are always surrounded by dark brown semndary biotite. Quartz and plagioclase make up the bulk of the slide
Photo kom western contact of the Copper Cliff Embayment with the Creightm Pluton. Depicted is a large pod of Creightori Granite in a fine grained quartz monzodiorite matrix. The edges of the pod are ragged and appear to have been partially assirnilated by the QMD. Large plagioclase grains, coarser grain size overall and much higher proportions of quartz are common in proximity to such large pods and within several meters of the contact.
Quartz rnmogabbronorite in handsample. This sample displays the characteristic blue quartz of the quartz rich norite or basal unit of the Main Mass of the SIC. Blue qtz grains range in sue fiorn < I mm to I cm in diarneter and makes up 65% of the total quartz in this sample.
Quartz mmzogabbronorite in thin section. This sample is one of the few with intact cumulus orthopyroxene (clinoenstatite). Altaatim of the rims of the opx to hornblende is common. Large zoned cumulus plagioclase grains make up 45% of the sample. Quartz, both blue and smoky grey, fiIl the intercumulus spaces. Biotite is mostly an alteration product and makes up les than 5% of this sample. Opaques include sulphide gains (cpy, po) rnagnetite and ilmenite. Chlorite and epidote are comrnon alteration minerais.
Gabbronorite in handsample. This is a good example of relatively unaltered GN. It is a dark black rock containing mostly opx, amphibole, plagioclase and biotite. Quartz is smoky grey and makes up les than 5% of this sample. Most of the GN fiom the Copper Cliff Embayment appears much greena fiom the green hœnblende (+ actinolite) contait.
Gabbronorite in thin section. This is a mesocumulate textured GN with rare intact opx (thin section not the same sample as handsample described above). Cumulus plagioclase and amphibole after opx rnake up the bulk of this ample with minor amounts ofqtz filling the intercumulus spaces. Biotite always accompanies sulphide grains, but may also occur as large grains and clots without sulphide. Amphibole is comrnonly hmblende and actinolite.
Photo of high weathering relief inclusions fiom ridge of inclusion rich GN in Copper Cliff Embayment. lnclusions are mostly rounded to subrounded laminated rnetasedirnents and mafic metavolcanics. The large inclusion in the rniddle of the plate has a minor amount of iron oxide staining that is common to a large proportion of the indusiais. Sarnples tend to be very thin in the Z direction, occurring as flat dim.
Photo of high weathering relief inclusions 6om ridge of inclusion rich GN in Copper CliE Embayment. included in inclusion set are laminated metasdirnaits, rnafic-ultramafic fragments, and anorthositic tfagrnents.
Photo of low weathering relief pyroxenite and amphibolite pods tiom NW corner of the Copper Cliff Embayment. These inclusims m u r in a wide imnd that extaids for over 100 meters to the southeni shore of Pump Lake. lnclusions range in size hm 1 cm to greater than 5 metas in length. The rnatrix is a coarse grained QMGN.
Photo stations CC 1 50- 1 and CC 150-2. The left-hand side of the photo shows the inclusion rich (>30%) GN while the middle depicts the abrupt transition to the inclusion fiee GN. To the extreme rigtit in the photo the eastern contact of the 2.5 meter wide inclusion fiee zone ends as abniptly as it began. Again the rock has >30% inclusions. The contact between inclusion rich and
inclusion poor trends perpendicular to the NE-SW trading îàult structure that nms across the Copper Cliff Embayment.
1 I ) Photo of large pod of what the Autha believes to be metadha i t with sericitized staurolite fkom the McKim Fm. This pod is located near the throat of the Copper Cliff Embayment at the southeni end of station CC63. The edges of the pod were obscured by the thick weathaing rind so the nature of the pods contacts with the GN are miknown.
12ab) Photos of large coarse-grained QMD pod in QMGN. These photos ilfustnte the partially resorbed nature of die pods contacts with the QMGN. The QMD is again amphibole-biotite and is inclusion k. A sample could not be collected. Station location is CC 145
13) Photo of 10 m wide band of pyroxenite pods on the NW side of the Copper Cliff Embayment. The largest pod is 5 m in length and 1 m wide, but thae are pods as srnall as several amtirneters. The uiclusions are hosted in a fine-grained QMGN and make up W90% of the outcrop. The inclusicmn'di band is not traceable no& of inlet of Pump Lake or south towarâs die contact of the Creighton Pluton.
