UTAH GEOLOGICAL SURVEY a division of Utah Department of Natural Resources in cooperation with Plate 1 National Park Service Utah Geological Survey Miscellaneous Publication 07-3 and Brigham Young University Department of Geological Sciences Geologic Map of the Twin Rocks Quadrangle

Qe JTRw Qal Qmt Jno Jno Qms Jn JTRw Jno Jk Jn Qe Qe Jn Jn Jpc Jk Jpcr Qe Qmt Qe Jno Jno Jno JTRw Jno Jk Qe Qe Jn Qms Jn Jno Jno Jno Jno Ti 4200 JTRw Jno Jno 4600 4000 Jk Jno W A T E R P O C K E T Jn Qmt Qe Jn Ti Jno Qe 5000 Jno Jn Ti Qms Qms Qms Qmt Qmt Qmt 4400 Jk Jn JTRw Jn Qe Jno Qms Jno Jn Qe Qe Jn Qe Jn Jn Ti Jno Jno Jno Jn Jno Jn Jn Jk JTRw Qe Qmt Jk Jno TRco Qmt JTRw Jno TRco Qmt Jn Jno Qe Qmt TRcm TRco Qmt JTRw Jno Jno TRcp TRcp Jno Qmt Qal Jk Ti Qal Qmt JTRw Jk TRcp TRcp Jno Jn Jn TRcm Qmt Jno TRco Jno 4800 Qmt TRcp TRco Qal C A P I T O L R E E F Jno TRco F O L D Qmt JTRw Jno Qe Jno TRcp Qmt Jn JTRw JTRw Spring Jk Jno

