GEOLOGIC MAP OF THE KELTON PASS QUADRANGLE, BOX ELDER COUNTY, UTAH, AND CASSIA COUNTY, IDAHO
by Michael L. Wells
Department of Geoscience, University of Nevada, Las Vegas 4505 S. Maryland Parkway, Las Vegas, NV 89154-4010
Cover Photo: Crystal Peak and the north side of upper Ten Mile Canyon, looking to the northeast. The Raft River detachment is marked by black ledge of resistant fault rocks, overlying the prominent gently dipping white Elba Quartzite. Photo by Michael L. Wells.
ISBN 1-55791-807-4
MISCELLANEOUS PUBLICATION 09-3 UTAH GEOLOGICAL SURVEY a division of Utah Department of Natural Resources 2009 STATE OF UTAH Jon Huntsman, Jr., Governor
DEPARTMENT OF NATURAL RESOURCES Michael Styler, Executive Director
UTAH GEOLOGICAL SURVEY Richard G. Allis, Director
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The Miscellaneous Publication series provides non-UGS authors with a high-quality format for documents concerning Utah geology. Although review comments have been incorporated, this publication does not necessarily conform to UGS technical, policy, or editorial standards. The Utah Department of Natural Resources, Utah Geological Survey, makes no warranty, expressed or implied, regarding the suitability of this product for a particular use. The Utah Department of Natural Resources, Utah Geological Survey, shall not be liable under any circumstances for any direct, indirect, special, incidental, or consequential damages with respect to claims by users of this product. CONTENTS
ABSTRACT ...... 1 INTRODUCTION ...... 1 STRATIGRAPHY ...... 3 Parautochthon ...... 6 Older Schist (Aos) ...... 6 Metamorphosed Mafic Igneous Rocks (Ami) ...... 6 Metamorphosed Adamellite (Aad) ...... 6 Elba Quartzite (
Figure 1. Tectonostratigraphic map of pre-Tertiary rocks and simplified Tertiary geology of the Raft River, Black Pine, Albion, Grouse Creek, and Matlin Mountains ...... 2 Figure 2. Comparison between attenuated stratigraphic thicknesses within the eastern Raft River Mountains and representative stratigraphic thicknesses from nearby localities in northwestern Utah ...... 4 Figure 3. Tectonostratigraphic column of the eastern Raft River Mountains ...... 5 Figure 4. Generalized geologic map of the eastern Raft River Mountains indicating distribution of allochthons and parautochthon and their bounding detachment faults, and axial traces of D3 (F3) recumbent folds and D5 (F5) open folds ...... 15 Figure 5. Time-temperature plot derived from thermochronometric data for the Ten Mile Creek canyon locality ...... 17
TABLES
Table 1. Deformation events in the eastern Raft River Mountains ...... 13 Table 2. Geochronologic data from the Kelton Pass quadrangle area, eastern Raft River Mountains ...... 17
PLATES
Plate 1. Geologic Map of the Kelton Pass Quadrangle ...... on CD Plate 2. Detailed Geologic Map of part of the Kelton Pass Quadrangle ...... on CD Plate 3. Explanation sheet for geologic maps ...... on CD GEOLOGIC MAP OF THE KELTON PASS QUADRANGLE, BOX ELDER COUNTY, UTAH, AND CASSIA COUNTY, IDAHO by Michael L. Wells
ABSTRACT plate, folded and tilted the Tertiary and older rocks. Exten- sive erosion in highlands and deposition at the range flanks The Kelton Pass 7.5' quadrangle is located in northwest- developed expansive alluvial fans of Pleistocene age. Late ern Utah and southern Idaho and contains portions of the Pleistocene Lake Bonneville covered the Curlew Valley, Raft River and Black Pine Mountains, and Curlew and Raft depositing a blanket of sediments, and cutting shorelines into River valleys. The quadrangle is so geologically complex bedrock and alluvial-fan surfaces. that a typical geologic map at 1:24,000 scale (plate 1) cannot show the detail needed to decipher the geologic history of the area. Therefore an additional map (plate 2), that shows an INTRODUCTION area of detailed bedrock mapping at 1:12,000 scale, has been included. Bedrock exposed in the quadrangle includes The Kelton Pass 7.5' quadrangle is located in northwest- Archean monzogranite, amphibolite, and schist; Proterozoic ern Utah and southern Idaho, 5 miles (8 km) northeast of metasedimentary rocks of enigmatic regional stratigraphic Park Valley, Utah, and 22 miles (35 km) west of Snowville, affinity; and Ordovician to Permian metasedimentary mio- Utah. The northern boundary of the quadrangle is 0.2 to 0.26 geoclinal rocks. These rocks contain a record of burial by mile (0.3 to 0.4 km) north of the Utah-Idaho border. Bedrock thrusting and protracted exhumation by normal faulting and exposures within the quadrangle form the eastern end of the plastic flow, in which tectonic contraction and extension Raft River Mountains and the southern terminus of the Black alternated during late Mesozoic to early Cenozoic time. Pine Mountains (figure 1). Archean to Pennsylvanian rocks were metamorphosed and Kelton Pass (elevation 5305 feet [1617 m]), on Utah penetratively strained at upper greenschist- to lower amphi- State Highway 42 in the northern part of the quadrangle, sep- bolite-facies metamorphic conditions in Mesozoic time, dur- arates the Raft River Valley to the northwest from the Curlew ing folding and thrusting related to the Sevier orogeny. Sub- Valley to the east and southeast. This divide separates sequently, Proterozoic to Pennsylvanian rocks were further drainage into the Great Salt Lake to the south from drainage attenuated by two episodes of low-angle normal faulting, the into the Snake River to the north. The lowlands to the east first prior to the middle Late Cretaceous, and the second in within the Curlew Valley are underlain, in part, by Tertiary the latest Cretaceous to early Paleocene. Following strati- strata. Between the 5200 foot (1585 m) and 4720 foot (1439 graphic attenuation, the Proterozoic to Pennsylvanian rocks m) (the lowest point in the quadrangle) elevations, these stra- were deformed into large-scale recumbent folds during ta have been modified and partially buried by the deposits of renewed crustal shortening prior to the late Eocene. The ear- latest Pleistocene Lake Bonneville. State Highway 42 liest crustal extension of Cenozoic age is manifest in a low- approximately marks the boundary between detritus shed angle normal fault (middle detachment) with westward trans- from the Black Pine Mountains (north of the highway) and lation that emplaced Mississippian to Permian rocks of the sediment shed from the Raft River Mountains (south of the middle allochthon over the recumbently folded Proterozoic highway). The topographically highest regions in the quad- to Pennsylvanian rocks of the lower allochthon, and juxta- rangle, maximum elevation 7957 feet (2425 m) in the Raft posed greenschist-facies over amphibolite-facies metamor- River Mountains, are underlain by the Permian and Pennsyl- phic rocks. Proterozoic to Permian rocks were subsequently vanian Oquirrh Formation. deformed into open folds with north-trending axes. The east- The Kelton Pass 7.5' quadrangle lies within the Cenozoic directed Raft River detachment fault began movement in the Basin and Range extensional province, and within the hinter- early Miocene; detachment faulting was over by 7.5 Ma (late land of the late Mesozoic to early Cenozoic Sevier orogenic Miocene). Miocene conglomerate, tuff, tuffaceous sand- belt (Armstrong, 1968a). Because of this superposition, dif- stone, and limestone were deposited within a deepening ferentiating Mesozoic from Cenozoic deformations is of basin or basins, either prior to or during movement along the first-order importance to structural investigations in this Raft River detachment fault. Continued movement on the region; hence the need for the detailed geologic map detachment fault, and high-angle faulting within the upper (1:12,000-scale plate 2) in addition to the typical quadrangle 2 Utah Geological Survey
Cottrell Mountains
Albion UTAH Mountains
42° 15'
Jim Sage Mountains Raft River Black Pine Valley Mountains Middle Mtn.
