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Tectonics of the Black Basin region of Arizona Vincent C. Kelley, 1958, pp. 136-145 in: Black Mesa Basin (Northeastern Arizona), Anderson, R. Y.; Harshbarger, J. W.; [eds.], Geological Society 9th Annual Fall Field Conference Guidebook, 205 p.

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FIGURE 1. Index map of the tectonic divisions of the Black Mesa basin region. NEW MEXICO GEOLOGICAL SOCIETY • NINTH FIELD CONFERENCE 137

TECTONICS OF THE BLACK MESA BASIN REGION OF ARIZONA

by VINCENT C. KELLEY University of New Mexico

In general, the region of the Black Mesa basin extends The sinuous, locally steep, Defiance forms the from the Kaibab uplift on the west to the Defiance uplift eastern limb, and the broad western limb is part of a low on the east and from about the Utah line on the north to regional inclination into the Black Mesa basin. A few the Mogollon Rim on the south. For the purposes of this small (Sheep Creek, Chinle, and Rock Mesa paper the limits are indefinite on the one hand and ar- locally interrupt the western limb and in a general way bitrary on the other. The field trip passes through only these are followed in drawing the border between the up- a small portion of the Black Mesa basin proper and con- lift and the basin. The crest of the uplift appears to be tinues into adjoining geologic divisions such as the Kaibab formed by several staggered axes. In general most lesser and Defiance uplifts that are clearly not a part of the folds on the uplift parallel each other and the general basin. The region has been partitioned for purposes of trend of the uplift. structural description into a number of minor elements which TYENDE SADDLE surround the Black Mesa basin proper (Kelley, 1955a and Tyende saddle bounds Black Mesa basin on the north- Kelley and Clinton, in press). To many geologists en- east and lies between the Monument upwarp to the north- gaged in stratigraphic studies and exploration all or parts west and the Defiance uplift to the southeast. Its boun- of the surrounding minor structural divisions (fig. 1 ) , such daries are largely arbitrary and gradational except against as the Preston (And Cameron benches, the Tyende and the Comb monocline of the Monument upwarp. The saddle Kaibito saddles, or the Mogollon slope, are within the plunges into the Blanding basin on the northeast and into broad confines or conception of the Black Mesa basin. To the Black Mesa basin on the southwest. The outline of a considerable extent these lesser structural elements are the saddle is irregular, but in general it averages about only justifiable as conveniences in the description of the 40 miles across. The saddle is broad and flat, and its regional structure. Only along a part of the northwestern over-all structural relief is less than 1000 feet. The lowest side of the restricted basin and locally along the eastern part is near the Comb monocline along the Tyende side can the boundaries be said to be clearly defined; (Witkind, Thaden, and Lough, 1952, fig. 4). elsewhere they are arbitrary for there is essentially im- PIUTE BELT perceptible gradation into the surrounding divisions. The The Piute fold belt, along with the Oljeto sag and the nature of these divisions and the reasons for making them southern tip of the Monument upwarp, bound Black Mesa are brought out in the following descriptions of the several basin on the north. The belt consists of several northerly lesser divisions as well as a few of the adjoining uplifts. trending folds most of which are steeper to the east. The BLACK MESA BASIN principal folds are the Organ Rock (fig. 2) and Balanced The restricted Black Mesa basin is a nearly circular Rock . Their strong monoclinal eastern flanks downwarp some 90 mi l es in diameter. It is essentially are set in echelon toward the northwest and form also the equivalent to the Tusayan downwarp of Gregory (1917, eastern boundary of the belt. Folds in the western part p. 112). It is characterized by very low regional dips and of the belt are smaller, the principal linear flex being the shallow structural relief. Below the highest closing contour long Rapids syncline, but the most pronounced fold is the the relief is only about 500 feet. Long, broad, nearly Navajo dome (Kelley, 1955a, fig. 2). The nearly circular parallel folds cross the basin in northwesterly directions. Navajo dome has been presumed by several geologists to Many of these, with dips commonly of only one or two de- be of laccolithic origin (Baker, 1936, p. 71-72), and Joest- grees, are scarcely noticeable without careful mapping. ing (Written communication) points out that