magmatic nickel potential in greenland · the former bmp, university of aarhus and private...

No. 24 - November 2013

Magmatic nickelpotential in Greenland

A workshop on the ‘Assessment ofthe nickel potential in Greenland’ wasarranged by the Geological Survey ofDenmark and Greenland (GEUS) andthe former Bureau of Minerals andPetroleum (BMP) on 27–29 November2012. The purpose of the workshopwas to assess magmatic komatiite-hosted, conduit- and contact-typenickel deposits, and also to assess thepossible presence of undiscoverednickel deposits in Greenland in theuppermost part of the Earth’s crustand to rank the most prospectiveareas. The procedures for the assess-ment and ranking of the individualtracts were designed to comply, asmuch as possible, with the ‘GlobalMineral Resource Assessment Project’(GMRAP) procedures defined by theU.S. Geological Survey (USGS).

This edition of Geology and Ore highlightssome of the results from the workshop,including descriptions of the most impor-tant nickel provinces in Greenland, theirknown mineralisations and the resultingpotential for undiscovered nickel depositswithin these provinces. A more compre-hensive GEUS survey report documentingthe results from the workshop has beenpublished in the GEUS report series (Rosaet al. 2013).

The methodology applied

The evaluation of the potential for undis-covered magmatic nickel deposits inGreenland was carried out according tothe standardised process utilised in theGMRAP. In this process, an assessmentpanel of experts discuss all availableknowledge and data for a specific area(tract) and assess the possibility of findingnew undiscovered deposits within thistract. The assessment panel constitutednineteen geologists from the USGS, GEUS,the former BMP, University of Aarhus andprivate exploration companies; each withspecific knowledge on aspects ofGreenlandic geology and/or expertise in

nickel deposits. Each tract was definedfrom the surface to 1 km depth (1.5 kmfor the conduit-type). The members of theassessment team made their individualestimates (bids) of the number of depositsof a specific size and grade they believedcould be found and mined in a specifictract. A panel discussion of the bids led toa consensus bid, which was used as inputto a statistical simulation. The result was a

grade-tonnage estimate (prediction) ofhow much undiscovered ore and metalcould be found within a tract under thebest circumstances. The consensus bidsand predicted number of undiscoverednickel deposits per tract are shown onpage 5, 8 and 10.

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Magmatic nickel potential in Greenland

Worldwide summary statistics for the mean tonnage and grade for the komatiite-hosted, conduitand contact nickel deposits. Based on data from Barnes (2006), Schulz et al. (2010) and Zientek(2012). Data extracted from Zientek’s (2012) workshop presentation (see Rosa et al. 2013).

Picrite lavas of the Vaigat Formation, Nuussuaq, central West Greenland. The formation consists ofolivine-rich mainly picritic lavas with a thickness of up to more than 5 km and an average thicknessof 1 km. Their extent is 22,000 km2. In parts the formation is crustally contaminated. Photo: L. M.Larsen

Deposit type Tonnage ore Nickel grade Copper grade Number metric tons per cent per cent of deposits

Komatiite-hosted 2.8 3.14 low 51Peridotite-subtype

Komatiite-hosted 148 0.69 low 7Dunite-subtype

Contact-type 62 1.00 0.64 55

Contact-type 206 0.19 0.26 37

Types of nickel mineralisation

It was agreed before the workshop to usethe following three deposit types as theyaccount for most of the world’s knownreserves of nickel:

• Komatiite-hosted deposits• Conduit-type deposits• Contact-type deposits

Descriptive characteristics of the threeknown deposit types (referred to as a min-eral deposit model) were used togetherwith a broader-scaled mineralising systemapproach to set up the targeting-elementsthat should be evaluated.

Each type of nickel mineralisation is asso-ciated with a grade/tonnage model that isobtained through a compilation of globalgrade and tonnage data from knowndeposits that have been formed throughthe same genetic process and can bemined and processed using similar meth-ods. The grade/tonnage models are usedas input for the estimation of undiscov-ered nickel deposits for the different tractand deposit models.

