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The geology of the northern part ofthe Huachuca Mountains, Arizona
Item Type text; Dissertation-Reproduction (electronic)
Authors Alexis, Carl Odman, 1918-
Publisher The University of Arizona.
Rights Copyright © is held by the author. Digital access to this materialis made possible by the University Libraries, University of Arizona.Further transmission, reproduction or presentation (such aspublic display or performance) of protected items is prohibitedexcept with permission of the author.
Download date 27/03/2021 18:16:02
Link to Item http://hdl.handle.net/10150/565345
THE GEOLOGY OF THE NORTHERN PART OF THEHUACHUCA MOUNTAINS, ARIZONA
Carl 0. Alexis•i
A Thesis
submitted to the faculty of the
Department of Geologyin partial fulfillment of the requirements for the degree of
Doctor of Philosophy
in the Graduate College, University of Arizona
1949
ApprovedsDirector of Thesis D a ^
SIT TO THAT TATnTAOT TUT TO YO'XIO-TD TATAuOSIHn ,?AKAmTa t AOiniOSJii
Xv2>:-:c£A .0 A-\ 3
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CONTENTS
In'broduction ......... . .,.,... . .,..,..., .. ,,
Location .
Culture . . . . . . . . . . . . . . . . . . . . . . .
Transportation...... ...............
Drainage
Topography .............. ......... .....
Flora .............................
F a u n a ............................
Previous investigations ..............
Purpose and scope of the examination .,
Field work ......... ....... ....... .
Acknowledgments ................. .
Stratigraphy ........... ............... ....
Pre-Cambrian rocks ...................
Cambrian sedimentary rooks ...........
Bolsa quartzite ......... .
Cochise formation ...............
Abrigo formation •. . .....,... .. . .
Devonian sedimentary rocks ...........
Mis sis sippian sedimentary rocks ......
Pennsylvanian sedimentary rocks ......
Permian sedimentary rocks
Lower Cretaceous rocks . . . . . . . . . . .
Parker Canyon section ........
2 0 3 2 4 %
ZagS... 1 ... 1 ... 1 ... 2 ... 2 ... 3
... 3
... 4
... 4
... 4
... 5
... 5
... 6
... 7
• •• 7
... 7
... 9
... 11
... 12
... 13
...13
,...16 ... 16
Stratigraphy (contd)
Limestone conglomerate formation ......
Lower elastic formation..........
Limestone formation .................
Upper elastic formation ...............
Correlation of the Cretaceous section .. ........
Distribution of Lower Cretaceous volcanic rocks
Tertiary rocks ........... .
Tertiary volcanic rocks....... ........ .
Gila conglomerate ........... .
Quaternary rocks ••••••••••••••«•••••••••••«•••
Igneous racks
Pre-Cambrian granite .........................
Lower Cretaceous volcanic racks
Parker Canyon section ................ .
Volcanic flow in Blackt&il Canyon .....
Tertiary volcanic racks ..........
Post-Cretaceous intrusive racks ....
Geologic structure ............. ......... .
Structure elements .................
Folds .....................«••«••••••
Rough Canyon anticline ......
Rough Canyon syncline .......
Drag folding ................
Folding of the Tertiary rocks
Page17
2023
25
26 28 29
29
30
32
33
. 35
. 35
. 37
. 38
. 39
. 41
. 41
. 41
. 41
. 41
. 42
, 43
.Page
Faults .. ..... . 44
Huachuca Canyon fault 44
Crest Line thrust fault ....................... 45
Basin Range fault ............................. 47
Lyle Peak fault 48
Lone Mountain fault structure 49
Structural history 50
Pre-Laraaide structures ....................... 50
Post-Permian Pre-Cretaceous, structure .... 50
Cretaceous structures ..................... 52
Laraad.de folding 53
Post-Laramida structures ................ ••••.« 54
Physiographic history 56
Ore deposits 63
Water supply ....................... 67
Bibliography ............................... 72
ILLUSTRATIONS
PLATES
1. Geologic map of the northern part of theHuachuea Mountaiae, Arizona ......................... In pocket
2. Geologic structure sections of the northern : part of the Huachuea Mountains along linesshown on Plate 1 .................................... In pocket
3. Index map (Arizona, New Mexico and northern Mexico., In pocket
4. Map of Benson and Hereford Quadrangles, Arizona(showing elevation of water table) In pocket
5# Generalized columnar section Huachuea Mountains,Arizona ............................................ In pocket
6. Stream piracy northern end of the Huachuea: Mountains ......... ............ ....... . In pocket
(following page 74) ;
7. A. Bobocomarl ValleyB. Northern end Huachuea Mountains
8. A. Summer thunderstorm over Huachuea Mountains.B. Summer thunderstorm over Mustang Mountains.
9. A. Southwest flank Huachuea PeakB. Northwest flank" Huachuea Peak
10. A. South side Garden CanyonB. South side Huachuea Peak
lie ki Cambrian Bolsa quartzite B. Cambrian Bolsa quartzite
12. A. Mississippiah Escabrosa limestone faulted over CambrianAbrigo formation
B. Cambrian Abrigo formation
13. A. Permian limestones on Lyle PeakB. Permian, limestones in Garden Canyon
14. A. Lower Cretaceous limestone conglomerate formationB. Transverse section of Araucarioxdvlon sp.
15. A, B,
16. A, B,
17. A, B,
18. A, B,
19. A,
B,
20. A, B,
21. A, B,
22. A, B,
23. A, B,
24. A, B,
25. A, B,
26. A, B,
27. A, B,
28. A B
ILLUSTRATIONS
Plates
Radial section of Arancarioxvlon sp.Tangential section of Arancarloxylon sp.
Oyster bed in Lower Cretaceous limestone formation Same as above
Ostrea ragsdalei Glauconia branneri
Northwest nose of the Rough Canyon anticline Same as above
Lower Cretaceous lower clastic formation near head to Huachuca CanyonLower Cretaceous upper clastic formation in Parker Canyon
Lower Cretaceous strata near head of Algerita Canyon Same as above
Tuffs and sandstones in Tertiary volcanic rocks Closer view of above
Tuffs and sandstones in Tertiary volcanic rocks Tertiary rhyolite porphyry flow ;
Pliocene Gila conglomerate Pliocene Gila conglomerate "
Boulder of conglomerate in Pliocene Gila conglomerate
Fine grained equivalent of Pliocene Gila conglomerate Same as above.
Crest Line thrust fault in Garden Canyon Same as above.
Crest line thrust fault on Huachuca Peak Same as above
Basin Range fault Basin Range fault
Plates
ILLUSTRATIONS
29* A, Basin Range faultB. Basin Range fault
Sags• ' >.o
Figures
!• . Geologic occurrence of springs in the Manila Mine Area...*, 70
2* Geologic occurrence of springs.in the Huachuca Mountains •• 71
•1<
INTRODUCTION
: v.'r Location L '
The Huachuca Mountains are in southeastern Arizona, where they fora
a northwest trending range about twenty miles long. The range lies in
the southwest corner of Cochise County. The Huachucas extend from Lat. 31° 20* N 0# Long. 110° 16* W. ( a point on the Mexican border) to Lat.
31° 36' N., Long. 110° 27' if.
The area mapped is about 10 miles square. It extends one to two
miles out from the base of the range on the north and east. The south
ern boundary is Garden Canyon, which flows eastward, and Copper Glance
Canyon, which flows westward. The area extends two miles west of Cochise
County into Santa Cruz County. All of Township R* 19 E,, T. 22 S., and
parts of Townships R. 19 £., T. 21 S.j R. 19 £., T. 23 S.j R, 18 E.,
T. 21 S.j R. 18 E., T. 22 S.j R. 18 E., T. 23 S.j R. 20 E., T. 21 S.,
and R. 20 E., T. 22 S. are in the area, making a total of approximately
100 square miles.
Culture:
Ranching and mining are the principal activities in the Huachuca
Mountains. Until 1947 the northern portion of the range was part of the
Fort Huachuca Military Reservation, which during World War II had a com
plement of fifteen to twenty thousand' men.
' ■' Transportation ’-r - v - ;•,
- -v ' ” ■ v; ' .• , : ' W ' ' - . : - ""The Douglas-Tucson line of the Southern Pacific Railroad runs up
the San Pedro River Valley, Fort Huachuca is connected with it at Lewis
Spring by a spur line fourteen miles long, A paved highway connects
Fort Huachuca with Tombstone, Bisbee, and Tucson. This road runs parallel
to the eastern front of the Huachuca Mountains. The northern, western,
and southern flanks of the range are served by graded roads, A road
passable by a small truck or jeep runs through the range up Garden Canyon
and down through Scotia and Copper Glance Canyons.z::y:.r \ " / -y: ■ y-., yy -y ;"y y-. ‘
v i-yy Drainage y,- ;
The east flank of the Huachuca Mountains is drained by streams
flowing eastward into the San Pedro River, which lies about ten miles
from the base of the range. The San Pedro flows northward and north
westward to the vicinity of Winkelman, Arizona, where it empties into
the Gila River,
On the west flank of the Huachucas the drainage goes into two
separate basins. The one to the north is formed by the Huachucas on
the east and the Canelo Hills to the west and south. The Bobocomari
River and its tributaries in Sycamore Gulch (Lyle Canyon) and O'Donnell
Canyon, drain this area, carrying the flow northward and eastward into
the San Pedro River,
The southern basin is bounded on the northeast and east by the
Canelo Hills and the southwestern flanks of the Huachuca Mountains, on
the north by the hilly volcanic area lying between the Canelo.Hills.and
-3-
the Patagonia Mountains, and on the west by the Patagonia Mountains.
This basin is drained by the Santa Cruz River, which flows southward
into Mexico, then west and north, re-entering the United States nearto too.- 15 3t. i v.-" 5.1 US,
Nogales, and farther north, passing through Tucson.ov;-:y, It; oot-tu OX: ;;o:;r-c xl ihx flol't tno
rol L '• loo' t-:.-.:,-'.-0 ' - Topography limvr roocxotoo.
.. : •• .a .'aa : x vlAa. a■ :,a : ; . a .The Huachuca Mountains rise abruptly from the gently sloping
5 ^ - a r t pui oog o t M.-t t a . a t a l a V-'.-d" C - 'tax taaotpediment surrounding them# The break between the pediment and the
hy .-ra'.vat:::'* v -ta I '-n '- t l / ' r - t ; p o e t t ; ; arange is at an elevation of about 5100 feet on the eastern and northern
flanks and near 5500 feet oh the western flank. From these elevations
the peaks in the northern.part of the range rise to 8400 feet. The peaks
in the southern part of the range are somewhat higher*XU yuOu-'X ..x'l ;u:: u/ .'uu :.".u:' ■ ?.>/ 5':x:: X. 5' xx,;,. ' -IXy :■ xv
Canyons on the east flank of the range have been cut back two-thirdsthe '::x V; 3 . "h. T XX-1'G: ■ ulx X ••’"'X'XX^ ":V; / . X ,X'. lu XXX.;.,:of its width# The principal ones are Huachuca Canyon (Post Canyon) andv; . C/'x x x n x x x : -xx- ;;.xx ;hx 5xxlxx:x X: ux.X.lxx, Yh’ r.yxxr ' XX X-.Garden Canyon (Tanner Canyon)* The pass at the head of Garden Canyon isO'/'1 u-u-uX • IxxX'Xu V-X';xx:- :: XX': hx'-,'X,~ ^X.CXpV ..Xr X-'- T'.TXuVx XX X‘ -.UX''.uat an elevation of 6550 feet,7X,xx;.- ; x: x: .uxox ox' thx orxux;; 'Ix-x - Ixxxl, - xx .x. xxo 5- ■,» xuu^xjx xx x
-xxX, . Flora
The flora of the Huachucas; represents three zones> controlled by the
amount of annual precipitation in each# Since the amount of annual preci-X : , X ; XX: ...u; ul .XYx: - X ;-:-:.-:,:;.;'.:.1 :-x xxx-::'X l:,;;. uX
pitation increases with elevation, these zones appear at definite altitudes*
In the order of increasing elevation they are: the grasslands zone,-the oak
woodland zone, and the conifer forest zone# ; A detailed description of these
zones is given hy Darrow*^ ' x :.,xx Uxx : l :'7x 1: x:.x.
1# Darrow, R.A«, Arizona range resources and their utilization, I, Cochise Countys Univ. of Ariz., Coll, of Agri., Tech. Bull. 103, 1944.
Fauna
Because the Fort Huachuca Military Reservation has been "out of
bounds8 to hunters from 1881 to the present time, the natural wild life
has been preserved in this area. During the course of the field work the
following animals were observed: deer, mountain lion, coati, peccaries,
squirrels, rabbits, gila monster, and snakes.
Detailed descriptions of the mammals and birds of the area are 2 3given by Cahalane and by Swarth respectively.
Previous Investigations
- The Huachuca Mountains were mapped on a reconnaissance basis for
the geological map of Arizona by Dr. Carl E. Lausen. This map shows
the areal distribution of the pre-Cambrian granite, the Paleozoic rocks,
the Cretaceous rooks, and the Tertiary volcanics. No reports or records
of previous investigations are known, except for the reports on ground
water in the offices of the Ground Water Division of the D. S. Geological
Survey in Tucson, Arizona.
Purpose and Scope of the Examination
This report is the result of a field investigation undertaken in: ' : - • ' - . ... ... . : - 2 3 *
2. Cahalane, V.H., Mammals of the Chiricahua Mountains, Cochise County, Arizona: Jour, of Mamaology, Vol. 20, pp. 418-439, November, 1939.
3. Swarth, H. S., Birds of the Huachuca Mountains: Pacific CoastAvifauna No. 4, Cooper Ornithological Club of California.
partial fulfillment of the> requirements for an advanced degree at the
University of Arizona# Its main purpose was to determine the structure
of the Huachuca Mountains# v ,
The stratigraphic study of the Paleozoic formations was confined toidentification of the formations present in order to show their boundaries
/
on the geologic map. The Cretaceous strata were studied in greater detail
because they are unusually thick for this part of Arizona, and because
they are not as well known as the Paleozoic strata#
... " " ' ' Field Work ^ " ' ' '
Field work during the summer of 1947 was confined to an area north
of Huachuca Canyon and east of the crest of the range* This area did not
include all of the features critical in working out the problem, there
fore, during the winter and spring months of 1947-48 the study was extend
ed south to Garden Canyon and west to the southern part of the Canelo
Hills# The last field work done was in February and March, 1949.
Acknowledgments
.... Many people aided the writer in preparing this report* Officials
of the U# S« Army, War Assets Administration, the University of Arizona,
the U# S# Forest Service, and the U# S. Geological Survey, Ground Water
Division, performed various services for the writer which made this
investigation.possible* Permission to work in the area, maps, and
reports were obtained from these sources# .
Menbere of the Department of Geology and Mineralogy at the
University of Arizona, both faculty and graduate students, were
freely consulted during the preparation of this report, and all gave
material assistance* Dr* E, Sw Butler, Dri A« A. Stoyanow, Dr* E, D*
Wilson of the Arizona State Bureau of Mines* and Professor E* D. McKee
accompanied the writer into the field on various occasions» Dr, /
Short arai Mr* C.J* Peng, graduate student in mineralogy, aided in the
thin section studies of the igneous rocks*
Appreciation is expressed to Mr* Robert Weber and Mr* Donald
Blackjj both graduate students in geology, for information and photo
graphs supplied by them. - : • - ' ' ; ' : '
Residents of the area were all hospitable and generous in giving
information which materially speeded up the field work®
^ - STRATIGRAPHY
Paleozoic, Mesozoic, and Cenozoie strata are exposed in the
northern part of the Huachuca Mountains* Paleozoic formations are
correlated with corresponding rock units present elsewhere in south
eastern Arizona, but they are so strongly faulted and folded that only
rotigh approximations of their thicknesses can be obtained* Until an
accurate, large-scale topographic map is available on which to show ' -
details of structure affecting the Paleozoic rocks, these stratigraphic
units can not be measured* In the Whetstone5 Mountains, which'lie to the
north of the Huachucae, Paleozoic formations are much less disturbed*
The section there closely resembles in character that in the Huachucas
and appears to b® of the- same approximate thickness* : - .
The Mesozoic era la represented in the Huachucae by rocks of Lower
Cretaceous age# : The principal section of these strata Is well exposed1
on the western slope of the mountains and Is relatively undisturbed by
faulting# Cenosoic beds are of two types: (l) volcanic flows and agglo
merates, and (2) later, semi-consolidated conglomerates and gravels which
are tentatively correlate! with the Gila conglomerate# -.
Pre-Cambrian Rocks
There are no .pre-Cambrian sediments exposed in the northern part
of the Huachuea Mountains# In other areas of southeastern Arizona, as
in the tihetstone Mountains, the Mule Mountains, and the Tombstone Hills,
the Pinal schist constitutes a part of the pre-Cambrian complex# This4schist was probably formed by the mmtamorphism of sedimentary rocks ,
The . pre-Cambrian age is represented in the Huachucas by a coarse
grained granite, almost pegmatitic in character# A detailed description
of it is given in the chapter on igneous rocks# . _
Cambrian Sedimentary Rocks
The lowest formation of the Cambrian sequence in the Huachuea
Mountains is tho Bolea quartzite, which lies on a surface of low relief
formed by the erosion of pre-Cambrian granite# The Bolsa quartzite crops
out in a continuous belt along the cast side of the range from the southern
limit of the area mapped to Blackball Canyon# It also.crops out on the
4« Butler, B#S#, et# al.. Geology and ore deposits of the Tombstone District Arizona; Ariz. Bur. of Mines, Gaol. Series 10, Bull. 143, p. 12, 1938*
...
ridge between the Manila Mine and Sycamore Gallon in the northwestern<L
corner of the range* Bald Knob is an outlier of/jsimilar quartzite, and
presumably is also Bolsa* It is located three quarters of a: mile north
of Garden Canyon and is near the Basin Range fault*
The nature of the contact between the Bolsa quartzite and the under
lying granite is best seen in Sycamre Canyon* Here the contact is not
obscured by float, as in most places* The pre-Cambrian granite is so
decomposed for two to three feet below the contact that it can'easily be
broken out with a pick. There is no fault gouge or evidence of movement
along this contact, so it clearly seems to be one of deposition.
The decomposed material is probably the old weathered surface upon
which the Bolsa quartzite was deposited.