aerial mag- The deepest part of the basin is formed by the Black Mesa netic traverses suggest the presence of igneous material be- syncline which extends from the Kaibito saddle on the neath the dome. The rome has a radius of about three miles, northwest to almost the southeastern boundary (see ac- and in that short distance possesses a minimum structural companying map by Doeringsfeld, Amuedo, and Ivey). relief of nearly 2000 feet .It has no obvious elongation Adjoining this syncline on the northeast is the long Cow and it does not possess a ring syncline. It is difficult to Springs which extends into the basin from the ascribe other than an igneous origin for it. northwest south of the Organ Rock anticline. In the north- KAIBITO SADDLE eastern part of the basin the long, curving, Rim syncline and Kaibito saddle bounds the Black Mesa basin on the Black Mountain anticline form the northeastern edge of the northwest and is separated from the basin by the Cow major topographic feature, Black Mesa. The principal de- Springs monocline, which lies along the northwest foot of formation in the southwestern part of the Basin parallels Black Mesa. The saddle trends in a northwesterly direction the curving Mount Beautiful anticline and Howell Mesa and is about 40 miles long and 25 miles wide. Only syncline. Although most of the folds within the basin are parts of the southwestern and southeastern boundaries of parallel and have northwesterly trends, the Big Mountain the saddle along the Red Lake and Organ Rock mono- anticline, and the Oljeto syncline are northerly trending. clines are sharp. Elsewhere, the boundaries are grada- Faults of any consequence are rare in the basin. tional with the adjoining tectonic divisions. In general DEFIANCE UPLIFT the saddle forms a saglike connection between the Black The Defiance uplift borders the Black Mesa basin on Mesa and Kaiparowits basins (fig. 1 ). Three northwester- the east. It is a broad, north-trending asymmetrical fold ly trending gentle folds, Black Mesa syncline, Cow Springs about 30 miles wide and 100 miles long. It is equivalent anticline, and Last Chance syncline (Kelley, 1955a) par- to the De Chelly upwarp of Gregory (1917, p. 111-112). allel the trend of the saddle. FIGURE 2. Aerial mosaic of 15-minute Arizona quadrangle A-35 showing the northern rim of Black Mesa basin near Marsh Pass at left. Curving Organ Rock monocline along left side. Inset is view north of the monocline near the northern edge of the quadrangle. NEW MEXICO GEOLOGICAL SOCIETY NINTH FIELD CONFERENCE 139

PRESTON BENCH by one parallel () and several lesser oblique The Preston bench is a flat-lying segment some 65 faults. The gently dipping western flank and crest of the miles long and 24 miles wide which together with the Kai- uplift are broken by several northerly trending faults, es- bito saddle separates the Kaiparowits basin of southern pecially in the middle and northern parts. Only the north- Utah from the Black Mesa basin. It principally lies below east-trending Bright Angel fault occurs in the southern part the Echo Cliffs monocline on the west and above the Red of the uplift. The throws on all the west flank and crestal Lake monocline, which separates it from the Kaibito saddle faults never exceed a few hundred feet, which is in con- and Black Mesa basin on the east. There is no marked trast with the 1700 feet of maximum throw of the Butte separation between the bench and the Kaiparowits basin fault on the east flank. or the Cameron bench. The over-all structural relief is Throughout much of the Kaibab uplift, except of course not more than a few hundred feet. It is only mildly and in the Grand Canyon, the surface generally follows the broadly folded by the north-northwesterly trending Tuba upper contact of the Kaibab limestone and the slopes gen- City syncline and the Preston Mesa anticline, both of which erally parallel the dips of the monoclines and terraces. In in their northern parts plunge gently northward into the the northern or Utah portion of the uplift, on the other hand, Kaiparowits basin. These folds, however, unlike those erosion has not penetrated as deeply and the monocline of Kaibito saddle to the east, do not extend southerly into forms a series of hogbacks in Mesozoic formations. Black Mesa basin. Numerous small faults lie along and COCONINO SALIENT nearly parallel the crest of the Preston Mesa anticline. The structural Coconino salient is one of the most un- These are displaced variously forming small , horsts, usual and striking uplifts on the Plateau. The Coconino or step faults. Along the northwestern border of the salient structure is a small protuberance (fig. 