BRIGHAM GEOLOGY YOUNG STUDIES UNIVERSITY Volume 19: Part 1 - December 1972 CONTENTS An Ealy Cembrian Trilobite Faunule from Utah .................... .... ......................... R. A. Robism and L. F. Hintze 3 Cbeirscystelld antiqm gn. d sp. nev. from the Lower Ordovician of Western Utah, and Its Bearing en the Evsluti~nof the Cheirocrinidae (Rhombifera: Glyptocystitida) ................... ...... ......................... C. R. C. Paul 15 Gc~lta~of the Mill Fork Area, Utah ................................ W. C. Metrill 65 Geology ef the Thistle Quadrangle, Utah ........................ M. L. Pinnell 89 Study of Internal Structures of Fine-Grained Clastic Rocks by X-radiography ........................................... A. M. Jones 131 Publications and Maps of the Geology Department ............................. 159 Brigham Young University Geology Studies Volume 19, Part 1 - December, 1972 Contents An Early Cambrian Trilobite Faunule from Utah ........................................................ R. A. Robison and L. F. Hintze 3 Cheit.orystella a~ztiua gen. et sp. nov. from the Lower Ordovician o Y Western Utah, and Its Bearing on the Evolution of the Cheirocrinidae (Rhombifera: Glyptocystitida) ........................................................ C. R. C. Paul 15 Geology of the Mill Fork Area, Utah ................................ R. C. Merrill 65 Geology of the Thistle Quadrangle, Utah .......................... M. L. Pinnell 89 Study of Internal Structures of Fine-Grained Clastic Rocks by X-radiography ............................................ A. M. Jones 131 Publications and Maps of the Geology Department ................................ 159 A publication of the Department of Geology Brigham Young University Provo, Utah 84601 Editor Jess R. Bushman Brigham Yourzg Universiiy Geology Stzrdie~is published semiannually by the department. Geology Studies consists of graduate student and staff research in the department and c~casionalpapers from other contributors. Distributed December 22, 1972 Prjce $4.50 Geology of the Thistle Quadrangle, Utah* MICHAELL. P~NNELL Humble Oil Company, !Midland, Texas ABSTRACT.-A regional pre-Price River (Cretaceous unconformity and a local pre-North Horn (Cretaceous-Paleocene) unconformity attest to strong Laramide compressive forces which folded Mesozoic strata at Thistle, Utah. Comparison of Mesozoic stratigraphic sections of equivalent autochthonous and allochthonous sediments implies that the leading edge of the Charleston-Strawberry-Nebo fault lies concealed within the Thistle Quadrangle. The basic westward-dipping monoclinal structure of the Wasatch Plateau was modi- fied first by early Cenozoic folding and by Oligocene and later high-angle normal faulting of Basin and Range affinity. Axes of Cenozoic folds show recurrent movement which may have begun in the Cretaceous but which definitely folded in earliest Cenozoic as shown by a local pre-Flagstaff unconformity. The greatest Cenozoic folding has been post-Green River (Eocene) in age. CONTENTS TEXT Page Age of Laramide Deformation 115 Introduction ................................... 90 Cenozoic Folds ............................ 11 5 Previous Work ........................... 91 Thistle Dome - Indianola Anti- Present Work ............................. 9 1 cline ...................................... 115 Acknowledgments ............................ 92 Pre-Flagstaff Unconformity .... 115 Stratigraphy ................................... 92 Age of Folding ...................... 118 General Statement ........................ 92 Cause of Folding .................... 118 Jurassic System ........................... 93 Cenozoic Normal Faults ............ 118 Nugget Sandstone ................. 93 Dairy Fork and Martin Moun- Twin Creek Limestone ............ 94 tain Faults ............................ 118 Arapien Shale ........................ 96 Birdseye Fault ........................ 119 Twist Gulch Formation .......... 96 Billies mountain - Thistle Entrada-Curtis-Summerville Canyon Fault ...................... 119 Formations ......................... 97 Minor Faults .............................. 119 Morrison Formation ............... 97 Joints ........................................ 119 Cretaceous System ........................ 98 Age of Faulting ........................ 119 Indianola Group .................. 98 Cause of Faulting ........................ 119 Cretaceous Sandstone .............. 100 Economic Geology ........................ 120 Price River Formation .............. 100 Metals ........................................ 120 Cretaceous-Tertiary Systems ........ 101 Nonmetals .................................... 120 North Horn Formation ............ 101 Water ......................................... 