JTRw Qmt Jno Jk Jk Qmt Qmt TRco 5 Jn TRco Ti Qmt Qmt Jno Jk Qmt JTRw Canyon R TRco Qmt T co Qe JTRw Qmt R Qe TRco TRco TRco Tco Ti Qmt Qal C A P I T O L Qmt TRco TRco Jk TRco 5800 JTRw Qal JTRw Jno Jk Jno Jno Qmt TRco Qe Qe JTRw Jk Qe Jn Jno Jno Ti Jn JTRw Qmt Jk Jk Jno Jno Jno Jn JTRw Jk 5000 Jno JTRw Jno 4 Qe Qe R A' T co Qmt 5400 Jk Jn Jno 5600 Qe Qe Jno TRcp Qe Jn TRcm Qe Qmt Jno Jno JTRw Qe M E E K S Jn Ti Qe 3 4800 Jno Qe R E E F Jno Jno Qe Qal JTRw Qe Qe Jno Jn Qmt Qe Qe Jk Jk R Jk Jno Jno JT w Qmt Jno Jno TRco M E S A Qmt Jno Jno Qmt Qal Jno Qe Qe Qe Qmt Jk Jn Qmt TRco Qe TRco Jno Jk Qmt Qe Qal JTRw JTRw Jk TRco TRcp TRcp 5200 JTRw Qmt Qms TRco TRco Qe JTRw TRcp Qmt Qmt Qmt TRcp Qmt Jn Jn Jno TRco Qmt TRco Jno TRcm Qmt TRcm Qmt Qe TRco Jn Jno Qms Cooks Qms Qmt 2 Qal Qmt Qmt TRcp TRcp Jno TRcp TRcs N A T I O N A L P A R K TRcm Qmt TRco Jn JTRw Jk TRcs TRcs Jno 4800 TRcs Qms Jno Qms JTRw TRcp Qal Qmt TRcp TRcs 5000 Qmt Mesa TRmm Qms Qal TRcp TRcm TRmm Jno 2 Jno Jk R TRcp R JTRw Qmt T co Qmtv T cm TRco TRcs TRcs Jn Qms TRcp Qatv Qms Jno 1 Qmtv TRcm g n pri S Qmt 4600 TRmm TRco Jk Jn TRcm TRcp Qmt Jn Qal TRcp TRcs 3 TRcp 2 Qatv2 Qmt TRco TRcp TRcm Qmt Qatv2 Qms R Qmt Jk Jno T cm Qmt R R TRcm TRcs Qmt Tcp JT w Qal Qmt Qal 4400 R Jk TRcm Qea TRcs Tco Jn 24 Qatv1 TRcm TRcm Qmt TRcp Qatv1 Qal Qal Qal2 Qms JTRw Qal2 Jk Qea TRco JTRw Jno Qal Qmtv TRcm TRcp R Qatv1 2 Qmt TRcp Tco Jno TRcm Qmt Qmt TRco Qatv2 TRcm TRcs Qms TRcm TRcm TRco Jn TRmm Sulphur Qmtv Twin Qmtv TRmm TRcm 8 4200 Jk Qatv Rocks Qms Ca ny o n 2 TRcs Qms TRcs Jk Qal2 JTRw Qatv2 Jn Qmt TRcs JTRw Qatv Qal 3 Qms TRcm Qmt Qatv1 Qatv Qmtv Qal2 Qmtv 4 Qatv2 Qmtv Qmtv Jn Qmtv Jno Qatv1 Qmt JTRw R TRmm 3 Qea TRcs T co TRmm Qmtv Qatv2 Qea Qmt Qal2 Qmtv Qmt Qal TRmm Qal2 Qmtv TRco TRmm Qmtv Qmtv Chimney Rock Qatv Qmtv Qal Trail Jn Jn Qal 2 R Jno TRmm 2 R R JTw Jk T mm Qatv2 T cs R Qatv2 Qal T cp Jn TRmm Qatv3 Qal2 Qal Qmtv Qmtv Qmtv Jk Jno Qal2 Qatv 2 Qatv2 Qal R Qmt 2 T cm TRcs Jno Jno Qal2 Qmtv Qmtv 3 Qal Chimney Jn The Motorman 2 TRcs TRco JTRw Qe Qatv Qatv Rock TRcs Qmt 2 3 Qatv Qatv TRmm TRcp TRmm Qmtv 3 4 Qmtv TRcp TRco 5400 4 TRcm TRmt TRcs Jno Jno Qatv4 TRco TRmm Qatv4 Qmtv Qmtv Qmtv Qms Qmt Qal Qal Qmtv Qal 2 2 R CreekTRmm TRmm T co Qatv TRcp 3 Qmtv Qmtv 4 TRcs Wh iskey JTRw Qmtv 5 Qms TRms Qal Qms TRmm Jk Qms Qms Qmt 9 Qmtv Flat TRcs TRmm Qmtv Qmt Jn Qatvu Qatvu TRmm 5600 TRms Qmt TRcp Qal2 TRmm TRmt Qal2 TRcm Qal Qmt TRms Qmtv TRmm TRms Qal Qal TRmb TRmb Qmt 9 Qal2 2 TRms Pk Qmt Qmt Jno TRmb Qal2 Pk Navajo Pk Road 4 3 Qmt Qal2 Qal TRco Qal TRmb Qal TRcm Qatvu TRmb TRmb TRms Qmt 12 Qmt Qmt TRmb Pk TRms TRms Qmt Qmt TRmb Goosenecks JTRw Qmt TRms TRmt Qmt Qmt TRmb Qmt TRcm Qal 10 TRmb TRcp TRcp Jk Knobs Qal Pk Qmt Goosenecks Qal Qal TRmb TRmb TRco Pk TRco Qmt Fl a t Qmt TRms The TRcm 5 TRmt JTRw Qe TRms Castle Trail 6 TRms 3 10 Qal TRcp TRmt TRcp Qmt TRcm Pk TRcp TRmb Qal TRcm 5800 Qmt Pc TRms Lo ng l eaf Qal Jno TRmt TRms TRmt Qal TRcp TRmb TRmt