Komatiite-hosted deposits

This type corresponds to the more extru-sive settings of the magmatic continuumand is therefore hosted by extrusive vol-canic rocks. Traditionally, this type hasbeen divided into two subtypes, accordingto their host-rock and correspondingfacies of the volcanic flow system. Sub-type 1 (or peridotite-type) deposits, related

to komatiite lava flows, in more distal set-tings of the volcanic flow-system, andtype 2 (or dunite-type) deposits, related todunite bodies, in more proximal settings.Komatiite-hosted magmatic nickeldeposits tend to be of higher grade, yetlower tonnage, and are typified by theKambalda deposits of Western Australia.

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M A G M A T I C N I C K E L P O T E N T I A L I N G R E E N L A N D

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Tasiilaq

Graah Fjord

Maniitsoq Norite Belt

Hammer Dal

Ilukunnquaq

Ikertoq

Fiskenæsset

Bjørnesund

Kvanefjord

Nuuk

East GreenlandFlood Basalt Province

West GreenlandFlood Basalt Province

Amassalik IgneousComplex

Left: Simplified geological map indicating main lithostratigraphic environments and favorable nickel tract localities in Greenland. Middle and right:Stream sediment and rock sample localities with nickel values higher than 250 ppm. From Steenfelt’s (2012) workshop presentation (see Rosa et al.2013).

Grade and tonnage for the different assessed mineral deposit types. Modified from Zientek’s (2012)workshop presentation (see Rosa et al. 2013).

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0.0110,000 100,000 1,000,000 10,000,000 100,000,000 1,000,000,000 10,000,000,000

1,000,000 tons nickel

100,000 tons nickel

1,000 tons nickel

10,000 tons nickel

Tons, metric

Explanation

Conduit-type

Contact-type

Komatiite-hosted type

Laterite

Deposit type

Conduit-type

Contact-type

Komatiite-hosted type

Conduit-type deposits

This deposit type typically has grades andtonnages that are intermediate betweenthe komatiite-hosted type (high grade,low tonnage) and the contact-type de-posits (low grade, high tonnage). Most ofthe global nickel production can be ac-counted for by this type. It includesdeposits with the largest total nickelresource, among the magmatic nickeldeposits, with giants such as Norilsk andPechenga (Russia), Jinchuan (China) andVoisey's Bay (Canada). The deposits ofSudbury (Canada) can also be consideredto belong to this type; although a uniquemeteorite, impact-related melt sheet hasbeen proposed to be related to theiremplacement (Naldrett 2004). For this rea-son, the Sudbury-type is not part of thegrade/tonnage model for the conduit-type.

This deposit type is associated with hypa-byssal dykes or sills that are associatedwith large volumes of mafic magmatism(such as a continental flood basalt pro-vince). This style of mineralisation is alsocalled conduit-type, a genetic name indi-cating that these deposits form in con-duits in large magmatic systems. Since theamount of metal in the deposits cannotbe derived from the limited volume ofmafic melt in the associated intrusion thisimplies that some type of open system,with a large throughput of energy andmatter, was present. The presence of suchan open system can be recognised by theexistence of bulk compositions which arenot those of liquids and by the evidencefor excess heat (thermal erosion and widecontact metamorphism aureoles). Thismeans that nickel is effectively scavengedfrom streaming magma, through sulphideimmiscibility driven by the assimilationwith crustal sulphur.

Contact-type deposits

In contrast to the komatiite-hosted de-posits, contact-type nickel deposits tendto be of lower grade but higher tonnage.These deposits also have important PGEcontents, and are mined mostly for theseelements. This type corresponds to the

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SourceActive

PathwayS saturation(chemical)

Trap(physical)

Critial• High degree partial melts

• Major metallogenic epoch

Lessrelevant

• Lithospheric architecture

• Paleocraton margins

• Synvolcanic crustal architecture

• Magmatic sulphides

• Chalcophile enrichment

• Olivine-rich cumulate

• Channels and channel size

• Amygdaloidal flows

• Structural complexityProspect

Camp

District

Targeting elements for komatiite-hosted, nickel-copper sulphide mineral systems. The relative impor-tance of targeting elements at various scales is denoted by box colour: red = critical, green = lessrelevant. Especially the elements in the district and camp scale are relevant for the assessed tractsizes. S = sulphur. Modified from McCauig et al. (2010).

