GEOLOGICAL SURVEY a divison of Utah Department of Natural Resources Plate 1 in cooperation with Utah Geological Survey Map 220 National Park Service Geologic Map of the Kolob Reservoir Quadrangle

Qmsy Kd Qmsy Qac Qmsy Qmt Qac Qac Qac Qac Kd Qmsy Qmt Kd Kd Kst Qmt Qmsy Qmt Qmsh Kd Qac Qac Kd Qmsy Kst Qmsh Qmsy Qmt Kst Jcw Qmsy Qac Ksu Qmsy Qmt Jcw Qac Qmt Qac Kd Qac Qmsy Qac Qaly Qmsy Jcp Qac Qac Qac Kd 4 Jcx Jcp Qmsy Qac Qmsh Qc Ksu Qac Qmsy Qac Qmt Kd Qac Qmt Qac KRF92800-1 Qac Qac 8900 Qaf1 9000

Kst 9100 Qmt Qmsy Qac Kd 9200 Kd Qmsy Qmt Qc Qc Qac Kst Qmsy Qmsy 2 Kd Jcx Qmso Kd Qc Qac Jcx Qmt (Kd) Kd Qmsh KRF92700-2 KRF92700-1 Kd KRF61801-1 Qac Qac Qc Ksu KRF61801-2 Jccu Qac Qmsy Qmsh KRF61801-3 Qac Qmsy Qac Kst 3 Qmsh Ksu Qmsy Qac Qmsy Qmsy Jccl Qmsh Kst Qac Qmsy Qac Kd Qmsy Qmsy Qmsy Qmsy Qmso Qmsh Kd Qmsy 1 Qmsh Jccu Qmso Kd Qac Qmsy Qmsh Qac Kd Jcx Qmsy Jcw (Kd) Qc Qc Qac Qc Qmt Qac Kd 2 Jcp Qac Qc Qaf1 Qac Qc Qmsy Qmso Kd Qac (Kd) Qmso(Kd) Jcx Jcx Qmt Kd Qac Qmsh 45 4 Jcw Jccu Jcw Kst Qmt Qmsy Qac Jcp Qc Qac Jccl Qmsh 20 Jcx Qmsy Qac Qmso Qaf Qmsh Kd Jccl 1 Qmt Qmt Qmsh Qmsh Qc Kd Qmsy Qaly Qaf1 Jts Qmt Kd Qac Jccl Jcp Qac Qmso Kst Jccl Jcx Qac Qmsh Jts Jts Jcp Qc (Kd) Ksu 5 Qac Kst A' Jts Jcw Jcw KR90100-1 Jccu Qac Jn Qac Kd Jn Jn 5 Kd Kd Qmt Qmso KRF71800-1 2 Qmt Qaly Qmsh Qc Qc Qc Jn Qmsy Kd 2 Qbhp 3 Qmso Qmt Jts Jts Qmsh Jts Qst Qc Jn Jcw Qmsy Qmsy Jts Jcw Jccu Qmsy Qmso Kd Jcp (Kd) Qmt Jts Qac Jcw Qac Qac Qac Qac Qmsh Qc Jccu Qmsy Qmt Kd Jcw Qc Jcw Kd Qac Jcp Qc Qac Jcx Jcp Qmsy Qac Qac Qac Jccl Jts Jcp Jccl Jcp Qc Qmt Jts Jcp Kcmc Qmt Jcw Qbhpc Qac Kd Jcx Jn Jcx Qac Qac Kst 5 Qmsy Qmt Jccu Qc Ksu c Qmsy Jcx Jcw Qmsh Kd Jcx Jccl Qc Jn 3 Qmsy Jcp Qmsy Qc Qac Kst A Qmt 4 4 Jcp Qac Qmso(Kd) Qmsy Qaly Ksu Jcx Jccl Jcp Jcx Qac Qac Qc Jts Qac Jccu Qmt Qmsy Kd Qmt Kst Qc Jcw Qmt Qac 3 Jccu Jts Qac Kd Qc Qmsy Jts Qac Kst Qmt 6300 Qc 12 Qc Kd Qmsy Jts Qmt Jn Jccu Qmsy Qmsy Kst Qac Qmt 1 Jts Jts Qmsy Kd 6400 Qac Qmt Qmt Jccl Jcx Qc Qac Jts Qmt Jccl Kd 4 Jccl Jcx Qmt Willis Qac Jcp Kd Qac Jn Qmsy Qc Ta Qmt Creek Jccl Qmt Willis Jcx Trail Qmsy KR72000-6 Trail Kd Jts Creek Qac Jcp Qmt Jts KR72000-5 Qac Qmt Jcx Jccl 6500 Qmt Kd Kd 4 1 Jcx Qac Qmt Ta Kd Creek Jccl Qmt Jccu Jts Qmsy Qmsh Bullpen Jccu Jcp Jts Mountain Jcx Qmt Kd 6600 Qmsy Jn Jccu Qla Jccl Qac Jcp Qac 5 Jcx La Verkin Jcw 5 Jcp Qmt ZION Qf Qmsy Qc Qmt Jcx Jcp Jn Qf KR72000-3 Qac Qac Jcp Canyon Jccl Jccl Qc Trap Qac Bear Qmt Qmt Jccu Qbkp 1 Jcp Jcw Qc Jcx Jts Jn Qmsy Kd Qmsy 3 Ta Jcx Jccl Jts Jcp Qmt Jts Jcx Qac Qmt KR72000-4 Qc Qmt Qmsy Jcp Qbkp Jccl Qac Qc Jccl Qc Jccu 6700 Jccu Jcw Jcp Jcx Qac Qmt Qc Qmt Jts Jccl Kd Jccu 6800 Qmsy Jccl Jts Qac Qmt Qac Qmsy Jccu Jts KR81200-1 Qaco Langston Jts Qac Qmsy Qmsy Qbkpc Qc 6400 Mountain Jccl Qmsy Jcx 3 Jccl Qmt Qc Jts Jccl 6500 Qmt Jccl Jcp Qmsy 6900 Qmt Jtw Jn Qmsy 6600 Qmt Qmt Jccu Qc Jccl Qmsy Jts Jccl Qmsy Qbkp Jtw Jts 6700 Jn Kd Jcx 6800 Jccu 7000 Qmsy Qmsy Jts Jccu Qac Qmsy Qmsy Qac Qmsy Qc Jcx NATIONAL Jccl 7400 Jcp Qac Jts Qmt 7100 7000 Jccl 7100 7500 Qaco Jcw Qmt Qmt Qac 7300 7200 Jccl Qac Jtw Qc Jcp Qac 6900 Jcw Qc Jcx Qc Kcmc Jccl Qmt Qmt Jcx Qmsy P o i n t Qac Jcp Jn 7600 Qc Jccl Jcp Jts 7700 Qblp Jccu Jccu KJu Qaco Qmt Jcw Qmt Qc Ko lo b Qc Qmt Jn Qmsy Qc Jcx KR72000-2 Jtw Qmt L o n g Jcp Jccu Qmt KR71599-2 Jcw Qac Qac Qmt Qmsy Jccl Qae Jcx Qmt Qac Jccl Qmt Qmt Jtw Qc Jcp Jccl Jccl Jcx 2 Jts Qmsy KR72000-1 Qc Qblp Qac Jtw Qblp? Jccl Qmt Jcx Jccu Jcp Qf Jts Qmt Jtw Jn Qmt Jn Jccl Qac Jts Jts Jtw Jcx Qmsy Jts Qmt KR81100-5 Jccl 2 KJu Qmt Jccl Qblc Qmt Jccl KR71399-1 Qac Qrlc Jtw Qmt LAVA POINT ROAD Qblp C r e e k Jts Qmsh Qc 3 Jccu Qac Kd Qmt Jccu Jtw Qblc Qaly Jts Qblp Qaco Jtw Qac Qac Qmsh Qac Jccl Jts Ta Qac ZION NATIONAL PARK Qer FAULT Jtw Kd Kcmc Qblp Qae Jccl Qc Qblp Jcx Jcp ROAD Qac Qac 2 Qmt PARK Qblc Jcx KR81100-3 Jcx Jn Jccu KR81100-4 Jtw Jccl Jcp Jccu Jcp CANYON ZP0601 Qmsy Jccl Qmsy 1 Qc ZP0901 Jtw Qblpc ZP0602 Jccl Jccu Barneys Qmt TRAP Qrlc Trail Jcp KR71399-3 Qblp Campground Jccu Qmt Qc Jccl Qc c Jccl BEAR Jtw Jtw Jccu Lava Qblc Qac Qc Qla Jts Jts KR71399-2 Jcp Jcx Jccl 7800 Qc Point Qer Jts Qblp Qac Jccu Qmt Jccl Qla Jcx Jcx Qmt Jccl Qmt TERRACE Qla Qc West Jcx Jku Jcx Jccu Qae Trail Qas Jccl Qmt Jccl Qla Jtw KOLOB Qblp Rim Jccl Jku Jtw Qblc Qblp Trail Qmsy Jn Jtw Qmt KR81100-1 Canyon Qla Jccu Jccl Jccu Qbg Qer 1 Qmsy Qc Qmsy Qmt Jccu Qac Qc Qmsy Qmt Jts Jts Jccu Jccl Horse Pasture Jtw Hop Valley Trail Valley Hop Qbg Jccl Jccl Qae Qae Qac Jts Jku Qas Qac Jn Ta Qblp Jccu Wildcat Plateau Qac Qmsy Qaeo Qac Qc Qc Qblp Qc Jccl