Qmt TRms Qatv2 15 TRmm Qmtv TRmm TRmm Qatv TRcm TRcp TRcp Qmt TRmb 3 Visitor 24 TRco Qatv Center Qal TRms Qmt 3 Qmt TRmb Scenic TRcm Qal L E W I S TRmt TRms 6000 Pk TRmb 15 Qal2 F L A T 18 Qatv Qatlo Qal 6 TRmt Qmt 4 TRmb Qatlo Drive TRmt TRms TRmt TRcm Qmt Qal Qatlo TRcs Qmtv B E A S TRmb Qmt R Qea TRms TRmb Qmt Pc T mm Qmtv Qmt Qmt R TRmb TRmb Qatlo T mt TRmb TRmb TRms TRmb TRmb TRmb Qmt Qatf5 Qal Pk Qmt Qmt Qatf5 TRms Qal Qmt TRmb Qmt TRmb TRmb TRmb Qmt TRmb Qmtv Trail TRmb Qmtv 6 Qmt TRmb TRmb 9 Qmt TRmt Trail TRmb Qatf5 Qmt TRmb Pk TRmb River Qmt Fremont Gorge TRmt Qal Qmt Qmtv Qal TRmt Pk TRmb TRmb TRms River TRmm TRms TRms 15 TRmb Qmt Qea Qal Pk TRmb 6200 Qmt 12 Fremont TRmb Pk TRmm TRmb Qmt TRmb Qmtv Qmtv TRmt Pc Pk Qal Qmtv TRmb 4 TRmt Qmtv 5 TRmt Pc Pk TRms Qatf4 Qatfu TRmm Pk TRmb Qmt 4 TRmb Fremont TRmb 2 TRmb 16 TRmt TRmb Pc 6400 Qmt Qatlo Pc TRms Qmt Qatf3 Qmt TRms Qmt Qal2 Pc Pk Pc Qmt Qal TRms 1 5 Qmt Qal R TRmb TRmb T mb Qmtv TRmb TRmb TRmb Qatf Qal Qmtv Pc Pk 2 TRms Qmtv Pc TRmb Pk TRmb Qmt Pc Qal2 Qmt Pk Pc Qe Pc TRmb Qal2 Qea Qal2 Fremont River Pc TRmb Pk Qmt Qatlo TRmb Qal Qmt TRmb Pk Qmt 12 Qe Qmtv Qmtv Qmt Qe Pk TRmb TRmm Qatf3 Qmtv Qmt TRmb TRmb Qmt Qea Qmtv Pc TRmb Qmt TRms Qmtv Qatlo Qe Qmt Hollow Qea Qmt Qea Pc Qmtv R Qea Qea Pk TRmb T ms TRmb M O U N T A Qe Qmtv TRmb Qmtv TRmb Qe Qmt TRmb Qmt I N Qal Qatf3 Qmt Pc Canyon TRmb Qal Qmtv Qmt M I N E R S Qmt Qatfu Qmtv Pk Qmtv TRmb Qal TRmb Qmtv TRmb Pk Qmtv TRmb Qmt Pk Qmt TRms TRmt Qe Qmtv TRmb Pc Qal R Cuts R Tmb R Pk TRmb T ms T ms TRmt TRmb TRms Qea WideQal Qmt Qmt 6600 R TRmb T mb TRmb TRmb Pk TRmt TRmt Qe TRmb TRmb Qmt TRms TRmb TRmb TRmb TRmt Pk TRmb TRms TRmt TRmb TRmt TRmb Qal TRms TRmb Qatfu Qmt Pk TRms TRmb TRmt Qal TRms TRmb R Pk TRms TRms TRmb TRms T ms TRms TRmb TRmb TRms Pk TRms A Base map from U.S. Geological Survey Twin Rocks 7.5' quadrangle, 2001 SCALE 1:24,000 Field mapping by authors, 2005 Geologic data and base map in NAD 1927 1 1/2 0 1 MILE GIS Analyst, J. Buck Ehler Cartographer, Lori J. Douglas Shaded topography generated from digital elevation data Project Manager, Grant C. Willis 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET Research suported by the United States National ISBN 1-55791-775-2 Parks Service, under NPS Grant #P2360032216 and the U.S. Geological Survey National 1 .5 0 1 KILOMETER Key access roads, selected trails, and prominent Cooperative Geologic Mapping Program under features in and near Capitol Reef National Park EDMAP Award #03HQAG0003. The views and CONTOUR INTERVAL 40 FEET shown in brown. Condition and status of roads and conclusions contained in this document are those of trails may change over time. Some not shown. the authors and should not be interpreted as From data provided by National Park Service. necessarily representing the official policies, either 12° 2' expressed or implied, of the U.S. Government. UTAH

The Utah Department of Natural Resources, Utah GEOLOGIC MAP OF THE TWIN ROCKS QUADRANGLE, Geological Survey, makes no warranty, expressed or implied, regarding the suitability of this product WAYNE COUNTY, UTAH QUADRANGLE LOCATION for a particular use. The Utah Department of 2007 MAGNETIC DECLINATION Natural Resources, Utah Geological Survey, shall AT CENTER OF SHEET not be liable under any circumstances for any by 321 1 Flat Top direct, indirect, special, incidental, or consequential 2 Cathedral Mountain damages with respect to claims by users of this 3 Fruita NW 4 Torrey product. 1 2 4 5 5 Fruita Samuel C. Sorber , Thomas H. Morris , 6 Blind Lake The Miscellaneous Publication series provides 7 Grover 2 8 Golden Throne non-UGS authors with a high-quality format for and Jeremy M. Gillespie 6 7 8 documents concerning Utah geology. Although review comments have been incorporated, this ADJOINING 7.5' QUADRANGLE NAMES publication does not necessarily conform to UGS technical, policy, or editorial standards. 2007 Utah Geological Survey, 1594 W. North Temple, P.O. Box 146100, Salt Lake City, Utah 84114-6100. 1 Phone: 801-537-3300; fax 801-537-3400; ExxonMobil Exploration Company, Houston, Texas geology.utah.gov 2Brigham Young University, Department of Geological Sciences, Provo, Utah UTAH GEOLOGICAL SURVEY Plate 2 a division of Utah Geological Survey Miscellaneous Publication 07-3 Utah Department of Natural Resources Geologic Map of the Twin Rocks Quadrangle in cooperation with National Park Service LITHOLOGIC COLUMN and Brigham Young University Department of Geological Sciences TRmt Torrey Member of the Moenkopi Formation (Lower Triassic) – Moderate-reddish-brown to moderate-reddish-orange mudstone, siltstone and very fine grained sandstone. Contains THICKNESS MAP “ripple-rock” and reptilian trackways. Bedding thickness ranges from 1-15 feet (0.5-5 m). Forms FORMATION MEMBER LITHOLOGY ENVIRONMENT DESCRIPTION OF MAP UNITS ledges and slopes. 190-210 feet (60-65 m) thick. feet (meters) SYMBOL SYSTEM