IDAHO 42° Strevell
UTAH Curlew Valley Kelton Raft River Mountains Pass
Tertiary volcanic and sedimentary rocks Park Tertiary plutons Valley Park Upper allochthon Yost Valley 41° 45' Middle allochthon
Grouse Creek Lower allochthon Mountains Matlin Mountains Quartzite assemblage N Parautochthon
0 5 10 km
113° 45' 113° 30' 113° 15'
Figure 1. Tectonostratigraphic map of pre-Tertiary rocks and simplified Tertiary geology of the Raft River, Black Pine, Albion, Grouse Creek, and Matlin Mountains, with locations of the Kelton Pass 7.5' quadrangle and other published geologic quadrangles in the region. Modified from Compton (1972, 1975), Compton and others (1977), Todd (1980), Smith (1982), Miller (1983), and author's mapping. Dashed line between Jim Sage-Cottrell Mountains and Albion Mountains is inferred breakaway to the Raft River detachment. Geologic map of the Kelton Pass quadrangle, Box Elder County, Utah, and Cassia County, Idaho 3 map (1:24,000-scale plate 1). Structural studies in the eastern (Wells and others, 2000a). Wells and others (2000a) inter- Raft River Mountains were initiated to correlate structural preted the shear zone as a low-angle, normal-sense shear events recorded in greenschist-facies metamorphic rocks in zone of Miocene age. The upper plate rocks to the Miocene the Black Pine Mountains, where the distinction between Raft River detachment in the eastern Raft River Mountains Mesozoic and Cenozoic deformations has been made (Smith, were described by Wells and others (1990) and Wells (1992, 1982; Wells and Allmendinger, 1990), to the stratigraphically 1997), and were mapped at 1:12,000 scale by Wells (1991) equivalent but more highly attenuated upper greenschist- to (area of detailed bedrock mapping on plates 1 and 2); these lower amphibolite-facies strata in the Raft River Mountains reports emphasized the pre-Miocene structural history. The (Wells and others, 1990). The sequence of deformation Black Pine Mountains (Strevell 15' quadrangle), to the north- events recorded in the Raft River Mountains (Wells, 1997) is east, were mapped and described by Smith (1982, 1983) (fig- largely borne out through detailed geologic mapping present- ure 1). The structural and metamorphic history of Devonian ed here and in Wells (1991). Because of the completeness of to Permian rocks in the Black Pine Mountains was re-evalu- the record, the structural history is described in some detail. ated and described by Wells and Allmendinger (1990). Further details of the structural history are described in Wells Mapped quadrangles adjoining the Kelton Pass 7.5' (1992, 1997, 2001). quadrangle are the Strevell 15' quadrangle (to the north) and Within the Sevier orogenic belt hinterland of northwest- the Park Valley 15' quadrangle (to the west, figure 1). There ern Utah, southern Idaho, and northeastern Nevada, faults are differences in the mapped geology between the Strevell that place older rocks on younger rocks, or place higher 15' and Kelton Pass 7.5' quadrangles, in particular, the loca- grade metamorphic rocks on lower grade metamorphic rocks tion of the contacts separating Quaternary deposits from both are rare, in marked contrast to the foreland fold and thrust Tertiary deposits and the Oquirrh Formation. These differ- belt to the east (Armstrong and Oriel, 1965). More common- ences reflect a greater emphasis in this study on the Cenozoic ly, low-angle faults within the Sevier belt hinterland place geology and the more detailed scale of the mapping in this younger rocks on older rocks, and unmetamorphosed rocks study (1:24,000 [plate 1], compared to 1:62,500). Plate 2 in on metamorphosed rocks (Armstrong, 1972). Many of these this publication is a modification of my Ph.D. map. The geo- younger-over-older faults have documented Cenozoic ages logic contacts match reasonably well across the boundary be- (for example, Miller and others, 1987; Compton, 1983). tween the Kelton Pass and Park Valley quadrangles, with However, there are also younger-over-older faults of Meso- several exceptions. The principal mismatches result from a zoic to early Tertiary age (for example, Allmendinger and greater emphasis on Cenozoic geology in the present study, Jordan, 1984; Wells and others, 1990, 1998). resulting in a greater subdivision of Cenozoic lithologic Both Mesozoic and Cenozoic younger-over-older faults units. For example, deposits mapped by Compton (1975) as Qo (a unit designation with a broad use as older alluvium and are present in the eastern Raft River Mountains. A generally 1 consistent tectonostratigraphy is preserved throughout an other deposits) in the NE ⁄4 section 6, T. 14 N., R. 12 W., area greater than 1560 square miles (4000 km2) in the Raft would be designated QTaf according to the lithologic map River, Albion, and Grouse Creek Mountains. Within this units used in the Kelton Pass 7.5' quadrangle. Additionally, stratigraphic succession, several major low-angle faults lithologies mapped as Ts (in the present study) were included divide the rocks into four major allochthons and a par- in the Qo unit of Compton (1975). I also mapped exposures autochthon, as defined by Compton and others (1977) and of the mafic intrusive rocks unit (Ami), located adjacent to Miller (1980) (figures 1 and 3). Numerous smaller low-angle the quadrangle boundaries in sections 17 and 20, T. 14 N., R. faults are found within these allochthons. All of these faults, 12 W., that Compton (1975) included within the older schist with few exceptions, place younger rocks on older rocks, and (Aos). apparently are subparallel to bedding over large areas. The Raft River Mountains were mapped at the scale of 1:68,500 and described by Felix (1956). More recently, areas STRATIGRAPHY to the west of the Kelton Pass 7.5' quadrangle (the Park Val- ley and Yost 15' quadrangles) were mapped at the scale of Overprinting Mesozoic and Cenozoic deformation 1:31,680 by Compton (1972, 1975) (figure 1). Compton and episodes have produced an incomplete and greatly attenuated others (1977) described the regional extent of low-angle stratigraphic section in the Raft River, Albion, and Grouse faults and the stratigraphic, metamorphic, and structural rela- Creek Mountains (figure 2). A tectonically thinned sequence tionships within and between low-angle fault-bounded of metasedimentary and sedimentary units of Proterozoic to allochthons. Additionally, they highlighted the youthfulness Triassic age overlies an Archean basement complex (figures of metamorphism. Miller and others (1983) described the 2 and 3) (Armstrong, 1968b; Compton and others, 1977; similarities in stratigraphy, and structural, metamorphic, and Wells and others, 1998). Within the eastern Raft River Moun- igneous histories between the Raft River, Albion, and Grouse tains, these rocks have been subdivided into three low-angle, Creek Mountains. Sabisky (1985) studied a shear zone pres- fault-bounded, tectonostratigraphic units (figures 3 and 4) ent at the Archean-Proterozoic unconformity in the eastern (Compton and others, 1977; Miller, 1980, 1983; Todd, 1980, and central Raft River Mountains, and determined the kine- 1983; Wells, 1992, 1997). From structurally lowest to highest matics to be top-to-the-east shearing. Malavieille and Cobb (figure 3), these are: (1) the parautochthon, (2) the lower (1986) suggested that the shear zone was a Mesozoic thrust, allochthon, and (3) the middle allochthon. An upper and later Malavieille (1987a, 1987b) suggested that the shear allochthon of unmetamorphosed Permian and younger rocks zone and associated brittle fault (Raft River detachment) rep- is present in the Grouse Creek Mountains (for example Todd, resented a Tertiary extensional fault system. This later inter- 1980), but is not represented in the quadrangle. Although pretation has been borne out by subsequent geochronology these allochthons are bounded by major faults in many areas 4 Utah Geological Survey
