Geology of the Upton Quadrangle, Crook and Weston Counties, Wyoming
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Geology of the Upton Quadrangle, Crook and Weston Counties, Wyoming By WILLIAM J. MAPEL and CHARLES L. PILLMORE CONTRIBUTIONS TO GENERAL GEOLOGY GEOLOGICAL SURVEY BULLETIN 1181-J v Prepared on behalf of the U.S. Atomic Energy Commission UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1964 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director The U.S. Geological Survey Library cards for this publication appear on page after Index. For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS > Abstract__-_____________-_-----_-_-__-__-__-_-__-_---_--___.____ J1 Introduction._____________________________________________________ 1 + Geography. _ _______________-___-_----_---______---------___-___-_. 3 Sedimentary rocks.._______________________________________________ 3 * Upper Jurassic Series__-_---_---_-----------_---------_---_-_-_- 6 Sundance Formation__-_----_----____-___-_--_---__-_____._ 6 Morrison Formation._______________________________________ 6 Lower Cretaceous Series__--_-----------_---__-----_----_--_--__- 7 Lakota Formation.-_----___-___--_________--___-___.______ 7 *. Fall River Formation.-_-____-----______--_--_-____-__.____ 10 Skull Creek Shale.__....._____._____--_--_.______..._._ 12 r Newcastle Sandstone___-_..____________-_---_--_____.____ 13 Mowry Shale_____----______-_--_--____--__---__---_--_._ 16 ^ Upper Cretaceous Series_------__-_-------_-__-------_----_-__._ 18 Belle Fourche Shale...--._-_-_--__-_--___------_-_-.--...__- 18 "*" Greenhorn Formation-_-___-_--_-__-___-_------_--------__. 22 Carlile Shale...._._------.--.-------.---..-...-.---------- 24 Pool Creek Shale Member.___-_.__.-_________._.__.._ 25 ' ^ Turner Sandy Member.._________________________________ 25 Sage Breaks Shale Member _____________________________ 27 * Niobrara Formation_-_-------_--_---_-_---_--.-_-__._______ 27 Pierre Shale__._..__._...._______________________________ 29 ^ Gammon Ferruginous Member._________________________ 29 Mitten Black Shale Member..__________________________ 31 * Middle part__._.-_--_-_____-_-_____-____________._.__ 32 Kara Bentonitic Member._...____.._________..._..._._. 32 Upper part____________________________________________ 35 ^ Fox Hills Sandstone-_____________________________________ 36 Lance Formation._________________________________________ 36 -i. Quaternary System_____-_---_---______-__-__-__-__-_______-_-. 37 Terrace deposits___--_-------_-__-_--___---_-__----_-__---_ 37 H Landslide material__------_---_-_________---_--__---_-__-___ 37 Slope wash.________.._._.....____.__.__...___.._.....____. 37 * Alluvium.-..--_-___-__-. ______--_-____--_--_____---_.___ 38 ..Structure.-.-.....-.._____________________________________________ 38 Folds.........................................._..-_........._ 38 X, Faults. _ _._._._..__.........___....._.......__.._...._...._ 40 Mineral deposits__________________________________________________ 40 .-» Oil and gas..________________________________________________ 40 Bentonite. _ _--_-_-_.-_____--___.-.-_._______._..-_____.__._..__ 43 * Sand and gravel.______________________________________________ 50 References cited.__-_______-___-______--.-___..-_--__-.-__-.-_.-._. 50 ^Index _-_--._.-_--___._.__-_-_.____..._____._________.._.._._.... 53 IV CONTENTS ILLUSTRATIONS Page PLATE 1. Geologic and structure maps, electric log, and section, Upton «. quadrangle, Crook and Weston Counties, WyO--____-_ In pocket FIGURE 1. Index map to Upton 15-minute quadrangle and adjacent areas 'J mapped by the U.S. Geological Survey, 1954-58--__--_--_ J2 2. Columnar sections of the Fall River, Lakota, and Morrison Formations, northeastern part of the Upton quadrangle..-. 9 ^ 3. Sandstone dike in the Skull Creek Shale.___________________ 13 '*' 4. Columnar sections of the Newcastle Sandstone and parts of ^ adjacent formations..-------------.-----------------.---. 14 ' 5. Columnar sections and electric log of the upper part of the * Belle Fourche Shale, Greenhorn Formation, and lower part of the Carlile Shale----_-_-_--__--_-_-__-_-_---_-_---_. 19 £ 6. Light-colored outcrops of bentonite in the southeast part of the Upton quadrangle--___---_-___.-_____-_________________ 43 ^ 7. Sections of bentonite beds at the top of the Mowry and base of the Belle Fourche Shales------___--_----_-__---------_ 44 ' 8. Sections of bentonite beds in the upper part of the Belle ^ Fourche Shale___-_-_----__-___--__---__-_._._.