14ab) Photos depicting inclusion and gossan rich outcrops proximal to the Clarabelle Open Pit. nie rock is believed to be GN but the extrane oxidatian of the sulphides in îhese samples has masked the otha rninmls.
Plate # 1
Plate #2 Biotiie
Quartz /
Plaie #3
Pod of Creighton Granite QMD d t r i x
Plate #4
-Qtz
Zoned P!ag
/'
Sul phide
Amphibole \
Plate #6
Field of View = 1.5 cm
Plag. -
Sulphide surrounded
Plate #8a
Plate #%b
Plate #9A
Plate #9B
82
Plate # 10
Plate # 1 1
Plate # 12A
Plate #12B
Plate # 14A
Plate # l4B
F i m Captions
Map of the general locatim of the Sudbtq lgneous Cornplex. The SIC is located at the contact between the early Proterozoic aged rocks of the Southan Province and the Archean aged rocks of the Superior Province. It occurs in mostly felsic plutons, metasedirnents and mafic metavolcanics.
Generalized diagram of the SIC showing the locations of the major o h and embayment environments. The Copper Cliff dike and embayment occur in the South Range of the SIC.
Diagram depicting the Capper Cliff environment in its aitirety. Shown are the major mines of the Copper Cliff o f k t and the relevant faults that offkt the dike. Also show is the study area for this report, and the location for the standards used for this report. Sarnples were collected to represent possible contarninants to the Copper Cliff embayment rocks. Samples of the Creighton Granite were collecteci both proximal to the embayment and distally. Samples fiom the Copper Cli ff dike were taken north of Hwy. 1 7 at two di fferent locations. Elsie Mtn. Fm. sam ples were collecteci cm the basis of needing both metadiment and mafic metavolcanics. n i e final sarnple location was at the Murray Mine Historical Site for samples of QRNR and SRNR.
Stratigraphie sections of the North and South Ranges ofthe SIC modified aîler Lightfoot et al. ( 1 997a)
Diagram of a typical o f k t dike. The inna core is a coarse-grained inclusion-rich, sulphide-rich, quartz diorite (quartz monzodiorite). The outer rind is an inclusion-fie, sulphidepoor quartz diorite. There is a variable thickness transitional zone in between the two extremes of the core and the margins. 'Ihe outer rind of inclusim fiee QD may represent an earlier pulse of injected magma while the a x e may be a later pulse.
Gmlogy Base map of the Copper Cli ff em bayment producecl by Clayton Capes and Jacob Hanley. Shown is the Creighton Pluton to the West (pink) and the Elsie Mtn Fm to the East (orange). n i e purple along the contacts of the embayment is the QMD, the green is the QMGN and the blue is the GN.
Diagram showing the inclusion populatim of the rocks of the Copper Cliffembayment. The inclusions are clustered on the east side of the embayment and along the fàult structure nmning NE-SW.
Air photo (89-46 18,32- 193) of the Copper Cliff embayrnent. Shown by white outline is NE-SW trmding hult structure that has both high levels of inclusions and sulphide.
Diagram showing the occurrence of gossan in the Copper Cliff embayment. Two types occur, either a pervasive gossan or a gossan relateû to the inclusion population. Again, the gossan tends to cluster on the East side of the embayment.
Station location map for the Copper Cliff embayment. 1W/o of the embayment was srunpled. B low up is the 75-meter traverse completed at on the west side of the em bayment. Sam pfcs were takm every 5 meters..