4) from the bench, between the Tuba City syncline and the Echo Cliffs south end of the much-larger Kaibab uplift. In detail the monocline there are several northeasterly trending short Coconino salient is formed by the intersection of the East faults and grabens that appear to be an extension of Kaibab, Grand View, and Coconino monoclines (Kelley, similar structures more common in the Echo Cliffs uplift 1955a, fig. 2), and, as roughly outlined by these features, to the west. Locally in the southern and southeastern parts trends northeasterly. The northeastern point is extremely of the bench there are faults of lesser prominence of abrupt with maximum dips on the monocline being vertical northwesterly and westerly trends. to slightly overturned and the structural relief is more than ECHO CLIFFS UPLIFT 2000 feet (Babenroth and Strahler, 1945, p. 113). To The Echo Cliffs uplift is a long, narrow, north-trending the southwest, on the other hand, the structure merges anticline which is concavely arcuate, and asymmetrically with the broad and only very slightly tilted structure of steeper, to the east (Gregory, 1917, p. 114-115). It is the general Grand Canyon section of the Plateau. The approximately 80 miles long and 30 miles wide and plung- nearly hairpin-shaped monoclinal flex which outlines the es northward into the Kaiparowits basin and southward salient is probably of Laramide age (Gregory and Moore, onto the Cameron bench. Only the eastern boundary of 1931, p. 131-132). It has been modified by possibly the uplift is sharp; all others are poorly defined and grade younger faults such as the Gray Mountain grabens (fig. into basins or benches. Structural relief along the Echo 3) that cross the top in northerly, easterly, and northwest- Cliffs monocline is more than 2000 feet in the northern erly directions, the Mesa Butte which roughly par- part and less than 1000 feet in the southern part. allels the Coconino monocline along the southeastern side, The main Echo Cliffs crestal axis is curving and is and an arcuate fault around Coconino Point. This last offset westward in the southern part. Soap Creek syn- fault, as interpreted by Babenroth and Strahler (1945, pl. cline and the Vermilion anticline are long, very gentle folds 2, fig. 2), is downthrown toward the uplift and has there- that lie along the western flank and are more or less fore somewhat reduced the original structural relief. Owing parallel with the main axis ( Kelley, 1 955a, fig. 2). to the fact that the structural relief is greatest and steepest In a general way the Echo Cliffs uplift occupies a around the northeasern end, and that the deformaion di- sort of intermediate structural step between the lower Pres- mishes along the flanking monoclines toward the west ton bench to the east and the Kaibab uplift to the west. and southwest, it appears that the structure may have re- The narrow East Kaibab syncline intervenes between the sulted from the pushing of a deep-seated block north- uplifts. eastward and upward between flanking zones that Numerous northerly to northeasterly trending high- lie beneath the Grand View and Coconino monoclines (fig. angle normal faults and small grabens cross the uplift in 4). If this be the case, the principal northeastward shift the central and southern parts. in the basement rocks would have been beneath the Mesa KAIBAB UPLIFT Butte fault and Coconino monocline, and indeed, this may The Kaibab uplift is a northerly trending uplift some have been the principal accommodating tear along which 125 miles long and 20-30 miles wide. It is asymmetrical the Kaibab uplift moved forward during its deformation. and concave toward the east. The structural relief along Therefore, the Mesa Butte fault may have right-lateral shift the East Kaibab monocline is about 2000 feet in the south- along it. ern part, 3000 feet in the central part, 4000 feet near CAMERON BENCH the Utah line, and diminishes to vanish at its northern end. The Cameron bench is an irregular, roughly diamond- The southern end terminates against the Grandview mono- shaped division that generally lies between Black Mesa cline and the northern foot of the Coconino salient (fig. basin on the east and Coconino salient and Wupatki bench 3). The East Kaibab monocline is the type for monoclines on the west and southwest (fig. 11. It trends northwester- and Powell in his early writings occasionally referred to ly and averages about 50 miles long and 25 miles wide. other monoclinals as "Kaibabs." In addition to being the The principal features that separate the Cameron bench type monocline it is characterized by much diversity of from the surrounding divisions are the Coconino salient structure and geomorphology. The monocline splits in and the Black Point monocline on the west and the southern two places developing structural terraces. It is also broken Red Lake monocline on the east. These bounding flexes 0 37°00