QUATERNARY DEPOSITS Carmel Formation, Paria River Member 150-200 (45-60) Jcpr marine TRms Sinbad Limestone Member of the Moenkopi Formation (Lower Triassic) – Very-pale-orange to grayish-orange limestone and dolostone with interbeds of calcareous siltstone and sandstone, and Page Sandstone 130-150 (40-45) Jpc eolian Qal Alluvial and floodplain deposits – Poorly to moderately sorted material in modern stream and algal boundstone. Upper beds commonly contain oolitic grains and bivalve fragments. Forms a river channels. Includes clay- to boulder-size sediments composed of mudstone, siltstone, cliff above the Black Dragon Member. 50-90 feet (15-25 m) thick. sandstone, and limestone particles. Includes low terrace deposits up to 10 feet (3 m) above the 450-550 upper member active channel. 0-10 feet (0-3 m) thick. (135-170) Jn TRmb Black Dragon Member of the Moenkopi Formation (Lower Triassic) – Moderate-reddish-brown eolian to moderate-reddish-orange interbedded mudstone, siltstone, and sandstone with gypsum Navajo Sandstone Qal Alluvial and floodplain deposits of a former river level – Located 10 to 20 feet (3-6 m) above stringers throughout. Forms slopes. In many areas undercuts, and is commonly covered by talus 2 current floodplain. Clay- to boulder-size sediments composed of mudstone, siltstone, sandstone, composed of, the overlying Sinbad Limestone. 80-120 feet (25-35 m) thick. 110-150 and limestone particles. 0-20 feet (0-6 m) thick. basal member Jno eolian (35-45) PERMIAN ROCKS J U R A S I C J U R A Qatv Volcanic boulder terrace deposits – Sediments overlying river-cut strath terraces sourced from 200-300 Kayenta Formation Jk fluvial Qatv1 volcanic covered highlands to the west. Composed of pebble- to boulder-size extrusive (basaltic Kaibab Limestone (Lower Permian) – Upper 100 feet (30 m) is composed of very-light-gray to (60-90)