C6

C7

C8

C10

C11

C12

C9

C4

C5C2

C3

C1

I3

I1

I2

Conduit-type tracts

300 km

Contact-type tracts

I3

K13

K5

K10

K7

K12b

K8

K12a

K16

K4

K15

K3b

K11

K3a

K14

K2b

K2a

K9

K12a

K2b

Tracts for conduit- and contact-type nickel deposits

Tracts for komatiite-hosted nickel deposits

Komatiite tracts

300 km

The areas (tracts) used for the nickel assessment workshop.More information about the individual tracts can be found in the tables included on page 5, 8, 10.

intrusive settings of the magmatic contin-uum and is therefore hosted by plutonicrocks. The plutonic rocks are mafic toultramafic and typically magmatically lay-ered. Immiscible sulphide, which collectsnickel, as well as other chalcophile ele-ments such as copper and PGE, is formedas the result of fractional crystallisation,magma mixing, assimilation of sulphur orcontamination leading to increase in silicacontent. The nickel-copper-PGE-enrichedsulphides subsequently form disseminated,net-textured and massive sulphide concen-trations, hosted by igneous rocks andcountry rocks, near the lower part or themargin of the layered intrusion. Irregulardistribution of the sulphide concentrationsin this deposit type makes it hard to es-tablish volumes that are large enough tobe mined and for this reason only thePlatinum reef in the Bushveld complex hasbeen mined to date. In order to identifyintrusions with a potential for nickel priorto the workshop, a stepwise filtering of anexisting database of intrusions in Green-land was carried out. Since the workshopwas focused on nickel, intrusions with

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Name Tract no.

Areal extent[km2]

Consensus bid on number of undiscovered nickel deposits at

di!erent con"dence levels

Statistical calculation of:

RankN90 N50 N10 N5 N1 Number of unknown deposits

Deposit density

Mean estimate of undiscovered nickel resources

[metric tons]

Taartoq K2a 380 0 0 0 2 2 0.15 0.00034 9,200 5 K2b 560 0 0 1 2 3 0.41 0.00073 22, 000 3

Paamiut S K3a 932 0 0 0 1 2 0.11 0.00011 6,200 8 Paamiut N K3b 220 0 0 0 0 2 0.06 0.00027 4,300 14 Fiskenæsset K4 463 0 0 0 0 1 0.03 0.000065 2,100 15 Nuuk - Akia K5 2535 0 0 2 3 4 0.71 0.00028 43, 000 2 Maniitsoq E K7 886 0 0 0 1 2 0.11 0.00012 5,900 11 Ikertoq K8 263 0 1 3 3 5 1.40 0.00532 79, 000 1 Nordre Strøm!ord K9 169 0 0 0 1 2 0.11 0.00062 6,000 10 Sisimiut – Illulissat K10 2796 0 0 0 1 2 0.11 0.000038 6,800 7 Inner Nordre Strøm!ord K11 75 0 0 0 0 1 0.03 0.00040 2,100 14 Eqi – Disko - Kullorsuaq K12a 960 0 0 0 1 2 0.11 0.00011 6,800 6 Karrat Group K12b 20 0 0 0 1 2 0.11 0.00580 6,100 9 Melville Bugt K13 734 0 0 0 0 1 0.03 0.000041 1,800 16 Ingle"eld Land K14 137 0 0 0 1 2 0.11 0.00077 5,400 13 Tasiilaq contact halo K15 1040 0 0 1 1 3 0.36 0.00034 21, 000 4 Tasiilaq North K16 1550 0 0 0 1 2 0.11 0.000068 5,700 12

Summary of consensus bids from the nickel assessment workshop on the number of undiscovered komatiite-hosted nickel deposits in Greenland.

N90, N50, N10, N05, N01 = Con�dence levels; a measure of how reliable a statistical result is, expressed as a percentage that indicates the probability of the result being correct. A con�dence level of 10% (N10) means that there is a probability of 10% that the result is reliable.