Regional Stratigraphic Thickness Penn- sylvanian
Missis- sippian
Devonian Eastern Raft River Mountains Stratigraphic Thickness Silurian Of Oe Ock
Ordovician Ogc IPot Emigrant Springs SOd Oe Fault Ock Ogc Mahogany Peaks Pla Fault
Cambrian 2000 meters
Figure 2. Comparison between attenuated stratigraphic thicknesses within the eastern Raft River Mountains and representative stratigraphic thick- nesses from nearby localities in northwestern Utah (from Hintze, 1988). Attenuation occurred during D1 and D2 deformation events (see table 1). Of = Ordovician Fish Haven Dolomite. Geologic map of the Kelton Pass quadrangle, Box Elder County, Utah, and Cassia County, Idaho 5
TECTONIC UNIT LITHOLOGY MAP UNIT
Permian-Pennsylvanian Oquirrh Formation [PPlo] Middle
Allochthon Pennsylvanian-Mississippian Chainman Shale and Diamond Peak Formation [PlMcd] Middle Pennsylvanian(?) Lower Oquirrh detachment Formation marble tectonite [Plot] Emigrant Spring Fault
Silurian(?) and Ordovician Dolomite [SOd]
Attenuation fault Ordovician Eureka Quartzite [Oe] Attenuation fault Ordovician Crystal Peak,Watson Ranch, Lehman, and Kanosh Formations [Ock] Attenuation fault
Ordovician Garden City Formation [Ogc] Lower Allochthon
Proterozoic schist of Mahogany Peaks Fault Mahogany Peaks [Pmp] Proterozoic quartzite of Raft River Clarks Basin [Pcb] detachment Proterozoic schist member of Elba Quartzite [Pes] Proterozoic Elba Quartzite [Pe] Unconformity
Archean older schist [Aos] metamorphosed mafic igneous rocks [Ami] Intrusive contact Parautochthon Archean metamorphosed adamellite [Aad]
Figure 3. Tectonostratigraphic column of the eastern Raft River Mountains. Thicknesses are maximums, and are highly variable. Positions of major faults are indicated. Note that all stratigraphic contacts within the lower allochthon are low-angle faults. 6 Utah Geological Survey of the Raft River, Albion, and Grouse Creek Mountains, the massive, generally medium-grained, gneissic and schistose faults or shear zones which bound them are not necessarily amphibolite, comprised of hornblende, andesine, quartz, and correlative in age or origin from one locality to another. Until zoisite comprise this unit. These mafic rocks are in turn further work is carried out, the allochthon designations imply intruded by monzogranite (Aad). The mafic rocks show a only stratigraphic affinity and general tectonostratigraphic wide variation in intrusive morphology and internal texture. position, rather than structural continuity. These older rocks Intrusive shapes vary from sheet-like, foliation-parallel, hor- are overlain by Tertiary sedimentary and volcaniclastic rock izontal sills to irregular pods highly discordant to foliation and deposits, and Quaternary deposits. and lithologic layering in country rocks. It should be noted, however, that much of the sheet-like morphology may partly reflect post-intrusive strain. At the structurally deepest lev- Parautochthon els within Ten Mile Creek canyon, this unit is locally unde- The parautochthon consists of the Green Creek Complex formed, and medium to coarse ophitic to subophitic igneous (Armstrong and Hills, 1967; Armstrong, 1968b) and the textures typical of gabbro are preserved. unconformably overlying Elba Quartzite. The Green Creek Complex is comprised of approximately 2.5 to 2.6 Ga gneis- Metamorphosed Adamellite (Aad) sic monzogranite (metamorphosed adamellite of Compton, The metamorphosed adamellite unit of Compton (1972) 1972; unit Aad of this report) that intrudes older schist (Aos) (Archean) is exposed within the Kelton Pass 7.5' quadrangle and metamorphosed mafic igneous rock (Ami) (Compton, only at the head of Ten Mile Creek canyon, although it prob- 1975; Compton and others, 1977). The Elba Quartzite forms ably underlies most of the quadrangle. The metamorphosed the lowermost part of the Raft River Mountains sequence of adamellite unit is monzogranitic in composition and is com- Miller (1983), and has been assigned Paleoproterozoic, Pro- prised of plagioclase, quartz, potassium-feldspar, biotite, and terozoic, and Paleozoic ages (Armstrong, 1968b; Compton and others, 1977; Compton and Todd, 1979; Crittenden, muscovite, with accessory garnet, zircon, and apatite. Tex- 1979). Rock units that normally lie above the schist member tures range from medium to coarse grained, granular to por- of the Elba Quartzite farther to the west (including the schist phyritic, and become more gneissic toward the upper contact. of the Upper Narrows, quartzite of Yost, and schist of Within the uppermost 50 feet (15 m) of the adamellite below Stevens Spring; Compton, 1972, 1975) have been structural- the unconformity, the rock fabric grades upwards into proto- ly omitted by the Raft River detachment fault in the Kelton mylonite, mylonite, and locally ultramylonite and phyllonite. Pass 7.5' quadrangle. This detachment separates the parauto- At least 130 feet (40 m) of adamellite is exposed. The meta- chthon from the lower allochthon. Following the usage of morphosed adamellite unit crops out extensively within the Compton (1972, 1975), the rock units comprising the Arch- Raft River Mountains outside of the quadrangle, and also in ean basement are the older schist (Aos), metamorphosed the Albion and Grouse Creek Mountains. In the latter two mafic igneous rocks (Ami), and the metamorphosed adamel- mountain ranges, the metamorphosed adamellite unit has lite (Aad) (figure 3). been dated at approximately 2.5 Ga by the Rb-Sr isochron method (Armstrong and Hills, 1967; Compton and others, 1977). Egger and others (2003) reported a SHRIMP U-Pb Older Schist (Aos) discordia-line upper-intercept age on zircons from the unit of The older schist unit of Compton (1972) makes up a ~2.62 Ga. large percentage of the Archean rocks in the quadrangle and is the oldest unit of the Green Creek complex. Light-brown Elba Quartzite ( < e) to medium-gray-weathering, monotonous, fine-grained biotite-muscovite-feldspar-quartz schist and schistose phyl- The Elba Quartzite (Proterozoic) unconformably over- lite comprise this unit. Foliation-parallel lensoidal quartz lies the Archean Green Creek Complex. Locally, at or near veins are locally common. A fine-grained schistose amphi- the base is a pebble and cobble conglomerate with clasts bolite that occurs near the top of this unit in the northwest composed of quartzite. This conglomerate, common on the part of the quadrangle was mapped as part of the metamor- north side of the range in the Park Valley 15' quadrangle, is phosed mafic igneous rocks unit (Ami), but may be part of only exposed west of Crystal Peak in the Kelton Pass 7.5' the older schist unit. A prominent 3 to 10 foot (1-3 m) thick, quadrangle. The overlying quartzite is white, muscovite greenish, chlorite-muscovite schist at the top of the older quartzite with thin beds of muscovite schist. The unit gener- schist directly underlies the Elba Quartzite, and may repre- ally becomes more feldspathic upwards. sent a metamorphosed paleosol. Compton (1975), in his The age of the Elba Quartzite has not been determined study of the older schist unit farther to the west, considered directly by isotopic methods, although reasonable inferences the protolith to be sandstone, siltstone, mudstone, and sandy can be made. The Elba Quartzite has been assigned various shale. This unit is especially well exposed in Ten Mile Creek ages including Paleoproterozoic, Proterozoic and Paleozoic canyon, where a 400-foot (122-m) vertical thickness is ex- (Armstrong, 1968a; Compton and others, 1977; Compton posed. and Todd, 1979; Crittenden, 1979). Recently, the structurally and probably stratigraphically overlying quartzite of Clarks Metamorphosed