Pre-Cambrian strata were folded and/ or faulted before deposition
of the quartzite-Bolsa. This relationship is shown in the Mule Mountains,
where Ransoms "’ found a strong angular unconformity between the Pinal
schist and the Bolsa quartzite* v:
The Bolsa quartette was formed by the cementation of buff-colored,
cross-bedded sandstones and conglomerates* In this area a basal con
glomerate with fragments varying in diameter from six inches to one foot,£
such as described by Ransoms from the Blsbee quadrangle, was not observed*
In the Huachucas the basal portion does not differ in any essential respect
from the remainder of the formation. Coarse gravel beds are found through
out the formation* Individual gravels are well rounded and are in most
5*. Ransome, F*L«, Geology and ore deposits of the Blsbee Quadrangle, Arizona* U.S. Geol* Survey, Prof. Paper 21, pp. 26-27, 1904.6. Ransoms, F.L.,-Geology and ore deposits of the Bisbee Quadrangle, Arizona: U.S. Geol. Survey, Prof. Paper 21, p. 29, 1904.
places not eiich larger* than a pea. Plate 11 shows the cross-bedding
and the coarseness of the gravel lenses* Concentration of dark
minerals In thin laminae or along crossbedding planes givesa grayish-
purplish cast to portions of the formation# V. - .
As no fossils have been found in the Bolsa either here or else
where in southeastern Arizona, the exact geologic age of the formation
Is not known* Conformably overlying it, however, is the Cochise''' for
mation which contains late mddle Cambrian fossila* The Bolsa quart- "
site is 430 feet thick in Bisbee and about 440 feet thick at Tombstone*
The Cochise formation, described by Stoyanow®, was not mapped as a
separate unit but was included in the overlying Abrigo formation* Its
presence in the northern part of the Huachuca Mountains .was established
by comparing strata there with the exposures of the Cochise formation
at the type locality which is the Whetstone Mountains*
z A blue limestone with algae-like spherical bodies similar to those
in the upper part of the Cochise formation in the type section, is well
exposed along the road in the lower part of Garden Canyon. In the Whet
stone Mountains the Cochise formation is 311 feet thick*
Lying conformably on the Cochise is the Abrigo formation* The
Abrigo is exposed as a continuous belt along the east side of the range
from Blacktail Canyon to and beyond Garden Canyon for an unknown dis
tance* It also crops out on the ridge between the Manila Mine and
Sycamore Canyon*
8* Stoyanow, A *4* Correlations of Arizona Paleozoic formations: Geol* Soc* America Bull., vol, 47, p. 466, 1936*
7* Stoyanow, A*A*, Correlation of Arizona Paleozoic formations: Geol*Soc* America Bull., vol* 47, p* 480,'1936.
■ The lithology of the Ahrigo formation is distinctive, so that the
formation is easily recognized in the field. The JLbrigo has a thin-bedded
structure produced by tl» alternation of thin, irregular beds of chert
with gray, greenish gray and yellowish gray limestones. Towards the
top of the formation the limestone beds aro more arenaceous. Sand
grains are etched out by weathering, giving the surface of the rock a
gritty feel.. The color of these higher beds is brown on freshly.broken
surfaces and rust brown on weathered surfaces. Individual beds of lime-
stone in the Abrigo are from one to three inches thick, while chert
layers are, in general, thinner. Plate 12 shows the thinbedded struc
ture of this formation.
The upper limit of the Abrigo formation, as mapped, is marked by
a prominent lithologic change expressed in the topography of the area.
Beds above the Abrigo contact are five to eight feet thick and have been
eroded back to form a series of lynches or steps which contrast strongly
with the twenty to forty cliffs of the thinbedded Abrigo formation below.
The beds above the Abrigo formation are sandstones and limestones. .
Fossils collected from the Abrigo formation in various localities „
in southeastern Arizona are of Upper Cambrian age^. ...
' ,, The thickness of the Abrigo formation as defined by Stoyanow^-® is
430 feet in the Whetstone Mountains and 420 feet in the Bisbee .quad- : ,
rangle. The symbol used for mapping in the Huachuca area, does not 10
10 Stcyanow, AJL«, op. cit., p. 480. . :
9 Stoyahow, A.A., Correlation of Arizona Paleozoic'formations: Geol*Soc. America Bull., vol, 47, pp. 467-469, 1936*
-11-
differentiate between th# Cochise formation and the Abrigo formation of -
Stoyanow and corrsspends to Abrigo limestone as defined by Ransom#, This
unit is therefore from 'TOO to 800 feet thick, >
The upper limit of the Abrigo does not mark the end of Upper Cambrian
deposition in Arizona, hying above it are the Copper Queen limestone
(81 feet thick) in Bisbee and the Rincon limestone.(42 feet thick) in
the Whetstone Mountains^, Since there were no fossils collected in
Cambrian beds above the Abrigo, they,were not separated from the Devonian
Martin limestone in mapping,
Devonian Sedimentary Rocks
: The Devonian Martin limestone lies with apparent conformity on
the underlying Cambrian formations. The Martin crops but from a point ,
approximately half way between Huachuca Canyon and Blackball Canyon to
and beyond Garden Canyon for an unknown distance. It is also found in
the Manila Mine area in the northwest corner of the range. In places it
forms part of the hanging wall of the Crest Line fault where it is folded
and faulted as the result of drag on the fault surface. The thickness in
this area is therefore difficult to determine. At Bisbee and Tombstone : -
the formation is 340 feet thick^, .. ;
. Lithologically the Martin limestone in the Huachucas is similar to
the type section in Bisbee, It is predominantly a dark gray compact 11 12
11, Stoyanow, A*A,, Correlation of Arizona Paleozoic formations: Gecl, Soc, America Bull,, yol. 47, P» 480, 1936,
12, Stoyanow, A^.,, Correlation of Arizona Paleozoic formations: Geol,Soc^ America Bull,, vol, 47, p. 486, 1936, / ..... .
-12-
limestone which weathers brown* on exposed surfaces* There are also
limestone beds of light gray and pink. The brown of the exposed sur
face serves to separate the Martin limestone from the light gray to ..
white Escabrosa limestone above and from the dark brown Abrigo formation
below. The exposure of Martin limestone in Garden Canyon is characterized
by the presence of small, well crystallized patches of calcite from one
to three inches across* The calcite is stained red by the inclusion of
hematite,:which causes it to stand out from the dark gray ground mass of
compact .limestone* : . \ ;
A number of fossils were collected from various exposures, and
these establish the age of the formation'in this area as Devonian* In
Huachuca Canyon a specimen of Spirlfer hunaerfordi was found, and in the
northwest corner of the range, about 220 yards south of the Manila Mine,
Atrvba reticularis was collected* * : . ■ v , :
Mississippian Sedimentary Rock®
The Escabrosa limestone is exposed on Huachuca Peak, in a small
area just north of Garden Canyon and also south of Garden Canyon* It
may be present in the Manila Mine area and in other places in the northern
part of the range* To the west it is cut off by the Crest Line:fault*13The Escabrosa limestone averages 700 feet in Blsbee and 500 feet in
24*Tombstone It was not measured in the Huachucas* The section exposed
14* Butler, B* S*, et al*. Geology and ore deposits of the Tombstone District, Arizona: Arizona Bur* Mines, Bull* 143, P* 14, 1938*
13# Stoyanow, A*A., Correlation of Arizona Paleozoic formations: Geol*Soc, Am. Bull*, vol* 47, p. 508, 1936.
.-13-
on Huachuoa Peak Is thick enough to Include all of the Esc&brosa and
part of the overlying Naco limestone* .: -., : v ;
The Bscahrosa is made up of thick bedded, cliff-forming, light gray
and white, massive limestone* A specimen of Homalouhvllitas sp. was
collected in it in Garden Canyon*
Pennsylvanian Sedimentary Rocks
The presence of the:Pennsylvanian Naco limestone on Huachuca Peak
is inf erred for two reasons* First, the section is thick enough above
the:Devonian to include not only a}l the Escabrosa but also 300 to 400
feet of the Saco, Second, the topographic expression of the beds above
the cliff-forming units definitely assigned to the Escabrosa is typical
of the Naco * The upper, beds are thinner than those referred to the
Escabrosa.and weather to a :series of steps or benches* In Bisbee the
beds of . k n o w Pemgylvanian age are 1180 feet thick. : . •
Permian Sedimentary Rocks'
' The nature of the contact between strata of; Permian and those of
Pennsylvanian age was not determined in the northern part of the Huachuca
Mountains * At no place i n :this area is there a continuous section in
which rocks of these ages form a continuous series* The top of the
Permian formation is probably absent, also. At the head of Garden
Canyon a pre-Cretaceous valley, cut in the Persian limestones," has :.
removed at least 2500 feet of strata. . : '
The Permian rocks are exposed at the head "of Garden Canyon, where
they are bounded on the east by the Lyle -Peak:fault, ’this’ fault brings
-14-
Permian and Cretaceous str&ta together, and are boundedon the west by the Cretaceous basal limestone conglomerate• Between these boundaries
Permian outcrops exterai in a nortitwest direction to a point roughly in
line with the extension of Huaehuca Canyon and in a southeast direction
off the area mapped* Other areas of Permian exposures are found in the'
northwest corner of the range west of Blacktail Canyon, where the Permian
beds hhve been thrust over Cretaceous rocks» . ^
The lowest Permian beds exposed in Garden Canyon are just west of
the Lyle Peak fault and consist of red, soft thin-bedded limestones*
Higher in the section along the Garden Canyon Road are cliffs of massive
gray limestone (see Plate 13)« A specimen of Euoiaphalus sp« was collect
ed here* ■ —- ■ - -• -• - • ••.*:..
At the head of the Cation, just west of the point where it widens
out to form Lone Cabin Valley, about 100 feet of black fetid limestone
is exposed* The outcrop is less than one hundred yards from the cabin ,
whence the valley gets its name* A well-preserved- specimen of. Orroholo-
trochus sp« was obtained here* Black, fetid limestone marks the top of ~ the Permian section at this point* Unconforrably above it lies Lower ? ;
Cretaceous limestone conglomerate« ' . v , v - -
At the northern end of Lone Cabin Valley Permian beds form the rim
of the valley, and the section continues to the west-northwest, exposing
an.additional.2000 feet of. Permian,sediments. These are.black.limestones,
varying in thickness from one. to-four feet* In the saddle between Lone
Cabin Valley and McClure Canyon, specimens of Meekella sp* were collected*
Farther up in the section and west of the saddle on a ridge leading to a
small unnamed peak, a fauna of small gastropods, haying the " Permian :
-15-
aspect” of Glrty1s Mansano fauna were collected# Lying batween the
black Permian limestones and the Lower .Cretaceous limestone conglomerate
are several hundred feet of red arkosic sandstones and red thin-bedded
limestones* The exact age of these bedsis unknown, but since they are
conformable with the underlying Permian limestones, they are probably, of Permian age also* . v. ' . ..x,
In HLacktail CEinypn Permian limestones are exposed on the west side
of that drainage on Sycamore Ridge. The only fossil remains found here
were a Productus sp. and many crinoid stems about half an inch in diameter.
Permian strata form the hanging wall of the Crest Line fault in this area
and are strongly disturbed by folding and/or faulting* x:.-i -x: 1
The Permian also crops out in the Manila Mine area. On the ridge
to the east of the mine Permian strata are faulted against the Abrigo
formation to the north and:are thrust over Cretaceous beds on the south*w .... - ' _ - >•*_..■ n - | ' ... , - - : - t w . •
Permian strata are - gray thick-bedded limestones with prominent chert beds*
These chert beds are irregular in thickness but are commonly from two to
four inches = thick. In places the chert forms nodules which when viewed at
a distance give the limestones the appearance of a conglomerate * Near the
top of the formation as exposed here is a brown quartzite about forty feet
thick. ;Quartzitebeds in the Permian sequence have been reported from16 17the Canelo Hills and the Empire Mountains « * 16
15
15* Glrty, G.H., Paleontology of the Mansano Group of the Rio Grande Valley, New Mexico $ U*S, Geol. Survey, Bull* 389# Plate XI, 1909*
16. Feth, _J*H* Permian stratigraphy and structure. Northern Canelo - Hills, Arizona: Am* Assoc* Petroleum Geologists Bull.,vol» 32# pp-88-99# fig* 3, 1948* ' ":: . :::
17* Alexis, C.O., Geology of the Lead Mountain area, Pima County,Arizona.j Univ* of Arizona Library, Master’s Thesis (unpublished) p. 1939
—16«* *
Fossils collected from- the limestone in this area are Echlnoconchus
sp», Productus sp.. and Agplexus sp#The Permian is also exposed to the south and west of the Manila
Mine, where it is"thrust over Lower Cretaceous beds* The Permian strata
are gray limestones with beds fro® one to four feet thick. Some quart
zite is also present* Fossils collected up the canyon fro® the McFadin
residence were Fenostolla sp*, Plaeioglypta sp. and-large crinoid stems*
- - ' - Lower Cretaceous Rocks
Lower Cretaceous sedimentary and volcanic rocks cover most of the
area west of the Crest Line fault and nearly all of the western slopes
of the northern part of the Huachuca Mountains.
The best exposures of the Cretaceous beds are found on the west
side of the range between Lyle Canyon and. Scotia Canyon. Here the beds
stand in a nearly vertical position and are well: exposed from their .
contact with the underlying .Persian limestones on ‘ the east, westward :
normal to tho strike for throe miles, where they are in contact with
Tertiary volcanic rocks and/or late Tertiary alluvium*
: Parker Canyon Sections In the northern'part of the Huachuca
Mountains the entire Lower Cretaceous section is exposed in Parker
Canyon east of the Montezuma Pass to Cenelo Hoad* Parker Canyon
crosses this road in the SW* corner of the MW* quarter of Section 17,
R* 19 E*, T* 23 S* The base of the section is at the head of Garden
Canyon* - The road from Garden Canyon across the range to Sunhyside is -
approximately normal to the strike of the Lower Cretaceous strata. ’
-17-
Follow the road to the Sylvanla Ranch and there cross the ridge to the
north which will put you at the head of Parker Canyon* Parker Canyon
was chosen for examining the section because of the excellence of
Lower Cretaceous fossils exposed in its walls#
; Lower Cretaceous beds in this area have been divided by the writer
into four formations, as follows; ..
Tertiary volcanic rocks and/or alluvium
Lower Cretaceous Feet: Upper clastic formation ............ . 4290 • ;
Limestone formation............. . 540 tVAVeLower clastic formation .............. 8000 " :Limestone conglomerate formation ..... 3300
Total ......16,130 :
Permian limestones J
The limestone formation is the only one definitely dated oh the
basis of fossils. It is of Lower Cretaceous (Trinity) age. The lower
clastic formation and the limestone conglomerate formation were included
in the Lower Cretaceous because Trias sic or Jurassic rocks have not as
yet been found in southern Arizona. The upper clastic formation was
included with the Lower Cretaceous because it lies conformably on the: :
limestohe formation. " 1 " '" '
The limestone cbnglOTOrate formation: The limestone conglomerate
crops out on the west side of the range near the ere st from a point
’which is approximately on the projection of the trend of Huachuca .
Canyon southeast to and beyond Lone Cabin Valley. It probably continues
to the southern end of the range and may be the same conglomerate as that
■18**
exposed near the top of Montezuma Pass• , .
The limestone conglomerate outcrops in several other localities
in the northern part of the Huachuca Mountains, but faulting has made
its exact nature obscure. Part of ■toe limestone breccia along the Crest-
Line* fault may have been formed from drag of this conglomerate. Hand
specimens of the limestone breccia and the limestone conglomerate can
not bo differentiated. The limestone breccia or conglomerate along
the Crest Line fault on Sycamore Ridge may be in sedimentary contact
with the Permian there. The ridge to the east and south of Woodyard
Canyon is capped with limestone breccia or conglomerate. It may result
from drag of the limestone conglomerate, or it may be a farigloserate
derived from an advancing thrust plate of Palesoic limestones and then
covered by the thrust plate*
.The following description of the limestone conglomerate is based
on studies of outcrops in Lone Cabin Valley, the head of Parker Canyon
and in Copper Glance Canyon. At these localities there is no doubtof its sedimentary origin, v - ^ ' ' ; f :
:• Tim conglomerate lies with strong erosional and structural uncon
formity on Permian limestones and red beds. At the head of Garden Canyon
2500 feet of Permian strata were removed before deposition of the lime
stone conglomerate, but one and one half miles northwest on Lyle Peak
these Permian strata are still present. To the south of Garden - C anyon
the thickness:of Persian rentoved by erosion appear t o b e greater than
2500 feet. This area was not mapped. -
The.limestone conglomerate is made up-of limestone boulders,' cobbles
•19-
and other gravels,■ fdiich in general, though not everywhere, show a ,
gradation in size dependent on its distance from the contact with the
underlying Permian. In the lower portion of the conglomerate, limestone,
blocks are larger than in the upper portion. Angular to subangular
blocks two to four feet long are not uncommon. The usual size range
is between three and eighteen inches. These smaller pieces are round-■■ ■ ■ - - ' - - ' - - •- - - ■ . , . ■ . .. :ed to subrounded in outline. The absence of rock types other than lime
stone and chert is remarkable.
. In the upper portion of the limestone conglomerate as exposed at
the head of Parker Canyon near, the contact with the overlying red shales
the conglomerate is finer. ..The larger blocks are absent, and the size
lunge drops to between eight and two inches. . The' matrix contains not
only limestone but also appreciable amounts of red shale similar to
that in the overlying beds, A zone separating beds containing mostly
limestone gravel from the overlying red shale which contains none is v -
less than six inches thick.
Volcanic activity during the deposition of the limestone conglomerate
is shown ty the presence of a vesicular flow about 2500 feet below the top
of the formation. The flow outcrops along the trail between the Sylvania
Ranch and Huachuca Canyon at a point southwest of Lyle Peak. Neither
its lateral extent nor its width were, determined.
Gravels composed of lirostone, volcanic rocks, quartzites, and
shales were found near the top of the limestone conglomerate in Copper
Glance Canyon. Here the limestone makes up less than half of the con
glomerate. The elastic materiel appears to have been derived from beds
similar to those overlying the conglomerate. The beds from which the
-20*
clastic and Tolcanic gravels were derived are not necessarily older than
the lower portion of the limestone conglomerate*
The source:of the limestone gravels.in the conglomerate is shown by
the fossils which are found in them. They include such Permian and Pennsy
lvanian forms as Dictyoclostus so., Euomhholus sol, and Beljlemphnp ep.