Bjørnesund & Kvane!ord

Detailed saw-channel sampling of the dunite-dominated ultramafic sills at Ikertoq in WestGreenland. Photo: 21st North.

potential for copper over nickel, and like-wise PGE over nickel (stratiform, reef-likemineralisation), were filtered out duringthe evaluation. Step 1 in the filtering ex-tracted all mafic and ultramafic intrusivecomplexes with peridotites, norites, maficgabbros and Mg-rich diorites (because Niand Pt are lost during fractionation) andthe individual intrusions were assigned asize-classification of 0–10 km2, 10–100km2 and >100 km2 based on theirjudged/known extent. All steps involved inthe filtering of the intrusions in Greenlandare described in the GEUS report from theassessment workshop. As very large intru-sive complexes are needed to provide theright settings for the contact-type nickelmineralisation style, the assessment panelfound it most reasonable to only focus onvery large intrusions/complexes in Green-land and a threshold value of >500 km2

on the areal extent was arbitrarily chosenby the panel.

Undiscovered komatiite-hostednickel deposits

Supracrustal (undifferentiated), mafic andultramafic rock units were extracted fromthe 1:500 000 scale geological map of

Greenland. Based on the characteristics ofkomatiite-hosted nickel deposits and theassociated mineralising system, these rockunits were used as a first proxy for permis-sive geology for this type of mineralisa-tion. Units within similar geological set-tings and with similar level of investigationand exploration were then grouped to-gether into tract groups. The groups wereused to define the tracts that were be-lieved to be permissive for komatiite-host-ed nickel mineralisation. A total of 21 ini-tial tract groups were identified in thisway. In total 24,656 km2 were defined asbeing permissive for komatiite-hostednickel. During the course of the workshopthe panel decided to split three of the ini-tial tract groups into two groups. Further-more, seven of the proposed tracts werenot assessed due to time limitations andlimited potential. As a result, a total of 17tract groups were assessed for undiscov-ered komatiite-hosted nickel deposits. Theconsensus bids on the number of undis-covered komatiite-hosted nickel depositsare summarised in the table below.

The Ikertoq K8 tract in central WestGreenland was found to be the area inGreenland that according to the assess-

ment had the highest number of undis-covered komatiite-hosted nickel deposits.This was probably largely attributed to thepresence of known nickel prospects in thearea and the presence of additional geo-physical anomalies. The Ikertoq K8 tractstraddles the foreland of the Palaeopro-terozoic Nagssugtoqidan orogeny in whichArchaean supracrustal, mafic and ultra-mafic rock units were reworked. To thesouth the tract is bounded by the non-reworked North Atlantic craton.

The Nuuk – Akia K5 tract was assessedas to have the second highest number ofundiscovered komatiite-hosted nickeldeposits. It is a large tract that includesseveral continuous belts of supracrustal(undifferentiated), mafic and ultramaficrock units. The tract includes several ter-rane boundaries, which in some cases canbe followed for 150 km, and also containsmany well-known ultramafic rock unitswith komatiites as well as exhalative sul-phides. While some of the ultramaficrocks are Neoarchaean, deemed to be afavourable period for komatiitic nickelmineralisation, pentlandite occurrences inthe area are actually related to Mesoarc-haean, gabbroic, mafic granulites and ser-pentine schist. Gold mineralisations arealso well-known from this tract.

The Bjørnesund & Kvanefjord K2b tractdefines another area that was ranked rela-tive high for its potential to contain undis-covered komatiite-hosted nickel deposits.The tract represents mapped ultramaficrocks and amphibolites but no metasedi-mentary rocks are known in the Bjørne-sund and Kvanefjord areas. Spinifex tex-tures in ultramafic rocks are reported fromKvanefjord. Although there are acid vol-canic rocks, no exhalative massive sul-phides have been documented, so thepotential for the ultramafic magmas tohave reached sulphur saturation from thissource is limited. Several gold showingsand one showing with pentlandite miner-alisation have been reported from theBjørnesund area.

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Typical weathered rusty boulder with disseminated and net-veined Ni-Cu-Co sulphides as theyappear within dunite-dominated ultramafic sills at Ikertoq in West Greenland. Photo: 21st North.

Undiscovered conduit-type nickel deposits

The assessment panel found that the tar-get parameters for the conduit-type nickelmineralisation were present in many partsof Greenland. Several regions hold evi-dence for large magmatic systems that inmany cases are associated with wide-spread swarms of dykes and sills. A totalof 12 tracts were assessed during theworkshop for their potential for undiscov-ered conduit-type nickel deposits.