120 Tertiary System ........................... 104 Petroleum Products .................... 120 Flagstaff Limestone ................ 104 Asphalt .................................... 121 Colton Formation .................... 108 Oil and Gas Possibilities ........ 121 Green River Formation ............ 109 Appendix 1, Measured Sections .... 121 Tertiary Volcanic Sedimentary Appendix 2, Identified Fossils ........ 127 Rocks ................................... 1 10 References Cited ............................ 128 Quatenary Deposits ................ 111 ILI.USTRATIONS Structural Geology ........................ 1 11 Text.figures Page General Statement ........................ 11 1 1. Index map ................................ 90 Cedar Hills Orogeny ................ 112 2. Geologic mapping adjacent to Laramide Deformations .......... 112 the Thistle Quadrangle ............ 92 Pre-Price River and Pre-North 3. Schematic interrelations of Horn Unconformities .......... 112 Price River, North Horn, and Laramide Folding .................... 112 Flagstaff formations of the Laramide Normal Faults ........ 11 2 northwestern Wasatch Plateau 102 Laramide Thrust Faults ........ 114 4. Approximate location of the Amount of Crustal Shortening covered leading edge of the Represented by Folds and Charleston-Strawberry-Nebo Faults .................................. 115 Fault ........................................ 116 - - *A thesis submitted to the faculty of the Department of Geology Brigham Young Uni- verstty, in partial fulfillment of the requirements for the degree Master of Science. 89 90 MICHAEL L. PINNELL 5. Form line structure contour formations ................................ 105 niap of the Thistle area .......... 117 3. Fault contact between Green Plates River and Twist Gulch forrna- 1. Unconformity between con- tions; angular unconformity glornerate of the Price River between North Horn Formation Formation and lndianola and Indianola Group .............. 113 Group; roadcut of Morrison 4. Con~parison of stratigraphic Formation ................................ 99 sections of central Utah with 2. Conglomerate filled channel in those of the Thistle North Horn Formation; Quadrangle ........................ in back angular unconformi ty between 5. Geologic map and sections of Flagstaff and North Horn the Thistle Quadrangle ...... in back INTRODUCTION Laramide tectonics, interpreted from structural and stratigraphic evidence within the Thistle Quadrangle, indicate that the covered leading edge of at least one of the major Laramide thrusts is located a few miles east and south- east of Thistle. Post-Laramide tectonics has produced potential petroleum traps in strata beneath and adjacent to the major thrust plate. The Thistle 7;-minute Quadrangle lies near the intersection of the Rocky Mountain, Colorado Plateau, and Basin and Range Physigraphic provinces (see Text-fig. 1). The quadrangle covers 58 square miles, with its northwest corner at 40'00' north latitude and 11'30' west longitude. The town of Thistle, popu- lation less than 50, is situated at the junction of U.S. Highways 89 and 50-6 in Spanish Fork Canyon and is in the northwest comer of the area. Dirt roads permit access to within three miles of any of the points in the quadrangle but are passable to autc.n~obilesonly during dry weather. The Wasatch Plateau of the High Plateaus secticm of the <:olorado Plateau Province is the dominant physiographic feature of the Thistle area. The Wa- satch Range of the Rocky Mountain Province is physiographically represented north of Soldier Creek in the northernmost portion of the area of study. Al- though the Basin and Range Province is not physiographically represented, TEXT-FIGURE1.-Index map of Thistle Quadrangle. GEOLOGY OF THE THISTLE QUADRANGLE, UTAH 91 normal faults similar to Basin and Range geology are present (Wooley, 1946, Plate I ). Prev~ous Work Howell, King, Dutton, Lcughlin, and other plotleer geolog~stsmade re- connaissance geologic investigation~of the general area covered 111 this report. Harris (1953, p. 7-10) describes the extent and importance of these regional rnvestigatlons. The prrnc~pal recent worker tn the area 1s E. M. Spieker, who delineated Jurass~c, Cretaceous, and Tertlary stratigraphy and the related tectonic hrstory of Central Utah (Spieker and Reeslde, 1925; and Spieker, 1936, 1946, 1949a, 1949b). Under the dlrectlon of S~ieker,several graduate students at Ohio State State University did thesis work which was, ~n part, within the Thistle Quad- rdngle. K. Y. Lee, In 1950, made a petrographic study of the Prlce River I:ornmt~on In Sanpete Valley. One of the sample 1ocatlc;ns was rn the Lake Fork area of the Thlstle Quadrangle. He expanded thls work ~n completing a Ph.D. thesis of a study of the petrography