Base from U.S. Geological Survey, Key access roads, selected trails, and prominent Fieldwork by author in 2000-01 Kolob Reservoir 7.5' quadrangle, 1980 SCALE 1:24,000 features in and near Zion National Park shown in Project Manager: Grant C. Willis Shaded topography generated from digital elevation data 1 0.5 0 1 MILE brown. Condition and status of roads and trails GIS Analyst: Kent D. Brown may change over time. Some not shown. From Cartographer: James W. Parker 1000 This geologic map was funded by the Utah Geological 0 1000 2000 3000 4000 5000 6000 7000 FEET data provided by National Park Service. ISBN 1-55791-739-6 Survey and the U.S. Department of the Interior, 1 0.5 0 1 KILOMETER National Park Service. The views and conclusions contained in this document are those of the author and should not be interpreted as necessarily CONTOUR INTERVAL 40 FEET representing the official policies, either expressed or NATIONAL GEODETIC VERTICAL DATUM OF 1929 implied, of the U.S. Government.

Although this product represents the work of 12°27' professional scientists, the Utah Department of Natural Resources, Utah Geological Survey, makes no GEOLOGIC MAP OF THE KOLOB RESERVOIR QUADRANGLE, warranty, expressed or implied, regarding its suitability for a particular use. The Utah Department of Natural Resources, Utah Geological Survey, shall not be liable WASHINGTON AND IRON COUNTIES, UTAH UTAH under any circumstances for any direct, indirect, TRUE NORTH special, incidental, or consequential damages with MAGNETIC NORTH by respect to claims by users of this product. APPROXIMATE MEAN DECLINATION, 2007 QUADRANGLE LOCATION For use at 1:24,000 scale only. The UGS does not Robert F. Biek guarantee accuracy or completeness of data. 2007 Utah Geological Survey, 1594 W. North Temple, P.O. Box 146100, Salt Lake City, Utah 84114-6100. Phone: 801-537-3300; fax 801-537-3400; www.geology.utah.gov See plate 2 references for geologic map list Utah Geological Survey a division of Utah Department of Natural Resources Plate 2 in cooperation with Utah Geological Survey Map 220 National Park Service Geologic Map of the Kolob Reservoir Quadrangle

DESCRIPTION OF MAP UNITS CORRELATION OF MAP UNITS LITHOLOGIC COLUMN

QUATERNARY unconformity histor- Qf THICK- ical Qas Alluvial deposits CRETACEOUS Qla FORMATION SYMBOL NESS LITHOLOGY pre- Qaf1 Qmsh Feet Younger stream deposits (Holocene) – Stratified, moderately to well- Straight Cliffs Formation upper historic Qaly Qac Qae Qst Member (Meters) SERIES Qaly sorted sand, silt, clay, and pebble to boulder gravel in river channels SYSTEM and flood plains; locally includes small alluvial-fan and colluvial Upper unit (Upper Cretaceous, Santonian[?] to Turonian) – Slope- middle Holocene

Ksu H. forming, grayish-orange to yellowish-brown, thin- to thick-bedded, and deposits, and minor terraces as much as 20 feet (6 m) above current Qc Qmt Qer stream level; equivalent to stream deposits (Qal ) and stream-terrace fine-grained subarkosic sandstone and gray mudstone and shale; lower Qmsy Surficial deposits Q 0-150 1 contains a few thin coal beds, common carbonaceous shale, and (0-40) deposits (Qat2) in the adjacent Kolob Arch quadrangle, but undivided here due to uncertain correlation between upper and lower reaches of several thin coquina beds; forms broad, rounded hills typically drainages; generally 0 to 30 feet (0-9 m) thick. mantled with unmapped colluvium; believed to be equivalent to the Qaco Smoky Hollow Member and possibly John Henry Member of the Grapevine Wash flows Qbg 0-20 (0-6) 0.22 to 0.31 Ma (Qbg) Alluvial sand deposits (upper Holocene) – Well-sorted, fine- to medium- Straight Cliffs Formation of the Kaiparowits Plateau (see, for example, Qas ? ? ? grained sand on the floor of Hop Valley, in the southwest corner of the Eaton and others, 2001); deposited in fluvial, flood-plain, and lagoonal Hornet Point flow and cinder cone Qbhp, 0-240 (0-73) upper ? Qbhpc 0.74 ± 0.05 Ma (Qbhp) quadrangle, where the Hop Valley stream has reworked the upper few environments of a coastal plain (Eaton and others, 2001); incomplete ? feet of sandy basin-fill deposits. thickness as much as 320 feet (100 m) in the quadrangle, but upper Pleistocene QUATERNARY Kolob Peak flow and cinder cone Qbkp,Qbkpc 0-100 (0-30) part not preserved. Qmso 1.05 ± 0.05 Ma ((Qbkp) Alluvial-fan deposits (Holocene) – Poorly to moderately sorted, non- Lava Point flow and cinder cones Qaf1 stratified, boulder- to clay-size sediment deposited as small alluvial Tibbet Canyon Member (Upper Cretaceous, Turonian) – Grayish- Qmso Qblp,Qblpc,Qblp? 0-120 (0-37) Kst Qrlc fans along major drainages; form active depositional surfaces, although orange to yellowish-brown, generally medium- to thick-bedded, (Kd) Little Creek Peak flow Qblc 0-30 (0-9) 1.02 ± 0.03 Ma (Qblp) locally the master stream is deeply entrenched; typically overlies planar-bedded, fine- to medium-grained quartzose sandstone and 1.08 ± 0.02 Ma (Qblp) Mio. Old boulder gravel deposits Ta 0-30 (0-9)