Three regions in Greenland are well-known for their presence of flood-basaltsand related major magmatic activityincluding numerous dyke and sill systems.The northernmost of these regions, tractC8, is defined by the Zig-Zag Dal basaltsand the presumed contemporaneousMidsommersø dolerites. These wereemplaced during rifting in the Indepen-dence Fjord Basin. The tholeiitic floodbasalt sequence is c. 1,350 m thick andextends over an area of c. 10,000 km2.The overall variation of Ni-MgO in samplesfrom the basalts points towards an olivinecontrol, however, a few more primitivesamples from the lowermost part of the

Zig-Zag Dal basalts are present and mightindicate that nickel was removed via animmiscible sulphide liquid. Tract C8 wasranked number 11 among the tracts forundiscovered conduit-type nickel deposits.The tract has seen very little exploration.

The tracts C6 and C7 cover the EastGreenland Flood Basalt Province(EGFBP) and associated intrusions (includ-ing numerous sill and dyke systems) thatare related to the Palaeogene volcanic-rift-ing and opening of the North Atlantic.The flood basalt sequence is up to c. 7 kmthick and consists of more than 260 flowsthat cover an area of more than 65,000km2 . More than sixty layered gabbrointrusions have been recorded in the pro-vince. The plutonic suite ranges fromultramafic to felsic, from depleted basalticto highly alkaline, and from upper crustalintrusion to sub-volcanic centres and brec-cia pipes with related epithermal vein sys-tems. The magmas were sulphur under-saturated and for most samples it seemsthat nickel is controlled by olivine fraction-

ation. Only the so-called Urbjerget lavasdepart from the olivine line of control ona Ni-MgO diagram which may suggestthat nickel may have been lost to sul-phides in these rocks. The province wassplit into two tracts. The reason for this isthat the lavas and associated dykes/sills tothe south were emplaced into a narrowand rather shallow sedimentary basin(tract C6), while those to the north wereemplaced into a more extensive and deep-er sedimentary basin (tract C7). Also thelevel of investigation and exploration fornickel is different from north to south,with the northern tract C7 having a high-er level. Tracts C6 and C7 were rankednumbers 7 and 8 among the potentialtracts for undiscovered nickel deposits.

The West Greenland Flood BasaltProvince (WGFBP) constituted the lasttracts, tracts C10 and C11, that are direct-ly related to known flood basalt regimesin Greenland. WGFBP is considered to bean analogue of the Siberian Traps inRussia to which the giant Norilsk nickel

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Sampling of nickel-copper sulphide mineralisation hosted within a metasedimentary sequence, associ-ated with dioritic and ultramafic rocks at Tasiilaq, South-East Greenland. Photo: NunaMinerals A/S

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A 10 tons boulder of iron found by Falconbridge in 1993 on western Disko Island. Photo: A. K. Pedersen.

Name Tract no.

Areal extent[km2]


di!erent con"dence levels

Statistical calculation of:

RankN90 N50 N10 N5 N1 Number of unknown deposits

Deposit density

Mean estimate of undiscov-ered resources [metric tons]


An asterisk (*) marks that the areal extent of the tract corresponds to the mapped rock units. The areal extent for those not marked with an asterisk corresponds to the entire area judged by the assessment panel to comprise the rock units and settings that are permissive for conduit-type

Maniitsoq Norite Belt C1 50* 0 1 2 3 5 1.10 0.25 490,000 270,000 19 1 Fiske!ord C2 420* 0 0 0 1 1 0.07 0.00018 27,000 15,000 1 10 Fiskenæsset C3 350* 0 0 0 1 2 0.11 0.0003 46,000 26,000 1 6 Gardar dykes (oldest) C4 6,570 0 0 0 1 2 0.11 0.000016 43,000 23,000 2 4 Tasiilaq AIC C5 250* 0 0 1 2 3 0.41 0.0017 160, 000 90, 000 7 3 S. of Scoresbysund C6 50,970 0 0 0 1 2 0.11 0.0000021 43, 000 24, 000 2 7 N. of Scoresbysund C7 2,510 0 0 0 1 2 0.11 0.000042 40, 000 22, 000 1 8 Zig Zag Dal C8 4,400 0 0 0 0 1 0.03 0.0000 068 12, 000 7,800 11 Ingle"eld Land C9 460* 0 0 0 1 1 0.07 0.00016 32, 000 18, 000 1 9 N. WG Basalt Prov. C10 10,730 0 0 1 2 3 0.41 0.000038 160, 000 88, 000 7 4 S. WG Basalt Prov. C11 10,880 0 1 2 3 5 1.10 0.0001 460, 000 250, 000 18 2 Skjoldungen C12 270* 0 0 1 1 2 0.33 0.0012 130, 000 73, 000 5 5