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FIGURE 3. Kaibab uplift; adapted from Strahler, 1948. NEW MEXICO GEOLOGICAL SOCIETY <> NINTH FIELD CONFERENCE 141

are short in terms of the total length of the boundaries of been presumed (McKee, 1951, p. 488, pl. 3) that the the bench, and in most places there is no clear distinction region was mostly positive through Silurian time. The between the bench and the adjacent tectonic divisions. The trend of the positive was probably east-northeast. The Cameron bench is essentially undeformed except for a tendency toward shoal and positive conditions continued very gentle regional dip toward the northeast. This dip during Devonian time except that the shore lines as indicat- may be as much as 2°-3° along the western side, but is ed by the strike of the sedimentary wedge took a west- less than 1° in the eastern part. The principal structural northwesterly trend (McKee, 1951, pl. 11. However, Hud- deformation takes the form of a few small grabens in the dle and Dobrovolny (1952, p. 80) have deduced the narrow western corner of the bench west of Cameron. The possible existence of a "Granitic Holbrook Ridge" trending principal fault structure, the Cameron graben, has been in a northeasterly direction between Holbrook and the De- shown by Reiche, (1937, p. 138) to be most likely Quater- fiance uplift, and there may be other similar basement nary in age. trends. During Mississippian time the hinge line between WUPATKI BENCH positive and negative tendencies took a northeasterly dir- The Wupatki bench lies between the Mogollon slope ection as the northwestern part of the region tilted slowly and the Coconino salient. It dips gently northeasterly and toward the Cordilleran geosyncline. During Pennsylvanian is about 60 miles long and 40 miles wide. The structural time a northwesterly positive trend may have been resum- relief is more than 1500 feet. Only the northwestern ed, and even continued through Permian time. It should limits are sharp along the Coconino and Black Point mono- be realized that the data supporting the above statements clines and the division between the bench and the Mogollon are meager and certainly subject to several different in- slope is for conveniece. The gentle folding of the bench terpretations. McKees map (1951, pl. 2) shows essentially is dominated by the long northwesterly trending Tolchaco- no Pennsylvanian strata beneath the central part of the Sunshine anticline. Black Mesa basin. Brown and Louth (1957, p. 80), on Several hundred volcanic cones, which comprise the the other hand, interpret the presence of about 750 feet San Francisco centers, l ie in the northwestern part of the of Pennsylvanian strata. They also indicate a small basin bench northeast of Flagstaff, Arizona (Robinson, 1913 and in the Black Mesa area during Permian time whereas McKee Kelley, 1955a, fig. 2). Many of these cones are aligned infers a thinning in the form of an isopach nose in the same in northwesterly, northeasterly, or easterly directions that area. Kelley (1955a, p. 77) deduced a combined Permo- are more or less parallel to the directions of prominent Pennsylvanian positive axis extending northwesterly across sets in the surrounding areas. the basin. Several other unpublished interpretations have Numerous small faults and grabens, principally of been made, but none of the interpretations made to date northerly and northeasterly trends, are distributed across should be considered very definitive of past swelling or the Wupatki bench ( Babenroth and Strahler, 1945, pl. 2). sagging in the area until more subsurface data are avail- MOGOLLON SLOPE able. However, it does appear safe to conclude that for The Mogollon slope bounds the Black Mesa basin on the Paleozoic as a whole the principal part of the region the south and forms a wide southern border of the was a stable shelf with notable positive tendencies from Plateau. Its primary characteristics is a gentle broad dip time to time in relation to the surrounding area, except the to the northeast ( Darton, 1925, p. 202-204). It is about Defiance uplift area. 200 miles long and 65 miles wide, trends west-northwester- During late Permian time the entire area was more ly, and has a structural relief of 2000 feet. Only where or less tectonically stable and rising very slowly while some the slope borders the Zuni and Defiance uplifts can a sharp widespread stripping