Pk Glen Canyon Group Qatv2 and andesitic) igneous rocks as well as clay- to boulder-size, locally-derived material consisting yellowish-gray shale and limestone beds with carbonate and silicate nodules. Lower portion is Qatv3 of mudstone, siltstone, sandstone, and limestone. Terraces have an easily recognized dark composed of interbedded pale-gray limestone and calcareous sandstone beds. Locally sandstone 260-310 Wingate Sandstone JTRw eolian Qatv4 coloration due to the presence of weathered black volcanic boulders. 0-50 feet (0-16 m) thick beds contain glauconite grains. Lower Kaibab interfingers with Cutler Group, creating a (80-95) Qatv 5 terrace deposits have been divided following Eddleman (2005) according to their associated gradational contact. Contact is drawn at the base of the lowest limestone bed. Forms slopes and Qatvu Owl Rock 150-200 drainage and height above present stream level as follows: ledges. 400-500 feet (120-150 m) thick. TRco Qatf Member (45-60) Qatv - Terrace deposits associated with stream drainages other than the Fremont River. Qatv1 Qatf1 Chinle lacustrine/ represents deposits 0-60 feet (0-18 m) above the present stream level, Qatv2 - 60-120 feet (18-37 Cutler Group undivided (Lower Permian) – Very-pale-orange to yellowish-gray, fine- to Petrified Forest Mbr. 110-135 (35-40) TRcp fluvial Qatf2 Pc Formation m), Qatv3 - 120-180 feet (37-55 m), Qatv4 - 180-240 feet (55-73 m), Qatv5 - 240-340 feet (73-104 Qatf medium-grained, trough cross-bebbed sandstone. Distinguished from the overlying Kaibab Monitor Butte Mbr. 120-150 (35-45) TRcm 3 m), Qatvu (undifferentiated) - >340 feet (104 m). Qatf Limestone by the absence of carbonate beds. Undivided in this locality due to the absence of the 4 Qatf - Terrace deposits associated with the Fremont River drainage. Qatf , Qatf , Qatf , Qatf , Shinarump Cgl. Mbr. 0-30 (0-9) TRcs Qatf 1 2 3 4 Organ Rock Shale between the White Rim Sandstone and Cedar Mesa Sandstone. Base not 5 Qatf , and Qatfu (undifferentiated) represent deposits divided in the same manner as Qatv Moody Qatfu 5 exposed within the quadrangle. Forms ledgy cliffs. Greater than 1000 feet (300+ m) thick. 220-280 (above). Canyon TRmm (65-85) coastal Paleozoic and Precambrian rocks undifferentiated. (Cross-section) Member Pu plain & Moenkopi T R I A S I C R I A T 190-210 tidal flat Qatlo Old locally derived terrace deposits – Terraced fluvial remnants derived from local, non-volcanic Formation Torrey Member TRmt sources composed of clay- to boulder-size particles of mudstone, siltstone, sandstone, and (60-65) limestone. Typically very well cemented. Equivalent to Qatv4 (180-240 feet [54-76 m] above MAP SYMBOLS Sinbad Ls. Mbr. 50-90 (15-25) TRms the present stream level). Located in the southeast part of the quadrangle. 5-30 feet (1.5-9 m) marine Black Dragon Mbr. 80-120 (25-35) TRmb thick. Contact 400-500 Kaibab Limestone Pk Qmt Talus deposits – Mass-movement talus deposits. Rock falls and rock slides. Composed of clay- to Fault - bar and ball on the downthrown block; dashed where approximate, (120-150) marine boulder-size particles. Commonly found where an easily erodible rock layer is located directly dotted where covered: arrow indicates oblique slip under a more resistant rock layer. For example, talus deposits composed of the Sinbad Member On cross-section indicates lateral movement towards the reader of the Moenkopi Formation overlie the Black Dragon Member in many areas, and talus deposits composed of the Wingate and Kayenta Formations overlie the Owl Creek Member of the Chinle On cross-section indicates lateral movement away from the reader 1000+ (300+) Formation. Rarely applies to deposits over pediment-like surfaces. 0-30 feet (0-9 m) thick. Cutler Group undivided Pc eolian 6000 Structural Contours - drawn on the top of the Cutler Group; units are feet above sea level; contour interval: 200 feet; dashed where projected above ground surface N E R M I A P Qmtv Volcanic boulder colluvial deposits – Predominantly composed of talus and colluvial material weathered from volcanic boulder terraces. Includes large extrusive (basaltic to andesitic) igneous boulders as well as other locally derived material. In the Fremont River canyon the unit Anticline - showing anticlinal axis; arrow shows direction of plunge includes volcanic-boulder-containing material stranded along the canyon sides during ancient floods not associated with overlying, bedded terrace deposits. 0-5 feet (0-1.5 m) thick. Syncline - showing synclinal axis; arrow shows direction of plunge