Ko definite evidence indicating the presence of Lower Paleozoic rocks in •
the conglomerate was found*
The topographic expression of the limestone conglomerate varies,,
depending on its limestone content. Where the conglomerate is composed
mostly of limestone, it forms high ridges# At the head of Parker Canyon
the limestone conglomerate rises so high above the more easily eroded red
shales and sandstones that it appears to lie horizontally on them# Hot
until the contact is mapped is it perfectly evident that the red shales
lie conformably on the limestone conglomerate#
The thickness of the limestone conglomerate varies between 1300 and
3300 feet in the northern part of the Huachucas# It appears to be even
thicker in the southern part of the range*
Lower clastic formation* Overlying the limestone conglomerate
conformably is a series of beds of red shale, sandstone or quartzite,
volcanic flows and a few thin limestone beds# The shales, sandstones,
quartzites and volcanic flows are found throughout the section but vary
in their relative proportions in various parts of the same section#
-21-
The section is as. follows t .
Idmestono formation . - v : : :r ' V,v
- Lower clastlo formation: • - ::: ;• . ;;; .m --.-; feet ;Andesite_flows (see chapter on Igneous rocks) 2000
v Red shale and brown to buff, fine-grained, : •. ■ ; vcroBC-bedded sandstones or quartzites in
■ nearly equal proportions .................. . 2000Dacite porphyry flow (see chapter on
igneous rocks) .............................. 300Red shale and brown to buff, fine-grained,
: crossbedded sandstones or quartzites innearly equal proportions .......................... 1700
• Red shale with subordinate amounts offine-grained, crossbedded sandstones and
.! quartzites, green and yellow shale . . . . . 500Dacite flow (see chapter on igneous rocks).......•.«« 300Red shale with subordinate amounts of
fine-grained cro s sbedded sand stones and quartzites, green shale and^yellowish shale ............ ..................,. 12CX)
...; ; , - , Total .................. 8,000 .Limestone conglomerate formation
'' Fossils" are very scarce in the lower clastic formation. A thin ; -
oyster reef was found just below the andesite flows in the upper portion •
of the formation but specimens were so fragmental that they could not
be identified specifically. The sand stone and shale beds are apparent
ly unfossiliforous except for petrified wood*
Petrified wood was found in a sandstone bed hear the base of the
section* The locality is just below the trams! of the Eureka M h e * J
The.wood m s identified by Mrs* R» A* Barrow of Tucson, Arizona, as
Araucarloxvlon sp. This is the genus which is found in the Triassic
-22-
Shinaruop conglomerate and Chlnle formations of northern Arizona ^
It is also the same genua collected by Stoyanow and identified by
Mrs* R* A* Darrow from the Lower Cretaceous Lowell formation in Bisbee,
Arizona. On the basis of wood structure alone it is not possible to make an age determination by using this genus*
The following description by Mrs. Darrow was based on thin sec
tions made of the wood: (See Plates 14 and 15*)
1. Annual rings not distinct*
2* Uniseriate and sometimes biseriate bordered pits (typical Araucarian pitting) on the radial walls of the tracheids*
3* Not pits on tangential walls*
4* Rays uniseriate, ftom one to eighteen or twenty cells high*
5* No branch traces in tangential section, thus ruling out genus Woodworthla*
The volcanic rocks described from the lower clastic formations in
Parker Canyon did not show conclusive evidence of their, extrusive origin*
It is possible that some are sills. Volcanic rocks exposed in Blacktail
Canyon and Bear Creek are clearly of extrusive origin. Their exact
stratigraphic position is unknown, but they are certainly in the lower
clastic formation.
An aBygdaloidal basalt in Blacktail Canyon lies southwest of the
Crest Line fault contact between the Permian and Cretaceous strata on the 18
18. Knowlton, F.H., The fossil forests of Arizona: American Forestry, vol* 19, p. 218, 1913*
19* Daugherty, L* H., The Upper Triassic flora of Arizona: Carnegie Institution of Wash. Pub. 526, pp. 86-89, 1941.
20* Stoyanow, A. A. personal communication, 1948.
east side of Sycamore Ridge and near the top. This basalt is described
in the chapter on igneous rocks.
During the; examination, o f t h e . lower. clastic. formation south of Lone
Mountain, the top of a volcanic flovr was found about two tenths of a
mile west of the Wakefield Camp. The concentration and increased size of
gas cavities toward the top of the.flow and.the flow,structure visible'
in the rock show its extrusive nature unmistakably. Further evidence is
that the sandstone which overlies the flow has not been altered at the
contact. . v ■ T • ■ : :: : V-'V; : .
Strati.graphically-higher in the lower clastic formation than the
flow in the Lone Mountain. area are beds of agglomerate. • These beds are
made up of pebbles and gravelo apparently deriyed from a volcanic flow
or flows similar to that described above. The prevalence of red in the
shales of the clastic formations may be :due in part at ; least to the
erosion of volcanic flows and the consequent oxidation of their iron
content. - Lr. ■ ; • yLimestone formation* The limestone formation lies with apparent
conformity on the lower clastic formation. It is 540 feet thick and
consists in greater.part of gray limestone beds. Associated o r ;inter-
bedded with the limestone are other beds of yellow to greenish yellow
shale o M brown sandstone or quartzite. In Parker Canyon the section
-24-
is as followsi
Upper clastic formation Feet
Limestone formationGray massive limestone in one to
three foot beds............ . 170Mostly sandstone or quartzite and
yellow to yellow green shales,remainder gray limestone........... . 200
Gray limestone in one to three footbeds with a few sandstone andshale beds.............................. 170
Total 540Lower clastic formation
In the upper part of the middle two hundred foot member are
several very fossiliferoua beds. : Reefs made up almost entirely of
Ostrea ragsdalei are present (see Plates 16 and 17). In the yellow
shales numerous specimens of Glaueonia branneri (Plate 17) are
present.' - ' • ' ' ■ 21Ostrea ragsdalei I s an index fossil for the Glen Rose , and
■ _ - •' * 22Glaueonia branneri occurs throughout the Trinity group . These
fossils were first reported from the Huachuca Mountains area by
Stoyanow •
The limestone formation was used as a marker in working out the
structure of the Cretaceous rocks. It was followed north from Parker 21 22 23
21. Hill, R. T., The paleontology of the Cretaceous formations ofTexas; The invertebrate paleontology of the Trinity division: Proc.Biol. Soc. Wash., p. 23, 1893.
- V - - - • : ' ::22. Hill, R.-T.,.op; cit., p.34
23. Stoyanow, A., Fossiliferous zones in the Cretaceous and Tertiary deposits of southeastern Arizona (Abstract): Geol. Soc. Am., Proc*,p. 2%, 1936; Lower Cretaceous stratigraphy in southeastern Arizona, Geol. Soc. Am., Mem. no. 36, p. 30, 1949
-25- .
Canyon to Woodyard Canyon, where it has almost 'pinched out* At the '
last outcrop mpp®4 it is less than twenty feet tMck,: whic& suggests '
that the jnorthern end of limestone depositicn is reached here* r ' "
Upper clastic^ formation: The upper clastic formation lies with
apparent,conformity on the limestone formation. The section as measured
in Parker Canyon is as follows* ij v^.v^'-vy
Tertiary alluvium - •
1 ' C l
: 3 v /• • Feet'
Upper clastic formtion . : , r.--. ; ; : ■ - - 'Volcanics (?), red shale and arkosic
sandstone .................. .............. • 1001 Covered by float and pediment
, . gravels .... .. . i V 1190Several beds of conglomerate with
rounded to subrounded pebbles of v- ^ ^volcanic material (see Plate 10) interbodded with red, yellow and brown shale beds 750
Mostly brown to buff, fine-grained crossbedded sandstones with red ;shale and volcanic flows (?) .............. 1350
Red to purple shales with some buff.fine-grained sandstone beds ............... 900
Total_;.........^-4,290
■I
, hi; -'ii
r : ; Llmstone formation IV.:- . V h nblrlll;-" 1, - 1 - he
;:i’i. hiiviivi;-: .1 i;:"'1} '‘h
In' Ferosa. Brushy and Algerita Canyons the upper clastic formation
contains beds of conglomerate made up in part of limestone gravels.
probably derived from Paleozoic formations• 1The componentsfof t6eT l i . >" * •* . : - ' . :
hfirv^i l'. rv./
conglomerate average less than three inches in length and are rounded
to subrounded-in outline. Most of the•conglomerate appears to have
been derived ftrom older Cretaceous fornatiohs*
-26-
In Parker Canyon there_ls a gap of one mile between the western-
most outcrop of nearly vertical- Cretaceous beds and the relatively flat-
lying Tertiary volcanic rocks. ; In order to determine the nature of this
contact, the southern end of Lone Mountain was examined. Lone Mountain
is south of the area mapped and is the southernmost outlier of the Canelo
Hills. The mountain is essentially a down-dropped block of Tertiary
volcanic rocks, mostly agglomerates, within the Cretaceous section.
This suggests that the contact between the Tertiary volcanics and the
Cretaceous beds in Parker Canyon may also be on a fault. If such is the
case, tire sedimentary contact between Cretaceous strata and Tertiary i
volcanic rocks will not be found in this area. In the Northern Canelo24 -- ; -Hills, Feth has reported a structural unconformity between these for-
•' - '• ' , - - •nations.
Correlation of the Cretaceous Section
The following correlation table is based on information collected by: 1- : ' ' : " '25 : , ■/ ;Inlay from his work in Sonora and various other published sources.
The thickness of the Upper Cretaceous in the Cabullona area is taken from26 " ! "■ ..... - • ' - :.-'Taliaferro • The Cretaceous section in the Huachuca Mountains is includ-
■ : c : - :ed for comparison. ; f * 25 26
24* Feth, J.H., The geology of the Northern Canelo Hills, Santa Cruz County, Arizona, Ph.D. thesis, 1947, pp. 41-45.
■■ : : ■; !■; : : ' 1 :25. Imlay, R. IT., Paleogeographic studies in northeastern Sonora: Geol.Soc. Am. Bull., vol. 50, pp. 1736-1738, 1939. ;
26. Taliaferro, N.L., Upper Cretaceous sediments in Mexico: Jour.Geol.,vol. 41, p. 16, table lj 1933. y j
•27-
Cintura
CRETACEOUS OF SOUTHEASTERN ARIZONA AMD HOBTHBigrRmf RQHORA. - . : : ' ' ;
• . ■Blebee,Arisona
1800
Cabullona Area Sonora
i Sierra de i San Jose,Sonorat '_______
(Siena de : los Ajos, i Sonora
UpperCretaceous3,000
!t(I
Huachuca Mountains, Arizona
UpperClastic 4290 Lower
Cretaceous
Mural * 650t
t 1,4001Sl
Present*i Present
"!i|
*----— --- ------- ------------Linestone 540-20
• formationf - -. - :.. .-. - . .- -.-.■ .. -. -.-.—i 1 Several t t LowerMorita $ 1800-2000 i 5,000 i*
2,000 1 thousand lt
t clastic 8000 Lower Cretaceoust - - ' - ... -_____- ..... ....
Glancet v •': 0-1500 i 2,500-3000
$i , * 5,000
1$ (( Limestones 1 t conglomerate 1300-3300
Conelation of Cretaceous in Sonora and southeastern Arizona (after Inlay and others)•
All thicknesses in feet.
Cretaceous section,Huachuca Mountains (this paper)
-28—
Distribution of Lower Cretaceous Volcanic Rocks .
Volcanic flows in the Lower Cretaceous have been described by 27L&sky . from the Little Hatchet Mountains, New Mexico. This area lies
80 miles cast northeast of Biebee. The Cretaceous beds there are rough
ly equivalent in age to the Bisbee group, but differ from it by being
much thicker (13>000 to 24>000 feet) and-by containing several volcanic
flows. Ransome* s subdivision of the Bisbee group could not be used in
this area. Several periods of erosion occurred during their deposition,
resulting in wide variation in the thickness of individual formations.
southern Sonora.near Arivechi, which is approximately. 170 miles south of
the International Boundary, near Douglas, Arizona. This section totals
10,000 feet in thickness and consists of-coarse" sandstones, shales, -
andesitic lavas and limestones. ; .
Volcanic rocks have been reported among rocks believed to be of Lower
Cretaceous age in the Courtland-Cleeson region northeast of Bisbee by 29Wilson • Here thin andesite flows (?) occur in a thick succession of
clastic rocks. ..." v 27 28 29
27. Lesley, S.G., Geology and ore deposits of the Little Hatchet Mountains, Hidalgo and Grant Counties, New Mexico, U. S. Geol. Survey, Prof. Paper 208, pp. 1-2, 1947.
28. King, R« E., Geological reconnaissance in Sierra Madre Occidental of Mexico: Gaol. Soc. Am. Bull., vol. 50, Plate 5, 1939.
29. Wilson, E. D., Geology and ore deposits of the Courtland-Gleeson region, Univ. Ariz. Bull. 123, pp. 21-22, 1927.
found volcanic rocks in the Lower Cretaceous section of
-29**
Tertiary Rocks
The Tertiary rocks of the Huachuea Mountains are divided into two
main groups• They are the Tertiary volcanics and the Gila conglomerate*
The contact between the two was not observed, but the Gila conglomerate
contains material derived from the Tertiary volcanics and is therefore
younger* The Tertiary volcanics lie in the southwest corner of the area
mapped* Access to the area is by a road leading to the Hathaway Ranch
buildings* This road joins the Montezuma Pass to Canelo Road where the
latter crosses Parker Canyon*
Tertiary volcanics form the first line of low hills to the wost of
the northern part of the Huachuea Mountains where they are called the
Canelo Hills* The area mapped is the southern end of the Canelo Hills*
The trend of the hills is west northwest* The Montezuma Pass to Canelo
Road follows the lowest area between the Huachueas and the Canelo Hills
and roughly marks the eastern limit of the volcanic outcrops in the area
mapped.
The volcanic rocks give the. hills an overall red to brown color* As *
exposed in Parker Canyon and in Collins Canyon they are mostly rhyolite
porphyry flows with minor amounts of tuffs and volcanic agglomerates* In
parts of the flows, pieces of solidified volcanic material have been incor
porated and arranged parallel to the line of flow, (See Plate 22.) Several
hundred feet of gray to red tuffs and agglomerates are exposed in Collins
Canyon, Some of the tuffs have been laid down in beds i to one inch thick.
Flagstones up to two feet long can be broken out of these beds (See Plate
22)* The volcanic agglomerate in.Collins Canyon is not thick*., It con-
.30-
taint? a few cobbles-of Paleozoic limestones* --
Thin sections were made of the rhyolite porphyry flow and the tuffa-
ceous sandstone* Their description is given under igneous rooks;-
The volcanic agglomerates in the southern mid of Lone Mountain are
derived from rhyolite porphyry flows. Their development is believed to
have taken place at a time closer to. that when the flows were extruded
than to the time of deposition of the Gila conglomerate, for the follow
ing reasons: • ■ r.: : :V:;- :
First, they < are firmly cemented or conrolidated while the Gila con
glomerate is not* ■...;v:. ' '' V r : :V;.
Second, the red, slabby, tuffaceous sandstone from Collins Canyon,
as shown on Plate 21, is present in volcanic agglomerate beds* In the
Lone Mountain area they are thin and lenticular, evidently deposited on
an uneven surface by small streams*
Third, limestone gravels form a minor part in the agglomerates
exposed in Collins Canyon and Lone Mountain but are a major constituent
of the Gila conglomerate as exposed in the northern part of the area*
The thickness of the Tertiary volcanics is not known# An estimate
of 4,000 feet was obtained by assuming that the volcanic rocks have an
average dip to the southwest of ten degrees# The average dip may be
greater in which case the Tertiary volcanic section would be oven thicker#30 ' :Imlay estimates that the Tertiary lavas in northeastern Sonora are over
5,000 feet thick# .
The Gila conglomerate: The conglomerate beds are exposed between 30
30, Imlay, R» ¥#, Paleogeographic studies in northeastern Sonora, Bull, Geol# Soc# of America, vol* 50, no# 11, Kov# 1939, p# 1738.
-31-
the Basin Ranga fault on tho north side of the Huachuca Range and the
Boboconari River. . . . : ,
Neither the base nor the top of this conglomerate has beenfound.
An eight inch test well northeast of Fort Huachuca penetrated 917 feet
of conglomerate without going through the entire formation. Whether this
entire thickness was in the Gila conglomerate is not known. ' : ,
The Gila conglomerate, as exposed near the Basin Range fault,
includes boulders, cobbles, and pebbles* The boulders range up to three
feet in diameter* As the beds are traced northward away from the Hua- ~
chucas, the conglomerate rapidly grades into finer sediments.
The conglomerate is composed of gravels derived from strata that,
range from pre-Cambrian to Tertiary in age. The following are estimates
of the composition of the conglomerate from localities within 200 yards
of the Basin Range fault, . I ■ '
1 * Cretaceous and Tertiary rocks 80%Paleozoic limestones 20%
2. Cretaceous and Tertiary rocks 90%Paleozoic limestones : 10%
3. Sandstone or quartzite : ' /: ; . : 55%Paleozoic limestone 20%Cretaceous and Tertiary rocks 15%Granite 10%
A large boulder in the conglomerate was derived from an earlier
conglomerate. The composition of the boulder is as follows:
Paleozoic limestones 35^Paleozoic (?) chert . 15%Cretaceous and Tertiary rocks 50%
Plates 23 and 24 show this conglomerate*
-32-
About one mile north of the Basin Range fault the Gila conglomerate,
as exposed in Sycamore Canyon, is much finer* Here'it 'is composed of
angular to subrounded gravels of Tertiary volcanics. Paleozoic lime
stones, and Cretaceous clastic and volcanic rocks. The individual pebbles
are from one to two inches long with a few up to five inches in length.
The Gila conglomerate has been disturbed by folding and/or faulting
and dips up to 45 degrees.
Near the railroad station in Elgin about 15 miles northwest of the
Huachuca Mountains, fine grained clastic rocks are exposed in banks of a
creek, (see Plate 25)•
They are limy clays, gray siltstones and sandstones. A few badly
weathered pieces of volcanic rock, ranging up to four inches long were
found in them. These beds are believed to be equivalent in age to the
Gila conglomerate found near the Huachuca Mountains* They ware deposited
farther from the mountains and are consequently made up of smaller parti
cles. The limy character of the beds suggest that they may have W e n
deposited in a lake occupying the intermontane basin (Sonoita Basin). :
Faulting and/or folding has disturbed these beds. The Gila conglomerate
is of Pliocene age.