Mafic Igneous Rocks (Ami) Basin has been shown to be of either Neoproterozoic or Pale- oproterozoic age, suggesting that the Elba Quartzite is at The metamorphosed mafic igneous rocks unit of Comp- least as old as Neoproterozoic (Wells and others, 1998). The ton (1972) (Archean) is well exposed in the quadrangle and Elba Quartzite may correlate with the Paleoproterozoic for- intrudes the older schist. Dark-green to dark-gray to black, mation of Facer Creek of the Willard Peak area (now known Geologic map of the Kelton Pass quadrangle, Box Elder County, Utah, and Cassia County, Idaho 7 as the Facer Formation [Crittenden and Sorensen, 1980]), as 165 to 1650 feet (50-500 m) thick in the quadrangle (figure suggested by Crittenden (1979). However, a cryptic low- 2). The attenuation is a result of penetrative plastic thinning angle attenuation fault separates the quartzite of Clarks Basin and later low-angle faulting. Two major low-angle faults from older metasedimentary rocks elsewhere in the Raft omit strata within the lower allochthon, the Emigrant Spring River, Albion, and Grouse Creek Mountains (Compton, and Mahogany Peaks faults. The Emigrant Spring fault 1972, 1975), allowing rocks above and below this fault to be removes about 3 miles (5 km) of stratigraphic section of different age. throughout the entire mapped area, including most or all of The present thickness of the Elba Quartzite in the Raft the Silurian, all of the Devonian, and all but thin (half inch) River Mountains is highly variable, principally as a result of remnants of Mississippian rocks (Wells, 1997). The Ma- strain within the Miocene shear zone (Wells, 2001). The hogany Peaks fault places Ordovician on Proterozoic rocks, shear zone is localized at the Archean-Proterozoic unconfor- and removes, at a minimum, the entire Cambrian stratigraph- mity, and the entire Elba Quartzite is mylonitic (Wells and ic section (Wells and others, 1998). Additionally, most other others, 2000a; Wells, 2001). In the Park Valley 15' quadran- formation contacts are low-angle attenuation faults. gle to the west, the maximum thickness of the Elba Quartzite Many attenuated rock units could not be represented at is 600 feet (180 m). In the Kelton Pass 7.5' quadrangle (south 1:24,000 scale. Where a map unit within the lower alloch- and west of Crystal Peak) the Elba Quartzite has a maximum thon is attenuated to less than 50 feet (15 m) in thickness, the thickness of 164 feet (50 m), and the unit thins to zero thick- unit is included in adjacent older or younger units, or lumped ness eastward at the mouth of Ten Mile Creek canyon. into an undivided unit, with the only consistency being inclu- sion in the same tectonostratigraphic package as the adjacent Schist Member of Elba Quartzite ( < es) units.
The youngest unit in the parautochthon in the Kelton Quartzite of Clarks Basin ( < cb) Pass 7.5' quadrangle is 16 to 82 feet (5-25 m) of Proterozoic, dark-brown to dark-gray, quartz-muscovite-biotite-feldspar The oldest unit within the lower allochthon is the quart- schist and foliated cataclasite that overlies the main part of zite of Clarks Basin (Proterozoic). The quartzite of Clarks the Elba Quartzite. This map unit is a tectonite produced by Basin characteristically consists of flaggy, muscovite movement along the Raft River detachment. However, the quartzite lacking feldspar, and lesser interlayered muscovite tectonite was not derived from the quartzite below because, schist and marble. The maximum thickness of this unit is where not an ultracataclasite, it is rich in biotite and mus- approximately 164 feet (50 m), and it crops out only along covite, similar to the schist member of the Elba Quartzite as the southeastern margin of the bedrock exposures in the mapped by Compton (1975). Overlying rocks within the quadrangle. The units stratigraphically beneath the quartzite parautochthon to the west (Compton, 1972, 1975), including of Clarks Basin farther to the west (Compton, 1972, 1975) the schist of the Upper Narrows, quartzite of Yost, and schist have been tectonically omitted by the Raft River detachment of Stevens Spring, have apparently been structurally omitted fault. The quartzite of Clarks Basin was tentatively assigned in the Kelton Pass 7.5' quadrangle by the Raft River detach- a Cambrian age (Compton, 1975) due to the apparent depo- ment fault. sitional contact between the overlying schist of Mahogany Peaks and Pogonip Group strata. However, the contact Lower Allochthon between the schist of Mahogany Peaks and Pogonip Group strata has been subsequently interpreted as a fault (Wells and The lower allochthon is separated from the parautoch- others, 1998), and carbon isotope analyses from marble thon by the Raft River detachment and from the middle interbeds, as outlined below, suggest a Proterozoic age (see allochthon by the middle detachment. The lower allochthon also Wells and others, 1998). in the quadrangle consists of Proterozoic quartzite and pelitic Samples from two, distinct, 3-foot (1-m) thick, calcite- schist; Ordovician calcitic marble, phyllite, quartzite and rich marbles (>93% calcite) in the quartzite of Clarks Basin dolomitic marble; Silurian(?) dolomitic marble; and Pennsyl- (300 feet [90 m] south of locality 11, plate 1), exhibit high vanian(?) calcitic marble. These units correlate with those δ13C values (δ13C = +6.4 and +7.6‰). These values are inter- mapped within the lower allochthon to the west (Compton, preted as primary δ13C values (Wells and others, 1998) 1975; Compton and others, 1977; Compton and Todd, 1979), because metamorphic processes (for example, decarbon- with the exception of two modifications to this stratigraphy: ation and/or fluid flow) will tend only to decrease the δ13C (1) rocks mapped as the Pogonip Group by earlier workers values of carbonate rocks (Wickham and Peters, 1993). are mapped as two units, the Garden City Formation and a The high δ13C values measured in marbles within the unit comprised of undivided Kanosh, Lehman, Watson quartzite of Clarks Basin are not present in Cambrian carbon- Ranch, and Crystal Peak Formations; and (2) two packages ate rocks in the western United States or worldwide. Except of Mississippian and Pennsylvanian rocks are differentiated, for multiple positive δ13C excursions of up to +4.5‰ in the one of upper greenschist- to lower amphibolite-facies rocks Cambrian (see for example Brasier and others, 1994; Saltz- in the lower allochthon and the other of lower to middle man and others, 1998), abundant data from Phanerozoic car- greenschist-facies metamorphic rocks in the middle alloch- bonate rocks worldwide reveal limited variation of δ13C val- thon. ues through time (δ13C = 0‰ ± 2) (Veizer and Hoefs, 1976; The stratigraphic section represented within the lower Veizer and others, 1980). The measured values are also high- allochthon has been greatly attenuated by several periods of er than those present in Mesoproterozic sequences (Buick deformation. This stratigraphic section in neighboring moun- and others, 1995), including the Belt Supergroup of western tain ranges is from 2.5 to 4.4 miles (4-7 km) thick, but is only North America (Mora and Valley, 1991). Analyses of two 8 Utah Geological Survey samples of the pale-gray, massive, limestone unit of the Pale- [1-m] thick resistant beds of pure (>93% calcite), light-blue oproterozoic Facer Formation (Crittenden and Sorensen, gray, fine-grained marble within this unit that were sampled 1980) revealed δ13C values of -0.1‰ and +0.7‰ (Wells and for δ13C analyses (Wells and others, 1998). others, 1998); these low values suggest that the lower Raft River sequence does not correlate with the Facer Formation, Garden City Formation (Ogc) a correlation proposed by Crittenden (1979). Though these Facer values resemble those