Triple plot of W-Fs-En orthopyroxene. Al l of the OPX grains analyzed in this report plot in the Clinoenstatite region bordering on Pigeonite. Roduced using MINPET
Al2@ VS. M g 0 fm surface and underground samples for the Copper Cliff Embeyment
A12Q variatim with distance flom East to West auoss the Copper Cliff Embayment
False colour SURFER image showing A1203 variatim for the entire Copper Cliff Embayment
1 2d)
12e)
13a)
13b)
13c)
1 4a)
14b)
1 Sa)
I Sb)
1 Sc)
16)
1 7a)
1 7b)
I Sa)
1 8b)
1 8c)
1 9a)
19b)
1 9c)
1 9d)
20a)
20b)
20d)
2 1 a)
2 1 b)
2 Ic)
22)
A1203 variation with distance for the Murray Mine Traverse
AI2Q VS. MgO for Copper CliR the Main Mass of the SIC, Inclusions and Country Rocks
Mg0 variatitm with distance fiom East to West auoss the Copper Cliff Embayment
False colour SURFER image showing M g 0 variation for the entue Copper Cliff Ernbayment
Mg0 variation for the Murray Mine Traverse
Si& vs. M g 0 for surtace and underground samples for the Copper Cliff Ernbayment
S i 6 vs. M g 0 for the Copper Cliff environment and major rock types of the SIC
FezO; vs. M g 0 for surface and drill core sarnples for the Copper Cl i ff Embayment
Fe2@ variation with distance fiom East to West aaoss the Copper Cliff Embayment
Fe@ variation for the M m y Mine Traverse
Ca0 vs. Mg0 for surice and drill core samples for the Copper Cliff Em bayment
Na-O vs. M g 0 for surfàce and drill core sarnples for the Copper Cliff Embayment
False colour image showing Na20 variation for the entire Copper Cliff Embayment
K20 vs. MgO for surface and drill m e samples for the Copper Cliff Embayment
KzO variatim with distance h m East to West aaoss the Copper Cliff Embayment
False colour image showing &O variation for the entire Copper Cliff Embayment
Ti% vs. Mg0 for surlàce and drill core samples for the Copper Cliff Embayment
Ti@ variation with distance fiom k t to West aaoss the Copper Cliff Ernbayment
False wlour image showing Ti- variation for the entire Copper Cliff Embayment
TiOl variation for the Murray Mine Traverse
Pz05 vs. M g 0 for surlàce and drill core samples for the Copper Cli ff Em bayment
PzOS variation with distance fiom East to West acrosç the Copper Cliff Embaynent
False colair image showing PzO5 variation for the entire Copper Cliff Ernbayment
P205 variation for the Murray Mine Traverse
S vs. Mg0 for underground and surfàce samples fiom the Copper ClifFEmbayment
S variation with distance for the entire Copper Cliff Embayment shown by false colour image
S variation with distance for the Murray Mine Traverse
Zr vs. Mg0 for surface and underground samples fiom the Coppa Cliff Embayment
Y vs. Mg0 fot surface and underground sarnples h m the Copper Cliff Emhyment
Y vs. Zr for sLnface and ctril l care samples for the Copper C li ff Embayment
False colour image showing Y variation for the entire Copper Cliff Em bayment
Lu vs. Zr for surtace sarnples for the Copper Cliff Embayment
Lu variation with distance fim East to West across the Copper Ciiff Embayment
Lu variation fot the Murray Mine Traverse
CI Normalized REE Spider Plot of Copper Cliff Rocks
Al,03 vs. M g 0 variation for the O f k t Dikes and Embayments fiom the entire Sudbury region
SiO2 vs. Mg0 variation for the Ofkt Dikes and Embayments tiom the entire Sudbury region
Diagram modified aller Morrison ( 1 984) of slump terraces which may help explain the formation and genesis of the Copper Cliff Embayrnent.
29abc) Diagrams showing a possible scenario for the formation of the Copper Cliff Embayment and Dike.