Quaternary Rocks
: No attempt was made to map separately the disturbed Gila conglomerate
from the undisturbed gravels lying on it. In general these gravels dip
gently toward the present drainage systems. The following section indica
tes two period of gravel deposition. This section was measured about two
miles northeast of "the Basin Range fault where it crosses Coyote Canyon*
Surface Thickness ,
Upper gravelReddish orange conglomerate of which
one half the volume is made up of granite and quartzite cobbles and 'boulders ranging up to 18 inches :long ..................... 15 feet
Lower gravelReddish brown conglomerate of which :
one quarter the volume is made up of cobbles ranging up to 6 incheslong ............................ J25 feet
• Total ....... AO feet
Creek bed
IGNEOUS ROCKS
The igneous rocks of the northern part of the Euachuca Mountains
are divided on the basis of age into four groups: the pro-Cambrian
granite, the Lower Cretaceous volcanic flows, the Tertiary volcanic
flows, and the post Lower Cretaceous intrusive rocks which are associated
with the mineralization of the area.
Pre-Cambrian Granite
The pre-Cambrian granite is exposed along the eastern and northern
flanks of the range. It is cut off to the east and north by the Basin
Range fault. To the west and south it is in sedimentary contact with the
Bolsa quartzite, except for Sycamore Ridge, where it is in fault contact
with Paleozoic limestone.
•34-
In the area mapped (Plate l), the pre-Cambrian granite covers twenty- five square miles*
The granite was eroded to a surface of low relief before the depo
sition of the middle Cambrian Boise quartzite. In general, the granite
is very coarse, with well developed crystals of orthoclaee up to one and
one and one half inches long. It has been intruded by dikes of quarts,
aplite, and lamprophyre. Most of these dikes are probably of pre-Cambrian
age*
The granite is broken by a strong joint system which in places has
been mineralized subsequently by fluorite deposited in open fissures,
which indicates that the granite was relatively near the surface during
mineralization* The fluorite mineralization is probably post-Cretaceous
in age.
The granite specimen described below was collected in a road cut
one half mile north of the north gate to Fort Huachuca* The granite is
sheared* The shearing probably occurred during pre-Cambrian time in a
period of mountain building during which the granite was at great depth
below the surface*
The specimen studied in thin section is a gray, coarse-grained
granite. It is essentially feldspar and quartz* The feldspars are
microclino, perthite, and oligoclase, all being anhedrons of considerable
size and many including flakes of white mica* The quartz occurs either
in large crystals or as aggregates of small anhedrons with sutured con
tacts* The quartz shows pronounced wavy extinction* Muscovite, the only
accessory mineral, shows bending of its crystals and wavy extinction*
Lower Cretaceous Volcanic Rocks
The stratigraphic occurrence of the Lower Cretaceous volcanic flows
has been discussed under stratigraphy (page 21). Here is presented a
petrographic description of those flows of which thin sections were made*
Parker Canyon Section: In the lower clastic section of Parker Canyon,
three igneous bodies were found« These are tabular, apparently conformable
to the bedding, and may therefore be either sills or flows. They do not
show positive evidence of extrusive origin, but they are tentatively
classified as such, because flows have been found elsewhere in this area
in the lower clastic formation.
The lowest flow (?) in the lower clastic formation is 300 feet of
dacite, the base of which is 1200 feet etratigraphically above the top
of the limestone conglomerate formation. In hand specimen, it is grayish
green aphanitic rock with some conspicuous phenocrysts of feldspar. There
are a few cavities on the weathered surface, probably due to the weathering
out of the feldspar phenocrysts*
In thin section the dacite shows a "felty* texture, consisting of
closely, random packed, platy, plagiodase crystals* The interstitial
spaces are largely filled by orthoclase and quarts* A few phenocrysts
of orthoclase and plagiodase are present, making up less than ten per
cent of the rock* Alteration has crowded the feldspars with sericite,
kaolin!to, and chlorite, and in some places also with epidote and calclte.
The epidote also occurs as grains in veinlets. Chlorite flakes and grains
of magnetite are widespread in the section.
A second flow occurs about 4700 feet above the base of the lower
clastic formation* It is about 300 feet thick* This rock is a red
aphanitic dacite porphyry*
In thin section, it consists essentially of a fine-grained ground-
mass, made up of tiny lath-shaped plagioclase crystals, with interstitial
quartz grains, and showing a heavy decoration of alteration products*
The phenocrysts of quarts and feldspar make up twenty percent of the rock.
The phenocrysts of feldspar are oligcclase, but the feldspar of the
groundmass Is undeterminable, due to alteration* Kaolinite and sericite
are the principal alteration minerals and are quite common in the .section*
The quarts is commonly more or less rounded and corroded with inlets of
groundmass* Magnetite grains are found throughout, the"section* Much
of the magnetite has altered to hematite, giving the rock part.of its
red color* ' : : ,
The upper 2,COO feet of the lower clastic formation consists of
volcanic flows (?) of andesite and quarts latite* The quartz latlte
wad collected near the base of the volcanics*
In hand specimen, the quarts latite is a dull gray, aphanitic -
rock containing dark gray spots, up to one half inch in diameter* - i "■
In thin section, the quarts latite was found to consist of lath
shaped plagioclase crystals in a felty texture, with "about fifteen per
cent of interstitial quartz and about twenty-five percent of orthoclase* '
The phenocrysts of plagioclase, orthoclase, and perthite are from one
to two millimeters long and make up three percent of the rock* All the
feldspars are altered to kaolinite, chlorite and a little sericite*
Chloritic pseudoabrphs after some,tabular"or prismatic mineral"are
-37-
cosimoR and are urually associated with magnetite, serlcite, and
occasionally, ©pidote* 2 Apatite is the common accessory mineral in
crystals up to .06 millimeters long*
Andesite was collected in the upper part of the 2,000 foot section:
of flows. In hand specimen, it is a dull greenish-gray aphanitic rock,
with a few phenocrysts of feldspar, dotted with grains of magnetite,
which has partly oxidised to limonite* A few cavities are observed
on the weathered surface. \ .....
In thin section, the andesite shows Hrachitic* texture," consisting
of densely packed slender crystals of plagiocla.se with fluxional arrange
ment. Phenocrysts of plagiocl&se, .orthoclase, and porthite make ;Up
about ten percent of the rock. The feldspars are largely altered to
' kaolin!te, sericlte, chlorite,, epidote, and calcite. . Patches.of chlorite
are scattered through the section, hut no crystal form is discernible.
A very little quarts is.present. - Apatite crystals are common. Grains -
of magnetite, which are partly altered to limonite, are widely distri
buted# t.A. - - l •: ; y
Volcanic flow in Blacktall Canyon:. An amygdaloidal basalt occurs in
the lower clastic formation of Blackball Canyon. The exposure from which
the specimen was collected lies cn the east side of Sycamore ridge near
the top, where the Crest Line fault has. t hr unted Permian limestone over
the Lower Cretaceous. .. -y; /.uv.,-.
In hand specimen, the basalt is a purple scoriaceous rock with
cavities filled with calcite and other minerals*
In thin section, the basalt shows "folty* texture,.consisting
essentially of random packed, tiny, lath-shaped feldspar;crystals.
The feldspar crystals are- so heavily crowded with soricite, calcite,
and chlorite, due to alteration^ that they cannot be determined* Blacks
ami brown dusts of iron oxides are widely distributed, Euhedral rutile
is unusually abundant* The cavities are largely occupied, by calcite with
subordinate chlorite and sericite, ' ; '
Tertiary Volcanic Rocks
The Tertiary volcanic s apparently lie with"strong structural and
erosional unconformity on the Lower Cretaceous-beds* The distribution,
thickness, and character of the volcanic rocks were discussed under
stratigraphy (page 29)* The following is a detailed description of the
two specimens chosen as reprctentative of the volcanic rocks,
A specimen of the flow rock collected near the Hathaway Ranch -
buildings was determined to be rhyolite porphyry. In hand specimen, it
is purplish red with conspicuous phenocrysts of quarts and feldspar about
two millimeters long, embedded in a reddish aphanatio groundmass* J
. . .In thin section,-the rhyolite porphyry shows a pronounced porphyritic
texture with euhedral orthoclase and quarts as phenocrysts* The feldspar
is largely but not uniformly altered to clay minerals, while the quarts
is corroded and embayed with groundmass. The groundmass is in part glassy
and in part cryptoerystalline and in many places shows excellent sphefulitic
texture. Flow structure is shown by hands of- spherulites or by layers of
glassy and cryptocrystalline groundmass, which usually wrap around the
phenocrysts,
A specimen of calcareous tuffaceous sandstone was collected from
beds lying between rhyolite porphyry flews. These bods are exposed in
tho stream bed of Parker Canyon between the Hathaway Ranch buildings and
-39*
the Canelo to Montezuma Pass read, !
In hand specimen, the sandstone Is a reddish, fine-grained, dense,
rock, : . . . . - : •; ■ - . , ; ■ ; :
In thin section, it is essentially cryptocrystalline, so that its ’
constituent minerals could not be determined. Abundant tiny fragments
with concave outlines give rise to an "ash structure”. The fragments
were glass and have now become crystalline by devitrification. Larger
corroded fragments of quarts are also common. Only & few feldspar crystals
are present. Grains of calcite are abundant. Flakes of biotite are
occasionally seen, : ; . .; ; \ ;
Post-Cretaceous Intrusive Rocks
Large intrusive bodies of post-Cretaceous age were not found in
the northern part of the Euachuca:Mountains, with the possible.exception
of sills (?) in the Cretaceous rooks. Quarts veins and lead and copper
minerals in this area are probably related to an igneous stock in the-31
southern part: of .the range, . Heber reports that this stock crops out
west of the Crest Line fault, ,During a .reconnaissance in the, southern
end "of the’range east of:Montezuma Pass the writer found that the Paleo
zoic formations had .been intruded by a granitic stock, '
If it is assumed:that the igneous stock in the southern part of the
range is the source.of the min eralizing.solutions which formed the Manila
Mine ore body, a tentative age for the period of. intrusion can be-assigned, 31
31 Weber, R, H,, personal communication, April, 1949.
Surfsea capocures near the Manila Mine, show that the mineralization
occurs both in the Paleozoic formations# forming the overthrust block#
and in the Cretaceous strata forming the lower plate* The mine workings
were not accessible, but a study of the dumps' revealed that the mineralised
fissure cut through the thrust fault plane, as both the Paleozoic lime
stones and the Cretaceous strata were mineralized* The mineralization
is therefore post-thrusting# hence the intrusion of the stock in the
southern portion of the range is probably post-thrusting*
GEOLOGIC STRUCTURE
. ’The northern part of the Huachuca Mountains constitutes a complete
geologic cross-section of Basin and Range Province structure* It'also shows
the nature of the folding and faulting of the Laramide Revolution, and
Tertiary time*
Internal features of the northern part of the Huachuca Mountains:
The most striking thing about this area is the large size of the struc
tures and their excellent exposures* The range is essentially a fold
or folds that have been broken by a reverse or thrust fault and were
then subject to normal faulting of the Basin and Range type*
In addition to these large structural features there are smaller
structures associated with them, such as drag folding and reverse fault
ing associated with the Crest Line thrust fault and other structures
connected with the mineralization of the area* These features could not
be mapped on the scale of map available*
Structure Elements
The various elements in the structure of the northern part of
the Huachucas will first be described. Structures developed in pre-
Laramide time will be discussed later under structural history*
Folds
Rough Canyon Anticline$ The Rough Canyon anticline is a major
structure in the Huachuca Mountains• Its northwest trend follows that
of the range. The northern nose is in Algerita Canyon, about half a
mile east of the Foster Ranch buildings (now the Page Ranch), From
this point it extends to the southeast for a distance of. six miles
(the limit of the area mapped)# Its extension beyond this point was
not mapped. The width of the structure cannot be determined because
its northeast flank has been dropped down along the Lyle Peak fault.
This fault has the same trend as the axis of the fold, suggesting a' *
genetic connection between the two. If the fault is along the axis
of the fold, then the width of the western limb through Parker Canyon
is three miles.
Except that the eastern limb has dropped down on a fault, the
Rough Canyon anticline has been little modified by major faulting.
Rough Canyon Synclines The Rough Canyon syncline lies adjacent
to and northeast of the Rough Canyon anticline at its northern end.
The structure is outlined by the limestone formation, except for its
northwest nose at the head of Algerita Canyon where the formation comes
within 150 yards of completely surrounding it. The measurements given
are based on the outcrops of the limestone formation. The southeast
Bose of "the structure lies on the crest line of the’Huachuca Mountains at
the head of the northwest fork of Huachuca Canyon. The axis of the syncline
trends north 60 degrees west from this point for one and one half miles to
the head of Algerita Canyon. The syncline is one half mile wide.
The axis of-the syncline extends west northwest along Algerita
Canyon where the synclinal structure becomes less pronounced and apparent
ly disappears altogether before the mouth of Algerita Canyon is reached.
The axis can be followed southeast for one mile from'the southeast
nose as outlined by the limestone formation. Its further extension to the
southeast is not known. • -
Drag Folding: Drag folding is well developed'on the Crest Line thrust
fault, where the beds have been isoclinally folded in places. The drag v
along the beds indicates movement of the hanging wall from the northeast*
Away from the fault zone the folding becomes less intense* - ;
In Woodyard Canyon the Lower Cretaceous strata have been overturned
by drag along the Crest Line thrust fault. These strata Were folded
before faulting during the Laramide Revolution, At the end of that orogeny,
they probably had the same attitude as the Lower Cretaceous strata farther
south in Algerita Canyon. That is, they dipped to the southwest.
During the overthnisting the Cretaceous strata in Woodyard Canyon -
were dragged along the fault surface* The result was the overturning of
these strata, so that they now dip to the northeast* The strata in Alger
ita Canyon were farther below the thrust fault surface and were therefore
less disturbed by the movement on the fault plane,'
The evidence for the thrusting causing the overturning of tbo beds
in Woodyard Canyon is seen by following the formations north from-Algerita
Canyon* About ono half-rail© northwest of the Foster Ranch buildings
(now the Page ranch) the Cretaceous beds as exposed In Algerita Canyon
dip 25 degrees to the west northwest. To the north, the dip gradually
Increases, and the strata begin to swing to the west. This change is
especially strong near and In Ferosa Canyon at the southwest end of the
ridge formed by the Paleozoic limestones thrust over the Cretaceous.
This suggests a genetic relationship. Here the strata swing from north
20 degrees west to north 50 degrees west within a quarter mile* The
change in dip is more pronounced* In the same area the dip of-the>strata
changes from AO degrees to the west southwest, to vertical, and finally
the strata are overturned, so that they dip 66 degrees to the northeast*
The drag in the Cretaceous strata in Wbddyard Canyon shows that the upper
thrust plate moved from the northeast,... -
Folding of the Tertiary rocks: The Tertiary rocks are all disturbed,
but it is not known whether this is due to folding or faulting. The Ter
tiary volcanlcs are competent and could transmit compressive stresses.
Folding of -these rocks woiild be possible. _ H ••
The Gila conglomerate (?) is semi-consolidated and therefore in- , •
competent* If the conglomerate is folded, it may be the reflection of
the underlying competent beds or it is due to drag along;the thrust faults*
Folding of the thrust fault: The Crest Line thrust fault dips about
A5 degrees to the east northeast from"Garden Canyon to Huachuca Canyon. In
the Manila Mine area, the fault is flatter (less than ten degrees) and dips
to the north. This relationship can be explained in three ways* One, the
fault surface has been folded; two, rotation of the fault surface by block
faulting; and three, the fault surface as originally formed was curved*
Any one of these or any combination of. them may be the explanation* It
is known, however, that arching on a broad scale took place subsequent to32thrusting in the Northern Canelo Hills, and it is probable that the
thrust faultIplane in the Huachucas was also arched* The original dip
of the Crest Line fault between Garden and Huachuca Canyons may there
fore be less than the 45 degrees observed now*. .- ; ; >
Faults
The faults mapped in the Huachuca Mountains are of two main types
as to origin. The earliest faulting is believed to be related to com
pressive forces which first folded the beds but:eventually thrusted the
Paleozoic limestones over the Lower Cretaceous strata. The Crest Line
thrust fault and the structures related to.it are examples of this type*
The later faults caused by tension, are of the Basin and Range type*
The best example is the normal fault which outlines the base of the Hua
chuca Mountains on its eastern aid northern sides*. ..