Copper PGENickel

Summary of consensus bids from the nickel assessment workshop on the number of undiscovered conduit-type nickel deposits in Greenland.

deposit is related. WGFBP is related to theinitial phase of continental break-up andinitiation of sea-floor spreading of theLabrador Sea in the early Palaeogene. Thebasalts vary in thickness from 4 to 10 kmand cover at least 68,000 km2. They weredeposited on a substrate of 6–8 km thicksediments in a Cretaceous-Paleocene sub-siding basin and a Precambrian basementof the continental interior. The WGFBP isespecially noted for its presence of nativeiron-bearing basalts and large volumes ofhigh-temperature picrites and olivinebasalts. The picrites probably are thelargest volumes of MgO-rich lavas knownglobally. Both basaltic and picritic parts ofthe lavas have been documented to becontaminated by sedimentary rocks and tohave reached sulphur saturation. Thelower part of the lava succession (mem-bers of the Vaigat Formation) is of signifi-cant volume and has undergone crustalcontamination. These magmas ascendedalong known focused magma conduitsdistributed along the N–S Kuugannguaq-

Qunnilik fault system. These conduits havenative iron and Fe-Ni-Cu-Co-sulphideoccurrences.

In the 1930s, 28 tons of massive nickelsulphide was extracted from theIlukunnguaq dyke located on the north-east part of the island of Disko. Since thenseveral exploration companies have active-ly explored for nickel in the area. Lately,magnetelluric and electromagnetic geo-physical surveys have identified large andstrong conductive bodies in the north-western part of tract C10. Tract C10 wasranked number 5, while tract C11 wasranked number 2 among all assessedtracts for conduit-type nickel deposits. Theconsensus bid on tract C11 resulted inone conduit-type nickel deposit at a 50%confidence level. Again, although the rocktypes and settings are similar, different lev-els in knowledge, exploration and datamake it appropriate to subdivide thebasalt province into different tracts. TractC10 is the northern part of WGFBP, which

comprises lesser volumes of picritic lavasand no known occurrences of native ironor nickel. Tract C11 contains large vol-umes of picritic lavas, occurrences ofnative iron and nickel, well-establishedpathways for ascending magmas andstrong, however deep-seated, EM anom-alies.

Tract C1 is defined by the distribution ofthe norite and leucogabbroic rock unitsthat are mapped as belonging to theManiitsoq Norite Belt which lately hasbeen suggested surrounding a largeArchaean impact structure that triggeredfracturing and magma ascension thatwere active for a long period. There areevidences for crustal accumulation, andiron-sulphide-bearing amphibolite layersare locally associated with the intrusivesand may have provided a source for sul-phur saturation. Exploration in the areason numerous rust zones was initiated inthe 1950s and 1960s and several nickel-sulphide showings were identified. The

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An eruption site for Kûgánguaq Member on Disko Island. Contaminated basalt forms basaltic ignimbrite, possibly by interaction with natural gas. Photo:A. K. Pedersen.

initial work was only followed up by shal-low drilling. Later, in 1995, fixed-wing air-borne electromagnetic surveys were car-ried out with limited follow-up. In 2011helicopter-borne TEM and magnetic sur-

veys were carried out. During these surveys many new conductive bodies wereidentified, and subsequent drilling hasresulted in very encouraging results withseveral new nickel occurrences. Tract C1 is

ranked number 1 among all assessedtracts for conduit-type nickel deposits.Consensus bid on tract C1 resulted, at a50% confidence level, in one conduit-typenickel deposit.

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Nickel exploration and drilling in the Maniitsoq Norite Belt in 2012. Photo: North American Nickel Inc.

Location Tract no.