went on. During early time demarcation be drawn. the region was tilted slightly westward (McKee, 1954, p. The general trend of the fold axes on the Mogollon 23), and during late Triassic the region subsided contin- slope is northwesterly; however, some small folds south of uously during the accumulation of nearly 2000 feet of the Black Mesa basin trend northeasterly. The western floodplain materials. This subsidence may have continued border of the Mogollon slope is modified by the Chevelon through time in the amount of 1000-2000 feet Creek-Holbrook buckle. This buckle is modified, in turn, as aeolian and playa deposits accumulated. Thus, from by a cross-fault and the north-trending Richard Lake anti- Permian through Jurassic time the Black Mesa basin region cline. subsided broadly on the order of about one mile without Only a few faults are exposed on the Mogollon slope. encroachment of the sea except in the western part during The Atarque fault, along the Arizona-New Mexico border, a relatively short time with the deposition of the Kaibab is the largest. This northwest-trending fault is downthrown limestone. This rate of epeirogenic downwarping was ap- on the southwest side on the order of 2000 feet. A par- proximately 10 times the rate of net subsidence during the allel fault with its downthrown side adjacent to the Atarque previous Paleozoic time. fault forms a narrow graben for a distance of about six In late Jurassic time the region was broadly tilted miles in New Mexico. The Atarque fault is clearly the northward on a hinge line that trended westerly across largest one within the southwestern part of the Colorado the southern part of the Black Mesa basin. From this line Plateau and it appears to be significant in the tectonic southward the gently upturned strata were broadly pli- framework. cated down to the Permian. The rise by tilting appears to TECTONIC HISTORY AND ORIGIN have amounted to as much as 2500 feet along the Mogollon Little or nothing is known of the Precambrian tectonics Rim where Dakota beds rest upon Permian ones, and all of the region. However, before Cambrian time began the the Triassic and Jurassic strata that intervene in the outcrops region must have been greatly deformed, uplifted, and to the north are missing. deeply denuded to a lowland during a protracted period of During time the entire region became a stability which prevailed from late Precambrian well into part of the Rocky Mountain geosyncline and subsided grad- Cambrian time. In the eastern and southern part of the ually until the basal beds of the sequence lay in the order region little or no Cambrian is present now, and it has of 4000 feet below sea level. This rate of geosynclinal 0 C 0 E 0

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subsidence was on the order of 8 times that of the Permian Cann (1938, p. 271-277) believed that west of the Zuni to Jurassic subsidence and 40 times that of the previous uplift on the Mogollon slope the present southwestward interval. At present all but some 1500 feet of Cretaceous tilt of the Bidahochi beds was greater than its original dip rocks have been eroded from the Black Mesa basin, the thereby suggesting some late Pliocene or early Quaternary base of the Dakota in the center of the basin is about 5000 tilting. On the other hand, Repenning and Irwin (1954, p. feet above sea level. In the San Juan Basin it is at about 1825) believed that an easterly upward projection or Bida- 2000 feet below sea level. Although some early Tertiary hochi beds of the Black Mesa basin to continuity with the sediments may have spread across the Black Mesa basin Chuska sandstone atop the Defiance uplift was possible, area, it does not appear to have been an early Tertiary and that tilting need not have been great. sedimentary basin. Most likely the entire area remained From a regional point of view Black Mesa basin lies relatively high during Paleocene and Eocene times, con- among a group of northerly trending uplifts, Defiance on tributing sediments to northern areas (Hunt, 1956, p. 76- the east, Monument and Piute folds on the north, and Echo 79). Cliffs and Kaibab on the west. The Black Mesa basin folds, Most of the structural features of the Black Mesa basin in turn, are a part of a wide belt of long, mild, northwesterly region are probably the result of Laramide disturbances oc- trending folds that extends from the Mogollon slope, south curring in late Cretaceous or possibly earliest Tertiary times. of the Defiance uplift, northwestward through the Kaiparo- Broad uplift with possibly some local tilting occurred during wits basin, a distance of some 300 miles. The belt, further- late