believed to be typical of most The stratigraphically lowest Ordovician unit mapped by Paleoproterozoic carbonate rocks (Veizer and others, 1992a, Compton (1972, 1975) was the metamorphosed limestone of 1992b), a major positive excursion of δ13C values in excess the Pogonip(?) Group and the metamorphosed Pogonip of +10‰ has been documented between ~2.22 and 2.06 Ga Group, respectively. These strata are here reassigned to the (Baker and Fallick, 1989; Karhu, 1993), including values Garden City Formation and the overlying Kanosh, Lehman, from the Paleoproterozoic Snowy Pass Supergroup of Watson Ranch, and Crystal Peak Formations. The Pogonip Wyoming (Bekker and Karhu, 1996); thus, a correlation with Group terminology (which includes the Kanosh and Lehman other Paleoproterozoic sequences in western North America Formations) as well as the overlying Watson Ranch cannot be precluded. Quartzite, Crystal Peak Dolomite, and Eureka Quartzite ter- The high δ13C values of marbles in the quartzite of minology is generally applied southwest of the Tooele Arch, Clarks Basin resemble those measured in Neoproterozoic and the Garden City Formation, and overlying Swan Peak sequences worldwide (Kaufman and Knoll, 1995; Halverson Quartzite, terminology is generally applied northeast of the and others, 2005). In the western Cordillera, high δ13C values Tooele Arch (Hintze, 1988). The Garden City Formation as have been measured in the McCoy Creek Group of Nevada used in this report could be termed lower Pogonip Group, but and Utah (Wickham and Peters 1993), the Brigham Group of the typical lithology of the House Limestone (basal Pogonip) Idaho (Smith and others, 1994), and the Windermere Super- is missing in the quadrangle. The Garden City Formation group and equivalents in Canada (Narbonne and others, here consists of up to 985 feet (300 m) of calcitic marble, and 1994). The data are, therefore, consistent with either a Neo- subordinate dolomitic marble, sandy marble, and quartzite. proterozoic or Paleoproterozoic age for the quartzite of Typically, this unit has a three-part stratigraphy, although Clarks Basin. these parts were not mapped separately. The lower part is pri- marily thin-bedded and laminated brown-weathering silty to Schist of Mahogany Peaks ( < mp) sandy calcitic marble, and a few beds of brown quartzite and muscovite phyllite (possible Fillmore Formation equivalent). Proterozoic pelitic schist, 0 to 33 feet (0-10 m) thick, The middle part of the unit is mainly massive light-gray separates the quartzite of Clarks Basin from the overlying dolomitic marble, and subordinate laminated calcitic marble Ordovician rocks, and is assigned to the schist of Mahogany and quartzite (more possible Fillmore Formation equivalent). Peaks of Compton (1972) because of its similar stratigraphic The upper part consists of medium- to thick-bedded, light- position and bulk composition. The mineralogy of the schist gray to buff calcitic marble, with abundant silty laminations varies with its bulk composition. Typically, near the base of (possible Juab Limestone and Wah Wah Limestone equiva- the unit, poorly exposed, graphitic schist contains the assem- lent). The top of the upper part is characteristically clean, blage muscovite + quartz + kyanite ± staurolite ± garnet ± finely laminated calcitic marble, underlain by 6 to 33 feet (2- zoisite. This grades upwards into a more resistant knobby, 10 m) of chert-rich calcitic marble. Conodonts extracted porphyroblastic schist containing the mineral assemblage from the upper part of the Garden City Formation yielded staurolite + biotite + garnet + muscovite + plagioclase + Early Ordovician ages and correlate to the lower half of the quartz, typical of the schist of Mahogany Peaks in the region upper part of the Garden City Formation near Logan, Utah (Compton, 1972, 1975). These assemblages indicate peak (J.E. Repetski, U.S. Geological Survey, written communica- metamorphic conditions in the amphibolite facies, and on the tion, 1989). petrogenetic grid for the KFMASH system, indicate mini- mum temperatures and pressures of approximately 600°C Crystal Peak, Watson Ranch, Lehman, and Kanosh and 6.5 kb (fields l-7 and m-7 in figure 2 of Spear and Formations, Undivided (Ock) Cheney, 1989). Extensive retrograde alteration of staurolite to chloritoid and white mica, biotite to chlorite, and kyanite The Garden City Formation is overlain by a unit as thick to white mica has taken place at greenschist-facies condi- as 230 feet (70 m) consisting of (from base to top) brownish tions. quartzite and muscovite phyllite (Kanosh Shale), interbedded quartzite and sandy calcitic marble (Lehman Formation and Schist of Mahogany Peaks and Quartzite of Clarks Watson Ranch Quartzite), and dolomitic marble (Crystal Basin, Undivided ( < la) Peak Dolomite). The calcitic marble is dark gray and com- monly contains quartz and feldspar sand, muscovite, and In several localities south of Ten Mile Creek canyon, much pyrite. The quartzite is commonly reddish brown, well lithologies that are representative of the quartzite of Clarks bedded, and has interbeds of clean white quartzite. At the top Basin and the schist of Mahogany Peaks (see descriptions of this unit, a light-gray, fine-grained dolomitic marble up to above) are interlayered in a non-systematic fashion. It was 13 feet thick (4 m) is commonly found. not determined whether the alternating lithologic layers or The lower part of this unit in the quadrangle is tentative- lenses represented repetition by faulting or folding, and the ly equated to the Kanosh Shale to the southwest, which is rock package was mapped as undivided Proterozoic rocks of correlative with the lower member of the Swan Peak the lower allochthon Lacustrine Lagoonal Deposits (Qll) Lacustrine and Alluvial Deposits that overlie Tertiary These fine-grained deposits of Lake Bonneville (latest Rocks (Qla/Ts) Pleistocene) are minor surficial deposits within the Kelton Tertiary sedimentary rocks (Ts) underlie thin, undivided Pass 7.5' quadrangle. They are restricted to exposures near lacustrine and alluvial deposits (Qla), as indicated by either the junction between State Highway 42 and the Cedar Creek 1 1 the occurrence of tuffaceous soils or exposures of Tertiary road (NE ⁄4 section 1, T. 14 N., R. 12 W.; NW ⁄4 section 6, T. deposits within "windows" through the Quaternary deposits. 14 N., R. 11 W.). However, they probably underlie many The deposits (Qla/Ts) occur below the Lake Bonneville high- lacustrine gravel deposits that form various barrier bar com- stand, are commonly marked by irregular topography, and plexes. Lagoonal deposits consist of unconsolidated buff- represent Holocene and Pleistocene lacustrine and alluvial white to tan, silty marl, calcareous silt, and fine sand. Lag- veneers on irregular topography formed in relatively resistant oon deposits are the same age as deposits in nearby beach Tertiary deposits. and offshore lacustrine environments. Colluvium (Qc) Lacustrine Sand (Qls) Colluvial deposits (Holocene and latest Pleistocene) are Lacustrine sand (latest Pleistocene) consists of fine to common along steep slopes flanking the deeper valleys that coarse sand and minor granule to pebble gravel deposited in dissect the eastern Raft River Mountains. The colluvium con- Lake Bonneville. In addition to the lacustrine sand deposits sists of unconsolidated gravel and sand locally derived from mapped on the eastern margin of the quadrangle, lacustrine Precambrian and Paleozoic strata. sand also underlies regressive barrier beach and gravel de- posits (Qlg). Mass-Movement Deposits (Qms) Lacustrine Gravel (Qlg) Incoherent landslide deposits and a single coherent slump (Holocene and latest Pleistocene) are present along the Lacustrine gravels (latest Pleistocene) were