Figure X 1
1 1 1 1 1 . X X X X X
c x x x x : cXxxxxx~xX: X X X W X
c x x x x : .*"X"X"X"X
Middle Proterozoic Felsic plutons and cornpleses
~.90~.~0w0~ GrcnvilleProvince B.... PO^.^^^& Early and Middle Proterozoic
Gneissic and Plutonic rocks
Archean rocks Felsic Plutons. Gneissic, rnigrnat itic. metavolcanics and metasediments
Proterozoic andior Archean Gneiss covered by Phanerozoic rnaterial
" , C , / ,- ,. .- / / ,' ,/ . .. , f Early Proterozoic rocks -. . , , , . - Huronian Supergroup , , a ,
Figure #2
Foy Offset 6 Frood-Stobie Offset
Tyrone Extension 7 Coppef C l i Offset
Hess Extensim 8 Creightorr Offset
ParMn offset 9 Vermillion Offset
Whistie Embayment 10 Mbîhington Offset
MocLenmn Offset 1 1 Trill Emboymerit
Manchester Offset 12 Minisiic Offset
Kirkwood & McConneil
Figure #3
# 1 Distal Creighton Granite Standards (unit a) #2 Copper Cliff Dike Standards (unit b) #3 Copper Cliff Dikc Standards #4 Elsie Mtn. Fm Standards (unit c) #5 Elsie Mtn. Fm Standards #6 Proximal Creighton Granite Standards #7 QRNR & SRNR Standards, Murray Mine Traverse (unit d)
A Creighton Pluton B Copper Cliff Dike and Embayment C Elsie Mtn Fm D Main Mass of SIC E Stobie Fm F Copper Cliff Fm G McKim Fm H Nippissing Intrusive rocks 1 Mississagi Fm J Ramsay Lake Fm K Pecors Fm
Figure #4
North Range South Range
-------------- Onaping Fm
Main Mass
Sublayer
-- Contact deposits . - Leuconorite
Footwall deposits
Offset deposits 1
Footwall
Modi fied afler Lightfoot et al ( 1997)
Fine grained ( o h n sphemlitic) Inclusions of primady country inclusion p r , sulphide poor, rocks (granites, metasediments, quartz monzodiorite (quartz diotite) metavolcanics) with occasional
examples of a different generation
Transitional quartz monzodiorite. occasional inclusions, minor sulphide, coarser grained
o f m o d i o r i t e and quartz monzogabbronorite (basal norite)
O Coarse grain4 inclusion rich, sulphide rich quartz monzodiorite. Often discontinuous along length o f dike
Figure #6
Figure 7
/ Inclusion Population of the Copper Clitr Embayment
Figure #8
1 Air Photo 89-46 18.32- 193
NE-S W Trending Fault Structure
Figure 9
Figure # 1 1
Figure # I 1
Figure 12b A1203 Variation from East to West across the Coppet Clin Embayment
East West
QMGN
6 7 8
Location
QMD
Figure 12c
N,0, Variation for thc Copper Cüfï Embaymçnt
+ Samplc Location
Figure I t e AI,O, vs. Mg0 for Copper Cliff Environment and selected rock types from the SIC
Contamination
20 f High Al
High AI-QMD
High AI-QMGN
A High AI-GN
x Creighton Gmnite
0 M a a ~ a b a a
Inclusions
O LW AI-QMD
O LW AI-QMGN
LW Al - GN
C o p w Cllff Dlke
a Gmnophyre
+OPX, Plag
X f eldc noriie
X Malanorita
a ITSM
o SuMayer Norite
-Mafic Norite
+ MELTS - -
I Melanorite I + OPX
10 15 20
Mg0 (wt. %)
Figure #13b
Mg0 Mation for the Copper CIifT Embaymcrit
+ Sample Location
Figure 158 FqOJ vs Mgû for Underground and Surface srmples Cor the Copper Cl in Embryment
OPX
Low Al
Contamination
High AI-QMD i High AI-QMGN A High AI-GN x Creighton granite (::4 MetasecilBas
Inclusions O LOW AI-QMD CI LOW ACQMGN A LOW AI-GN + OPX, Plag, K-Spar + - - - MELTS - - - - .. - - . . - - - . . . - -.