A A' Line of cross section Qms Landslide deposits – Semi-coherent mass movement slump blocks and landslide deposits composed of Chinle, Moenkopi, and the lower portion of the Navajo Formations, which have 111°30' 111°15' 111° 110°45' 10 slid at low angle onto underlying strata. Slide planes in Navajo slumps correspond to bedding Strike and dip of bedding surfaces within the red mudstone at the Kayenta-Navajo contact. While basal slide-planes are 15 commonly seen, scarps at the head of the slump are not mappable due to subsequent erosion. Joints - showing trend of prominent joint sets 38°30' Cathedral Valley Fruita 20-80 feet (6-24 m) thick. Quadrangle Salt Lake UTAH Joints - showing location of major near-vertical joints in the Glen Canyon Group City 6 89 Qe Eolian deposits – Very well sorted, fine-grained, well-rounded, commonly frosted, wind-blown, Caineville 70 sand-size particles. Commonly associated with outcrops of Navajo Sandstone, but also present 24 N.P. 24 Jn JTRw in other areas. 0-10 feet (0-3 m) thick. Visitor 191 Jk 24 15 TRco 24 Center 12 95 JTRw TRcp Torrey 89 TRcm TRmt TRmm Eolian-alluvial deposits – Windblown, fine-grained sand to silt locally mixed with alluvial sand, 38°15' Qea Notom gravel and clay. 0-10 feet (0-3 m) thick. SOURCES OF DATA Twin Rocks 4-wheel drive TERTIARY ROCKS Quadrangle Unpaved road Anderson, R.E., and Barnhard, T. P., 1986, Genetic relationship between faults and folds Pleasant Paved road Ti Intrusive igneous dikes – Dark-gray trachybasalt to basanite with diabasic textures. Locally and determination of Laramide and neotectonic paleostress, western Colorado Plateau- Creek Capitol Reef National Park Paved highway highly altered and easily eroded with poorly-defined margins. Intruded along Golden transition zone, central Utah: Tectonics, v. 5, n. 2, p. 335-357. 38° north-south-trending near-vertical fractures in the Glen Canyon Group. 4.35±0.04 Ma 12 Throne Looking northwest into the Twin Rocks quadrangle along a strike valley eroded into the upper Quadrangle N (40Ar/39Ar) (Doelling and Kuehne, 2007). Referred to as shonkinite in Delaney and Gartner members of the Moenkopi Formation. Beds dip north-northeast off of Miners Mountain anticline (1997). 2-10 feet (0.5-3 m) thick. Billingsley, G.H., Huntoon, P.W., and Breed, W.J., 1987, Geologic map of Capitol Reef Boulder west of the photo. The sandstone “wall” on the right makes up part of “Capitol Reef.” Early National Park and vicinity, Emery, Garfield, Millard and Wayne Counties, Utah: Utah Road trappers and pioneers called any long barrier to travel a “reef.” Thousand Lake Mountain forms Trail Waterpocket fold the dark highlands in the background. JURASSIC ROCKS Geological and Mineral Survey Map 87, scale 1:62,500. Burr

Burr Jcpr Paria River Member of the Carmel Formation (Middle Jurassic) – Moderate-reddish-brown Delaney, P.T., and Gartner, A.E., 1997, Physical processes of shallow mafic dike emplace- 38°45' mudstone and siltstone, yellowish-gray siltstone, and light-gray to white gypsum. Forms ledges. Trail ment near the San Rafael Swell, Utah: Geological Society of America Bulletin, v. 109, 0 10 150-200 feet (45-60 m) thick. 20 Miles n. 9, p. 1177-1192. Road 0 10 20 Kilometers Page Sandstone (Middle Jurassic) – The Page Sandstone in this area is composed of two members: Jpc Doelling, H.H. and Kuehne, P.A., 2007, Provisional geologic map of the east half of the the Harris Wash Member (lower), and the Thousand Pockets Member (upper), which are Loa 30' x 60' quadrangle, Utah: Utah Geological Survey Open-File-Report 489, scale Location of Twin Rocks quadrangle in Capitol Reef National Park. separated by the Judd Hollow Tongue, a member of the overlying Carmel Formation that is Jn included in the Page map unit. The Harris Wash Member is 92 to 113 feet (28-35 m) thick. It is 1:62,500. JTRw composed of very-pale-orange to pale-yellowish-orange, fine- to medium-grained, cross-bedded Eddleman, J.L., 2005, Elevation, longitudinal profile, and Schmidt Hammer analysis of sandstone. Based on pollen assemblages and ages, the upper part of the Judd Hollow Tongue ROADS AND TRAILS TRcs TRco correlates with the Crystal Creek Member of the Carmel Formation as mapped in southwestern strath terraces through Capitol Reef National Park; Bedrock channel response to TRcp Utah, and the Judd Hollow Tongue as mapped in south-central Utah (Douglas A. Sprinkel and TRcm climate forcing?: Provo, Utah, Brigham Young University, M.S. Thesis, 111 p. TRcs Hellmut H. Doelling, personal communication, 2005). It is composed of ripple-laminated, Paved road TRmm moderate-reddish-brown to dark-reddish-brown mudstone and sandstone with local interbeds of Hintze, L.F., 1993, Geologic history of Utah: Brigham Young University Geology Studies, limestone. The Judd Hollow Tongue forms a slope and ranges from 10 to 17 feet (3-5 m) thick. TRmt Special Publication 7, 189 p. The Thousand Pockets Member is composed of very-pale-orange to pale-yellowish-orange, fine- Gravel and dirt road to medium-grained, cross-bedded sandstone with planar and contorted beds. It is 17 to 32 feet Martin, D.H. Morris, T.H., Sorber, S.C., and Eddleman, J.L., 2007, Geologic map of the (5-9 m) thick. The Page Sandstone can be distinguished from the underlying Navajo Sandstone Trail by the abrupt change in weathering styles. The lower portion of the Page Sandstone forms sheer Golden Throne quadrangle, Wayne and Garfield Counties, Utah: Utah Geological cliffs above the rounded expression of the Navajo Sandstone. Map unit is 130-150 feet (40-45 Survey, Miscellaneous Publication 07-1, 2 plates, scale 1:24,000. Key access roads, selected trails, and prominent features in and near Capitol Reef National Park m) thick. shown in brown. Condition and status of roads and McLelland, B.E., Morris, T.H., Martin, D.H., and Sorber, S.C., 2007, Geologic map of the trails may change over time. Some not shown. Navajo Sandstone (Lower Jurassic) – Mapped as upper and basal members, divided by a locally Fruita quadrangle, Wayne County, Utah: Utah Geological Survey, Miscellaneous Publi- From data provided by National Park Service. The great wall or escarpment north of Highway 24 is carved into the Jurassic-Triassic continuous, thin (5-10 feet [2-3 m]), reddish-brown to reddish-orange slope-forming mudstone. cation 07-2, 2 plates, scale 1:24,000. Wingate Sandstone. Photo by Grant Willis.

