GEOLOGIC MAP of the DUNCAN and CANADOR PEAK QUADRANGLES ARIZONA and NEW MEXICO by Roger B

DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEOLOGIC MAP OF THE DUNCAN AND CANADOR PEAK QUADRANGLES ARIZONA AND NEW MEXICO By Roger B. Morrison' MISCELLANEOUS GEOLOGIC INVESTIGATIONS MAP 1-442 PUBLISHED BY THE U. S. GEOLOGICAL SURVEY WASHINGTON. D. C. 1965 DEPARTMENT OF THE INTERIOR TO ACCOMPANY MAP 1-442 UNITED STATES GEOlOGICAl SURVEY GEOLOGIC MAP OF. T'HE DUNCAN AND CANADOR PEAK QUADRANGLES ARIZONA AND NE\V MEXICO By Roger B. Morrison PRECA.\1 BRIAN ROCKS Colorado, but the apparent maximum exposed thickness is at least 500 feet and possibly as much as 700 feet. GRANITE The lower part, about 230 feet thick, is gray to black The granite is red, pink, and pinkish gray, generally coarse generally calcareous shale, interlayered with a few to many grained and equigranular, but locally porphyritic. It is com black concretionary limestone beds. The middle part, about posed of red to pink feldspar-mostly microcline with 200 feet thick, consists of zones of olive-gray and gray to variable quantities of oligoclase and locally perthite locally black shale alternating with approximately equally quartz, and commonly small quantities of biotite. Pegmatite, thick zones of pale-gray to white locally pink and tan sand aplite, and diorite dikes and quartz veins occur locally. The stone that are well bedded to thick bedded and locally cross south and southwest boundaries of the granite area are bedded on a small ~cale. The upper part, about 100 feet faults having more than 4,000 feet <;fisplacement. thick, is mainly light-olive to black calcareous shale inter A profound erosion surface, probably of low relief, sep bedded with sandstone. arates the granite from the overlying Beartooth Quartzite. Calcareous shale about 30 feet above the base of the Beneath this surface the upper few feet of the granite is deeply Colorado Formation, in the NWI/4NEI/4 sec. 20, T. 18 S., weathered to a dark-red grus. R. 20 W ., yielded the shallow-water marine pelecypods The granite closely· resembles granite of probable \Pre Cyprimeria(?) sp. and Exogyra co/umbel/a Meek (identified cambrian age exposed in the Big Burro Mountains-Redrock by W. A. Cobban, U.S. Geol. Survey). Exogyra co/umbel/a area (Hewitt. 1959. p. 66-78) east of th·e mapped area, is in rocks equivalent to the Graneros Shale and the lower Knight Peak area (Ballman, 1960, p. 9-10) east of the part of the Greenhorn Limestone. In the SW I /4SE I /4 sec. mapped area. and near Clifton, Ariz. (Lindgren, 1905). 17, T. 18 S., R. 20 W., a limestone bed approximately in the CRETACEOUS ROCKS middl<: of the formation yielded the shallow-water marine BEARTOOTH QUARTZITE pelecypods Ostrea soleniscus Meek and Exogyra cf. E. olisiponensis Sharpe (identified by W. A. Cobban), which The Beartooth Quartzite. is mainly light-gray to almost suggest a Late Cretaceous age, equivalent to that of the white sandstone and orthoquartzite consisting of medium lower part of the Greenho.rn. The Colorado Formation coarse-. and granule-sized grai.ns. The maximum thickness is apparently is approximately equivalent in age. to the Pinkard about 85 feet. The lower two-thirds of the formation is well Formation of the Morenci and other areas in southeastern bedded quartzose sandstone that is locally crossbedded on a Arizona. small scale. The beds are generally 1/2-3 feet thick. The well rounded quartz grains commonly have overgrowths of CRETACEOUS AND TERTIARY(?) ROCKS secondary quartz that firmly cement the rock, making this NONMARINE SHALE, SANDSTONE, AND part of the formation a cliff former. Fine-pebble sandstone CONGLOMERATE and fine-pebble conglomerate interbeds are locally present: A unit consisting of nonmarine shale. sandstone. and the pebbles are chert that probably was derived from chert conglomerate. overlying the Colorado Formation with bearing Paleozoic limestone exposed elsewhere in the region. apparent conformity, is exposed in the slightly dissected The basal several feet is arkosic and was derived from the area of pedimented bedrock north of Riley Peaks. This underlying granite. The upper third of the formation is unit is the approximate equivalent of the Virden Formation. interbedded sandstone and gray to black shale. The top of named by Elston ( 1960) and described by Pradhan and Singh the formation is placed at the t<?P of a 2-foot bed of hard ( 1960). who considered the Virden to be unconformable on silty' orthoquartzite. The formation, which was deposited in a transgressive the Colorado. Poor exposures. especially in sheared zones. inland sea, is nonfossiliferous, and is considered by Paige make it difficult to assess the effect of the faults on repeti ( 1916) to be Late(?) Cretaceous in age; some more recent tion and omission of beds, but the ·apparent maximum ex workers consider it equivalent to the Lower Cretaceous posed thickness of the formation is about I ,500 feet. Dakota qf northeastern New Mexico and adjoining areas. The basal