Plate 1 UTAH GEOLOGICAL SURVEY Utah Geological Survey Open-File Report 444 a division of the Provisional Structural Geologic Map of the Jericho Quadrangle, UTAH DEPARTMENT OF NATURAL RESOURCES Juab County, Utah 29 Cpm Qafo Tl Tlrw Ts Tlrw Tlrw Ts Ts Qafy Qal Ts Qafo Qal Ts Ts Qafo Qafo Qafo Ts Qal Qal Qafo Ts Qafy Ts Qal PIPo Ql Ql Qafo 70 48 Ts 48 Qal Ts Ts PIPo Ts 47 Ql Qal Qa Ts Qal Qafo Qafo Ts Qal Qa Ts Qafy Ts Qafo Ts Qal Ts Ts Qafy Ts Qafo Ts Ts Qafo 12 Qal B PIPo Ts Qafo Ts 36 20 A PIPo 45 42 45 PIPo Ts 44 40 50 23 25 12 49 20 25 JERICHO 37 23 Ts C PIPo HORSE 54 20 42 23 12 afo 22 13 10 25 Q 28 PIPo 24 23 20 52 Mh 33 24 3 25 36 18 42 23 Md 60 20 Sl 52 16 62 14 15 50 9 40 Sl 15 15 13 59 Dse 16 42 11 65 75 14 25 17 50 20 T Dsl 53 60 37 49 35 IN 15 20 28 19 3 19 T T 10 17 15 40 10 S IC 20 28 34 28 U 20 30 63 15 24 65 R PIPo 14 15 20 VA 20 25 52 H Dpv 25 T LL Mg 65 21 E 16 MDf 30 49 Qafo Y 25 20 33 37 TH 9 14 f RUST MDf Mg Md MD 24 Y 11 46 E 10 L 2 27 L 8 20 15 20 33 30 A 20 13 15 15 20 65 V 19 15 8 Mh 26 30 30 U 15 38 9 D C 6 20 40 I 58 T PIPo Qafo 6 N 12 13 33 30 14 40 I 18 38 T 32 35 81 11 9 20 20 14 28 12 23 50 10 16 45 6 33 32 10 29 53 45 9 Mh 30 35 Tvu 20 18 20 16 21 30 44 30 Qafo 77 9 20 60 60 20 32 7 32 88 10 10 14 40 46 10 75 18 22 11 10 10 20 15 Mh 9 18 5 12 31 25 80 Qal 16 14 21 Mh 39 14 13 24 32 70 6 24 32 9 16 20 16 57 14 17 85 15 26 7 21 Mh 14 14 7 26 34 21 9 15 32 Md 32 20 16 10 13 16 24 20 20 PIPo Tvf 6 63 Qafo 15 11 65 60 24 12 21 25 25 15 Mh 65 Mh 25 23 C' B' A' This geologic map was partly funded by the Utah Geological Survey 1:24,000 Field mapping by authors, 2002 and the U.S. Geological Survey, National Cooperative Geologic Mapping Program Cenozoic Geology from Pampeyan (1989) through USGS EDMAP award number 01HQAG0146. The views and conclusions 1 0.5 0 1 Digital map preparation by Darryl Greer. contained in this document are those of the authors and should not be interpreted as Miles necessarily representing the official policies, either expressed or implied, of the U.S Government. This open-file release makes information available to the public that has not been fully reviewed according to UGS policy. It may not conform to UGS standards; therefore it may be premature for an individual or group to take actions based on its contents. Provisional Structural Geologic Map of the Jericho Quadrangle, Although this product represents the work of professional scientists, the Utah Department of Natural Resources, Utah Geological Survey, makes no warranty, expressed or implied, regarding its suitability for a particular use. The Utah Department of Natural Resources, Utah Geological Survey, shall not be liable under any circumstances Juab County, Utah for any direct, indirect, special, incidental, or consequential damages with respect to claims by users of this product. by Sanghoon Kwon and Gautam Mitra 2005 Utah Geological Survey Plate 2 a division of Utah Geological Survey Open-File Report 444 Utah Department of Natural Resources Provisional Structural Map of the Jericho Quadrangle 113 00' 45' 30' 15' 112 00' ABSTRACT WEST TINTIC MOUNTAINS SHEEPROCK MOUNTAINS 40 00' The Jericho 7.5-minute quadrangle covers the northern Gilson Mountains in central Utah. The Gilson Mountains are one of the first Provisional Structural Geologic Map of the TINTIC Eureka (a) (b) Simpson fault-bounded ranges of the Basin and Range province west of the Wasatch Front. Within the Gilson Mountains, Sevier (Late Cretaceous to Eocene)-age SLOW Mountains A' ELK EAST TINTIC MOUNTAINS shortening structures are preserved; the most prominent are the Tintic Valley thrust and the Leamington Canyon fault and their associated structures. The VALLEY HILLS SRT Jericho Quadrangle, Juab County, Utah SRT Leamington Canyon fault, exposed along the southern margin of the Gilson Mountains south of the quadrangle, is a thrust fault that is folded by ERICKSON underlying structures and shows top down-to-the-southeast shear. The Tintic Valley thrust sheet is folded into an anticline-syncline pair by a Jericho KNOLL horse in the footwall of the Tintic Valley thrust; this fold pair is partly exposed in the quadrangle. The Tintic Valley thrust has a leading branch-line with by ISF Old River Bed ALLISON KNOLLS the Leamington Canyon fault in the southwestern Gilson Mountains outside the Jericho quadrangle. In the Jericho quadrangle, both Tintic Valley hanging wall and footwall rocks and structures and late normal faults