Huachuca Canyon fault> The Huachuca Canyon fault in the bottom of
Huachuca Canyon is probably responsible for the location and the straight
character of this;drainage* The fault trends north 40 degrees east and
has offset the Bolea quartzite about 1300 feet stratigraphically* The • -
northwest block is down thrown. It. does not offset the Crest Line thrust
fault or the Cretaceous beds west of the Crest Line thrust fault. This
suggests that the Huachuca fault may be pre-Crest Line thrust faulting
32^ Feth, J,H* The geology of the Northern. Canalo Hills, Santa Crus County,Arizona: Library University of Arizona, Ph.D. thesis, 1947, pp. 121-122*
•45
and also pre^retaceous, such as the Dividend fault in Bisbeo. It is
equally probable that the over riding Paleozoic formations on the Crest
Line fault moved as blocks, being separated by tear faults, and not as
a continuous sheet* ■
The Crest Line thrust fault: The Crest Line thrust fault is the
major structure running through the central portion of the range. It is
roll exposed along the slopes of Huachuca Peak and in Garden Canyon (see
Plates 9# 26, and 27)„ Following the northwest trend of the- range, it
extends from the Manila Mine area in the northwest corner of the range
through Garden Canyon, continuing five miles southeast of Garden Canyon,33where it has been mapped by R. H* Weber * The fault is therefore at least
13 miles long* ' • ' ■ - ■■ - ,• " -- ' ■ - - - - - ' -
The fault plane dips to the northeast about 45 degrees in Huachuca,
McClure and Garden Canyons. In the Manila Mine area it dips to the north
at an angle less than ten degrees* In the southern part of the range*
Weber states that the fault dips from 0 to 30 degrees to the"oast*
The displacement along this fault is unknown, because the'original * f-
average dip of the fault surface has not been determined. The stratigraphic
throw exceeds 5>000 feet in Huachuca and Garden Canyons and is over 13,000
feet in the Manila Mine- area* Net slip would be" larger than the strati
graphic throw and•would depend on the - dip of the fault plane* By using " 'or
the trigometric relation described by Billings'73, assuming" dips of- the - 33 34 35 *
33 Weber, R*H« "personal communication, 1943*
34 Weber, R.H* personal communication, 1949• • ■
35 Billings, M*P* Structural geology: New York, Prentice-Hall, Inc*1942, p. 178.
fault plane and using 13,000 feet as.the stratigraphic throw, the
following net slips were calculated;
Dip of fault plane : "Net slip on the thrust *
' •■'■■■■' ' 10° - ■ - 14»7 niles - - - -
- - - '■ ■' - ■- 20° -- ..." "' ' ' 7*4 Biles ' - -- " — ,
' ■ - 30° : : 5.0 miles
": ’ ^ 3.9 miles
•The folding caused by drag along the fault plane shows that move
ment of the hanging wall came from the northeast, as indicated in the
Manila Mine area, and along the slopes of Huachuca Peak (see Plates 9, •
26, and 27) • - , - - V. y 1: ••
Part of the fault zone is marked ly a limestone breccia up to 250
feet thick. The limestone cobbles and pebbles were derived from the •
Paleozoic formations a M are rounded to subrounded. The breccia also •-
show shearing and stretching of the pebbles. Thb shape of the fragments
suggests that they were derived from the erosion of the exposed Paleozoic
formations of the advancing thrust sheet which later overran them, causing
the shearing. The limestone breccia capping.the ridge to the east and
south of Woodyard Canyon lies relatively horizontal on the overturned. -
Lower Cretaceous strata* If the limestone breccia is a fanglomerate derived
from the advancing thrust plate then the Lower Cretaceous strata would have
had to be eroded subsequent to their folding in Laramide time and prior to
the deposition of the fanglomerate and -the thrust faulting. : . _ . . ■
It is also possible that the breccia is drag from the Lower Cretaceous
limestone conglomerate formation. This is suggested by the fact that the
breccia lies next to the Permian strata in the Manila Mine area. Geologic
sections: of:’this area X i ^ t e 2) shciw t4mt.1±ds-.intei*pretatic«f.is reason-
1able* : 'ii- -T-- * A" \ , ‘"•is r ' l d ,':5v
.. . The evidence for thrusting in the Manila Mine area is quite definite.
An outlier (klippe):of limestone (presumably Paleozoic) lies a feir hundred
yards east of the Pyeatt ranch: buildings. It is surrounded on all sides
:by Cretaceous beds. That the Cretaceous.beds underlie the Paleozoic- is
shown by the.deep reentrants of Cretaceous in the drainage cutting through
them,. The; Cretaceous shales below the Paleozoic have been rolled up into
forms. resembling logs by the thrust* The: springs .at the.-, northern end .of
the thrust outcrop show.that the dip of;the-thrust plane is-to the north.
The water feeding these springs -follows the dip of the fault;plane flow-:
ing top pf - the impervious Cretaceous beds, :-,n : , 1:
^ B a s i n Bange fault : The Basin Range* fault - outlines the northern and
eastern flanks of the Huachuea Mountains in; the area: mapped, ; It, extends
from, an, uritopwn point west of . the Pyeatt Ranch buildings - east along the
northern edge of the range and then southeast, along the. east .side- of: the
range to Gold,Hill, where it.is.last exposed.
The Basin Range, fault is a normal fault, dipping about 45; degcees,
away from the range. The foot wall is pre-Cambrian granite esobept west.
of the: Manila Mine area, where the foot wall is Cretaceous rocks, ; The
hanging.wall on the north^side of the range, consists;of Tertiary opn-: ,;
glomerate and gravels, _ On.the east side, part of the hanging wall is;
made up of red fine-grained sandstones, siltstones, and buff fine-grained:
sandstones, which may be Cretaceous, but most of thorhanging-wall here.
also consists of Tertiary conglomerates and gravels,
‘v " The; Ba sin- Range rfault: it self is displaced normally' in the vicinity
of Fort Huachuca by a fault-with a northeast trend and a displacement of
a few hundred feet* There may be others of this type which have not been
mapped.
In the southern part of the range, the Basin Range fault is not 36exposed * It is, however, reasonable to extend it farther southeast
along the front of the range on the basis of information obtained from
wells. As shown on Plate 4, the ground water level drops rapidly east
of the Basin Range fault. This is caused by the difference in rock types
on the foot wall and hanging wall of the fault. The foot wall is granite
and relatively impervious, while the hanging wall is largely made of Ter
tiary conglomerates and gravels which are relatively pervious. Therefore
the water upon striking the fault sinks rapidly in the Tertiary conglom
erates and gravels, and the water table is consequently deeper.
As shown on Plate 4, the rapid drop off on the water table in the
southern part of the range occurs just east of the projection of the Basin
Range fault into that area. The writer concludes that the fault continues
to the southern end of the range.
Lyle Peak faults The Lyle Peak fault can be followed from a point
near the crest of the range at the head of Huachuca Canyon southeast for
five miles to the head of Garden Canyon. It continues southeast off the
area mapped for an unknown distance. The fault follows the axis of the
Rough Canyon anticline* In its present attitude, it is a normal fault
dipping 76 degrees to the northeast in Garden Canyon* Fault grooves found
southeast of Garden Canyon show dip slip movement* The hanging wall is
36. Weber, R*H. personal communication, 1949.
-49**
Lower Cretaceous strata, and the foot wall Is Permian limestone*. Because
the Lower Cretaceous limestone conglomerate formation occurs.on the.hang-
ing wall of the fault. In McClure Canyon, it is possible to make an estimate
of. the stratigraphic throw, which is from two to three thousand feet*
The age of the Lyle Canyon fault is not definitely known. It is
believed by the writer that it is due to tensional forces, which would
classify it with the late Tertiary Basin Range fault* The close relation
with the axis of the Rough Canyon anticline is interpreted as meaning
that the axis of the fold was a zone of weakness and that the position
of the fault was determined by it* It is possible, however, that the
fault is contemporaneous with the formation of the anticline, which would
mean that the displacement along the fault died out by the time the struc
ture approach®! the Lower Cretaceous limestone formation, which in this
area is about 10,000 feet stratigraphically above the Permian*
..... . Lone Mountain Fault Structure
Lone Mountain lies outside of the area mapped and was studied only
at its southern end. The structural relations"shown probably have a
direct bearing on the relationship of the Cretaceous and the Tertiary
volcanics mapped (Plate 1), and it is, therefore, included* Where
observed. Lone Mountain is made up of volcanic agglomerates, largely
derived from the Tertiary volcanic flows* The agglomerates dip from
10 to 35 degrees to the southwest* On either side of the agglomerates
are Cretaceous beds in fault contact with them. The fault on the east
side was not well exposed but appears to be steep* On the west the
fault dips 60 degrees to the southwest* The Cretaceous beds make the
-50-
hanging wall of this reverse fault# On "either side of this down dropped
block (gi%ben) the Cretaceous beds dip about 70 degrees to the southwest.The contact between the Cretaceous strata and the Tertiary volcanics
in the area napped (Plate 1) was not observed. The structure of Lone
Mountain suggests that it may be a fault contact#
Structural History
Pre-Lararaide Structures
The structures shown on the geologic map (Plate l) and the cross-
sections which accompany it (Plate 2) are either of Laramide age or
later. Stratigraphic evidence indicates that strong structural breaks
occurred prior to the deposition of. the Middle Cambrian Bolsa quarts!te,
during the interval between the deposition of the Permian limestones and
the basal limestone conglomerate of the Lower Cretaceous, and that some
diastrophism occurred in Cretaceous time.
Post Permian Pre-Cretaceous structures: The basal limestone con
glomerate of the Lower Cretaceous overlaps Paleozoic and even the pre-
Cambrian rocks in southern Arizona and Hew Mexico. The unconformity is
both erosional and structural. In the Huachuca Mountains a pre-Cretace-
ous valley 2500 feet deep has-been cut out.in.the.Permian limestone, .
In the Bisbee quadrangle"5 , the pre-Cretaceous Dividend fault has a
-throw of 2,OCX) to 5,000 feet. Erosion subsequently stripped almost all 37
37, Butler, B.S., et, al.. Some Arizona ore deposits: Ariz. Bureau of Mines, Geol, Series, No, 12, Bull, No, 145 Oct. 1932, pp. 32-33*
-51-
of th©’ Paleosoic rocks ' ftom the %JthrOwh gide of the Ditidenf ‘'fifllt,
exposing the pre-Cambrian Pinal schist« In the Lead Mountain area*'0
of the southern part of the Sajrflre Arisosa^ aiwtfmr pro-Cretaceous -fault M e been • mapped, - The /Hmchuea Canyon fault may also;■ 1 '? • r.!:' :: v .... - ' : ; -bo of this age* ' : " r. •■■■/' v:; - r-:. ; : : ; ■. ' w -
'1:: ; i-': ■: .vZm;- . L::":The age of these structures Is not definitely known, A e dlstrl- -
r.-xv:;-.;;-: vi.r., ' ■ v.. r : '• - / ' -button and character of the Triassic and Jurassic rocks of Sonora and
northern Aid zona suggest that mountains were present in southern Arizona
during the late Tri&ssic and early Juraesio and that they were tha source
of the material in these rocks.
In regard to Sonora/ Xing‘S believes that the Bar ranee basin mist -
have covered horthea stern • Sonora at some point n^u* or south of > • -
Nacozazd, extending thence southeastward across western Chihuahua, The -■
Mrrahca formtion hear* this-"supposed 'northeastern margin of the basin consists wholly of Upper Triassic end Lower Jurassic continental deposits.
Toward! the west: a»i south, marine 'sjeabers become intercalated *in Increas
ing proportion. The source of the sediments for this formation would# therefore,: be to the north and east,. • ’ > -• -• . • ' - : - .
■i McKee^ suggests a land mass to the routhweSt as the source of the 38 39 40
38 Alexis, C,0,,' % e geology of the M a d Mountain area, Pima Comity, :- Arizona* Library Univ* of Arizona, Master* s Thesis, 1939# p.
39 King, R, E., Geological reconnaissance in northern Sierra Eadre Occidental of Mexico: Geoli’ Soc# Am, Bull* vol, 50, p?* 16^-1659,
40 McKee, E«D,, Triassic pebbles in northern Arizona containing invertebrate fossils: Am, Jour, Sci,, 5th series, vol, 33, 1937, p* 261,r.''; i v.'., : :: : • 'y V V.. '• y y
V.y“Lv::-"'i ■■. :yyv- -
r;: ' - r ,
- 5 *
Upper Trlassie eedimentsula northern Arizona. HI#, evidence is as ■PF-'--follows:
"Invertebrate fossils of Permian age have been; found in a- of the rounded pebbles occurring at various horizons and localities in the Upper Triassic deposits of northern Arizona. Recent examination of these fossils has indicated that they are all of species typical of the marine.facies of the Kaibab limestone which occurs to the west and southwest, thus suggesting that the pebbles were derived from a land mass in that direction ... General increase in average size of pebbles toward the southwest and a definite decrease in limestone beds within the formation in that direction, tend to substantiate the theory [advanced on the basis of fossUs.* ; . —
The extent and character of this mid-Mesoseic diastrophism is not
known* • V. c
; Cretaceous structures: During the deposition of the. Lower Cretaceous beds in the Huachucas, there was apparently little folding* The beds from the top of the basal limestone conglomerate through the entire Cretaceous section exposed; here do not show singular unconformities. The major fold
ing, therefore, came sometime after the deposition of these beds.Tbat
there was some structural movement duripg this period is suggested by (1) the presence of ▼olcanio flows in the section, (2): the p-eat tMeiaiess of the section (over 15,000 feet) would require subsidence, and a source sufficient to furnish sediments in such volumethat sedimentation would
keep up with the subsidence, since the beds are largely of shallow near
shore origin, (3) a conglomerate of volcanic material,found in the Sunny-
side beds in Bear Canyon, and (4) the conglomerates in the Scotia beds,
which are largely of volcanic origin but also eontain -pebbles of Paleozoic
(?) limestone.At the northern edge of Sonora in the Cabullonevdistrict,TaliaferroT.
'•re. ■v.^ ^ y . . • <• r _ ___ ___41 In King, R. E., Geological.reconnaissance in northern Sierra Madre Occidental of Mexico: Geol. Soc. Am. Bull., vol. ^), Nov. 1939, P» 1714*
-53-
has found evldence of considerable disturbance between Lower and Upper Cretaceous time. : ia unconformity between the Lower and Upper Cretaceous may account for the thick development of the Lower Cretaceous in this region and its apparent absence at nearby local!ties, where Upper Cretaceous beds overlkp still elder rocks. : • v
■: w.- . V : x - v - ^ U v r i . r . v . ; • i x ' . i v
: x7 : . J. VI"':: \ .'t -v:x o f - V t 1 ;..V' . . x;" i::x.-: r x 'icx .x:t V : ~ Am 44mg :i
At the close of Cretaceous time, tiie Rocky Mountain region was-L'-v x'1 r ; :f x'.
thrown into a series of mountains by the Laraaide revolution. Foldingx x v /U, .,v x ; r; v .--.iv'^-."y }r. v;x : !‘Ax ’x ■
and thrust faulting occurred on a large scale. Much of the folding• ' '■ * r** , ' • '* 'I ; : '• *•• • • ■ •• • - . • -• -- J . * M. . * •• 1 - > " ‘ •' : . % •>"' V . »9 ' * * « I* • ‘ f • • " ♦ 4 i.' \ S •!- . <t *• * .11 * • - * » - - ■ 1 • J m. - 1 r-. ‘ S - r < " ' -
shown in the Huachuca Mountains probably occurred at this time.The Laraaide folding was intense, as is shown by the near vertical
An .■ .yf A*; -, V \ --:nn: .O.y .n- ny n-nn- '-n- x : v x nxnn:. .attitude of the Cretaceous beds on the west side of the range in Parker
IA nx-- x'i:;'inri.r. x- {'X/.A) ' v.) I A n . litCanyon. That the principal folding of the Cretaceous beds was completedv.n: v A n : t.:n nnI n - : -xn tn-nn - r; t . . r- -f,t: n - nn.:: ' nnn:
dip recorded is 40 degrees. Unfortunately, the stratigraphic contactbetween the Cretaceous strata and the Tertiary volcanic# was not foundnil; ' nto.y. : -..v.:: c 1 1 - x I I - : y.-v.-y-ntn:..in this area. As suggested under Lone Mountain Fault Structure, the
J . ; , : i ' 4 * r r- . . . „ . . x- - ' - - » - - ■ -r r ■' '*- " * * . ' < j
contact may be on a fault. The Tertiary volcanics and Cretaceous haw,-■ -x I X ■ .... . : I « - ri "* .: * -- :' x . ■ "yx--* ' V- A- - ’ ; , . > xhowever, been observed elsewhere in this general area. This information •
is summarised by lmlay as follows*
„ - .“All available evidence indicates.that the principal folding of the - Cretaceous rocks of northeastern Sonora and adjacent parte of Aris
ons. occurred during the Laramide revolution and ims completeda! Ay'..... y ;’y . .--.y ' yr x. I.?-.. ■'•••'.x x y . '- ' i ' x x c
A2 Inlay, R. W., Paleographic studies in northeastern Sonora: Geol.Soc. Am. Bull., vol. 50, Nov. 1939, p. 1728. -
-54-
_ - . _ _ _ _ / '- before Tertiary-vuloanlsm began. In Camon Santa R o m n ^ r II
..., Tigre, the writer noted that the Cretaceous and upper PaleozoicforaationsarestrbnglyoTertumed toward the west and are bver-
. lain by several thousand feet of nearly flat-lying lavas whose lower part fills the irregularities of a ragged erosion surface. Similar relations between the Mesozoic sedimentary rocks and Tertiary volcanic rocks wore ‘rioted by King (1939) In the Chihuahua plateau east of central Sonora. In the Bisbee district at
• least part of the strong folding of the Cretaceous formations ‘ occurred at the end of the Cretaceous or in early Tertiary time (Tenney,1932, p. 49). South of the international boundary in the region east of Caballona, volcanic rocks rest on the eroded , edges of strongly folded Cretaceous rocks.* r ; -
Post-Laramide Structuresl vr-1 ■ "r r 'T; i v j V' .vX" . ’The writer believes that the principal way in which the rocks
V O-; i h;- i .:.n pv" \ V-; ' . p "*r>: V/: -
yielded during the Tertiary to compression was by thrust faulting.
Some folding may have occurred, but this only in the fore of broad warp-«■*:. f . • ^ , * • . « V 1 i - ' •• - . . . « • »' - s - • ■. ' ■ t »•" r ■* -:•» * ••
ing of the crust or as the result of drag near the thrust planes.
