UNITED STATES DEPARTMENT OF THE INTERIOR .Hay Lyman Wilbur, Secretary GEOLOGICAL SURVEY W. C. Mendenhall, Director Bulletin 841 GEOLOGY AND OIL POSSIBILITIES OF THE MOAB DISTBICT, GKAND AND SAN JUAN COUNTIES, UTAH BY A. A. BAKER UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON: 1933 For sale by the Superintendent of Documents, Washington, D. C. - - Price 50 cents (Paper covers) c*, "* i A. * * CONTENTS * Page ^ .Abstract. ______ _ ;. __ ,. - ----------- 1 Introduction..... _ ___ _ -- - 2 Search for oil in the region..... -- ____ _--- _-_ 2 Location and extent of area._ --_-_ _ ---_-- 2 * Purpose and scope of work.. __--______ _ 2 Field work. _ _ _ _- _ -_ 3 '*" Acknowledgments _________--_------______--___-_---------_____ 5 Geography _____________________________ _ _________________________ 5 Topography-____________._-_______--_--_--------------------- 5 Drainage and water supply..__ -_ ____ _-_ 7 Climate __ ___ - --_-_ _ _-__ 8 * Population. _________.________-__-___-_ ----_---_--._ 9 y Accessibility and routes of travel.------------------------------. 9 * Fuel....---------..--.-------------------------- 10 Previous publications._______ _ - _-_ - 10 ** Stratigraphy.. __ ____ _ ^.. 12 General features.______ __ __ -_-_ _--_---------_-__ 12 Carboniferous system_______________________________________ 13 y, Pennsylvanian (?) series-__ __ ____ _ _ 13 Paradox formation.. ___ - 13 Pennsylvanian series ___-_---___-___-_-____-____-_--_____ 18 Hermosa formation________ r _________________________ 18 Permian series.__-_____------_------__-_____---_----__.___ 23 Rico formation--. --_ _ 23 Cutler formation... 0 -__-_ __ 29 Unconformity between Cutler and Moenkopi formations. .. 33 Triassic system ______ _ _ __ _______ _ _ ____ 34 Lower Triassic series. - __ 34 Moenkopi formation.___ _ ______ ______________________ 34 Unconformity at the top of the Moenkopi formation. _____ 36 Upper (?) Triassic series__------_-____-_----__-_---_--._-__ 37 Shinarump conglomerate...____________________________ 37 Upper Triassic series.... __ 38 Chinle formation____________________ _ ______________ 38 Contact of Chinle and Wingate formations_______________ 41 . Jurassic (?) system _____- -_________ __ __ _ _ ___- 42 Glen Canyon group_____------------__--____ ____________ 42 Wingate sandstone.___________________________________ 42 Kayenta formation..__________________________________ 44. Navajo sandstone. ______________________________________ 46 Unconformity (?) at the top of the Navajo sandstone.. 47 Jurassic system_______________________________________________ 48 Upper Jurassic series.___----____--_-__--_____-____________ 48 San Rafael group_____------_--__-_-_-_-_____-___-.__. 48 Carmel formation. __ _ _ ._ __. _..____ 48 Entrada sandstone.___-___--_-___-___________--__. 49 Contact of Entrada and Summerville formations...___ 50 Summerville formation__________________________ 51 IV CONTENTS Stratigraphy Continued. Page Cretaceous (?) system_____________________.___________________ 52 Lower Cretaceous (?) series.._____________________________ 52 Morrison formation,__________________________________ 52 Cretaceous system.___________________________________________ 54 Upper Cretaceous series..__________________________________ 54 Dakota (?) sandstone---_----__--_-_-_____-____________ 54 Mancos shale.___--___________________-_____.__________ 55 Tertiary (?) system..________________________________________ 56 Quaternary system.___________________________________________ 57 Igneous rocks.____________________________________________________ 59 Structure-_______________________________________________________ 59 General features.___-_--------_--_____-____-----_-__-_____.___ 59 Methods of representing structure___________________-____.________ 60 Details of folds..._____...___________________________ 61 Castle Creek anticline.____________ ________________________ 61 Courthouse syncline.---_--_---------_--____-_--_--._______ 62 Moab and Spanish Valleys_____________________________ 63 General features.--_-------_---------__-_--------_---- 63 Moab anticline__________--_------_--__----_----_---_- 64 Spanish Valley syncline._____--_-__-____-_-_--_--__--__ 66 Pack Creek synclinal graben.._______-___--_--_:_-______ 66 Kings Bottom syncline--_____-_-_--------_-_----_--_-----_- 67 Cane Creek anticline.______-_________-_--__---_-_--__--___ 68 Shaferdome____________________________________________ 68 Hatch Point area of irregular low folding._-___--________-_-__ 69 Lockhart anticline__-_______-_-____--_-___-_--___-_-_-_- 69 Rustler dome----------_-__-----_-------_-_--------------- 69 Gibson dome.__-_--_______-_-_---____----_----_----_----- 70 Lockhart syncline--_--_________________---_-_-_-_-____-___ 70 Monocline in southern part of district.