Figure 16 Ca0 vs Mg0 for Underground and Surface samples for the Copper CliR Embayment
. - - - - -. - - - - - . - - - - - - - - - -- - HIgh Al-QMD
Contamination 61 i High AI-QMGN A High AI-GN
O % Creighton granite 53 MetasedlBas
Inclusions 0 LOW Al-QMD O LOW ACQMGN A LOW AI-GN + OPX, Plag, K-Spar + MELTS
A
O O*
Crystal Accumulation
+ OPX
Figure # 1 7b
N a 0 Variation for the Copper Clin
Figure # 18c
&O Mation For Lhe Copper Cliff Ernbaymem
Figure 19a TiOz vs Mg0 for Underground and Surîace samples for the Copper Clifi Embayment
Contamination
+ High AI-QMD i High AI-QMGN A High AI-GN x Creighton granite s:( MetasedlBas
Inclusions 6 LOW AI-QMD CI LOW AI-QMGN A LOW AI-GN + OPX, Plag, K-Spar + MELTS
O Crystal Accumulation
T i 0 Mal ion for the Coppcr Cliff Embaymcnt
P CC) Ui
Figure #20c
P20, Variation for the Copper ClH Embaymcnt
+ Sample Location
Figure 2 1 b
S variation t'or the Coppcr Cli fî Embqmcnt
.-O 18 O -- Cr. 6 =. Q rn
Figure 23s Y vs. Mg0 for underground and surfice snmples from the Çopper Cliiï Embsyment
O High Al
. . . .. . - -- .- - - . . - - -. . -- - . --
0 Hbh AI-QMD
i High AI-QMGN
A High AI-GN
X Creighton granite
(3 MaawûiBiir
Inclurlonr,
O LW AI-QMD
O LW AI-QMGN
A LW AI-GN
A
Low Al
Figure #23c
Figure 24b Lu variation from East to West across the Copper Cliff Embayment
East West
1 +Syn. Trav. Y1 1
-- -- --
QMD 1 QMGN 1 GN QMD
1 2 3 4 5 6 7 8 9 10 11 12 13
Location
Figure #3 1 a
SIC Liquid
Q.G.
Brecciated Fodwali rocks
I I Inclusion Free QMD
After Momson ( 1 984)
Figure #3 1 b
Figure #29 b
SIC Liquid
Main h i a s SIC (Solid)
QMGN
inclmion Fnw QMD
n inclusion Rich QMD
V V
<4 <rit
l m 1 I m
147 2 l m 2 1% 3
147 107 O
l m i n i l a 5 IlYO 213 1 153 5 t n a l n 7 1 8 9 140 8 41 9
167 3 151 1 1574 174 2
l a s 103 5
147 1% 5 1s 2
z z 2 I r 1 $75 1 13t 9 155 4 14.3 2 1 s 8 la1 9 1 9 5 1.5 3
1Q 13.3 1104 I l 5 7 164 8 m 7 187 7 la3 8 m 7
1x3 3 ma0
I I O 1523 l e z i S S 1 0 7 1 1 3 m a
219 1 9
154 8 177 3 171 3 167 8 1 0 s 74 3
l n 2 153 4 14a 1 152 7
474s P a m s i 0247 n m raw
Iril N
37 0- n a n . sa a003 34 0003 118 a m n a m 25 a m U o m 31 a002 37 O003 13 a m n o o m Y OQY U o m l 31 0- 17 o m l5 a m 19 O aC s a m 37 OQY 24 o o m 2m aQY 31 OQY f) 0- 19 a m 25 o m 24 0-
31 0 an Jd a m 74 OOm 4a 0- JO a m 3 41 O O m 31 OQlJ Y o m UI 000s 32 a m Y o a u O4 am5 a2 Oom 63 0- 5a oam %a 000s 31 O O m Q C O I d -7 O rm 31 o m a a o s 1 o m Al o m Q 0m7 Y O a m Y 0- JI 0- JI a m .O o a s 90 Omo n o o m Y OOOD 3s 0aDI 21 0- a 0- Q o o m a a a n S3 0- 27 0003 57 OOaOS
C4
R C i l
I) 20 11 P m *i Y) XI ;D m SD YI 4 XI SD 30 a m Y) O JO a a m a ?a a
m m Y)
UJ JO a P X1 Y) X)
m Yi m m 50 YI a Y)
n> a rn 30 X) 70 m m 50 a YI m Y) m 0 Q m m a a 36 Y)
0013 0- 0- 0000 0011 o m 0011 0 31
a m 0 01
0- 0 01
0- o m o m o m O o a OOOS OODD 0000 0 01
o m 0 0 I f 0- CODD 0 Ol4 Oms
0- 0 01
oam 0- OODD 0- o m 001 0 or
a m O o a a m 0 01s o m 0011 0011 o o a OCll o m 0 01 0 01
o m a m o m a m 3 0- o m o m r Oms
0 01 0 or2 o m 0- o m s o o a 0 01s om o m 0 01 0 01
m oms IW 224 0011 110 M O M 25m
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