It has already been indicated (p. 46 ) that the Crest Line fault in the Manila Mine area has thrust Paleozoic beds over folded Cretaceous ;
beds «id tiiat, $nrior to thrusting, these fblded beds had been eroded.''.",V:v t b 'T-'.r. ' r,i ; v-r," t'-
The age relations between the tlmisting and the Tertiary TOlcanics are not shown in the area mapped but can be observed in the Northern Canelo Hills about fourteen miles west of the Huachuca Mountains. * ' '
„ v - ' ■ r - 1 ", - . .. t : f J, r ; ' p * '■ ' t » - -v •» - * ^ .*-< <■—
Feth4*' has mapped Permian limmtones thrust o v m t Trotlary (?)/ /
volcanics. Wilson has found thrusting over the Pliocene (?) Pantano 43 * * *
43 Feth, J.H., The geology of Northern Canelo Hills, Santa Cruz County,Arizona: Univ. of Ariz., Ph.D. thesis, 1947, pp. 109-U4* ‘' . "
•44 Wilson, E. D., % e basin aori- iva^e province in Arlzbria: ta^MLldwd manuscript,Ari*.Bur.of Mines files.'1^; ’ -
-55-
lie about 25 miles northeast of the Hwtiraoas, GiUuliy^ places the thrusting as post Tertiary (?) volcanics. He also states that the principal deformation in this range was Tertiary (?) thrusting*
In his paper on the Uncle Sam Porphyry of the Tombstone district, Gillully^ has postulated two periods of thrusting, the one younger and ’ the other older than the Bronco volcanics. The Bronco volcanics lie
unconformably on the Lower Cretaceous and are either Cretaceous or early
Tertiary in age* The Unde Sam porphyry was intruded into the later
thrust fault zone, probably during the early Tertiary. Lying unconform
ably on the Uncle Sam porphyry is the Gila conglomerate of Pliocene age*
The Tertiary structural history of the parallel valleys and ranges of southern Sonora is similar to that in the Huachuca Mountains. King*
writes as follows:"After the early Tertiary eruptions there was further mountain making ... Farther west, as in the province of parallel ranges and valleys, the mid-Tertiary deformation apparently equals or exceeds the earlier, post-Cretaceous movement, and it was probably at this time that the mountains begain to assume their present form. At any rate, the early Tertiary volcanic rocks are generally unconform— able below the later Tertiary Baucarit formation and that formation seems to have been deposited in intermontane basins which had nearly the same positions and outlines as the prerant longitudinal valleys ... At the close of Baucarit time, there was renewed erogenic activity ...The baucarit formation mas tilted and thrown into low folds. North of the 28th parallel, the rocks of each of the high
45. Gillully, James, Thrust faulting in the Dragoon Mountains, Arizona (abstract): Geol. Soc. Am. Bull., vol. 52, no. 12, pt. 2, Dee. 1949,P» 1949*46. Gillully, James, Emplacement of the Uncle Sam Porphyry, Tombstone district, Arizona: Am. Jour Sc., vol. 243, no* 12, Deo. 1945,pp*643-666e 47
47. King, R. E., Geological reconnaissance in northern Sierra Kadre Occidental of Mexico: Geol. Soc. Am. Bull., vol. 50, Nov. 1939,pp. 1715-1716. „ ,: \ - : - v.:\\
-56-
raountain ranges, from the Great of the Sierra Madre westward into Central Sonora were pushed to the west on overthrust faults,
. which partly overrode the Baucarit formation lying in the valleys' next to the west*"
Sometime during the late Tertiary, perhaps in the Pliocene time, tensional forces became active* The result was the normal faulting
which has outlined the limits of the present day ranges* The Basin Range fault on the northern and eastern flanks of the Huachuca Moun
tains is an example. :
The Basin Range fault plane has been offset by faults of a few
hundred feet displacement, :
The latest events in the geological history of this area will be
considered in the chapter on physiographic history*
PHYSIOGRAPHIC HISTORY
The physiographic history of the San Pedro Valley has been described by Kirk Bryari^®• A summary of his conclusions is presented * here, followed by observations made in and near the Huachuca Mountains
by the writer* . • ■: : rBryan! s views follow* The mountains of the San Pedro Valley
Region in southern Arizona are the residual elevations resulting from
an uplift that involved the Gila conglomerate* * The Gila conglomerate
is a valley fill now deformed and dissected, but accumulated under arid
conditions in enclosed or partly enclosed valleys* Late Pliocene verte-
48, Bryan, Kirk, San Pedro valley, Arizona, and the geographic cycle,(abstract). Bull, G,S,A., Vol, 37, No. 1, March 1926, pp. 169-170.
57-
brate remains were found in the fine-grained equivalent of this conglomerate In localities between Benson and Tombstone.
Gidley^ writes the following in regard to the fine-grained - yequivalent of the Gila conglomerates
"The stratified beds of these localities consist principally of red days, sands, ami soft limestones that were evidently laid down in salt lakes of small extent in the central part of the Pliocene basin. The bones occur for the most part in relatively small patches or layers of greenish tuffaoeous day, which, according to Bryan, interfinger on one side with arkosic gravel and conglomerate typical of deposition on alluvial slopes and on the other with lake beds. This position seems to confirm
: Bryan’s view that these bone-bearing patches of greenish shale represent the marginal and fresh water springs that are characteristic of the borders of salt lakes in such basins. The i localities thus probably constituted the chief watering places for the animals of the region, and here naturally occur their fossil remains."
Since Bryan found these vertebrate remains near the top of the for
mation, he concluded that the deposition of the Gila conglomerate was
completed by the end of Pliocene time, and that the uplift is subsequent but not necessarily much later. He goes on to say that*
"The deformed Gila conglomerate everywhere rests unconfonaably on older rooks, including the Tertiary lavas. The nature of the deformation which produced the basins is not known, but it is certain that the mountains of that time were detached ranges located essentially but not precisely in the position of the present mountains ... The post-Gila uplift of the mountains is of the fault block type ... The blocks were pushed through the less competent Gila causing minute faulting end crumpling of the formation*.
The last statement made by Bryan merits special comment. The Gila
4f Gidlay, Fossil cprobbscidea and (edentata of the San Pedrb 'Valley,Arizona: U.S. Geol. Surv. Prof. Paper UO-B, Jan. 1926, p. 84.
V: V': ."'.vy-V::'
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conglomerate did not cover the entire region before block faulting occurred, because the conglomerate is of local origin and therefore the source of the material making up the conglomerate must of necessity have been left exposed. That the Huachuca Mountains were a source of r supply and were never completely covered by the Gila conglomerate is shown by its character near them. The formation as exposed near the ■ -northern end of the range (hanging wall side of the Basin Range fault)
is extremely coarse and poorly sorted (see Plates 23 and 24), but as -
it is followed north and west, the material becomes finer, finally grad
ing into sandstones, silt stones, and limy clays hear Elgin (see Plate
25). This suggests that the area to the south and east (the Huachuca
Mountains) was the source of the material in this formation.
Bryan1 s views on the post block-faulting history of the region are ; «
as follows* A long continued period of erosion formed a widespread sur
face, the Tombstone pediment. Before this cycle was completed, the streams
began to cut down to form a lower pediment, the Whetstone pediment. This second cycle was also interrupted by the incision of the streams to form
the Ar&vaipa terrace. The valleys of the present streams lie below this terrace. - ' ' "■■■ - ' ' - - ‘ ;
The physiographic history of the Huachuc&s appears to follow the
pattern outlined by Bryan. The Gila conglomerate (?) exposed north of
the range is folded and/or faulted. The writer does not believe that
all of the deformation of the Gila was caused by block faulting, because
the beds of Gila conglomerate in Sycamore Canyon are approximately at
right angles to and are cut off by the Basin Range fault. This suggests
that post-Gila thrust faulting may have been responsible for the disturbed
- 59-
VOL: :erBatura of the con*lo«I,t.. . -
Following the ULook-faultlng along the Baeln Range fault, erosion formed a pediment around the range. This pediment was cut on the tilted
Gila conglomerate and the pre-Cambrian granite. The pediment creeses the Basin Range fault without a marked topographic break to indicate that the pre-Cambrian granite is more resistant to erosion than the semt-consolidat-
ed Gila conglomerate. This indicates that the period of erosion was
sufficiently long so that the course of the streams was no longer controll
ed hy the underlying rock. . , , , , :
; ; . Sufficient regional work has not been done to correlate the pediment
developed around the Huachuoas with those described by Bryan. Hence this pediment will be referred to as. the Huachuca pediment. Following the development of the Huachuca pediment, regional uplift rejuvenated erosion,
so that the pediment is now being dissected. . , ; .
An interesting feature of this dissection is the capture of. several north northeast flowing streams lying between Huachuca Wash and Sycamore
Gulch by Sycamore Canyon. Plate 6 shows the location of the streams and valleys involved. Similarity of names may cause some confusion. For
example. Sycamore Gulch is a tributary of the Bobooomari River, while
Sycamore Canyon is a tributary of Sycamore Gulch. A tributary of the
Bobocomari River drains Huachuca Canyon. Therefore when Huachuca Wash
is used, the stream on the pediment is referred to, and when Huachuca
Canyon is used, the stream in the mountains proper Is meant.
The streams beheaded by Sycamore Canyon are tributaries of the Bobo
comari River lying between Huachuca Wash and Sycamore Gulch. Evidence
that these streams once drained part of the area immediately west of
' -60-
Sycamre Gazynon is the wind gap which ia w e t ©f the point where
the Canelo Road croesee Sycamore CaDyoh.’ '’The' w ^ ^ :'dbrain^vly,"thi8 beheaded stream has gently sleplng Md##, a M the stream channel itselfhas banks with a mocimum height of three feet; In many places banks are' so low that a ear can easily be driwem aoMss the etr^uh bed. In contrast to this Sycamofe Canyon (the beheading stream) ha# steep aides with banks
from 20 to 30 feet high along the channel. Where the canyon traverses
the Basin Range faiiit, it M s ctit a narrow gof^ about 100 feet long in
the pre-Cambrian granite footwall. The stream drops about 40 feet in
this gorge. Both above and below it^ the gradient is mmch lose, (see
Plates 28 and 29)•A branch of Sycamore Canyon is advancing into the drainage of
Blacktail Canyon, and it has captnrW a portion of the west drainage of
that stream. It is expected that eventually the entire drainage of
Blacktail Canyon will be directed into Sycamore Canyon, just as was done with the streams betweem Hlaektail Wash and Sycamore Gulch.
The development of stream piracy is closely associated with thehistory of the Bobocomari River. The average gradient of this stream
is about 35 feet per mile from Elgin to where it enters the San Pedro
River, except along the proj ection of the trend of the Mustang Mountains
across the stream, where the gradient is about 60 feet per mile. These
gradients suggest a ridge between the Mustang Mountains and the Huachuoa
Mountains which at one time separated the Sonoita and the San Pedro
Valley basins. The semi-consolidated Gila conglomerate (?) probably
thickens on either side of this ridge toward the-©enter of the basins.
As the Bobocomari River eroded headward toward the Sonoita Basin,
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it was held up by the ridge. During this time the drainage pattern that developed between the Huachucae ard the Bobocomari River was one of north northeast trend. Upon breaking through the ridge, the Bobo- comari River started to erode the semi-consolidated Gila conglomerate (?) in the Sonoita Basin. Headward erosion proceeded:rapidly, enlarging the drainage;area of the river from 185 to 330 square miles. The first
tributary of the Boboeomittl M v e r on the west side of the ridge and
from the southwest is Sycamore Gulch, which drains about 40 square miles,
including the northwest portion of the Huachuca Mountains.
The piracy of drainage in this area has caused the drainage from
the captured basins to flow a longer distance than before capture. For
example, the drainage from the west side of HLacktail Canyon captured
by Sycamore Canyon now has to flow 10 miles in order to reach the same point (the outlet of Bl&cktail Wash) which it formerly reached by flow
ing 6 - miles down Blackball Wash.Despite the longer route Sycamore Canyon is the beheading stream,
because its gradient is steeper than that of Blackball Wash. This is caused by the low gradient along the Bobocomari River and Sycamore Gulch,
as shown in the following data* : : .
Distance ^ Difference in Average(in miles) Elevation
(in feet) .to^ient
(feet per mile)Outlet of Huachuca Wash to .. :v - .outlet of Sycamore Canyon 6 5L0 51,6
(A to C) - - L
Outlet of Sycamore Canyonto B in Huachuca Canyon 4 660 165,0
(C to B) . . / : " ' ' . " .Total 10 970
Distance ; Difference in Average(in miles) Elevation Gradient
(in feet) (feet per mile)Outlet of Huachuca !7ash to : .B in Hmehuca Canyon 970 149*2
(A toB) - :■ ! :: y i ■- iV.^rBoth Sycamore Canyon and Huachuca Wash have steeper gradients as
the mountains are approached. Using the distances between B and where
the 5000 foot contour outs these streams, the following;gradients were
^computed: ;. - . i-.-.x /Distance Difference in Average (in miles) Elevation Gradient
(in feet) (feet per mile)
Sycamore Canyon 1.25 300 240
Huachuca Wash " i V- , v . ; 1 . 5 . : 300;,,;,,,.; ■ 2 0 0 _• ' ' 'In both oases Sycamore Canyon M s the steeper gradient. The
actual gradient of Sycamore Canyon is steeper, because the distances
used were to point B in Huachuca Canyon. . ; > >
The lower gradient shown in the Bobocomari River and Sycamore Gulch in the above data results from this portion lying at the baud of the
drainage of the Sonoita Basin. This drainage area is 145 square miles.
The flow is therefore sufficient to remove the sediments brought down
by Sycamore Canyon, thus maintaining the steep gradient of that stream.
The steepest gradient on the Bobocomari River east of Elgin is
near its junction with the San Pedro River. As erosion moves this
gradient headward, the tributary streams along its course will be
rejuvenated in turn. .: ■
For the future, we have in this area conditions for continued
deepening of the gulches and canyons, the eventual destruction of the
Huachuca pediment, and the formation of a lower pediment surface.
o r e i m m a s
Mining In the Huachuca Mountains has been carried on in a small way since the 1880*8 except in the Fort Huachuca Military Reservation area, which has been closed to prospecting and mining operations• Most of the mining has been done in the southern part of the range. Mining
operations in the northern part of the Huachucas, west of the Military
Reservation, have been on a very small scale. During the past twenty
years they have been almost negligible.
Hartford District (Huachuca Mountains) 1907-194750 51
GochiseCo., _ . v ; ; . v <
GoldLode
SilverPlacer
Lead;:V,Y
Copper Zinc
380.75 oa. 109.58 osi 22,948 oa. 487,185 1 W . 71,250 lbs. 348,000 lbs. i $15,495.00 $15,335.00 $36,462.00 $10,048^0 $39,247.00
m:-': Total : $116,587.00 Vvv '-Y :
Huachuca District, Cochise Co.. 1900-1934 ' ''
Copper Glance Mine 300,000 lbs. Cm, $4,000 An, $50,000 AgY Total value $100,000 ' : U-'.;.: • Y- :
Eureka Mine 470,000 lbs. Pb. Total value $15,000
50 Statistics from Aria* Bur. of Mines, Dniv. of Aria., Tucscm
51 Rising, M.J., and Heineman, R^.S., Arizona Metal production: Aria. Bur. of Mines, Dniv. of Aria., Bull. 140, p. 91, 1936.
In the irrltar's opinloay tho data given in the aeocod tabie (1900-1934) are unreliable. First, the silver production should be
associated with: the lead production of the Eureka Mine. 1 Second, the minerals found on the dump of the Eureka Mine are copper minerals and not lead. Third, the known producers of lead.are not listed. They are the Manila or Panama Mine and the Cave Greek (?) Mine. The latter
is located in the southern part of the range. : :: .
v:;:ivh -Liv; : / V ' ‘ Vr"-. V' .. - ' , •Panama Mine
: /The Panama Mine, the largest in the area mapped, is in the mctreme
northwest-portion of the range, just east of the Military Reservation boundary fence and one half mile south of the Canelo-Fort Huachuca Road.
The discovery date of the mine is not known. It was certainly later
than the fomriing of Fort Huachuca in 1877 because the area was not safe
from the Apache Indians before that time. The mine is located on; the U. S. Geological Survey topographic map which: was published in 1904#
; r: During, the 1920* a a small mill operated on the ores from the :, • property. The mine workings were apparently never deep. later, wee
encountered.125;feet below tiie surface in the main shaft, and pumping
was required. The pumping was stopped by court injunction on June 9,
1928, because the spring on the Pyeatt Ranch ran dry allegedly as the
result of the pumping operations.
Sometime after the court injunction had been issued, a re survey •„
of the reservation found that the mine was. two hundred yards within . -
the Military Reservation.The operators were then obliged to move
their equipment from the property and cease all operations.
... - 65-
fhe major structure In the Panama Mine area is the Crest Line fault, which has thrust Paleozoic limestones over Lower Cretaceous • strata, mostly red shales and sandstone# The fault surface dips to the north less than ten degrees. The overthrust plate of Paleozoic limestone has largely been removed by erosion, so that the overthrust
block is less than 100 feet thick. :The mineralization is on'a steeply dipping northeast flitmre
which cuts the Paleozoic limestones and the Cretaceous strata below
the thrust fault surface* Specimens of ore collected, from the adit
level consisted of oerussite in a quartz and ealcite gangue with a
little malachite* Except for the adit level, the mine was not accessible for study* t % /. ■
Joe Bailey Prospect
The Joe Bailey prospect is located cm Brushy Canyon between the McDaniel two story adobe house and the Wills Camp* The country rock is Cretaceous red shale. A little malachite and chalcbcite in a quart gangue were found on the dump* Water was encountered within 100 feet of
the surface. The size of the dumps indicates that the workings are very
limited in extent. r';': ‘
Sunnyside Mining Area
The "ghost town" of Sunnyside lies in the center and on the west
side of the Huachuca Mountains. It can be reached by driving two miles
from the Montezuma Pase-Canelo Road up Copper Glance Canyon*
The Eureka and the Copper Glance mines lie farther up Copper Glance Canyon. These mines were operated about the turn of # e e#atury by a small religious sect living in Sunnyside* Specimens containing native copper and reported to resemble the copper ©ree In the Keeiree- nawan lavas of northern Michigan are said to outcrop in Copper Glance
Canyon5 . A large slab of native copper from the Huachuca Mountains is on exhibit in the mineralogy museum of the University of Arizona*
It may have come from Copper Glance Canyon* Copper carbonate showings
are reported ffom a. group of claims near the Sylvania Ranch.
Fort Huachuca Military Reservation
- Numerous stories have been told about the richness and the large amount of ore to be found on the Military Reservation, especially with
reference to gold. Skepticism regarding the validity of these stories is eoBBon* " vV' - ‘ : -v ; '
• During the course of the field work not one specimen of mineralized
float was found in the canons and washes, and only a few outcrops showing mineralization were seen*
On the east side of the ridge west of Sycamore Canyon, a veinlet of galena one eighth inch thick was found in the Abrigo formation* 0m
the north side of Huachuca Canyon, several c&lcite stringers less tiMm
one inch thick, containing copper carbonate, were found in the Devonian
-66-
53 Private engineering report*
Martin liiaeatone noar the Crest Llne fault, , . '
Fluorite veins less than one inch thick were found in^the pre-, Cambriem granite north of the north gate to Fort Huachuca. Fluorite and lead minerals are reported from Blackball Canyon but have not been found by the writer. , : ^
' , .. • 4- - ■ -j • - - '■■■*- • • i - . - ■ , ' - i! »* * * ■. •
V; WATER SUPPLY - ..:V , ,V
'] , , r.-- \..L : J. .1 C" i'i :. v: " . ' '■The Huachuca Mountains because of their greater height receive
more rainfall than most ranges in southeastern Arizona. This relative
abundance of water was in part responsible for the establishment of :
Fort Huachuca there in 1881. Until the outbreak of World War II, the .