Areal extent[km2]


di!erent con"dence levels Mean estimate of undiscov-ered resources [metric tons]

RankN90 N50 N10 N5 N1

Number of

deposits

Deposit density

Statistic calculation of:


Innartivaq (Tasiilaq) I1 >500 0 0 0 1 2 0.11 0.000021 26,000 1 Kap Edvard Holm I2 >500 0 0 0 1 2 0.11 0.000021 1 Qaqujârssuaq I3 >500 0 0 0 0 1 0.03 0.000006 2

CopperNickel

Summary of assessment results including consensus bids on undiscovered contact-hosted nickel deposits in Greenland and statistically derived estimations.

26,0008,100

53,00053,00020,000

Undiscovered contact-type nickel deposits

This type of mineralisation is characterisedby being associated with very large maficand ultramafic complexes. Subsequently,the assessment panel found it appropriateonly to focus on this type of complexesand a threshold value of 500 km2. Onlythree complexes were found to meetthese criteria.

Tract I1 constitutes the ArchaeanInnartivaq gabbro-diorite-tonalite-granite intrusive complex north ofTasiilaq, South-East Greenland. The com-plex is presumed to be emplaced early inthe Proterozoic evolution of the Nagssug-toqidian orogeny in South-East Greenland.Minor sulphide occurrences, includingpentlandite mineralisation, have beenfound in small gabbroic bodies within thecomplex. The complex is hosted north of asupposed Palaeoproterozoic crustalboundary. The complex has not beeninvestigated.

Tract I2 the Palaeogene Kap EdvardHolm complex, South-East Greenland,covers c. 800 km2 and constitutes a large

layered, tholeiitic gabbro complex thatsubsequently was intruded by syenite,granite and wehrlite that reflect multiplemagma pulses injected over an extendedtime period. The complex is hosted byPrecambrian gneisses, near a supposedcrustal triple-junction. There is evidencefor crustal contamination, including sul-phur-rich sediments. Exploration in thecomplex has identified a c. 40 km longgold and platinum anomalous zone.

Tract I3 hosts the Archaean Qaqujârs-suaq complex, south of Thule, North-West Greenland. The complex coversmore than 1,000 km2 and is mostly madeof anorthosite but also contains gabbroand leucogabbro. The complex is intrudedinto gneisses, iron formations andmetasedimentary rocks. The complex isvery poorly known and has not seen anyexploration.

Concluding remarks

Greenland comprises geological environ-ments that are highly prosperous for nick-el mineralising processes. Considering thehistorically limited exploration activities

that have been carried out in many partsof Greenland and the limited amount ofdata and information that are available,the assessment still resulted in an estimateof undiscovered nickel deposits and anassociated nickel endowment that can beconsidered significant and warrants fur-ther opportunities and exploration. Whenthe few historical exploration campaignsthat have been directed towards nickelmineralising systems in Greenland, e.g.those on the West Greenland Flood BasaltProvince and those within the ManiitsoqNorite Belt, are taken into consideration, itis worth noticing that each new campaignhas resulted in new targets for nickel. Thisis mainly due to technical advancementsin geological models and the availablegeophysical methods. Recent and on-going exploration campaigns have thusresulted in identification of new nickeldeposits that might represent larger nickeldistricts. The assessment of undiscovered

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Massive sulphide sample from diamond drillhole MQ-13-026 at the Imiak Hill occurrence,part of the Maniitsoq Norite Belt. The sample,which comes from 158.5 metres down thehole assayed 5.26% Ni, 1.78% Cu and 0.18%Co. Photo: North American Nickel Inc.

Coarse-grained pyrrhotite-pyrite-pentlandite-chalcopyrite mineralisation from Imiak Hill. Photo: NorthAmerican Nickel Inc.

Key references

Barnes, S.J. 2006: Komatiites: Petrology,

Volcanology, Metamorphism, and Geochemistry.

Society of Economic Geologists, Special

Publication 13, p. 13-49.

Barnes, S.J., 2006: Komatiite-Hosted Nickel Sulfide

Deposits: Geology, Geochemistry, and Genesis,

Society of Economic Geologists Special Publication

13, 2006, p. 51-97.

Barnes, S.J. & Fiorentini, M.L. 2012: Komatiite

Magmas and Sulfide Nickel Deposits: A

Comparison of Variably Endowed Archean

Terranes. Economic Geology 107, p. 755-780.