alluvial channel deposits at the toe of the fans, and locally includes lesser interbedded, grayish-orange to gray mudstone and siltstone; T. 1.44 ± 0.04 Ma (Qblc) ? 0.22 ± 0.03 to minor slope wash and talus along the upslope margins of the fans; locally contains pelecypods, gastropods, and thin to thick beds of Qbg Large quartz monzonite boulders many small fans, because they are too small to depict at this scale and oyster coquina; typically forms cliffs, but in this quadrangle more 0.31 ± 0.02 Ma because they are typically poorly developed, are lumped with mixed commonly weathers to steep, vegetated slopes; upper contact corre- Numerous landslides middle upper unit Ksu 320+ (100+) alluvial and colluvial deposits; generally 0 to 30 feet (0-9 m) thick. sponds to a break in slope and is placed at the top of a coquinoid QUATERNARY

oyster bed that caps the member; deposited in shoreface, lagoonal, Pleistocene Qbhpc 0.74 ± 0.05 Ma Artificial-fill deposits estuarine, and flood-plain environments of a coastal plain (Laurin Qbhp Straight Cliffs Artificial-fill deposits (historical) – Engineered fill used to create the and Sageman, 2001; Tibert and others, 2003); thickens eastward Qf across quadrangle from about 240 to 450 feet (75-135 m) thick. Formation Kolob Reservoir and Blue Springs Reservoir dams; unmapped fill is Qblpc Qbkpc Qblp: locally present in developed areas; as much as 60 feet (18 m) thick. Dakota Formation, Cedar Mountain Formation, and Winsor Member 1.02 ± 0.03 Ma KJu 1.08 ± 0.02 Ma Tibbet Canyon Kst 240-450 Colluvial deposits of the Carmel Formation, undivided (Upper Cretaceous to Middle Member (75-135) Jurassic) – Mapped in the vicinity of Little Creek Peak, where access Qblp Qbkp: Colluvial deposits (Holocene to upper Pleistocene) – Poorly sorted, to private land was denied; the Dakota Formation is present over most Qblp? Qbkp 1.05 ± 0.05 Ma Qc angular, clay- to boulder-size, locally derived sediment deposited of this area, Cedar Mountain strata may be present, and Winsor strata lower Admentopsis n. sp. principally by slope wash and soil creep; gradational with talus deposits are likely present at the lowest elevations. Gastropods, coal

and mixed alluvial and colluvial deposits; locally includes large areas Upper Dakota Formation (Upper Cretaceous, Cenomanian) – Interbedded, Qblc 1.44 ± 0.04 Ma Two prominent sandstone beds of talus where slope angles increase such that colluvium and talus form Kd a thin mantle that grades from one deposit to another; may include slope- and ledge-forming sandstone, siltstone, mudstone, claystone, Craginia sp. gastropods unconformity undifferentiated landslide deposits; generally less than 20 feet (6 m) carbonaceous shale, coal, and marl; sandstone is yellowish brown or Coal thick. locally white, thin to very thick bedded, fine to medium grained; includes two prominent cliff-forming sandstone beds, each several Miocene Ta Lacustrine and basin-fill deposits tens of feet thick, in the upper part of the formation; mudstone and CRETACEOUS Dakota Formation Kd 850 (260) Coal claystone are gray to yellowish brown and commonly smectitic; oyster unconformity Lacustrine and basin-fill deposits (Holocene) – Well-stratified sand, TERTIARY Poorly exposed Qla coquina beds, clams, and gastropods, including large Craginia sp., are silt, and minor peat deposited in the Hop Valley basin in the southwest common, especially in the upper part of the section; uppermost marl Ksu Numerous landslides corner of the quadrangle; grades into colluvial, alluvial, and alluvial- beds above the uppermost sandstone cliff contain distinctive gastropods KJu fan deposits at basin margins and in upper part of deposits; forms with beaded edge Admetopsis n. sp. indicative of a latest Cenomanian Kst planar surfaces that slope downstream, which are incised about 40 feet brackish environment (Eaton and others, 2001) (samples KRF in (12 m) at the south end of Hop Valley; a radiocarbon age of 2640 ± Cedar Mountain sections 14 and 23, T. 38 S., R. 11 W.); Dakota strata are typically Kd conglomerate member Kcmc 0-35 (0-11) 60 14C yr B.P. establishes a minimum age for the formation of Hop Upper Formation poorly exposed and involved in large landslides; includes the overlying L. Pebbly conglomerate Valley Lake (Biek and others, 2003; Biek, 2007), and Eardley (1966) Tropic Shale, which is restricted to the east part of the quadrangle unconformity K unconformity obtained a radiocarbon age of 670 ± 200 14C yr B.P. from the upper where it is silty and sandy and no more than a few feet thick (see, for part of the deposits; deposits in Hop Valley are probably about 250 240-320 CRETACEOUS Kcmc KJu Winsor Member Jcw example, Eaton and others, 2001); upper contact placed at the top of (73-98) feet (75 m) thick (Biek, 2007), but are probably less than 60 feet (18 a slope-forming, coaly and marly mudstone sequence and at the base Lower m) thick in this quadrangle; also mapped at Potamogeton (Chasm) of the typically cliff-forming sandstone of the Tibbet Canyon Member K unconformity Lake, a permanent pond about 2 miles (3 km) west of Kolob Reservoir of the Straight Cliffs Formation; deposited in a variety of flood-plain, "Chippy" limestone that formed behind a rockfall of Navajo Sandstone; “Potamogeton” is 50-160 estuarine, lagoonal, and swamp environments (Gustason, 1989; Laurin Jcw Paria River Member Jcp (15-48) Latin for pondweed, which sometimes covers the pond’s surface. 14C and Sageman, 2001; Tibert and others, 2003); invertebrate and palyno- MAP SYMBOLS Carmel Alabaster gypsum analytical data is available on the Utah Geological Survey Web site morph fossil assemblages indicate shallow-marine, brackish, and fresh- Jcp Formation (http://geology.utah.gov/online/analytical_data.htm). water deposits of Cenomanian age (Nichols, 1995); probably about 150-250 Contact, dashed where approximately located Crystal Creek Member Jcx (45-75) Mass-movement deposits 850 feet (260 m) thick. Jcx Isocrinus sp. Landslide deposits (historical to middle[?] Pleistocene) – Very poorly unconformity Jccu Middle 100-140 Qmsh upper Jccu Poorly vegetated sorted, clay- to boulder-size, locally derived material deposited by Cedar Mountain Formation Normal fault, dashed where approximately Co-op Creek (30-43) rotational and translational movement; characterized by hummocky Jccl located, dotted where concealed; bar and Qmsy Limestone topography, numerous internal scarps, and chaotic bedding attitudes; Conglomerate member (Cretaceous, Cenomanian to Albian) – Thick- Middle ball on downthrown side Member lower Jccl 240-380 Well vegetated basal slip surfaces most commonly form in the lower unit of the Co- Kcmc to very thick bedded, yellowish-brown, channel-form conglomerate, J-2 unconformity (73-115) Qmso op Creek Limestone Member of the Carmel Formation, the Dakota pebbly sandstone, and pebbly gritstone; clasts are subrounded to J-2 unconformity Qmso Formation, and the upper unit of the Straight Cliffs Formation, and rounded, pebble- to small-cobble-size quartzite, chert, limestone, Jtw Structure contour on top of Navajo Sandstone White Throne Member Jtw 0-130 (0-40) Pinches out westward (Kd) the slides themselves incorporate these and overlying map units; the and rare, reworked petrified wood; locally stained reddish brown to Temple Cap (south and west part of map) and on top of Formation Dakota Formation especially forms very large, complex mass move- dark yellowish brown; forms two small exposures southwest of Birch Jts Tibbet Canyon Member (northeast part of Sinawava Member Jts 10-40 (3-12) J-1 unconformity ments; Qmsh denotes slides with historical movement; younger land- Spring and southeast of Little Creek Peak; deposited in river-channel map); contour interval 100 feet; short dash slides (Qmsy) may have historical movement, but typically are char- environment on broad, coastal plain (Tschudy and others, 1984; JURASSIC J-1 unconformity where projected, long dash where control is acterized by slightly more subdued landslide features indicative of Kirkland and others, 1997); Biek and Hylland (2007) reported a poor early Holocene to late Pleistocene age; older landslides (Qmso) are single-crystal 40Ar/39Ar age of 97.9 ± 0.5 Ma on sanidine from a Jn deeply incised and their main scarps and hummocky topography have volcanic ash in Cedar Mountain mudstone immediately above this been extensively modified by erosion, suggestive of late to possibly conglomerate bed in the Straight Canyon quadrangle to the east; Jku middle(?) Pleistocene age, but they too may be locally active; Qmso(Kd) pollen analyses indicate an Albian or older age for these beds (Doelling Major joint denotes large, relatively coherent bedrock blocks of the Dakota and Davis, 1989; Hylland, 2000); upper contact not exposed, but Jks Formation as much as about 150 feet (45 m) thick that slumped regionally, east of the Hurricane fault, is unconformably overlain by Lower downslope under the influence of gravity and which are late to possibly the Dakota Formation (see, for example, Kirkland and others, 1997); unconformity Landslide or slump scarp, hachures on down- Vertical cliffs middle(?) Pleistocene in age. previously mapped as the lower part of the Dakota Formation, but dropped side the lithology, age, and stratigraphic position of these beds suggest JT m Large, sweeping crossbeds Talus deposits (Holocene to upper Pleistocene) – Very poorly sorted, R Qmt correlation to the Cedar Mountain Formation; 0 to 35 feet (0-11 m) angular boulders and finer-grained interstitial sediment deposited thick. J-0 unconformity principally by rock fall on and at the base of steep slopes; typically 2 Approximate strike and dip of inclined bedding grades downslope into colluvial deposits, and may include colluvial unconformity (K) determined photogrammetrically TRc deposits where impractical to differentiate the two; generally less than Upper 30 feet (9 m) thick. JURASSIC JURASSIC 2100-2200