are exposed. The Jericho 1 2 DESERT horse and reclined folds associated with emplacement of thrusts are also exposed. These older structures are covered by Tertiary rocks and Quaternary Sanghoon Kwon and Gautam Mitra KEG MOUNTAIN MOUNTAIN JERICHO deposits in the northern half of the Jericho quadrangle. A RIDGE Jericho quadrangle 45' 2005 SRT ? Jericho RIDGE LONG INTRODUCTION The Jericho 7.5-minute quadrangle covers part of the northern Gilson Mountains in central Utah (figure 1). The town of Jericho is 45 miles (72 PICTURE km) northeast of Delta, Utah, and is accessible by U.S. highway 6 and secondary paved roads. The Gilson Mountains are south of the town of Jericho 1 ROCK TVT Presently Seoul, Korea. Formerly University of Rochester, Department of Earth & Environmental Sciences, Rochester, NY 14627 HILLS (figure 2) and are accessible via dirt roads and 4-wheel-drive trails. The highest elevation in the Gilson Mountains (Champlin Peak) reaches 7,504 feet 2 University of Rochester, Department of Earth & Environmental Sciences, Rochester, NY 14627 THE HOGBACK BLACK JH TVT MOUNTAINS (2,288 m), and is about 2,400 feet (732 m) above the surrounding valleys. U.S. Highway 6 passes between the Gilson Mountains and the Black Mountains to the west. Utah State Highway 148 passes between the Gilson Mountains and the East Tintic Mountains that lie to the northeast. Utah State SRT ? Highway 132 passes between the southern Gilson Mountains and the Canyon Mountains to the south. DRUM MOUNTAINS SAGE VALLEY GILSON MOUNTAINS The Gilson Mountains are one of the first fault-bounded ranges of the Basin and Range Province west of the Wasatch Front. Within the Gilson THE KNOLL Mountains, shortening structures were formed during the Late Cretaceous to Eocene Sevier orogeny (structures shown regionally on figure 1a). The most LTZ CRATER Sevier River prominent Sevier-age structures are the Tintic Valley thrust, the Leamington Canyon fault, and associated folds (figure 2). Both the Tintic Valley thrust Leamington BENCH Lynndyl and the Leamington Canyon fault are folded by underlying structures (figure 3). In the Jericho quadrangle, erosion through the anticlinal portion of the CRT Tintic Valley thrust exposes an underlying Jericho horse with overturned beds of upper Paleozoic rocks (Mu in figure 2, figure 3). The Leamington CANYON MOUNTAINS 30' Canyon fault is south of the Jericho quadrangle. Costain (1960) was the first to describe the geology of the area; his mapping covered the entire Gilson Mountains and he identified two US - 6 high-angle reverse faults (north Gilson fault and south Gilson fault); these faults were later referred to as the Tintic Valley thrust by Morris and Kopf Sevier CRT MAP SYMBOLS Desert (1969), Wang (1970), and Morris (1987a, 1987 b), although there is some controversy regarding the exact exposure of the fault(s). Higgins (1982) Delta mapped the part of the Gilson Mountains in the Champlin Peak quadrangle, south of the Jericho quadrangle (figure 2). Most recently the overall structural geometry of the Gilson Mountains, including the Leamington Canyon fault and the Tintic Valley thrust, were described by Kwon and Mitra Contact, dashed where approximately located or gradational, dotted where concealed. Thrust fault (2001, 2002) and Kwon (2004). The mapping of the Gilson Mountains was done at a scale of 1:24,000 (at 1:12,000 where more detail was required), B CRT B' with the aid of black and white aerial photographs. The Cenozoic geology is modified slightly from Pampeyan (1989). Refer to plates 1 and 2. Normal fault Normal fault, dashed where approximately located, dotted where concealed CANYON RNAGE STRATIGRAPHY Upright & overturned Antiforms Map units in this quadrangle belong to four main structural packages: (1) Cambrian strata in the hanging wall of the Sheeprock thrust, (2) Silurian to Mississippian strata in the hanging wall of the Tintic Valley thrust, (3) Pennsylvanian and Permian strata that form the footwall of the Tintic 15' Thrust fault, teeth on hanging wall, dashed where approximately located, Upright & overturned Synforms Valley thrust, and (4) Cenozoic rocks and sediments that were deposited on top of the thrust sheets. dotted where concealed. 0 40km Strata of the Hanging Wall of the Sheeprock Thrust Costain (1960) first mapped the lower Cambrian quartzite of Jericho Ridge as Tintic quartzite, and Morris (1987a) reinterpreted it as Prospect (c) Mountain Quartzite.