Tertiary time. Brown (1956, p. 70) appears to believe more, takes the form of an irregular long sag or open syn- that "the Defiance uplift has been a positive area since clinorium whose trough is roughly formed, from northwest Pennsylvanian time, while the other uplifts surrounding the to southeast, by the Last Chance (Kelley, 1955, fig. 2), Black Mesa Basin are much younger ( Laramide-Tertiary Warm Creek, and Black Mesa and the downthrown in age)." However, all Mesozoic formations are strongly side of the Atarque fault (Kelley, 1955a) south of the Zuni and about equally deformed along flanks of the uplift uplift. The southwestern side of the synclinorium is bounded and it therefore appears that the structural form as shown by the Kaibab and Echo Cliffs uplifts, the Wupatki bench, by contours on Kaibab, Chinle, or Dakota horizons are and the Mogollon slope. The northeastern side is bounded largely of Laramide deformation. by the Circle Cliffs, Monument, and Defiance uplifts to- The principal evidence for the age of the folds of gether with the Piute folds. These, with the exception of the region lies in the Kaibab uplift and the Kaiparowits the Circle Cliffs uplift, terminate obliquely against the syn- basin, where late Cretaceous beds are folded and overlain clinorium. On the southwest side, the Mogollon slope to- by undeformed early Tertiary "Wasatch" beds in southern gether with the southern parts of the Echo Cliffs and Kai- Utah. Elsewhere, the regional structures are covered by bab uplifts parallel the trend of the synclinorium belt, but essentially untilted Miocene, Pliocene, or Quaternary vol- at the northern end, opposite the Circle Cliffs uplift, the canics; by the Pliocene Bidahochi formation; and by the Kaibab and Echo Cliffs uplifts obliquely intersect the syn- Miocene (?) Chuska sandstone. Such pronounced folds clinorium axes. It may be noted that the northwesterly trend- as the Organ Rock, Echo Cliffs, and Comb monoclines have ing synclorium belt, of which Black Mesa basin is a part, no direct stratigraphic means of dating them as Laramide. is the most persistent trend of folds on the Colorado Pla- They have customarily been assigned to Laramide because teau. It is in a sense a lineament which may be thought of of similarity to, or extension from, the folds where the re- as one of the tectonic splays from the Sierra Oriental far lations are conclusive. For example, the Echo Cliffs mono- to the southeast and shows some expression in the way of cline may be so dated because of its parallelism and prox- deflections of the north-trending Basin and Range structures imity to the Kaibab monocline. The Last Chance syncline of Utah and Nevada (A.A.P.G. tectonic map of the United (Kelley 1955, fig. 2, no. 126) is well-dated as Laramide States). It may be noted that the Black Mesa-Kaiparowits at its northern end, and it has been traced southeastward synclorium is not sharply separated from the adjoining into the Black Mesa basin where its limbs involve the Organ northerly trending uplifts in that northwesterly folds lie to Rock antic l ine. If it becomes reasonable to accept the some extent between the uplifts. These two principal tect- Echo Cliffs monocline as Laramide then the Tuba City syn- onic trends, northerly and northwesterly may be the pro- cline at the foot of the monocline must also be Laramide duct of two phases of Laramide deformation perhaps over- and it, according to Doeringsfeld, Amuedo, and Ivey, con- lapping in part. If so, I am inclined to believe that the tinues southeastward into the French Springs syncline in large and more prominent northerly trending uplifts formed the Black Mesa basin. One may progress in this manner, first. The northwesterly trending folds of the synclinorium by extrapolation and reasoning by analogy, to most of the may have formed later by somewhat differently oriented folds of the region, and not without some justification. exterior forces which may have modified the earlier uplifts Judicious caution should be exercised, however, for a to some extent just as the uplifts may have in themselves long monocline or syncline well dated in one end may modified the more local fields. have been extended to another part during a later or In addition to the above two principal tectonic trends, earlier phase or period of deformation. there is a third lesser one of northeasterly trend. This takes Although a Laramide age for most of the folds is gen- the form of a sort of lineament of monoclines extending erally accepted, Brown (1956, p. 70) reasoned that the across the region from Coconino salient toward the San shorter northeast-trending folds in the southern part of the Juan dome in Colorado and including, on line, Coconino, basin between Holbrook and Winslow, are younger. Mc- Cow Springs, and the southern Comb monoclines. 144 NEW MEXICO GEOLOGICAL SOCIETY <> NINTH FIELD CONFERENCE