cross section only Navajo Sandstone Jn Middle TR-3 unconformity (640-670) Carmel Formation TRIASSIC Joint, near vertical Mixed-environment deposits and TRm Alluvial and colluvial deposits (Holocene to upper Pleistocene) – Poorly Winsor Member (Middle Jurassic) – Light-reddish-brown, very fine Lower Qac Jcw to medium-grained sandstone and siltstone; poorly cemented and to moderately sorted, generally poorly stratified, clay- to boulder-size, Pit - sand and gravel (no letter), cinders (c) locally derived sediments deposited principally in swales, small weathers to densely vegetated slopes; upper contact is the basal Qaco drainages, and along the upper reaches of larger streams by fluvial, Cretaceous unconformity; near Birch Spring, Winsor strata are slope-wash, and creep processes; gradational with both alluvial and overlain by Cedar Mountain conglomerate, but in the northwest colluvial deposits; Qac deposits form active depositional surfaces and corner of the quadrangle, the conglomerate is missing and the Winsor Quarry Lower are generally less than 20 feet (6 m) thick; Qaco deposits are deeply Member is overlain by Dakota strata; deposited on a broad, sandy incised and of similar thickness. mudflat (Imlay, 1980; Blakey and others, 1983); thickens westward from about 240 to 320 feet (73-98 m) thick. Alluvial and eolian deposits (Holocene to upper Pleistocene) – Locally Spring Qae Paria River Member (Middle Jurassic) – Laminated to very thin derived, fine- to coarse-grained sand and silt with subangular to angular Jcp gravel; deposited in topographic depressions by small streams, slope bedded, light-gray argillaceous limestone and micritic limestone that wash, and wind; includes small alluvial fans and colluvium along locally overlies a thick, white, alabaster gypsum bed common in the Volcanic vent Planar bedded, sabkha margins of deposits; 0 to 20 feet (0-6 m) thick. basal part of the Paria River Member; limestone weathers to small environment chips and plates and locally contains small pelecypod fossils; forms Eolian and residual deposits (Holocene to upper Pleistocene) – Reddish- steep, ledgy slopes; upper contact is sharp and planar; deposited in Qer orange, fine- to medium-grained sand with residual Navajo Sandstone shallow-marine and coastal-sabkha environments (Imlay, 1980; Collapse feature (sinkhole) pebbles, cobbles, and boulders; forms irregular sheets on top of the Blakey and others, 1983); about 50 to 160 feet (15-48 m) thick. Navajo Sandstone, from which it is derived, in the southwest corner upper unit Jku 700-1000 of the quadrangle; generally less than 3 feet (1 m) thick. Crystal Creek Member (Middle Jurassic) – Thin- to medium-bedded, KR81100-1 Sample location and number Kayenta (210-300) Jcx reddish-brown gypsiferous siltstone, mudstone, and very fine to Formation Residual deposits medium-grained sandstone; typically friable and weakly cemented with gypsum; forms vegetated, poorly exposed slopes; upper contact Residual deposits (Holocene to lower[?] Pleistocene) – Residual lag of is sharp and broadly wavy and corresponds to the base of a thick Springdale Sandstone 100-150 Qrlc angular to subangular basalt blocks derived from the Little Creek Peak Member Jks (30-45) Paria River gypsum bed or argillaceous limestone interval; deposited ACKNOWLEDGMENTS lava flow, which is preserved in place on the ridge to the west; includes in coastal-sabkha and tidal-flat environments (Imlay, 1980; Blakey very rare blocks of Dakota Formation sandstone; although Little Creek and others, 1983); about 150 to 250 feet (45-75 m) thick. I appreciate the assistance of Dave Sharrow, National Park Service, who helped coordinate this mapping project. Pete Rowley, Geologic Mapping Inc., and Grant Willis and 200-350 Peak basalt is virtually the only rock type seen in this unit, nowhere Moenave Formation, undivided JTRm is it clearly in place; probably represents a lag of basalt let down by Co-op Creek Limestone Member (Middle Jurassic) – Thin- to Mike Hylland, both with the Utah Geological Survey (UGS), provided constructive reviews of this map. Gary Christenson, Sandy Eldredge, Hugh Hurlow, and Dave Tabet, each (60-105) erosion of underlying beds, but may represent a flow that cascaded medium-bedded, light-gray micritic limestone and calcareous shale; with the UGS, also reviewed parts of this map. Thanks to Jim Kirkland for identifying Cretaceous gastropods and for sharing his knowledge of the Cretaceous strata of southwest southeastward from the adjacent ridge; thickness uncertain, but probably locally contains Isocrinus sp. columnals, pelecypods, and gastropods; Utah. Kent Brown (UGS) provided photogrammetric support and GIS digital cartography. Bill McIntosh and his colleagues at the New Mexico Geochronology Research Laboratory as much as several tens of feet thick. deposited in a shallow-marine environment (Imlay, 1980; Blakey provided 40Ar/39Ar analyses. and others, 1983). Spring deposits 450-650 Shown on cross section only Selected geologic maps available for the Zion National Park area Upper Chinle Formation, undivided TRc Upper unit – Thin- to medium-bedded, light-gray micritic limestone; In addition to the 1:24,000-scale geologic quadrangle maps listed below, Hamilton (1978) provided a 1:31,680-scale geologic map of Zion National Park. See index map on (135-200) Spring tufa (Holocene) – Light-gray to light-brownish-gray, porous, Jccu Qst locally oolitic and sandy; forms sparsely vegetated, ledgy slopes plate 1 for quadrangle locations. calcareous tufa characterized by a sponge-like network of cavities; and cliffs; upper contact is sharp and planar; about 100 to 140 feet mapped at Birch Spring, about 2 miles (3 km) northwest of Kolob (30-43 m) thick. Reservoir; 0 to about 20 feet (0-6 m) thick. Lower unit – Mostly thinly laminated to thin-bedded, light-gray Cedar Mountain Averitt (1962) Smithsonian Butte Moore and Sable (2001) Volcanic rocks Jccl calcareous shale and platy limestone; forms steep, vegetated slopes; Clear Creek Mountain Hylland (2000) Springdale East Doelling and others (2002) Cogswell Point Biek and Hylland (2007) Springdale West Willis and others (2002) Major- and trace-element geochemistry and 40Ar/39Ar raw data is available contact with upper unit is gradational and corresponds to a subtle Elephant Butte Sable and Doelling (1990) Straight Canyon Cashion (1967), Sable and Hereford (2004) 1700-1800 on the Utah Geological Survey Web site (http://geology.utah.gov/online/ break in slope and vegetation patterns; about 240 to 380 feet (73- TRIASSIC Moenkopi Formation, undivided TRm analytical_data.htm); rock names are after LeBas and others (1986). 