widely de- flanks of canyons cut into Precambrian bedrock, and along posited along shorelines of Lake Bonneville in beach and the northern dip slope to the range-scale anticline within Pre- barrier beach complexes. These materials are unconsolidat- cambrian rocks. The landslide deposits create hummocky ed, generally moderately to well-sorted, well-rounded cobble and irregular topography, and generally have headwall and pebble gravel with subordinate sand. A particularly well- scarps. The slump on the north wall of Ten Mile Creek exposed example of a barrier beach is on the south side of canyon contains a coherent but displaced section of Precam- State Highway 42, just east of the intersection with the Cedar brian rocks. Creek road. There, gravels in a barrier bar have well-bedded, silty lagoonal deposits draped over and infilling the lagoonal Stream Alluvium (Qal) trough on the shoreward side of the bar. The silt is in turn overlain by sand, which is capped by a deposit of gravel. The Deposits of unconsolidated, poorly sorted gravel, sand, barrier beach complexes in the Kelton Pass 7.5' quadrangle silt, and clay (Holocene and latest Pleistocene) are mapped in generally have steep sides that faced towards open water, and active ephemeral stream beds and washes. The grain size of are elongate north-south, parallel to the shoreline. Second- these deposits generally decreases downstream. Included order, low-amplitude arcuate depositional ridges are promi- within these deposits is locally derived colluvium along the nent on aerial photographs, and are convex northward, indi- base of slopes bordering these drainages, particularly in cating northward progradation. Long- shore transport is also mountain valleys. 12 Utah Geological Survey Younger Alluvial-Fan Deposits (Qaf1) D1 - Stratigraphic Attenuation Unconsolidated alluvial-fan deposits (Holocene) of The Proterozoic through Pennsylvanian(?) units within poorly sorted gravel, sand, and silt form small alluvial fans the lower allochthon are markedly attenuated by both plastic that breach Lake Bonneville shorelines and overlie lake and brittle deformation. The attenuation was achieved by deposits. These fans postdate the development of the Bon- penetrative plastic thinning during metamorphism at upper neville and younger shorelines, and are located along the greenschist- to lower amphibolite-facies conditions (D1), and eastern margin of the quadrangle. later by low-angle younger-over-older ductile and brittle faulting (D2) (referred to here as attenuation faulting, after Eolian Sand and Silt (Qe) Hintze, 1978). The D2 attenuation faults are interpreted as postdating penetrative foliation development (D ) for the fol- Eolian sand and silt (Holocene) is present in small dunes 1 lowing reasons: (1) attenuation faults locally truncate D and sheets south of Hardup (site), mostly in deposits less 1 foliation; (2) quartzite microstructural fabrics within attenu- than 6 feet (2 m) thick. These unconsolidated, light-gray to ation fault zones are of distinctly lower temperature than D light-brown deposits are most likely locally derived from 1 fabrics, and (3) D fabrics have distinct kinematics from the stratified alluvial sand and silt deposits (Qla) present in the 1 attenuation fault zones (Wells, 1997). surrounding region. The eolian sand and silt accumulations The most pervasive fabric in the lower allochthon is a are associated with vegetation, commonly cedar trees. penetrative foliation that is generally parallel to lithologic layering and inferred bedding. At the few locations where STRUCTURE foliation is distinct from bedding, foliation is slightly in- clined to the southwest relative to bedding, whether in The eastern Raft River Mountains display many features upright or overturned rocks. Lineation varies in degree of of crustal extension. In particular, the Raft River Mountains development, is not ubiquitous, and generally trends north- expose a Miocene low-angle normal fault (the Raft River east. With the exception of a few asymmetric structures that detachment) that separates mylonitic Precambrian rocks in indicate eastward and northeastward shearing, the majority the footwall (lower plate) from Proterozoic, Paleozoic and of strained features are symmetric, suggesting a major com- Tertiary strata in the hanging wall (upper plate). The Pre- ponent of shortening nearly perpendicular to bedding. cambrian rocks are the parautochthon and the overlying The D1 fabric in the lower allochthon is interpreted as a prograde metamorphic fabric (Wells, 1997). Oxygen isotope upper plate contains the lower and middle allochthons in the 18 eastern Raft River Mountains (figures 3 and 4). In contrast to (δ O) mineral-pair geothermometry of muscovite, biotite, Miocene plastic deformation of Precambrian footwall rocks, and quartz that microscopically define the D1 foliation in the hanging-wall rocks were rotated and extended along Ordovician rocks yields temperatures between 490° and 520°C high-angle brittle normal faults that root into the Raft River (Wells and others, 1990; Wells, 1991). This is consistent with detachment, also in the Miocene. These structural features conodont color alteration index (CAI) values >7 (Wells and are common to metamorphic core complexes (for example, others, 1990; J.E. Repetski, U.S. Geological Survey, written Crittenden and others, 1980), which are products of large- communication, 1989), and calcite-dolomite thermometry on magnitude crustal extension. the Garden City Formation in the western Raft River Moun- Study of allochthons of the upper plate enabled recon- tains (Wolff, 1997; Wells and others, 1998). Additionally, the struction of the deformational sequence that predates metamorphic assemblages from the Proterozoic schist of Miocene detachment faulting, and provided constraints on Mahogany Peaks (as outlined earlier) suggest pressures and the absolute age of metamorphism. Study of Precambrian temperatures in excess of 6.5 kb and 600°C, respectively rocks in the lower plate of the Raft River detachment yielded (Spear and Cheney, 1989), further suggesting a doubling of the stratigraphic section (Wells and others, 1998). Thus, the information on the timing and kinematics of Miocene move- metamorphic conditions indicate tectonic burial, not thermal ment on the Raft River detachment fault. metamorphism at stratigraphic burial depths (in contrast to The eastern Raft River Mountains show seven phases of metamorphism in the Pilot Range to the southwest) (Miller deformation (table 1): (D ) attenuation of units within the 1 and Hoisch, 1992). lower allochthon by intrabed plastic flow at upper green- In contrast to the Proterozoic to Permian rocks above the schist- to lower amphibolite-facies conditions; (D ) attenua- 2 Raft River detachment, the Archean and Proterozoic rocks tion of lower allochthon units by top-to-the-west low-angle below the detachment exhibit vestiges of a variably directed, normal faulting; (D ) recumbent folding (F ) of attenuated 3 3 top-to-the-NNE to -NNW shear zone. This shear zone clear- strata and faults; (D4) emplacement of the middle allochthon ly predates, and is preserved beneath, the D6 top-to-the-east (to the west) over the lower allochthon along the middle de- extensional shear zone. Additionally, the generally top-to- tachment fault; (D5) upright, open folding (F5) of the middle the-N fabric is also preserved locally within the D6 shear and lower allochthons; (D6) progressive top-to-the-east nor- zone, in lenses that have escaped the younger deformation, mal-sense shearing along the shear zone at the top of the commonly in mechanically strong amphibolites. This fabric parautochthon and along the Raft River detachment fault, represents the earliest deformation fabric within the parauto- with