REFERENCES

Babenroth, D. L., and Strahler, A. N., 1945, Geomorphology and struct- Kelley, V. C., 1955a, Regional tectonics of the Colorado Plateau and ure of the East Kaibab monocline, Arizona and Utah: Geol.Soc. relationship to the origin and distribution of uranium: Univ. New America Bull., v. 56, p. 107-150. Mexico Pub. in Geol. No. 5, 120 p. Baker, A. A., 1936, Geology of the Monument Valley-Navajo Mountain , 19556, Tectoncs of the Four Corners region, in Geology region, San Juan County, Utah: U. S. Geol. Survey Bull. 865. 106 p. of Paradox, Black Mesa and San Juan basins: Four Corners Geol. Brown, S. C., 1956, Petroleum and natural gas potentialities, in Mineral Soc. Field Conf., p. 108-117. resources, Navajo-Hopi Indian reservations, Arizona-Utah, v. 1, , 1955c, Monoclines of the Colorado Plateau: Geol. Soc. Metalliferous mineral and mineral fuels, geology, evaluation, and American Bull., v. 66, p. 789-803. uses and a section on the general geology: p. 64-72, Tucson, Univ. , and Clinton, N. J., 1959, systems and tectonic Arizona Press (1955). elements of the Colorado Plateau: Univ. New Mexico, Pub, in , and Louth, R. E., 1957, Oil and gas potentialities of Geol., (In press). northern Arizona, in Geology of southwestern San Juan Basin: Four Kiersch, G. A., 1956, Mineral resources, Navajo-Hopi Indian reservations, Corners Geol. Soc., Second Field Conf., p. 77-84. Arizona-Utah, v. 1, Metalliferous mineral and mineral fuels, geology, Dorton, N. H., 1925, a resume of Arizona geology: Univ. Ariz. Bull. 119, evaluation, and uses and a section on general geology: 75 p., Geol. ser., no. 3, 298 p. Tucson, Univ. Ariz. Press (1955). Dutton, C. E., 1882, The physical geology of the Grand Canon district: McCann, F. T., 1938, Ancient erosion surface in the Gallup Zuni area, U. S. Geol. Survey 2d Ann. Rpt., p. 49-166. New Mexico: Am. Jour. Sci., v. 236, p. 260-278. , 1882a, Tertiary history of the Grand Canon district: McKee, E. D., 1951, Sedimentary basins of Arizona and adjoining areas: U. S. Geol. Survey Mon. 2, 264 p. Geol. Soc. America Bull., v. 62, p. 481-506. Gregory, H. E., 1917, Geology of the Navajo country, a reconnaissance of , 1954, Stratigraphy and history of the Moen kopi forma- parts of Arizona, New Mexico, and Utah: U. S. Geol. Survey Prof. tion of Triassic age: Geol. Soc. America Mem. 61, 133 p. Paper 93, 161 p. Reiche, Parry, 1941, Erosion stages of the Arizona Plateau as reflected Gregory, H. E., and Moore, R. C., 1931, The Kaiparowits region, a geo- in a headwater drainage area: Plateau, v. 13, no. 4, 53-64. graphic and geologic reconnassiance of parts of Utah and Arizona: Repenning, C. A. and Irwin, J. H., 1954, Bidahochi formation of Ari- U. S. Geol. Survey Prof. Paper 164, 161 p. zona and New Mexico: Am. Assoc. Petroleum Geologists Bull., v. Harshbarger, J. W., Repenning, C. A., and Callahan, J. T., 1953, The 38, p. 1821-1826. Navajo country, Arizona-Utah-New Mexico, in The physttal and Robinson, H. H., 1913, The San Franciscan volcanic field, Arizona: U. S. economic foundation of natural resources, IV Subsurface facilities Geol. Survey Prof. Paper 76, 213 p. of water management and patterns of supply-type area studies: Int. Strahler, A. N., 1948, Geomorphology and structure of the West Kaibab and Insular Affairs Comm., House Rep., U. S. Congress. Chap. 7, fault zone and Kaibab Plateau, Arizona: Geol. Soc. America Bull., p. 105-131. v. 59, p. 513-540. , Repenning, C. A., and Irwin, J. H., 1957, Straitgraphy Wanek, A. A., and Stephens, J. G., 1953, Reconassance geologic map of of the uppermost Triassic and the Jurassic rocks of the Navajo the Kaibito and Moenkopi Plateaus and parts of the Painted Desert, country: U. S. Geol. Survey Prof. Paper 291, 74 p. Coconino County, Arizona: U. S. Geol. Survey Oil and Gas Inv. Map OM 145, Sheet 1. Huddle, J. W., and Dobrovolny, Ernest, 1952, Devonian and Mississip- pian rocks of central Arizona: U. S. Geol. Survey Prof. Paper 233-D, Witkind, I. J., Thaden, R. E., and Lough, C. F., 1953, Preliminary report p. 67-112. on geologic investigations in Monument Valley area, Arizona, 1952: Hunt, C. B., 1956, Cenozoic geology of the Colorado Plateau; U. S. U. S. Geol. Survey TEM Rpt. 536, 8 p. Geol. Survey Prof. Paper 279, 99 p. UTAH 1. 7- 2 9 ie —7w 1301,4— ARY 13L197,E±, NONp I ARIZON ANTI CL INE 41; SYNCLINE OITA PEX AII BEAVER RAR ANTICLINE SYNCD ALANCED ANTICLINE ROCK ANT RAT TLESNAKE ANTICLINE

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