115 m) thick. Hildale Sable (1995) Temple of Sinawava Doelling (2002) (520-550) Kanarraville Averitt (1967) The Barracks Sable and Doelling (1993) Grapevine Wash lava flows (middle Pleistocene) – Medium-gray, unconformity (J-2) Little Creek Mountain Hayden (2004) The Guardian Angels Willis and Hylland (2002) Qbg Navajo Lake Moore and others (2004) Virgin Hayden (in preparation) weathering to dark-brownish-gray to dark-brownish-black, fine-grained Temple Cap Formation olivine basaltic trachyandesite lava flows; erupted from a number of Kolob Arch Biek (2007) Webster Flat Doelling and Graham (1972) Lower and Middle vents on the Lower Kolob Plateau, including the Firepit Knoll and White Throne Member (Middle Jurassic) – Very thick bedded, Smith Mesa Sable and others (in prep.) Spendlove Knoll cinder cones; five 40Ar/39Ar plateau ages on these Jtw yellowish-gray to pale-orange, well-sorted, fine-grained quartz flows range from 0.22 ± 0.03 Ma to 0.31 ± 0.02 Ma (Willis and Hylland, sandstone with large high-angle cross-beds similar to the Navajo 2002); only distal end of one flow is preserved at the south end of Hop Sandstone; upper contact is sharp and planar; deposited in coastal Valley, in the southwest corner of the quadrangle, where it is about 20 dune field (Blakey, 1994; Peterson, 1994); pinches out westward feet (6 m) thick. under the Upper Kolob Plateau due to truncation beneath the J-2 unconformity; 0 to 130 feet (0-40 m) thick. Hornet Point lava flow and cinder cone (middle Pleistocene) – Medium- Qbhpc to dark-gray, medium- to coarse-grained olivine basalt to trachybasalt Sinawava Member (Middle Jurassic) – Interbedded, slope-forming, Kst lava flow containing abundant pyroxene phenocrysts; locally deeply Jts moderate-reddish-brown mudstone, siltstone, and very fine grained Qbhp weathered to gruss-like soils; boulders typically have concentric silty sandstone; forms narrow, but prominent, deep-reddish-brown, Kst weathering rinds; erupted from vent at deeply eroded cinder cone vegetated slope at the top of the Navajo Sandstone; upper contact (Qbhpc) at Hornet Point; yielded 40Ar/39Ar isochron age of 0.74 ± is gradational and interfingering with the White Throne Member, 0.05 Ma from sample CP83100-3 in the Cogswell Point quadrangle and, in western exposures, unconformable with light-gray calcareous Kd (Biek and Hylland, 2007); lava flow is as much as 240 feet (73 m) shale and micritic limestone of the Co-op Creek Limestone Member; thick in this quadrangle. deposited in coastal-sabkha and tidal-flat environments (Blakey, 1994; Peterson, 1994); about 10 to 40 feet (3-12 m) thick. Kolob Peak lava flow and cinder cone (lower Pleistocene) – Medium- Qbkpc to light-gray, fine-grained olivine basaltic trachyandesite lava flow; unconformity (J-1) forms densely vegetated dip slope on the east side of Kolob Peak; Qbkp Navajo Sandstone (Lower Jurassic) – Moderate-reddish-orange to erupted from vent at Kolob Peak, a cinder cone (Qbkpc) now eroded Jn nearly in half; sample KR81200-1 yielded 40Ar/39Ar plateau age of moderate-orange-pink, massively cross-bedded, poorly to moderately 1.05 ± 0.05 Ma; thickness uncertain, but likely in excess of 100 feet well-cemented sandstone that consists of well-rounded, fine- to medium- (30 m) thick where it fills paleodrainages. grained, frosted quartz; contains few planar interdune deposits of sandstone and siltstone; forms spectacular, sheer cliffs and is locally Lava Point lava flow and cinder cones (lower Pleistocene) – Light- to prominently jointed; upper, unconformable contact is sharp and planar Qblpc medium-gray, fine- to medium-grained olivine basaltic trachyandesite and corresponds to a prominent break in slope, with cliff-forming, to borderline basaltic andesite and trachybasalt lava flow; query indicates Qblp cross-bedded sandstone below and reddish-brown mudstone above; Ta uncertain correlation near Blue Springs Reservoir; erupted from vents corresponds to the "pink Navajo" and "brown Navajo" of Willis and at Home Valley Knoll, a group of three overlapping cinder cones Hylland (2002); deposited in a vast coastal and inland dune field with (Qblpc); yielded 40Ar/39Ar plateau ages of 1.02 ± 0.03 Ma (sample prevailing winds principally from the north (Blakey, 1994; Peterson, Above: View northwest to old boulder gravel deposits (Ta) along the east side of Kolob ZP-0601) and 1.08 ± 0.02 Ma (sample ZP-0602) for this flow at Lava 1994); lower few hundred feet is characterized by planar sandstone Reservoir. These deposits are characterized by very large boulders of quartz monzonite as Point, consistent with several published K-Ar and 40Ar/39Ar ages (Best beds and represents deposition in a sand-dominated sabkha environment much as 24 feet (7.3 m) long, 22 feet (6.7 m) wide, and at least 8 feet (2.4 m) high, and and others, 1980; Hamblin and others, 1981; Willis and Hylland, 2002); (Tuesink, 1989; Sansom, 1992); about 2100 to 2200 feet (640-670 m) quartz monzonite boulders 10 to 15 feet (3-5 m) long are common as shown in the as much as 120 feet (37 m) thick where it fills paleodrainages. accompanying photo. These deposits also contain abundant smaller quartz monzonite thick. boulders, and cobbles and small boulders derived from Cretaceous fossiliferous sandstone, Little Creek Peak lava flow (lower Pleistocene) – Medium-gray, fine- the Carmel Formation, and Claron limestone, as well as recycled, rounded pebbles and Qblc to medium-grained olivine basalt; locally caps ridge south of