Fort received. all of its simply from springs and shallow wells in•v* -Garden, McClure, and Huachuca Canyons. The expansion of the Fort .
during.World War II created a demand for a larger and more dependable source of water. On the recommendation of the ground water division of the U. S. Geological Survey, deep wells were. sunk in the valley fill
r, cwist of the range.
... Tombstone, Arizona, also received its water from the Huachucas.
Its source was in the springs and shallow wells located in the canyons• . . . . . .. - '• ■ * - . . . » • ’• •• • - - ' ' * • • • •• •
south of the Fort Huachuca Military Reservation. Tombstone was drill-... • . t • . ■ ■ • ' •• ' - • * ' • ' ' -
ing for water within its city limits during 1947. The success of this
program is not known to the writer. ..... . .... , . ,
The water supply la the northern part of the Huachuca Mountain can
be classified into two groins s the deep wells and the shallow wells or
springs. >L: UT : \ ' v* . >.
The deep wells are located north and east of the Basin Range fault
and are drilled into the valley fill. The water table drops rapidly just
east and north of the Basin Range fault because of the relative pervious
ness of the fill. Farther east the water table slopes gently toward the
San Pedro River. Plate 4 shows the nature of this drop off by contour
lines, drawn on the elevation of the water table. The reader who wishes
further information is referred to the offices of the ground water divis
ion of the TJ. S, Geological Survey in Tucson, Arizona.
The shallow wells and springs are located south and west of the
Basin Range fault, in the valleys and canyons of the Huachucaa, Here
the rocks are relatively impervious, with the exception of water solution
crevices through the limestones, and if water is found at all it should
be close to the surface. Wells dug in the alluvium at the lower end of the valleys should all reach water at shallow depths (less than 30 feet).
It is much easier to locate a spring than to dig a well.
In general, the springs are formed in the following pattern. Some of the precipitation finds its way into the permeable rooks, usually
limestones, which have developed solution channels and caves. There it soon reaches the water table. The impermeable beds check the water and
compel it to follow the contact between the permeable and Impermeable
beds to the point where it is cut by a canyon. There it issues forth as a spring. Figure 2 shows diagrammatically where these springs are located.
The springs in the northwest corner of the range are related to
the Crest Line thrust fault. The Paleozoic limestones and limestone
fault breccia lie on Cretaceous red shales, which are relatively im
permeable. The water follows this thrust down dip to the north and
-68-
issue forth as springs where this contact has been exposed by erosion# Pumping operations at the Manila Mine were stopped by court injunction in 1928, when the Pyeatt Ranch spring ran dry. Figure:! shows dia- grammatlcally the relations of these springs to geologic structure.
" -70 -
Figure I
i t - 4"
'H.r-
Me Fad in Spring P yeett SpringManila , Mine
Crest Line thrust ~ fault
WESTEASTLooking South
# indicates spring
llynestone breccia
__— ' —~^Z.
Impervious^ Lower ^ Cretaceous
NORTH Looking East SOUTH
DIAGRAMMATIC STRUCTURE SECTIONS SHOWING OCCURRENCE OF SPRINGS IN THE MANILA
MINE AREA
Figure 2
profile along canyon floor
* Impervious *, flR gran ite *
a \ 1 * ——^•oPirvlou.'\5.*GiTo‘f6onglomerate
EASTWESTBasin Range faultL y le P e a k f a u l t Crest Line fault
e indicates spring
DIAGRAMMATIC CROSS-SECTION OF THE HUACHUCAMOUNTAINS, SHOWING RELATION BETWEEN PERMEABILITY OF ROCKS, AND THE OCCURRENCE OF SPRINGS
-72-
„ BIBLICKHtAPHY
Alexis, 0.0. The geology of the Lead Mountain area, Pima County, Arizona: Dnir. of Ariz., *. S. thesis, unpublished, 1939.
Billings, M.P. Structural geology* Prentice-Hall Inc., New York, N.Y* 1942.
Bryan, Kirk San Pedro valley, Arizona, and the geographic cycle (abstract): Geol. Soc. Aa. Bull., vol. 37, no. 1, March 1926.
Butler, B. S. Geology and ore deposits of the Tombstone District, Arizona* Ariz* Bur. of Mines, Geol. Series 10,Bull. U 3 , 1938.
Some Arizona ore deposits: Ariz. Bureau of Mines, Geol. series, no. 12, Bull. no. 145, October, 1938.
Cahalam, V.H. Mammals of the Chiricahua Mountains, Cochise County, Arizona* Jour, of Mammology* vol. 20, November, 1939.
Barrow, R, A. Arizona range resources and their utilization, I, Cochise County* Unix, of Ariz., Coll, of Agri., Tech. Bull. 103, 1944. r
Daugherty, L.H. The Upper Triassic flora of Arizona* Carnegie Institution of Wash., Pub. 526, 1941.
Elsing, M,J# and Heln«mn, R.E.S., Arizona TOtal production: Aria,Bur. of Mines, Dnir. of Aris. Bull. 1*0, 1936.
Path, J. H. Permian stratigraphy and structures. Northern Canelo Hills, Arizona* Am. Assoc. Petroleum Geologists Bull. vol. 32, 1948.
The geology of the Northern Canelo Hills, Semta Cruz County, Arizona* Uhiv. of Ariz., Ph.D. thesis, 1947.
Gidley, J. W. Fossil proboscides and edentate of the San Pedro Valley, Arizona* U.S. Geol. Survey, Prof. Paper 140-B, Jan. 1926. ,
•73-
GiUully, James Thrust faulting in the Dragoon Mountains, Arizona (abstract): Geol* Soc. Am. Bull., vol. 52, ne. 12, pt. 2, December, 1939#
Girty, G* H«
Emplacement ef the Uncle Sam Porphyry, Tombstone District, Arizona, Am* Jour. Sci. vol. 243, me# 12, December, 1945#
Paleontology of the Manzano group of the H e Grande Valley, New Mexico: TJ* S. Geol. Survey, Boll# 389, 1909.
Hill, R. T. The paleontology of the Cretaceous formation of Texas: The invertebrate paleontology of the Trinity division: Proc. Biol* Soc* Wash., 1893.
Islay, R. W. Paleogeographic studies in northeastern Sonorai Geol. Soc. Am. Bull., vol. 50, 1939.
King, R. E, Geological reconnaissance in Sierra Madre Occidental of Mexico: Geol. Soc. Am. Bull, vol. 50, 1939.
Knowlton, F. H. The fossil forests of Arizona: American Forestry, vol. 19, 1913#
Laslty, S, G. Geology and ore deposits of the Little Hatchet Mountains, Hidalgo and Grant Counties, New Mexico: U. S. Geol* Survey, Prof* Paper 208, 1947.
McKee, E. D, Triassic pebbles in northern Arizona containing invertebrate fossils: Am. Jour. Sci., 5th series, vol. 33, 1937.
Ransome, F.L. Geology and ore deposits of the Bisbee quadrangle, Arizona: U. S. Geol. Survey, Prof. Paper 21, 1904.
Stoyanow, A. A* Correlation of Arizona Paleozoic formations: Geol* Soc* America Bull*, vol. 47, 1936.
Lower Cretaceous stratigraphy in southeastern Arizona: Geol. Soc. Am., Mem. no, 36, 1949#
Swartb, H, S. Birds of the Huachuco. Mountains: Pacific Coast Avefatma No. 4, Cooper Ornithological Club of California*
Taliaferro, N. L* Upper Cretaceous sediments in Mexico: Jour.Geol* vol. 41, 1933*
Wilson, E. D. Geology and ore deposits of the Courtland-Gleeaon region: Univ. of Ariz. Bull. 123, 1927*
PLATE 7
A - View of Bobocomari valley taken from northwest corner of the
Huachuca Mountains# The mill site of the Panama Mine appears
in the middle foreground# The Mustang Mountains appear against
the skyline in the middle background# To the right (east) of
the Mustangs, the Whetstone Mountains form the skyline#
B - View of the northern end of the Huachuca Mountains#
(1) Blacktail Canyon
(2) Fault scarp of the Basin Range fault
(3) Sycamore Canyon
(4) Hill of limestone breccia
P/a/ e 7
PLATE 8
Thunderstorm forming about noon over the Huachuca Mountain
in August, 1947#
Thunder shower over the eastern end of the Mustang Mountains*
Viewed from the northern end of the Huachuca Mountains,
August, 1947#
Plaie
A
PLATE 9
A - Upper and smaller picture. View of the southwest corner of
Huachuca Peak looking across McClure Canyon# Paleozoic strata
are faulted over Cretaceous strata along the Crest Line thrust
fault* The fault dips about 45 degrees to the northeast, but
since this view is taken nearly normal to the strike of the
fault the angle appears to be much less#
B - Lower and larger picture# View of the northeast side ofHuachuca Canyon and Huachuca Peak, showing Paleozoic strata
faulted over Cretaceous strata along the Crest Line thrust fault*
0-
NorthWest
SourtkjE’aLS't
< Look Sf’o f/o>iHU.O. o/» K C O u PcokA
North e*.st Serstii wej/
PLATE 10
A - View taken looking south across Garden Canyon toward Scheelite
Ridge# The Paleozoic beds are dipping southwest 40 degrees#
B - View of Huachuca Peak from the south showing the Paleozoic beds
faulted over the eastward dipping Cretaceous beds#
(1) Devonian Martin limestone
(2) Mississippian Escabrosa limestone
(3) Pennsylvanian Naco limestone
(4) Lookout station on Huachuca Peak
R/afc /O
£nst West
PLATE 11
A - Bedding Cambrian laminae in Bolsa quartzite® Picture taken
near road in Huachuca Canyon.
B - Cross-bedding in Cambrian Bolsa quartzite® Notice coarser gravels
in this formation® Picture taken near road in Huachuca Canyon®
0
Plate //
PLATE 12
A - Mlsslsslpplan Esoabrosa limestone lying in fault contact
on the Abrigo formation north side of Garden Canyon*
B - Abrigo formation exposed in road cut in Garden Canyon
Plate IS
PLATE 13
A - View of Lyle Peak from the southeast, showing steeply southwest
dipping Permian limestone beds*
B - Gently southwest dipping Permian limestones in the upper part of
Garden Canyon west of the Garden Canyon fault*
Pta+e 13
B
PLATE 14
A - View of Lower Cretaceous limestone conglomerate from the south
at a point near the Sylvania Ranch• The ridge is a southwest
spur off Peterson Peak. The vertical dip of the beds is shown
on the small peak in the right hand side of the picture»
B - Transverse section of Araucarioxylon sp. This specimen was
collected from a sandstone bed east of and near the Eureka Mine
tunnel.
Description of section.
Annual rings not distinct; no resin ducts; uniseriate rays.
Magnification xlOO
A
PLATE 15
A - Radial section from same specimen of Arajicarloxvlon sp.
shown in Plate 14*
Description of sections
Uniseriate and sometimes biseriate bordered pits (typical
Araucarian pitting) on the radial walls of tracheids*
Magnification x 100•
B - Tangential section of above •
Description of sectionsNo pits ontangential rails of tracheids• rays uniseriate
from one to 18 or 20 cells high; no branch traces, thus
ruling out genus Woodworthia.
Magnification x 100.
Plats ]5
PLATE 16
A - Oyster bank in the Lower Cretaceous limestone formation. The
exposure is about two miles up Parker Canyon from the Montezuma
Pass Road. The Lower Cretaceous beds in Parker Canyon are near
vertical. In this picture the hammer head is horizontal, while
the handle roughly approximates the dip of the beds. The yellow
shale beds to the right (east) of the oyster reef contain many
remains of Glauconia branneri.
B - A closer view of the oyster bank described above.
Plate 16
PLATE 17
A - Specimens of Ostrea ragsdolei found in the oyster reef
illustrated on Plate 16• About 1/6 natural size.
B - Specimens of Glauconla branneri found near the oyster reef
illustrated on Plate 16. About natural size.
P/ate 17
PLATE 18
A - Looking north across the head of Rough Canyon on the west
slopes of the Huachuca Mountains* All the beds shown are
of Lower Cretaceous age* The northward dipping ridge shown
in the middle foreground is the nose of the Rough Canyon anti
cline, which plunges to the northwest*
B - Same as A above.
P/afe f 8
West S O L j t
A
V
West SosT
B
PLATE 19
A - Lower Cretaceous strata seen looking north from up the south
fork of Huachuca Canyon• The axis of the Rough Canyon syncline
passes through the low point on the skyline in the extreme left
(west) of the picture*
B - Vertical Lower Cretaceous strata of the upper clastic formation
about one mile up Parker Canyon from the Montezuma Pass road*
The prominent beds are conglomerate containing some pieces of
volcanic origin* The weak beds shown are red and yellow shales*
Plate 1
A
j.s'Oj
T
PLATE 20
A - Cretaceous beds on the west side of the Huachuca Mountains
up Algerita Canyon and about 3/<4 miles east of the Foster
Ranch buildings# The strata appear to dip east (right) but
actually dip west (left) 65 degrees# The limestone formation
is exposed in the saddle shown in the lower middle foreground
of the picture*
B - Cretaceous strata seen looking eastward into the head of
Algerita Canyon* These beds appear to dip east but actually
dip steeply to the west*
P la te 2 0
iVesV'
A
)VesY ^ a -sT
PLATE 21
A - Sandstone, siltstone and tuff beds found in the Tertiary
volcanics» This exposure is one mile up Collins Canyon, which
is located in the southwest corner of the area mapped (Plate !)•
Collins Canyon runs into Parker Canyon about one hundred yards
west of the Hathaway Ranch buildings.
B - Closer view of A above. These beds are sandstones probably
derived in part from earlier volcanic flows. The material
shown breaks out as flag stones one to two inches thick and from six to eighteen inches in length and breadth.
Plate 21
PLATE 22
A - Flat lying sandstones, tuffs and conglomerates# These beds are
found interbedded with the Tertiary volcanic flow. The exposure
is in the stream bed of Parker Canyon downstream (west) of the
Montezuma Pass Road and upstream (east) from the Hathaway Ranch
buildings# These beds are believed to lie stratigraphically
in the same position as the beds illustrated on Plate 21#
B - Tertiary rhyolite porphyry flow exposed in Parker Canyon down
stream from the Hathaway Ranch buildings# The angular inclusions are of volcanic origin and are found throughout the flow#
Top
PLATE 23
Pliocene Gila conglomerate exposed north and within 200
yards of the Basin Range fault in the drainage of Sycamore
Canyon* These beds are semi-consolidated* The boulders
are primarily from earlier Tertiary volcanic flows, but
boulders derived from the Paleozoic limestones are also
found*
Same as above
PLATE 24
A -
B - Pliocene Gila conglomerate exposed near Basin Range fault in
Sycamore Canyon. The boulder upon which the hammer rests is
derived from post Tertiary volcanic conglomerate made up of
Tertiary volcanic rocks and Paleozoic limestones.
Plate 2 f
r
B
PLATE 25
A - Exposure of semi-consolidate silt stones, clays and sandstones
in the creek down stream and within two hundred yards of the Elgin
railroad station. These beds contain completely weathered vol
canic fragments from one to five inches in their longest dimension.
They are believed to be equivalent to the Gila conglomerate shown
in Plates 23 and 2A but are finer because they were deposited
farther away from the source.
B - Same as above. The faulting and tilting of beds since their
deposition are shown in this view.
Plate 25
PLATE 26
A - View seen looking southeast down Garden Canyon from on top
Permian limestone ridge. Mississippian Escabrosa limestone
is faulted over east dipping Lower Cretaceous beds along the
Crest Line thrust fault#
B - Closer view of Crest Line thrust fault# This is the same area
shown in the left side of A above#
P/af e
2 6
Av>
A Z5
PLATE 27
Huachuca Peak as seen from the southwest* The Paleozoic beds
are faulted over the Cretaceous along the Crest Line thrust
fault* The eastward dip of the Cretaceous can be discerned
just above the point marked x on the photograph* Note the
drag folding in the Pennsylvanian strata*
View of the southeast spur of Huachuca Peak, taken from the
south across McClure Canyon*
Plate 27
ft/eirth VV G'S'f' S o i m TH © cu T*
6
PLATE 28
A - Looking west along the scarp of the Basin Range fault on the
northern edge of the Huachuca Mountains in the drainage of
Sycamore Canyon. On the left (south) is the upthrown pre-
Cambrian granite forming the foot wall of the fault. To the
right is Pliocene Gila conglomerate which forms the hanging
wall of the fault.
B - Same area as in A above but looking south toward the Huachuca
Mountains. Notice the gorge cut in the pre-Cambrian near the
fault. Further south the stream is not so deeply entrenched
nor is its gradient as steep as that near the fault.
Plaie 2 8
9
A
PLATE 29
A - Closer view of gorge described on Plate 28. The abrupt change
in gradient is seen near point x. The Basin Ranch fault is
less than 100 yards north of this point*
B - Another view of A above except at a greater distance* In the
background and forming the skyline is the northern end of the
Huachuca Range* The grass covered slope in the foreground is
underlain by Pliocene Gila conglomerate* Notice the fault
surface in right (west) side of the picture* This surface
is nearly a smooth plane*
P/afe
29
West
CD
E X P L A N A T I O NSEDIMENTARY ROCKS IGNEOUS ROCKS
volcanic k*ockQ u a te r n a r y and TertiaryCenozoid
u pper c la s t ic -fot-mcdion P f -e - 'C | /4R^r| g r a n i t e
l im es to n e form ation SYMBOLS
\owe<rClasrte fo r m a t ; . , . ------)
l im estone conqlomerorfe■i *
- ^ Idefin ite con tac t-»• ^ raul+j sJipwi-ng dip ( ^het~e
l im e s t o n e
( » < • .) Fault showing relative m ove m en t Trfust or low angle reverse fau/ft( X upper Plate) .Avffic,lrne ,(sho*n-nq Yre-cr »f axial — — p I cm e ) . poshed' where a.ppro%- iwted-ely located.