Garde, A.A., Pattison, J., Kokfelt, T.F.,

McDonald, I. and Secher, K. 2013: The norite

belt in the Mesoarchaean Maniitsoq structure,

southern West Greenland: conduit-type Ni-Cu

mineralisation in impact-triggered, mantle-derived

intrusions? Geological Survey of Denmark and

Greenland Bulletin 28, p. 45 – 48.

Larsen, L.M. & Pedersen, A.K. 2009: Petrology

of the Paleocene Picrites and Flood Basalts on

Disko and Nuussuaq, West Greenland. Journal

of Petrology 50, p. 1667-1711.

McCuaig, T.C., Beresford, S., Hronsky, J. 2010:

Translating the mineral systems approach into

an effective exploration targeting system. Ore

Geology Reviews 38, p. 128-138.

Naldrett, A.J. 2004: Magmatic Sulfide Deposits:

Geology, Geochemistry and Exploration, Springer,

Heidelberg, 728 pp.

Rosa, D., Stensgaard, B.M. & Sørensen, L.L.

2013: Magmatic nickel potential in Greenland.

Reporting the mineral resource assessment work-

shop 27-29 November 2012. Danmarks og

Grønlands Geologiske Undersøgelse Rapport

2013/57, 134 pp.

Secher, K. & Stendal, H. 2010:Greenland’s nickel

resource potential. Geology and Ore no. 17, 12 pp.

Schulz, K.J., Chandler, V.W., Nicholson, S.W.,

Piatak, Nadine, Seall, II, R.R., Woodruff, L.G.,

and Zientek, M.L., 2010: Magmatic sulfide-rich

nickel-copper deposits related to picrite and (or)

tholeiitic basalt dike-sill complexes - A preliminary

deposit model, U.S. Geological Survey Open-File

Report 2010–1179, 25 pp.

Stensgaard, B.M. & Sørensen, L.L. 2013:Mineral

potential in Greenland. Geology and Ore no. 23,

12 pp.

Thorning, L. 2012: Greenland Mineral Resources

Portal, www.greenmin.gl. Fact Sheet no. 26, 2 pp.

Zientek, M.L., 2012: Magmatic ore deposits in

layered intrusions—Descriptive model for reef-

type PGE and contact-type Cu-Ni-PGE deposits,

U.S. Geological Survey Open-File Report

2012–1010, 48 pp.

nickel deposits also concluded that num-erous tracts are highly prosperous for nick-el, but more investigations and data areneeded to increase the certainty withwhich to evaluate the favourability ofthese tracts. Greenland is especially

enriched in geological environmentsfavourable for hosting conduit-type nickeldeposits. However, environments forkomatiite-hosted nickel deposits are alsopresent, although to a lesser degree.

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Front cover photographIn the inner parts of the ScoresbySund area(70°N) the lowest units ofthe plateau basalts rest directly ongneisses from the Caledonian foldbelt. The basalt succession shown isabout 800 m thick.

Ministry of Industry and MineralResources (MIMR)Postbox 1601 Imaneq 1A, 2013900 Nuuk Greenland

Tel: (+299) 34 50 00Fax: (+299) 32 43 02E-mail: [email protected]

www.bmp.gl / www.naalakkersuisut.gl

Geological Survey of Denmark and Greenland (GEUS)Øster Voldgade 10

DK-1350 Copenhagen KDenmark

Tel: (+45) 38 14 20 00Fax: (+45) 38 14 20 50E-mail: [email protected]: www.geus.dk

AuthorsBo Møller Stensgaard, Lars Lund

Sørensen, GEUS

EditorsLars Lund Sørensen, GEUS

Graphic ProductionHenrik Klinge Pedersen, GEUS

PhotographsGEUS unless otherwise stated

PrintedNovember 2013 © GEUS

PrintersRosendahls • Schultz Grafisk a/s

ISSN1602-818x

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Drill rig and casings used in connection with Vismand Exploration Inc.’s drill programme onNuussuaq in 2007. The aim was to locate nickel-enriched, deeper-lying, lava conduits that con-nect to successions of contaminated flood basalts.

magmatic nickel potential in greenland · the former bmp, university of aarhus and private...

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