Little small cobbles of Precambrian and Cambrian quartzite. These old boulder gravels likely Creek Peak, and a basalt lag (Qrlc) derived from this flow covers the Marzolf (1994) and Blakey (1994) presented evidence to restrict the represent Miocene-age debris-flow deposits shed off the ancestral Pine Valley Mountains, Moenave Formation to the Dinosaur Canyon and Whitmore Point prior to development of the Hurricane fault. Boulders of the one-million-year-old Horse slope to the southeast of Little Creek Peak; yielded 40Ar/39Ar plateau Ranch Mountain lava flow are locally incorporated into these deposits, but the mechanism age of 1.44 ± 0.04 Ma from sample VR43-01 in The Guardian Angels Members, with a major regional unconformity at the base of the Springdale Sandstone. Further work supports this evidence, indicating by which they became incorporated into the deposits remains unclear. quadrangle (Willis and Hylland, 2002); source unknown; 0 to 30 feet Left: The hill in the distance is capped by the Tibbet Canyon Member of the Straight (0-9 m) thick. that the Springdale Sandstone is more closely related to the Kayenta Formation and should be made its basal member (see, for example, Cliffs Formation (Kst), which overlies the Dakota Formation (Kd). unconformity Lucas and Heckert, 2001; Molina-Garza and others, 2003; Steiner, 2005). We anticipate that this change will be formalized, and so here REFERENCES resources, geologic hazards: Utah Geological and Mineral Survey Bulletin 124, 192 p., Kirkland, J.I., Britt, Brooks, Burge, D.L., Carpenter, Ken, Cifelli, Richard, Decourten, Frank, Franczyk, K.J., editors, Mesozoic systems of the Rocky Mountain region, USA: Denver, TERTIARY informally reassign the Springdale Sandstone as the basal member of 10 plates, scale 1:100,000. Eaton, Jeffrey, Hasiotis, Steve, and Lawton, Tim, 1997, Lower to middle Cretaceous Colorado, Rocky Mountain Section of the Society for Sedimentary Geology, p. 233-272. the Kayenta Formation. Doelling, H.H., and Graham, R.L., 1972, Southwestern Utah coal fields – Alton, Kaiparowits dinosaur faunas of the central – a key to understanding 35 million years Sable, E.G., 1995, Geologic map of the Hildale quadrangle, Washington and Kane Counties, Old boulder gravel deposits (Miocene?) – Poorly sorted, clay- to very of tectonics, sedimentology, evolution and biogeography, in Link, P.K., and Kowallis, B.J., Ta large boulder-size sediment characterized by very large quartz monzonite Anderson, R.E., and Mehnert, H.H., 1979, Reinterpretation of the history of the Hurricane Plateau, and Kolob-Harmony: Utah Geological and Mineral Survey Monograph Series Utah and Mohave County, Arizona: Utah Geological Survey Map 167, 14 p., 2 plates, Upper unit (Lower Jurassic) – Interbedded, thin- to very thick bedded, 1, 333 p. editors, Mesozoic to recent geology of Utah: Brigham Young University Geology Studies, scale 1:24,000. boulders; clasts also include large boulders of Cretaceous fossiliferous Jku fault in Utah, in Newman, G.W., and Goode, H.D., editors, 1979 Basin and Range v. 42, part 2, p. 69-103. moderate-reddish-brown siltstone, fine-grained sandstone, and Symposium: Rocky Mountain Association of Geologists, p. 145-165. Doelling, H.H., Willis, G.C., Solomon, B.J., Sable, E.G., Hamilton, W.L., and Naylor, L.P., Sable, E.G., and Doelling, H.H., 1990, Geologic map of the Elephant Butte quadrangle, Kane sandstone, cobbles and small boulders derived from the Carmel mudstone with planar, low-angle, and ripple cross-stratification; Laurin, Jiri, and Sageman, B.B., 2001, Tectono-sedimentary evolution of the western margin Formation, recycled, rounded pebbles and small cobbles of Precambrian Averitt, Paul, 1962, Geology and coal resources of the Cedar Mountain quadrangle, Iron II, 2002, Interim geologic map of the Springdale East quadrangle, Washington County, County, Utah and Mohave County, Arizona: Utah Geological and Mineral Survey Map contains several thin, light-olive-gray weathering, light-gray dolomite Utah: Utah Geological Survey Open-File Report 393, 20 p., 1 plate, scale 1:24,000. of the Colorado Plateau during the latest Cenomanian and early Turonian, in Erskine, 126, 10 p., 2 plates, scale 1:24,000. and Cambrian quartzite, and uncommon cobbles and boulders of Claron County, Utah: U.S. Geological Survey Professional Paper 389, 72 p. M.C., editor and Faulds, J.E., Bartley, J.M., and Rowley, P.D., co-editors, The geologic beds; upper contact is conformable and gradational and corresponds Eardley, A.J., 1966, Rates of denudation in the High Plateaus of southwestern Utah: Geological —1993, Geologic map of The Barracks quadrangle, Kane County, Utah: Utah Geological limestone; most clasts are subangular to subrounded, but the quartzite to the top of the highest thin siltstone and mudstone beds, above —1964, Table of post-Cretaceous geologic events along the Hurricane fault near Cedar City, transition, High Plateaus to Great Basin – a symposium and field guide, The Mackin clasts are well rounded; quartz monzonite boulders as much as 24 feet Iron County, Utah: Geological Society of America Bulletin, v. 75, p. 901-908. Society of America Bulletin, v. 77, p. 777-780. Volume: Utah Geological Association Publication 30 and Pacific Section American Survey Map 147, 11 p., 2 plates, scale 1:24,000. which lie the towering cliffs of Navajo Sandstone; deposited in Eaton, J.G., Laurin, Jiri, Kirkland, J.I., Tibert, N.E., Leckie, R.M., Sageman, B.B., Goldstrand, Association of Petroleum Geologists Publication GB 78, p. 57-74. Sable, E.G., and Hereford, Richard, 2004, Geologic map of the Kanab 30'x60' quadrangle, (7.3 m) long, 22 feet (6.7 m) wide, and at least 8 feet (2.4 m) high are fluvial, distal fluvial/playa, and minor lacustrine environments —1967, Geologic map of the Kanarraville quadrangle, Iron County, Utah: U.S. Geological present in the vicinity of Kolob Reservoir, and subspherical quartz Survey Geologic Quadrangle Map GQ-694, 1 plate, scale 1:24,000. P.M., Moore, D.W., Straub, A.W., Cobban, W.A., and Dalebout, J.D., 2001, Cretaceous