A/aco h m eston c a n d _ _ v / , , , ^ , ,.E s c a t o r o s a h m es+ on e - 1 + ? - Doubtful or probable a -it ie l.p e
. - Sync!me Cshowmq tra-oe of axiaj plane,_ 1 ****> / # ted ^^<r6 'apprex/mcCtely
M a r t i n l i m e s t o n e Doubtful or proijajjfe syncJt'ne
/■so S tr ik e an d d ip o f b e d sAbrigo and. C o c h is e ><30 S t r i k e and dip of o v e r tu rn e d beds torm aTro/TS
So/s a q u a r t 2.1 fe/ t o S t r i k e of v e r t i c a l b eds
6* H o r iz o n ta l beds
P L A T E 2
\ > A/c //___wsw
j 7500- - 7000
/ Kuc
W
7500 - ■ 750Q ■■ 7000 •" Co50C
7000
-- 4000 - - 3500
\
^500 y fOOO --7500 -- 7000 " 650O --(oDGO ~ ■
#000
\ ' \ -■ 4500 *-4ooo -- 3 5 0 0
700 0 t 70(00 " 6 5 0 0 -- 6000 "55( 0
Z < /
/ C n/ i
3 5 0 0
GEOLOGIC S T R U C T U R E SECTIONS OF T H E N O R T H E R N P A R T OF T H E H U A C H U C A M O U N T A I N S A L O N G LINES S H O W N ON P L A T E |Sc die 3/ 6 y c
0 yi 1 I?* 2 m i /q s1 1 1 ■— Le— ■e—*- - ^
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A 0 Q
PLATE 3
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CASA G R A N D E
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Little Ha.tc.hAt Me.\u*nia.!vsSierra. De Los Ajos Sierra . De S a n Jo^e P a t a g o n i a . M o u n t a / e sO ESQUEDA
MAGDALENA
O h a c o z a r i
MONTEZUMA
S A H U A R f P AO H ER NI OS l LL O
A R i V E C H f O
INDEX M A P
TJOTTED S T A T E SD E P A R T M E N T O F T H E IN T E R IO R
THE TOPOGRAPHIC MAPS OF THE UNITED STATES
ey is making a series of e United States. This
and the published maps country, exclusive of outlying
The United States P? standard topographic work has been in progr cover more than 47 percent possessions.
The maps are published on sheets that measure about 16£ by 20 inches. Under the general plan adopted the country is divided into quadrangles bounded by parallels of latitude and meridians of longitude. These quadrangles are mapped on different scales, the scale selected for each map being that which is best adapted to general use in the development of the country, and consequently, though the standard maps are of nearly uniform size, the areas that they represent are of different sizes. On the lower margin of each map are printed graphic scales showing distances in feet, meters, miles, and kilometers. In addition, the scale of the map is shown by a fraction expressing a fixed ratio between linear measurements on the map and corresponding distances on the ground. For example, the scale 5 55 means that 1 unit on the map (such as 1 inch, 1 foot, or 1 meter) represents 62,500 of the same units on the earth’s surface.
Although some areas are surveyed and some maps are compiled and published on special scales for special purposes, the standard topographic surveys and the resulting maps have for many years been of three types, differentiated as follows:
1. Surveys of areas in which there are problems of great public importance—relating, for example, to mineral development, irrigation, or reclamation of swamp areas—are made with sufficient detail to be used In the publication of maps on a scale of 5-555 (1 inch = one-half mile) or -555 (1 inch = 2,000 feet), with a contour interval of 1 to 100 feet, according to the relief of the particular area mapped.
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The aerial camera is now being used in mapping. From the information recorded on the photographs, planimetric maps, which show only drainage and culture, have been made for some areas in the United States. By the use of stereoscopic plotting apparatus, aerial photographs are utilized also in the making of the regular topographic maps, which show relief as well as drainage and culture.
A topographic survey of Alaska has been in progress since 1898, and nearly 44 percent of its area has now been mapped. About 15 percent of the Territory has been covered by maps On a scale of —555 (1 inch = nearly 8 miles). For most of the remainder of the area surveyed the maps published are on a scale of 55 (1 inch = nearly 4 miles). For some areas of particular economic importance, covering about 4,300 square miles, the maps published are on axscale of 5 55 (1 inch —nearly 1 mile) or larger. In addition to the area covered by topographic maps, about 11,300 square miles of southeastern Alaska has been covered by planimetric maps on scales of and 5 ^ .
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The features shown on topographic maps may be arranged in three groups— (1) water, including seas, lakes, rivers, canals, swamps, and other bodies of water; (2) relief, including mountains, hills, valleys, and other features of the land surface; (3) culture (works of man), such as towns, cities, roads, railroads, and boundaries. The symbols used to represent these features are shown and explained below. Variations appear on some earlier maps, and additional features are represented on some special maps.
All the water features are represented in blue, the smaller streams and canals by single blu^ lines and the larger streams by double lines. The larger st:'earns, lakes, and the sea are accentuated by blue water lining or blue tint. Intermittent streams—those whose beds are dry for a large part of the year— are shown by lines of blue dots ai d dashes.
Relief is shown by contour lii es in brown, which on a few maps are supplemented by shading showing the effect of light thrown from the northwest across the area represented, for the purpose of giving the appearance of relief and thus aiding in the interpretation of the contour lines. A contour line represents an imaginary line on the ground (a contour) every part of which is at the same altitude (ibove sea level. Such a line could be drawn at any altitude, but in practice only the contours at certain regular intervals of altitude are shown. The datum or zero of altitude of the Gd logical Survey maps is mean sea level. The 20-foot contour w arid be the shore line if the sea should rise 20 feet above nwau sea level. Contour lines show the shape of the hills, mountains, and valleys, as well as their altitude. Successive contour lines that are far apart on the map indicate a gentle slope, lines that are close together indicate a steep slope, and lines that run together indicate a cliff.
The manner in which contour lines express altitude, form, and grade is shown in the figure jtelow.
ing spurs separated by ravines. The spurs are truncated at their lower ends by a sea cliff. The hill at the left terminates abruptly at the valley in a steep scarp, from which it slopes gradually away and forms an inclined tableland that is traversed by a few shallow gullies. On the map each of these features is represented, directly beneath its position in the sketch, by contour lines.
The contour interval, or the vertical distance in feet between one contour and the next, is stated at the bottom of each map. This interval differs according to the topography of the area mapped: in a flat country it may be as small as 1 foot; in a mountainous region it may be as great as 250 feet. In order that the contours may be read more easily certain contour lines, every fourth or fifth, are made heavier than the others and are accompanied by figures showing altitude. The heights of many points—such as road intersections, summits, surfaces of lakes, and benchmarks—are also given on the map in figures, which show altitudes to the nearest foot only. More precise figures for the altitudes of benchmarks are given in the Geological Survey’s bulletins on spirit leveling. The geodetic coordinates of triangulation and transit-traverse stations are also published in bulletins.
Lettering and the works of man are shown in black. Boundaries, such as those of a State, county, city, land grant, township, or reservation, are shown by continuous or broken lines of different kinds and weights. Public roads suitable for motor travel the greater part of the year are shown by solid double lines; poor public roads and private roads by dashed double lines; trails by dashed single lines. Additional public road classification if available is shown by red overprint.
Each quadrangle is designated by the name of a city, town, or prominent natural feature within it, and on the margins of the map are printed the names of adjoining quadrangles of which maps have been published. More than 4,100 quadrangles in the United States have been surveyed, and maps ofthem similar to the one on the other side of this sheet havebeen published.
The sketch represents a river valley that lies between two hills. In the foreground is the sea, with a bay that is partly enclosed by a hooked sand bar. On each side of the valley is a terrace into which small streams have cut narrow gullies. The hill on the right has a rounded summit and gently slop-
maps have been published in the form of folios. Each folio includes maps showing the topography, geology, underground structure, and mineral deposits of the area mapped, and several pages of descriptive text. The text explains the maps and describes the topographic and geologic features of the country and its mineral products. Two hundred twenty-five folios have been published.
Index maps of each State and of Alaska and Hawaii showing the areas covered by topographic maps and geologic folios published by the United States Geological Survey may be obtained free. Copies of the standard topographic maps may be obtained for 10 cents each; some special maps are sold at different prices. A discount of 40 percent is allowed on an order amounting to $5 or more at the retail price. The discount is allowed on an order for maps alone, either of one kind or in any assortment, or for maps together with geologic folios. The geologic folios are sold for 25 cents or more each, the price depending on the size of the folio. A circular describing the folios will be sent on request.
Applications for maps or folios should be accompanied by cash, draft, or money order (not postage stamps) and should be addressed to
THE DIRECTOR,United States Geological Survey,
November 1937. Washington, l). C.
.m a .jnfr-- ------- yB r a n s Cliff
dwelling
S T A N D A R D S Y M B O L S
C L i T U R E(printed #j black)
NOTE:—Effective on ami after October 1, 194H, the price of standard topographic quadrangle maps will be 20 cents each, with a discount of 20 percent on orders amounting to $10 or more at the retail rate.
Toeud private r o a d.Trail Eleetfic r«i Ire < < I Tunnel P o w e r
t r a n s m i s s i o nline
W h a r v e s B r e a k w a t e ra n d j e t d e s
H E * M BBridge Drawbridges Ferry
(•point upstr'aam )
P a m with lock C a n a l l o c k U S . t o w n s h i p a n d State line County" line! p o i n t v p o tn o a m Section lillCS
a n d r e c o v e r e d c o m e r s
> Township ■ >1 li strict line
Le" ’] ffl j nB o u n d a r y B e n c h m a r k m o n u m e n t (auj-plementcay benofi
rruirto shown. Ijy oroma andblat'ht dffuros without
I + tta r in g j
Cemereries Church, School Coke ovens(ebiatuu/taxhod on
rmoont rruxps)
T a n k s a n d oil reservoir-h
Oil a n d gas wells
R E L I E F1 printed in brown)
Iteservatimih n e
M i n e o r quarry P r o s p e c t
L a n d grant o rn e
S m a l l p a r k o r h-rangedalion (J. S . m i n e r a l c e m e t e r y line point or transit- m o n u m e n t
traverse station
Shaft. M i n e tunnel Mine tunnel(showing direction)
. L.S S. . c as
Lighthouse or b e a c o n
C o a s t G u a r d station
Elevation a b o v e m e a n s e a level
(in biaok >n rv<wmt mapa)
W a s h
| C o n t o u r sWConi. ’/rm \\owingprxri: «t Hi, Vb<* /
fof' sTionyx if)
D e p r e s s i o ncontoxmef%
L e v ee Streams
WATER(printed in blue)
.ills a n d tpids
Intermittent s t r e a m s and.
ditches
, ^ U!M i n e d u m p s
mitring dfjfcd-is
A.*
p tha111 a*>y p
_Aroians 01 longitux. juadndifferent scales, the scale selected for each map being that which is best adapted to general use in the development of the country, and consequently, though standard maps are of nearly uniform size, the areas that they represent are of different sizes. On the lower margin of each map are printed graphic scales showing distances in feet, meters, miles, and kilometers. In addition, the scale of the map is shown by a fraction expressing a fixed ratio between linear measurements on the map and corresponding distances on the ground. For example, the scale 5 55 means that 1 unit on the map (such as 1 inch, 1 foot, or 1 meter) represents 62,500 of the same units on the earth’s surface.
Although some areas are surveyed and some maps are compiled and published on special scales for special purposes, the standard topographic surveys and the resulting maps have for many years been of three types, differentiated as follows:
1. Surveys of areas in which there are problems of great public importance—relating, for example, to mineral development, irrigation, or reclamation of swamp areas—are made with sufficient detail to be used in the publication of maps on a scale of — (1 inch = one-half mile) or — (1 inch = 2,000 feet), with a contour interval of 1 to 100 feet, according to the relief of the particular area mapped.
2. Surveys of areas in which there are problems of average public importance, such as most of the basin of the Mississippi and its tributaries, are made with sufficient detail to he used in the publication of maps on a scale of ^ (1 inch = nearly 1 mile), with a contour interval of 10 to 100 feet.
3. Surveys of areas in which the problems are of minor public importance, such as much of the mountain or desert region of Arizona or New Mexico, and the high mountain area of the northwest, are made with sufficient detail to he used in the publication of maps on a scale of —55 (1 inch = nearly 2 miles) or — 5 (1 inch = nearly 4 miles), with a contour interval of 20 to 250 feet.
The aerial camera is now being used in mapping. From the informat ion n v oiritri on the nhotoir ranhs . nlanimetrin mans.
.
C a n a l s o r ditehes
m n
A q u e d u c t s o r water-pipes
Aqueducttunnels L a k e o r pond.
TIri s u r v e y e d s t r e a m a n d
a b a n d o n e d c a n a l
Intermittent lake
Glariet
W O O D S(w‘U» ehown, printed in green)
ripring Well M a r s h S u b m e a • g'ecl
> as; u
I iti
i....some earlier maps, and additional features are represented on some special maps.
All the water features are re .-resented in Blue, the smaller streams and canals by single blue lines and the larger streams by double lines. The larger streams, lakes, and the sea are accentuated by blue water lining or blue tint. Intermittent streams—those whose beds are dry for a large part of the year— are shown by lines of blue dots and dashes.
Relief is shown by contour flues in brown, which on a few maps are supplemented by shading showing the effect of light thrown from the northwest acroLs the area represented, for the purpose of giving the appearance of relief and thus aiding in the interpretation of the contour lines.
This interval differs according to the topography of the area mapped: in a flat country it may be as small as 1 foot; in a monnbtiimm region it may be as gm il as 250 feet. In order
scuts an imaginary line on the of which is at the same altitude
A contour line repreground (a contour) every part above sea level. Such a line
could be drawn at any altitude, but in practice only the contours at certain regular intervals of altitude are shown. The datum or zero of altitude of the Geological Survey maps is mean sea level. The 20-foot contour would he the shore line if the sea should rise 20 feet above mean sea level. Contour lines show the shape of the hills, mountains, and valleys, as well as their altitude. Successive contour lines that are far apart on the map indicate a gentle slope, lines that are close together indicate a steep slope, and lines that run together indicate a cliff.
The manner in which contour lines express altitude, form, and grade is shown in the figure below.
that the contours may be read more easily certain contour lines, every fourth or fifth, are made heavier than the others and are accompanied by figures showing altitude. The heights of many points—such as road intersections, summits, surfaces of lakes, and benchmarks—are also given on the map in figures, which show altitudes to the nearest foot only. More precise figures for the altitudes of benchmarks are given in the Geological Survey’s bulletins on spirit leveling. The geodetic coordinates of triangulation and transit-traverse stations are also published in bulletins.
Lettering and the works of man are shown in black. Boundaries, such as those of a State, county, city, land grant, township, or reservation, are shown by ■continuous or broken lines of different kinds and weights. Public roads suitable for motor travel the greater part of the year are shown by solid double lines; poor public roads and private roads by dashed double lines; trails by dashed single lines. Additional public road classification if available is shown by red overprint.
Each quadrangle is designated by the name of a city, town, or prominent natural feature within it, and on the margins of the map are printed the names of adjoining quadrangles of which maps have been published. More than 4,1(X) quadrangles in the United States have been surveyed, and maps of them similar to the one on the other side of this sheet have been published.
Geologic maps of some of the areas shown on the topographic maps have been published in the form of folios.. Each folio includes maps showing the topography, geology, underground structure, and mineral deposits of the area mapped, and several pages of descriptive text. The text explains the maps and describes the topographic and geologic features of the country and its mineral products. Two hundred twenty-five folios have
1 • 1 V 1 1 . ■ 1 » >-x - 1
P L A T E 5
t e r r a c e g r a v e l s-------------- u n v o n f o t - r r t i i y ------------
G//a Conglomerate .C .o n t< xc .t m art s e e u n c , o n f o r m / t \ C1? ~
,'Q 9 A P.V
r h y o l i t e p o r p h y r y t / o w s + U f f S , CLnd a g g / o m e r a t
contact not seenunconformity (?)
u p p e r e l a s t i c f o r m a t t o n (sandstones, shales, <xncL c o n g t o m e r a t e s )
/ o w e r c / a s / / c. t o r iv at 'on
(sandstones , sho-les, xnd. vole an I c, tio )
/ 1 m r s t o / y e c o / i g / e m e r-o J e
r . . imostly dio.*-K limestonessome rea c/a-sf/v heUs
-i 2 u Li P e r n s y a.ni <x. - p e r m
N a c o l i m e s t o n e
Ii m est oneE s cabr o s <x
/ W e t / v? / i n i e s t o n €
A brig o f i r>C o c>i / S g. _t_m .B o l S a c f v a r t z. i te
u n c o n f o r / r
Rre - Cambr.ar coarse granite
G E N E R A L I Z E D C O L U M N A R SECTION H U A C H U C A M OUNTAINS, A R I Z O N A
o to oo u.ooo 3 co o 4 c c o ffooo 6000 f e e t I r— 1 , ' , 1 . ' , 1 v— 1 _ .
S O 0 I S O O Z S O O 3 S O O 4 B O O S S O O -Tc CT
c o m a r/ ft/%
/ S y c xm orc Can vo/7• /k Ccipturinq 1 n<t
J Q'-ct/ttAae oT yRfctaKfail Wasn
/ °
U \ ,/J iaij r S c a l e : one inch =r one m i ie
> o o I n c h ' c a t es/ / / n i t s o f jb a s / n s
PLATE 6 - S T R E A M P I R A C Y N O R T H E R N E N D O F T H E H U A C h U C AM O U N T A I N S
70
Ft ur-Q. 1
I limestoneb r e e d aP.kI^ox. i . c. hrneslone
Af c F'cl a < ri ^>pr i r> j/v'arJa Mine
L.ov^'ir Cretaceous
W e sT
• l/7j/cat e1* t.prnij
\ T
C r e 5" Line thr-vsl
/ / / ' /. ' .
z
Norih\
J m fj C r v I u U 5 zv c. r C retexe e ni'
Soufh
D ia g r a m meet ic. ' S t r u c t u r e • S e c t i o n s S h o w i n g
O c c u r r e n c e o/" S p r i n q s in 1 nc. /Vlanii*, M in e
Area
vs
"d jr* SI
Figure 2. ,3o
profile along canyon floor
p e r v i o u r ^ / P e j r V ' 5 ^
A m astonc
Crest Line Paott B a s i n R a n g e f a u l t• Indlcectes sp r in g
Pi a^ ra t n m a t ic C r o s e - Sec . f i o n o f t h e ZVuac h u o a M o u n t a i n s jS h o w / h g t h e R e l a t i o n b e t w e e n S t r u c t u r e } P e r m e (xb ih t y o*f R o z Ks } and the O c c u r r e n c e of Springs
Sfr !
VNO
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