______________________ 71 Big Indian-Lisbon Valley faulted anticline_____-__-____-_-____ 71 Meander anticline_____-____________-___-_-_--___--___---__ 71 Faults. 72 General features._____-___-______-___-----_----_---------- 72 Shay graben__________________________________________ 73 Needles fault zone____________--___-_-___---_.-----.---- 73 Effect of movements in the salt on geologic structure ______________ 74 Periods of deformation___________________-____----__------_-_ 77 Oil and gas________---___--__----___-------_------_---_----------- 80 History of drilling_______ ________________._-_______--__---__ 80 Possibility of oil and gas production______-_---___---__----_-_-_- 83 Uranium and vanadium_____ _____________________________________ 84 Salt, gypsum, and potash______--________-------------------------- 84 Records of wells-.-----.--- _ ________ ___ 85 ILLUSTRATIONS Page PLATE 1. Geologic map and sections of Moab district. ____.__-.____ In 2. Map showing geologic structure of Moab district.___.___._ In-podse*. *' t 3. A, Moab Valley looking east from a point near the entrance to the canyon of the Colorado River below Moab; B, Forma- * tions exposed west of the Colorado River at the crest of the Shafer dome_________-_____-_-----_---_-----.__--______ 10 * 4. A, Intraformational unconformity in the Rico formation in Indian Creek Canyon, in sec. 4, T. 29^ S., R. 20 E.; B, North Sixshooter Peak in Indian Creek Valley near the mouth of +. Da vis Canyon...____.____.___.____________ 10 5. A, Outcrop of Moenkopi formation on the north side of Indian * Creek Valley near the mouth of Hart Draw; B, Outcrop of Moenkopi formation in an isolated butte near the mouth of *» - Castle Creek_________________________________________ 10 6. A, Angular discordance between Chinfe and Moenkopi forma­ tions on northeast side of Cane Creek anticline in the valley of v Cane Creek in sec. 33, T. 26 S., R. 21 E.; B, Formations ex­ posed at crest of Cane Creek anticline on west side of Cane Creek in narrow ridge between it and the Colorado River, in sec. 32, T. 26 S., R. 21 E________________________________ 10 > c 7.. A, Formations exposed on east side of Davis Canyon about 1 mile west of the southwest corner of sec. 19, T. 31 S., R. 21 E.; x B., Sandstone dome near the upper road crossing of Indian Creek in sec. 20, T. 32 S., R. 22 E________________ 10 8. A, Outcrop of Navajo sandstone in Mill Creek Canyon showing . typical cross-bedding; B, Cliffs of Entrada sandstone at Cane Springs, in sec. 1, T. 28 S., R. 22 E_______________._ 10 . 9. A, Dakota (?) sandstone forming bench in SE. % sec. 23, T. 28 S., ff R. 23 E., near head of Muleshoe Wash; B, View south along ^, Twin Valley graben from a point near the north end.________ 10 10. A, View north along Devils Pocket graben; B, South end of Devils Pocket graben.__________________________________ 10 11. Generalized columnar section of the rocks exposed at the surface *" in the Moabdistrict__.__________________________________ 10 )N FIGURE 1. Index map of Utah showing location of the Moab district..... 3 2. Diagram illustrating inferred lateral changes in Paradox forma- tion and changes in thickness resulting from movement in the *" salt________________.___...._____________ 15 3. Tentative correlation of part of the Carboniferous formations between southwestern Colorado, the Moab district, Utah, * and the Grand Canyon district, Ariz. ____________________ 19 v GEOLOGY AND OIL POSSIBILITIES OF THE MOAB DIS- TEICT, GKAND AND SAN JUAN COUNTIES, UTAH By ARTHUR A. BAKER ABSTRACT + . The Moab district is part of the Colorado Plateau and includes an area of about 1,000 square miles east of the Colorado River in Grand and San Juan ^ Counties, southeastern Utah.' The study of the geology presented here was made in 1926 and 1927, after drilled wells had encountered showings of oil and ^ gas and had disclosed the presence of thick beds of salt. The Paradox formation, which contains the salt, is the oldest exposed forma- *. tion and lias been tentatively assigned to the lower Pennsylvanian. Most of the information concerning the Paradox has been obtained from wells, for its surface outcrops are limited to small masses of gypsum. Younger rocks that crop out include the Hermosa formation, of Pennsylvanian age; the Rico and Cutler formations, of Permian age; the Mo.enkopi, Shinarump, and Chinle for­ mations, of Triassic age; the Wingate sandstone, Kayenta formation, and Navajo sandstone, tentatively assigned to the Jurassic; the Carmel formation, ± Entrada sandstone, and Summerville formation, of Jurassic age; the Morrison formation, tentatively assigned to the Cretaceous; and the Dakota (?) sandstone ».; and Mancos shale of Upper Cretaceous age. This area is a.critical one in the study of Permian stratigraphy, because there