LeBas, M.J., LeMaitre, R.W., Streckeisen, A., and Zanettin, B., 1986, A chemical classification Utah and Arizona: U.S. Geological Survey Geologic Investigations Series Map I-2655, (Tuesink, 1989; Sansom, 1992; Blakey, 1994; Peterson, 1994); only and early Tertiary geology of Cedar and Parowan Canyons, western Markagunt Plateau, of volcanic rocks based on the total alkali-silica diagram: Journal of Petrology, v. 27, p. 1 plate, scale 1:100,000. monzonite boulders 10 to 15 feet (3-5 m) long are common; most Best, M.G., McKee, E.H., and Damon, P.E., 1980, Space-time-composition patterns of late upper few tens of feet of the formation is exposed in the quadrangle Utah, in Erskine, M.C., editor and Faulds, J.E., Bartley, J.M., and Rowley, P.D., co-editors, 745-750. Sable, E.G., Biek, R.F., and Willis, G.C., in preparation, Geologic map of the Smith Mesa quartz monzonite clasts, however, are 1.5 to 3 feet (0.5-1 m) in diameter; at Hop Valley, but the entire upper unit is about 700 to 1000 feet Cenozoic mafic volcanism, southwestern Utah and adjoining areas: American Journal of The geologic transition, High Plateaus to Great Basin – a symposium and field guide, The forms a deeply eroded surface that drapes over pre-existing topography; Science, v. 280, p. 1035-1050. Lucas, S.G., and Heckert, A.B., 2001, Theropod dinosaurs and the Early Jurassic age of the quadrangle, Washington County, Utah: Utah Geological Survey Map, 2 plates, scale (210-300 m) thick. Mackin Volume: Utah Geological Association Publication 30 and Pacific Section American 1:24,000. probably deposited by debris flows or possibly a gravity slide originating Association of Petroleum Geologists Publication GB 78, p. 57-74. Moenave Formation, Arizona-Utah, USA: Neves Jahrbuch fur Geologic and Paläontologie Biek, R.F., 2007, Geologic map of the Kolob Arch quadrangle and part of the Kanarraville Mh., Stuttgart, Germany, v. 7, p. 435-448. in the ancestral Pine Valley Mountains; this hypothesis, however, Springdale Sandstone Member (Lower Jurassic) – Shown in cross quadrangle, Washington and Iron Counties, Utah: Utah Geological Survey Map 217, 3 Sansom, P.J., 1992, Sedimentology of the Navajo Sandstone, southern Utah, USA: Oxford, Gustason, E.R., 1989, Stratigraphy and sedimentology of the middle Cretaceous (Albian- England, Wolfson College Department of Earth Sciences, Ph.D. dissertation, 291 p. requires a complete eastward-to-westward reversal of drainage across Jks section only; about 100 to 150 feet (30-45 m) thick (Willis and plates, scale 1:24,000. Cenomanian) Dakota Formation, southwestern Utah: Boulder, Colorado, University of Lucas, S.G., Tanner, L.H., Heckert, A.B., and Hunt, A.P., 2005, Tetrapod biostratigraphy across the Triassic-Jurassic boundary on the southern Colorado Plateau, USA, in Tracking dinosaur the Hurricane fault; Averitt (1962, 1964) first described similar deposits Hylland, 2002; Biek, 2007). Biek, R.F., and Hylland, M.D., 2007, Geologic map of the Cogswell Point quadrangle, Colorado, Ph.D. dissertation, 376 p. Steiner, M.B., 2005, Correlation of Triassic/Jurassic boundary strata of North America through farther north, east and southeast of Cedar City, and Anderson and origins, the Triassic/Jurassic terrestrial transition, abstracts volume, a conference held at paleomagnetic characteristics, in Tracking dinosaur origins, the Triassic/Jurassic terrestrial Washington, Kane, and Iron Counties, Utah: Utah Geological Survey Map 221, 2 plates, Hacker, D.B., 1998, Catastrophic gravity sliding and volcanism associated with the growth Dixie State College, St. George, Utah, March 14-16, 2005, p. 16. Mehnert (1979) interpreted those exposures as debris-flow deposits unconformity scale 1:24,000. transition, abstracts volume, a conference held at Dixie State College, St. George, Utah, of laccoliths – an example from early Miocene hypabyssal intrusions of the Iron Axis March 14-16, 2005, p. 24. shed off the ancestral Pine Valley Mountains; Hacker (1998) and magmatic province, Pine Valley Mountains, southwest Utah: Kent, Ohio, Kent State Marzolf, J.E., 1994, Reconstruction of the Early Mesozoic cordilleran cratonal margin adjacent JURASSIC AND TRIASSIC Biek, R.F., Willis, G.C., Hylland, M.D., and Doelling, H.H., 2003, Geology of Zion National to the Colorado Plateau, in Caputo, M.V., Peterson, J.A., and Franczyk, K.J., editors, Hacker and others (2002) provided evidence that the Pine Valley Park, Utah, in Sprinkel, D.A., Chidsey, T.C., and Anderson, P.B., editors, Geology of University, Ph.D. dissertation, 258 p. Tibert, N.E., Leckie, R.M., Eaton, J.G., Kirkland, J.I., Colin, Jean-Paul, Leithold, E.L., and Mountains stood very high and shed gravity slides, volcanic rocks, Moenave Formation, undivided (Lower Jurassic to Upper Triassic) – Mesozoic systems of the Rocky Mountain region, USA: Denver, Colorado, Rocky Mountain McCormic, M.E., 2003, Recognition of relative sea-level change in Upper Cretaceous Utah’s parks and monuments: Utah Geological Association and Bryce Canyon Natural Hacker, D.B., Holm, D.K., Rowley, P.D., and Blank, H.R., 2002, Associated Miocene laccoliths, Section of the Society for Sedimentary Geology, p. 181-216. JTRm History Association, Utah Geological Association Publication 28, Second Edition, p. 107- coal-bearing strata – a paleoecological approach using agglutinated foraminifera and and debris flows about 20.5 million years ago, long before initiation Shown in cross section only; age from Lucas and others (2005); about gravity slides, and volcanic rocks, Pine Valley Mountains and Iron Axis, southwestern ostracods to detect key stratigraphic surfaces, in Olsen, H.C., and Leckie, R.M., editors, of the Hurricane fault; blocks of the Pine Valley laccolith caught in 200 to 350 feet (60-105 m) thick (Willis and Hylland, 2002; Biek, 137. Utah, in Lund, W.R., editor, Field guide to geologic excursions in southwestern Utah and Molina-Garza, R.S., Geissman, J.W., and Lucas, S.G., 2003, Paleomagnetism and magneto- stratigraphy of the lower Glen Canyon and upper Chinle Groups, Jurassic-Triassic of Micropaleontologic