part is a distinctive white thick-bedded sand stone, a marker bed that is locally light gray and light tan. COLORADO FORMATION It is 40 feet thick, commonly contains eolian-type crossbeds, The Colorado Formation consists of marine shale, sand is well indurated. and forms a persistent. minor hogback. stone, minor limestone, and conglomerate and conformably This sandstone is the lowermost definitely subaerial unit in overlies the Beartooth Quartzite. Poor exposures and faulted the Cretaceous sequence. zones preclude accurate determination of the thickness of the The unit is mainly shale. and some sandstone. in its lower 1 part, but it becomes coarser upward, through a middle part unit. Its maxim urn thickness is at least 1,400 feet. The that is sandstone and conglomerate, to an upper part about Datil was first regarded as Oligocene (Winchester, 1921, 230 feet thick that is almost entirely andesitic conglomerate. p. 4), but more recently has been considered to range in age The sandstone is mainly olive green and gray green and from Oligocene to early Miocene (Cooley and Akers, 1961, locally light tan to light gray, mostly soft but locally hard, f~g. 237.2). and commonly tuffaceous. The shale is mainly olive green, The Datil is subdivided into lower and upper units and a yellow green, and olive gray, and locally dark gray to black. local latite-andesite unit. The individual zones (tuffs and The conglomerate is made up mostly of pebbles, cobbles. and flows) within these units differ both in lithologic facies and locally boulders. Except at the top of the unit. the round in thickness, but each unit preserves its general character stones consist of intermediate lavas in a medium to dark throughout the area of exposure. The whole sequence olive-gray tuffaceous, poorly sorted sand matrix. At the appears to be essentially conformable, in spite of small local top of the unit is about 135 feet of conglomerate composed unconformities. All three units are best exposed in the entirely of red granite similar to the Precambrian granite Gila Lower Box-Canador Peak-Rimrock-Deadman Ridge exposed in the mapped area. It is devoid of andesitic debris, area. although it rests conformably on the andesitic conglomerate Lower unit.-The lower unit in the vicinity of Gila Lower that is entirely devoid of granite. Box consists of, from top to bottom: Plant remai~s are locally abundant in the lower and middle Approximate parts of the unit. Sandstone in the middle part yielded the thickness (feet) conifer A raucarites /ongifolius (Lesquereux) Dorf (identified Lithic tuff, pale-yellow to nearly white, weathers by J. A. Wolfe, U.S. Geol. Survey). Pradhan and Singh to darker yellow and tan, massive to very (1960) reported also Salix(?) sp., Juglans. leconteana, thick bedded, well-indurated, prominent cliff Virburnum sp., Canna(?) magnifolia, and Cinnamomum sp.: former; locally at top is a 20:.. to 25-foot zone of they considered these fossils indicative of late Montana to hard (welded?) rhyolitic lithic tuff, red brown early I ance (Late Cretaceous) age. at top, grading downward through pinkish TERTIARY ROCKS gray to light gray . 200 OLDER ANDESITE Lithic tuff, red in upper part, grading down The older andesite is mainly andesite flows and flow ward through orange and yellow to pale yel breccias, with local andesitic tuff and other intermediate low in lower two-thirds . 150 lavas. It is dark gray to black, brown, maroon, and purple. Andesite or latite flow . 25 Spotted greenish-gray andesite which has strong platy struc Lithic tuff, greenish-gray; massive in upper ture is common. The andesite is commonly vesicular, amyg part, well-bedded in lower part. 150 daloidal, and(or) porphyritic, and contains small phenocrysts Lithic tuff, pale-yellow, well-indurated, strongly of plagioclase and mafic minerals. It is commonly closely columnar-jointed; cliff former ........ 10- 30 sheared and somewhat hydrothermally altered or propy Lithic tuff, light greenish-gray, locally light- litized. Its total thickness is difficult to estimate because tan; thick-bedded ............... 10-100 of poor exposures and faulting but it probably is more than Basaltic andesite flow and flow breccia, dark- I .000 feet. gray to black, very lenticular ...... 0- 50 Correlation of the exposures on the west side of Old Camp Lithic tuff, light greenish-gray to light-gray 100 Canyon in the southwest corner of the Duncan quadrangle Total thickness ............ : 645-805 with those in the northeast corner is problematic: the older andesite possibly belongs in the lower part of the young The boundary between the lower and upper units of the basaltic andesite unit. Northwest of Riley Canyon, in the Datil Fqrmation is placed at the conspicuous and persistent Canador Peak quadrangle, the older andesite overlies the contact between the massive thick yellow tuff below and the nonmarine shale, sandstone, and conglomerate unit conform green tuffaceous sandstone zone above.

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