Jn Upper member – Very-pale-orange to pale-gray, large-scale cross-bedded, very fine to fine-grained sandstone. Localized soft-sediment deformation observable in the top 200 feet (60 Morris, T.H., Manning, V., and Ritter, S.M., 2000, Geology of Capitol Reef National Park, CORRELATION OF MAP UNITS m). Forms cliffs and rounded domes. Base is marked by sharp contact with underlying Utah, in Sprinkel, D.A., Chidsey, T.C., Jr., and Anderson, P.B., editors, Geology of mudstone in the basal member. 450-550 feet (135-170 m) thick. Utah’s Parks and Monuments: Utah Geological Association Publication 28, p. 84-105. Qal Jno Basal member – Same as upper member, except contact with underlying Kayenta Formation is ACKNOWLEDGMENTS ? gradational. Includes the mudstone that separates basal from upper member. Forms prominent Qea Qmt cliffs at the base. Represents tongue of Navajo Sandstone into upper part of Kayenta Formation. The authors express their appreciation to the Utah Geological Survey for its help and Holocene Qal2 110-150 feet (35-45 m) thick. Qe support in the process of publishing this map. We thank Grant Willis for his helpful TRcm Qatv Qatf Qmtv reviews, Darryl Greer and Buck Ehler for cartographic and GIS assistance, Hellmut Doel- Qatv Qatf Qms Kayenta Formation (Lower Jurassic) – Moderate-reddish-brown to moderate-reddish-orange, 1 1 ? TRcs Jk ling for his willingness to share his great knowledge of the Colorado Plateau and his Qatv2 Qatf2 irregularly bedded sandstone, siltstone, and mudstone. Forms stepped topography composed of QUATERNARY Qatv3 Qatf3 ledges (local cliffs) and slopes. Upper 50-80 feet (15-25 m) locally contains blocky, mapping expertise, and Robert Ressetar, Kimm Harty, and Hellmut Doelling for helpful Qatv4 Qatf4 TRmm cliff-forming, very fine to fine-grained, cross-bedded sandstone. 200-300 feet (60-90 m) thick. reviews. Thanks to Tom Clark of Capitol Reef National Park for his support and logistical Qatv5 Qatf5 Qatlo ? Pleistocene help throughout the project, and to Drs. Bart Kowallis and Ron Harris for their valuable Qatvu Qatfu JURASSIC - TRIASSIC ROCKS suggestions, edits, and technical expertise. Financial support for this project has been provided by the United States National Park Service and the Brigham Young University Ti Wingate Sandstone (Lower Jurassic to Triassic[?]) – Light-brown to moderate-reddish-brown,

R College of Physical and Mathematical Sciences. Their support was greatly appreciated. Tertiary-

JT w (~ 4 Ma) cross-bedded to massive, very fine to fine-grained, calcite-cemented sandstone. Forms the sheer Pliocene cliffs of the western escarpment of the Waterpocket Fold. Cliff faces are commonly highly DISCLAIMER fractured and covered with black to brown desert varnish. 260-310 feet (80-95 m) thick. Jcpr