proxies for sea-level change and stratigraphic discontinuities: Society the Hurricane fault zone (Biek, 2007) show that the laccolith once 2007). Blakey, R.C., 1994, Paleogeographic and tectonic controls on some Lower and Middle Jurassic adjacent areas of Arizona and Nevada: U.S. Geological Survey Open-File Report 02-172, for Sedimentary Geology Special Publication no. 75, p. 263-299. p. 235-283. northern Arizona and northeast Utah: Journal of Geophysical Research, v. 108, no. B4, likely reached east of the Hurricane fault, thus providing a somewhat erg deposits, Colorado Plateau, in Caputo, M.V., Peterson, J.A., and Franczyk, K.J., editors, 2181, doi: 10.1029/2002JB001909. J-0 unconformity Mesozoic systems of the Rocky Mountain region, USA: Denver, Colorado, Rocky Mountain Tschudy, R.H., Tschudy, B.D., and Craig, L.C., 1984, Palynological evaluation of Cedar closer source for the large Pine Valley boulders; thickness uncertain, Hamblin, W.K., Damon, P.E., and Bull, W.B., 1981, Estimates of vertical crustal strain rates Mountain and Burro Canyon Formations, Colorado Plateau: U.S. Geological Survey Section of the Society for Sedimentary Geology, p. 273-298. along the western margins of the Colorado Plateau: Geology, v. 9, p. 293-298. Moore, D.W., and Sable, E.G., 2001, Geologic map of the Smithsonian Butte quadrangle, but probably less than 30 feet (9 m) thick in this quadrangle; some TRIASSIC Washington County, Utah and Mohave County, Arizona: Utah Geological Survey Professional Paper 1281, 24 p., 9 plates. deposits may contain just a lag of widely scattered larger clasts over Blakey, R.C., Peterson, Fred, Caputo, M.V., Geesman, R.C., and Voorhees, B.J., 1983, Hamilton, W.L., 1978 (revised 1987), Geological map of Zion National Park, Utah: Zion Miscellaneous Publication MP-01-01, 30 p., 2 plates, scale 1:24,000. Paleogeography of Middle Jurassic continental, shoreline, and shallow marine sedimentation, Tuesink, M.F., 1989, Depositional analysis of an eolian-fluvial environment – the intertonguing poorly exposed bedrock, the matrix having been eroded away. Chinle Formation, undivided (Upper Triassic) – Shown in cross section Natural History Association, scale 1:31,680. of the Kayenta Formation and Navajo Sandstone (Jurassic) in southwestern Utah: Flagstaff, TRc only; about 450 to 650 feet (135-200 m) thick (Willis and Hylland, southern Utah, in Reynolds, M.W., and Dolley, E.D., editors, Mesozoic paleogeography Moore, D.W., Nealey, L.D., Rowley, P.D., Hatfield, S.C., Maxwell, D.J., and Mitchell, Eric, Two basalt boulders clearly incorporated into the deposits at Kolob Hayden, J.M., 2004, Geologic map of the Little Creek Mountain quadrangle, Washington 2004, Geologic map of the Navajo Lake quadrangle, Kane and Iron Counties, Utah: Utah Northern Arizona University, M.S. thesis, 189 p. Reservoir (samples KR72000-5 and KR72000-6) have a chemical 2002; Biek, 2007). of west-central United States: Denver, Colorado, Rocky Mountain Section of Society of Economic Paleontologists and Mineralogists, p. 77-100. County, Utah: Utah Geological Survey Map 204, 2 plates, scale 1:24,000. Geological Survey Map 199, 2 plates, scale 1:24,000. Willis, G.C., and Hylland, M.D., 2002, Interim geologic map of The Guardian Angels signature similar to the Horse Ranch Mountain lava flow, and one —in preparation, Geologic map of the Virgin quadrangle, Washington County, Utah: Utah quadrangle, Washington County, Utah: Utah Geological Survey Open-File Report 395, 27 40 39 TR-3 unconformity Cashion, W.B., 1967, Geologic map of the south flank of the Markagunt Plateau, northwest Nichols, D.J., 1995, Palynology and ages of some Upper Cretaceous formations in the boulder (KR72000-6) yielded a maximum Ar/ Ar age of 0.97 ± Geological Survey Map, 2 plates, scale 1:24,000. Markagunt and northwestern Kaiparowits Plateaus, southwestern Utah, in Maldonado, p., 1 plate, scale 1:24,000. 0.18 Ma, analytically indistinguishable from the 1.03 ± 0.06 Ma Horse Kane County, Utah: U.S. Geological Survey Miscellaneous Geologic Investigations Map Moenkopi Formation, undivided (Middle to Lower Triassic) – Shown in I-494, 1 plate, scale 1:24,000. Hylland, M.D., 2000, Interim geologic map of the Clear Creek Mountain quadrangle, Kane Florian, and Nealey, L.D., editors, Geologic studies in the Basin and Range–Colorado Willis, G.C., Doelling, H.H., Solomon, B.J., and Sable, E.G., 2002, Interim geologic map of Ranch Mountain lava flow (Biek, 2007); how the basalt boulders came TRm cross section only; about 1700 to 1800 feet (520-550 m) thick (Willis County, Utah: Utah Geological Survey Open-File Report 371, 12 p., 2 plates, scale Plateau transition in southeastern Nevada, southwestern Utah, and northwestern Arizona, the Springdale West quadrangle, Washington County, Utah: Utah Geological Survey Open- to be incorporated into these assumed Miocene-age deposits is not Doelling, H.H., 2002, Interim geologic map of the Temple of Sinawava quadrangle, Washington 1995: U.S. Geological Survey Bulletin 2153-E, p. 81-95. and Hylland, 2002; Biek, 2007). County, Utah: Utah Geological Survey Open-File Report 396, 13 p., 1 plate, scale 1:24,000. 1:24,000. File Report 394, 19 p., 1 plate, scale 1:24,000. known. Peterson, Fred, 1994, Sand dunes, sabkhas, streams, and shallow seas – Jurassic paleogeography Doelling, H.H., and Davis, F.D., 1989, The geology of Kane County, Utah – geology, mineral Imlay, R.W., 1980, Jurassic paleobiogeography of the conterminous United States in its continental setting: U.S. Geological Survey Professional Paper 1062, 134 p. in the southern part of the Western Interior Basin, in Caputo, M.V., Peterson, J.A., and

A WEST EAST A' Elevation (feet) Hornet Point Elevation (feet) Upper Kolob Plateau Qbhp 9000 9000 Kolob Kst Ksu Creek Qmsy Kst Kcmc Bear Trap Kcmc 8000 Canyon Kcmc Kd 8000 fault Jcx Kcmc Jcp Jccu La Verkin Qmsy Jcw Creek Jcp Jcp Jcx 7000 Jccu Jcw Kcmc or Kd 7000 Jts + Jccl Jccu Jts + Jccl Jcx Jts + Jccl 6000 6000 Jn

5000 Jn 5000

Jku 4000 Jks 4000

Jku JTRm Jks 3000 TRc 3000 JTRm

TRc Thin surficial deposits not shown. TRm TRm