-_____ 45 TABLES TABLE 1. Generalized stratigraphic section of rocks in the Upton quad- rangle_________________________________________________ J4 2. Selected wells drilled for oil and gas in the Upton quadrangle. _ 42 3. Analyses of grab samples from some bentonite beds in the Upton quadrangle.. ____________________________________________ 46 CONTRIBUTIONS TO GENERAL GEOLOGY GEOLOGY OF THE UPTON QUADRANGLE, CROOK AND WESTON COUNTIES, WYOMING By WILLIAM J. MAPEL and CHARLES L. PILLMORE *"' ABSTRACT -f The Upton 15-minute quadrangle includes about 215 square miles on the west side of the Black Hills in Crook and Weston Counties, Wyo. ^ Exposed sedimentary rocks, exclusive of surficial deposits, are about 5,900 feet thick and range in age from Late Jurassic to Late Cretaceous. Sandstone, *" siltstone, and shale make up most of the sedimentary sequence; limestone and bentonite are present locally. The Sundance Formation of Late Jurassic age is the oldest formation exposed. It is overlain by the Morrison Formation of ^ Late Jurassic age, followed in turn by the Lakota, Fall River, Skull Creek, New castle, and Mowry Formations of Early Cretaceous age, and the Belle Fourche, x' Greenhorn, Carlile, Niobrara, Pierre, Fox Hills, and Lance Formations of Late Cretaceous age. The Morrison Lakota, and Lance Formations, which have an aggregate thickness of about 1,000 feet, are nonmarine; the remaining rocks are marine. The main structural feature is the Black Hills monocline, which is a moderately ^ steep fold that extends northwestward across the quadrangle in a slightly sinuous band 3-4 miles wide between much more gently dipping rocks to the northeast -, and southwest. Structural relief across the monocline is about 4,000 feet, the northeast side being uplifted relative to the southwest side. A few shallow » folds, including the Thornton dome and the Pump Creek and Arch Creek anti clines, occur in the northern part of the quadrangle, and four minor faults cut ^ rocks along the monocline. Oil is produced from the Lakota Formation in the shallow Wind Creek oil field, and bentonite is mined from the Newcastle, Mowry, and Belle Fourche Formations. ^ INTRODUCTION ^ The Upton quadrangle includes about 215 square miles on the /, a, west side of the Black Hills in Crook and Weston Counties, Wyo. (fig. 1). It is bounded by long 104 °30' W. and 104°45' W., and ^ lat 44°00' N. and 44°15' N. The quadrangle is about 17 miles ..> northwest of Newcastle, 10 miles east of Moorcroft, and 12 miles southwest of Sundance. * The quadrangle is in the southwestern part of the large area de- ^ scribed by Darton (1909) in an early report on the northern part of the Black Hills. Small areas in the southeastern and southwestern - Jl J2 CONTRIBUTIONS TO GENERAL GEOLOGY 106° 105° 104° !' ¥ , 44° FIGURE 1. Index map to Upton 15-minute quadrangle (crosshatched) and adjacent areas mapped by the U.S. Geological Survey in 1954-58. 1, Nefsy Divide 15-minute quadrangle (Pillmore and Mapel, 9 1963); 2, Inyan Kara Mountain 15-minute quadrangle (Mapel and Pillmore, 1963a). parts of the quadrangle were mapped by Longwell and Rubey (1923) in their study of the Pump Creek anticline, and by Hancock (1920) in his study of Thornton dome and vicinity. J. C. Davis (1963, Geology of the Clay Spur bentonite district, Crook and Weston Counties, Wyoming: Univ. Wyoming M.S. thesis, Laramie, Wyo.) reviewed the history of bentonite mining near Upton, and discussed the geology of the bentonite deposits. Several other writers, notably Dobbin and Reeside (1929), Grace (1952), Haun (1958), Mapel and Gott (1959), Reeside and Cobban (1960), and Wulf (1962), described some aspects of the stratigraphy of outcropping rocks near Upton in studies of larger areas in the Black Hills and nearby regions. Mapping for the present report was done mostly from 1956 to 1958 on behalf of the U.S. Atomic Energy Commission as part of a study of a J3 larger area on the west and north sides of the Black Hills. Some additional mapping was done and several stratigraphic sections were measured during brief periods in the summers of 1959,1960, and 1962. Unpublished data by W. W. Rubey and C. R. Longwell covering their fieldwork in 1922-24 were consulted frequently during the initial stages of the work. J. R. Gill made available the results of his 1957 and 1958 studies of the lower part of the Pierre Shale along the west side of the Black Hills. R. F. Schryver helped map Lower Cretaceous rocks along Mason Creek in 1958. T. C. Nichols and L. G. Schultz maole X-ray analyses, and Nichols and J. C. Thomas made physical tests on samples of bentonite. GEOGRAPHY Low hills, broad flats, and local areas of badlands constitute most of the land surface. A low ridge about 2 miles wide covered with pine trees trends diagonally northwestward across the middle of the quadrangle northeast of Up ton; elsewhere the vegetation is mostly sagebrush and grasses native to the northern Great Plains. Streams in the northern part of the quadrangle drain northward to the Belle Fourche River, and those in the southern part drain south eastward to the Cheyenne River. Mason Creek in the northeastern part of the quadrangle and Iron and Turner Creeks in the southeastern part are the only perennial streams. Altitudes range from about 4,100 feet along Beaver Creek at the southeastern corner of the quadrangle to about 4,700 feet north of Mason Creek. Up ton, which had a population of about 1,200 in 1960, is near the center of the quadrangle.