TRIASSIC ROCKS Research supported by the United States National Parks Service, under NPS Grant # Middle Jpc P2360032216. The views and conclusions contained in this document are those of the Owl Rock Member of the Chinle Formation (Upper Triassic) – Orange and purple mudstone, authors and should not be interpreted as necessarily representing the official policies, J-2 Unconformity TRco Chimney Rock consists of a resistant sandstone cap of the Shinarump Member of the Chinle siltstone, and sandstone with 1- to 3-foot- (0.5-1 m) thick interbeds of mottled dusky-red to either expressed or implied, of the U.S. Government. Jn Formation sitting unconformably on the Moody Canyon Member of the Moenkopi Formation. The pale-yellowish-green limestone, representing highly bioturbated paleosols with abundant Monitor Butte Member of the Chinle Formation forms the upper slope. rhizoliths and large burrows (up to 2 inches [5 cm] diameter). Member commonly covered by For use at 1:24,000 scale only. The Utah Geological Survey (UGS) does not guarantee Jno talus deposits of the overlying Wingate and Kayenta sandstones. 150-200 feet (45-60 m) thick. accuracy or completeness of data. JURASSIC

Lower Jk Petrified Forest Member of the Chinle Formation (Upper Triassic) – Moderate-reddish-brown TRcp mudstones and siltstones interbedded with carbonate nodule horizons 2 feet (0.6 m) thick, The Utah Department of Natural Resources, Utah Geological Survey, makes no warranty, JTRw interpreted to be paleosols. Basal portion contains a locally continuous, dark-reddish-brown, expressed or implied, regarding the suitability of this product for a particular use. The ledge-forming, medium- to coarse-grained sandstone called the “Capitol Reef Bed.” Contains Utah Department of Natural Resources, Utah Geological Survey, shall not be liable under Unconformity petrified wood. Most of the member forms a slope with local small ledges. 110-135 feet (35-40 any circumstances for any direct, indirect, special, incidental, or consequential damages m) thick. with respect to claims by users of this product. TRco Monitor Butte Member of the Chinle Formation (Upper Triassic) – Light-olive-gray to TRcm The Miscellaneous Publication series provides non-UGS authors with a high-quality TRcp greenish-gray bentonitic claystone with thin dusky-brown to dark-yellowish-orange, medium- to format for documents concerning Utah geology. Although review comments have been coarse-grained, cross-bedded, channelized sandstone beds. Forms a slope with small ledges. incorporated, this publication does not necessarily conform to UGS technical, policy, or Middle TRcm Contact with overlying Petrified Forest Member is poorly defined and approximated in this map. 120-150 feet (35-45 m) thick. editorial standards. TRcs Shinarump Conglomerate Member of the Chinle Formation (Upper Triassic) – Grayish-orange TRcs Unconformity to very-pale-orange, medium- to very coarse grained, cross-bedded sandstone and conglomerate.

Contains petrified wood. Shinarump beds are discontinuous and commonly channelized due to TRIASSIC TRmm fluvial depositional history. The basal unconformity is scoured with 0-5 feet (0-1.5 m) of relief and is typically overlain by a gravel lag. The unconformity is regionally continuous and is found TRmt even where no Shinarump accumulation is present. The member contains uranium that has been historically mined within the quadrangle. Forms ledges and cliffs. 0-30 feet (0-9 m) thick. Lower TRms Moody Canyon Member of the Moenkopi Formation (Lower Triassic) – Moderate-reddish-brown TRmm TRmb to moderate-reddish-orange laminated mudstone and siltstone with sparse, very fine grained, Twin Rocks are formed of coarse sandstone of the Shinarump Member of the Chinle Formation and rest on the Moody Canyon Member of the Moenkopi Formation. The Wingate Sandstone ripple-laminated sandstone beds. Small-scale soft-sediment deformation common in silt and Unconformity sandstone beds. Bedding-parallel gypsum veins and stringers common throughout. Typically forms the cliff in upper right. Photo by Grant Willis. forms a slope but locally cliff-forming where overlain by the Shinarump Conglomerate. 220-280 Pk feet (65-85 m) thick. Pc Lower

PERMIAN Pu

A SOUTHWEST C A P I T O L R E E F NORTHEAST A΄ Feet Fremont Sulphur Feet TRmb TRms 7000 River TRmb Jno 7000 TRms Creek Jno Highway 24 Jn Jk Jn Pk Pk Jno Jno Jno Jno JTRw Pk Jk TRms TRcp Jk TRmb 6000 TRcs TRcm JTRw 6000 Pc TRco JTRw

TRmt TRmm TRmt 5000 5000 Pk Pk Pc 4000 Pc 4000

3000 3000 Paleozoic and Precambrian undivided

2000 2000

1000 1000

0 0 Thin surficial deposits not shown.