concomitant high-angle normal faulting in the upper chthon, and may be coeval with D1 described above (table 1). plate; and (D7) doming of the Raft River detachment fault and earlier structures. A brief description of these deforma- tions follows; for a more complete description and a discus- D2 - Attenuation Faults sion of these deformations, see Wells (1991, 1992, 1997, 2001) and Wells and others (1998, 2000, 2008). Two major discontinuities in stratigraphy within the Geologic map of the Kelton Pass quadrangle, Box Elder County, Utah, and Cassia County, Idaho 13 Table 1. Deformation events in the eastern Raft River Mountains. Sources for upper plate (Lower and Middle Allochthons) are: Wells and others (1990, 2008) and Wells (1992, 1997). Sources for lower plate (Parautochthon) are: Compton and others (1977), Compton (1980), Sabisky (1985), Malavieille (1987a), Wells (1992, 1997), and Wells and others (2000, 2008). Arrows between two deformations of Parautochthon indicate that these deformations may be part of a single progressive deformation, rather than two distinct events. LOWER AND MIDDLE ALLOCHTHONS (UPPER PLATE) Deformation event Mesostructures Kinematics Interpretation Timing D1: Penetrative attenuation of strata (S1) Low angle to bedding Flattening and Extension Pre-90 to 102- within lower allochthon during (L1) NE-trending top-to-NE shear 105 Ma amphibolite-facies metamorphism D2: Attenuation faulting within lower (S2) Low angle to S1 Top-to-west shear Extension ~90 Ma allochthon during greenschist-facies (L2) E-trending metamorphism D3: Recumbent folding of lower Contraction allochthon D4: Middle Detachment (places Top-to-WSW shear Extension Late Eocene- middle on lower allochthon) Oligocene(?) D5: Open folding of middle and N-trending fold axes, lower allochthons generally upright D6: Raft River Detachment (RRD) RRD top-to-the-east Extension Middle - early and high-angle faulting (HAF) HAFs generally Late Miocene down-to-the east D7: Doming ~E-W axis, doubly plunging PARAUTOCHTHON (LOWER PLATE) Deformation event Mesostructures Kinematics Interpretation Timing Northward shearing Subhorizontal foliation; Northward-shearing Pre-90 to 102- ~N-S lineation and apparent 105 Ma constriction Footwall shear zone (D6 of upper plate) Subhorizontal foliation; Top-to-the-east Extension Late Early - ~E-W lineation; recumbent shearing and Middle Miocene folds w/E-W hingelines vertical shortening Raft River Detachment (D6 of upper plate) Top-to-the-east brittle Extension Middle - early faulting Late Miocene Doming (D7 of upper plate) ~E-W axis, doubly plunging lower allochthon mark faults: the Emigrant Spring fault Spring fault. This marble is highly foliated, and locally con- (Wells, 1997; LAF1 of Wells, 1992) and the Mahogany tains a well-developed east-trending stretching lineation that Peaks fault (LAF2 of Wells, 1992; Wells and others, 1998) is parallel to fold axes of locally developed isoclinal folds. (figure 3). The fault placing Pennsylvanian(?) lower Oquirrh Crystallographic preferred orientation and microstructural Formation tectonite marble (*ot) over Ordovician and Silur- analysis of this marble indicate a significant component of ian(?) dolomitic marble (SOd) is named the Emigrant Spring westward shearing (Wells, 1992, 1997). fault for a well-exposed locality of this fault near Emigrant The second major discontinuity in stratigraphy separates Spring in the quadrangle. This fault removes most or all of the Proterozoic schist of Mahogany Peaks < mp) and quart- the Silurian, all of the Devonian, and all but thin slivers of zite of Clarks Basin ( (1992, 1997). The faulted nature of this stratigraphic discon- of the middle allochthon. Highly asymmetric quartz and cal- tinuity has recently been clarified by carbon isotopic data, cite pressure shadows around pyrite consistently indicate metamorphic petrology, 40Ar/39Ar thermochronology, and top-to-the-west shearing (Wells, 1992, 1997). This transla- structural data (Wells and others, 1998). Together, these data tion direction is consistent with data from the Black Pine suggest that the contact is a large-displacement low-angle Mountains (figure 1) that also indicate westward transport of normal fault that excised 2.5 to 3 miles (4-5 km) of strati- the middle allochthon (Wells and Allmendinger, 1990). graphic section; it has been named the Mahogany Peaks fault Movement along the middle detachment fault probably (Wells and others, 1998). occurred at metamorphic conditions no higher than lower In addition to the two major low-angle faults described greenschist facies. This is evident from the metamorphic dis- above, all other formational contacts within the lower alloch- continuity across this fault in the study area and farther to the thon are low-angle attenuation faults that place younger west (Compton and others, 1977; Wells and others, 1997), rocks on older rocks. The faults are generally subparallel to and the deformation mechanisms within the sheared base of foliation (and bedding) in the adjacent units, and are recog- the middle allochthon (Wells, 1997). The displacement along nized by ductile high-strain zones localized along bedding- the middle detachment was, therefore, probably late meta- parallel contacts between stratigraphic units along which sec- morphic to post metamorphic. tion is commonly missing. However, locally there is moder- ate discordance between the fault zone and the adjacent units, and between units on either side of faults. Slivers of D5 - Open Folding (F5) units are commonly strung out along low-angle faults, and locally, units have been completely omitted. Additionally, Both the lower and middle allochthons are folded into significant lateral changes in map-scale unit thicknesses indi- broad, upright, open folds whose axes generally trend N-S cate faulting. (figure 4). The most prominent of these folds lies southeast Within the attenuation fault zones, fabrics range from of Crystal Peak, where an open fold (F5) with a wavelength ductile to brittle, and in many localities a progression from greater than 4900 feet (1500 m) is well exposed. This fold early ductile to later brittle shearing is evident. The majority clearly deforms both the middle detachment and underlying of observations from within these fault zones suggest top-to- low-angle faults within the lower allochthon and is truncated the-west shearing. Mylonitic shear zones, ranging in thick- by the Raft River detachment (see cross-section B-B'). ness from 0.4 to 60 inches (1-150 cm), are recognized within quartzites of the greatly attenuated undivided Crystal Peak, D6 - Raft River Detachment Fault and Shear Zone Watson Ranch, Lehman and Kanosh Formations map unit (Ock) and the Eureka Quartzite (Oe). Kinematic indicators Structurally beneath the Raft River detachment and including S-C fabrics, oblique grain-shape fabrics and asym- within the parautochthon is an approximately 660-foot (200- metric lattice-preferred orientations indicate westward shear- m) thick shear zone that is parallel to bedding in the Protero- ing (Wells, 1997). The shear zones separate Silurian(?) and zoic units and the underlying unconformity with Archean Ordovician dolomite (SOd) from the Garden City Formation rocks. There is a close spatial and kinematic association (Ogc). between the detachment fault and the underlying shear zone. The shear zone always directly underlies the brittle detach- D3 - Recumbent Folding (F3) ment fault. Fabrics within the uppermost shear zone are com- monly retrograded, and where a cataclasite is present, the Large inverted sequences of Ordovician to Pennsylvan- mylonite is progressively overprinted by cataclastic deforma- ian(?) rocks, coupled with upright packages of the same tion structurally upward toward the detachment fault. Both rocks, are common in the lower allochthon (figure 4). These plastic and brittle structures exhibit the same top-to-the-east relationships indicate the presence of upright and overturned shear sense. limbs of large recumbent folds. The hinges of these inferred Mylonitic fabrics are most highly developed within the folds, however, are not unequivocally exposed, and because Elba Quartzite and its schist member, and fabric intensity later high-angle normal faults have since altered the dips of related to eastward shearing typically dies out abruptly the fold limbs, their geometries are not known. The youngest downward within the Green Creek Complex. Studies of the unit involved in the recumbent folding is the Pennsylvan- * shear zone have documented large-scale, top-to-the-east dis- ian(?) marble tectonite ( ot); it generally occupies the cores placement (Compton, 1980; Sabisky, 1985; Malavieille, of recumbent synclines (figure 4; cross-section A-A'). D3 1987a; Wells and others, 2000; Wells, 2001; Sullivan, 2008). recumbent folds deform D1 foliation and unequivocally fold The shear zone is continuous to the extreme eastern expo- the D2 Emigrant Spring fault. sures of the parautochthon within the Kelton Pass 7.5' quad- rangle. Within the shear zone, a generally flat-lying foliation D4 - Emplacement of the Middle Allochthon along and a pronounced stretching lineation (trending 083 ± 10°) the Middle Detachment Fault record significant strain resulting from a combination of ver- tical flattening and top-to-the-east simple shear (Compton, Subsequent to recumbent folding, greenschist-facies 1980; Sabisky, 1985; Malavieille, 1987a; Wells, 1992, metamorphosed Permian and Pennsylvanian rocks (Oquirrh 1997, 2001; Sullivan, 2008). Formation) of the middle allochthon were emplaced onto the Superposed on the shear zone in the parautochthon is the lower allochthon along the middle detachment fault. The brittle Raft River detachment fault. This major structural dis- transport direction for this fault is derived from study of a continuity everywhere forms the upper contact of the schist thin sliver of Chainman Shale present locally along the base member of the Elba Quartzite. The detachment fault is con- Geologic map of the Kelton Pass quadrangle, Box Elder County, Utah, and Cassia County, Idaho 15 41°57' UTAH N Crystal 0 1 2 km Peak 41°55' D 5 Anticline D 5 Syncline D 3 Recumbent syncline D 3 Recumbent anticline Foliation High-angle normal fault; bar and ball on downthrown side Attenuation fault or contact Middle detachment fault Raft River detachment fault Middle Permian and Pennsylvanian allochthon Oquirrh Formation Middle detachment fault Pennsylvanian(?) Lower Oquirrh Formation marble tectonite Lower Ordovician; patterned unit is allochthon Ock, shown to highlight structure Proterozoic schist of Mahogany Peaks and quartzite of Raft River Clarks Basin, undivided detachment fault Precambrian rocks, undivided Parautochthon 41°52'30" 113°15' 113°07'30" Figure 4. Generalized geologic map of the eastern Raft River Mountains indicating distribution of allochthons and parautochthon and their bounding detachment faults, and axial traces of D3 (F3) recumbent folds and D5 (F5) open folds. Note that the Pennsylvanian(?) marble tectonite (IPot) com- monly occurs within the cores of D3 (F5) recumbent synclines. cordant with foliation and bedding within the lower plate, but Both brittle and ductile cataclastic rocks are present, as are truncates most structures within the upper plate. The fault many shear fabrics common to ductile shear zones. surface is not exposed, but float blocks of brecciated and oxi- The rocks above the Raft River detachment fault are cut dized marble are common. However, on the east side of Indi- by numerous high-angle normal faults with displacements an Creek in the southwest corner of the Kelton Pass 7.5' from an inch to about 1.25 miles (cm to km) (plate 2 and 3). quadrangle, and in lower reaches of Ten Mile Canyon, fine- The strikes of the faults vary greatly, but the majority are grained schist in the footwall adjacent to the detachment has roughly north. Only two faults, both of small displacement, been subjected to cataclasis. In these localities, resistant were noted that cut the Raft River detachment fault, and their ledges of black cataclasite demarcate the detachment fault. separations were too small to map, even at 1:12,000 scale 16 Utah Geological Survey (plate 2). All other high-angle faults, therefore, root geomet- with earliest Late Cretaceous cooling; however, the cooling rically into the Raft River detachment fault, and formed age may predate D2 deformation as the temperatures of either prior to or during movement of the detachment fault. deformation may have been less than argon closure in mus- covite. Phlogopite growing in D1 strain fringes around pyrite D7 - Broad Folding from the Oquirrh Formation of the middle allochthon in the The present structure of the rock units in the Raft River Grouse Creek Mountains yielded laser-probe 40Ar/39Ar ages Mountains is an east-west trending, doubly plunging anti- of ~105-102 Ma (Wells and others, 2008). Evidence for phl- cline of 16.25 miles (26 km) length and 3960 feet (1200 m) ogopite growth in lower greenschist-facies metamorphic of exposed structural relief (figure 1). The shear zone, strata conditions (~300-350°C) together with incomplete resetting in the parautochthon, and the detachment fault outline this of step-heated detrital muscovite, indicate that the UV laser- large structure. The axis of the elongate anticline is parallel probe 40Ar/39Ar ages reflect growth and hence deformation to the transport direction of both the footwall shear zone and ages, not cooling ages (Wells and others, 2008). the Raft River detachment fault. The near parallelism of the Thermochronological results from within and beneath shear zone and detachment fault to the footwall strata over a the D6 shear zone in the parautochthon contrast markedly wide area of the Raft River Mountains, particularly in the ori- with the Late Cretaceous muscovite ages from the lower entation perpendicular to the anticlinal axis, strongly sug- allochthon (Wells and others, 1990, 2000a). Late early to gests that the fold developed after detachment faulting. early late Miocene cooling ages (40Ar/39Ar from muscovite, biotite, and potassium feldspar; fission track in apatite) (Wells and others, 2000) collectively indicate rapid cooling Other during the Miocene, during footwall unroofing related to Tertiary sedimentary rocks exhibit variable bedding atti- extensional displacement. tudes suggesting they have been folded and tilted. Generally, Samples collected from Ten Mile Creek canyon con- bedding strikes northward and dips westward, possibly due strain the cooling history of the lower plate to the Raft River to down-to-the-east faulting in the upper plate of the Raft detachment fault (Wells and others, 2000). Muscovite from ± River detachment fault. However, locally continuous out- mylonitic Elba Quartzite yielded total-gas ages of 14.66 ± crops in washes indicate that the Tertiary rocks are also 0.09 Ma (RR91-6) and 14.57 0.1 Ma (MWRR100-89) from involved in large-wavelength (>1.25 miles [2 km]) folds that quartzite and a muscovite-schist interbed, respectively (table plunge moderately (30° to 35°) to the southwest. It is unclear 2). Biotite from the older schist unit yielded a well-defined ± whether these folds were generated during detachment fault- plateau age of 13.76 0.15 Ma (RR91-13). The discordance ing (D ), or during the more recent doming of the range (D ). of these ages is consistent with closure temperatures for mus- 6 7 ± No range-bounding faults were identified along the covite and biotite—approximately 350° and 300°C 25°C, northern, southern, and eastern margins of the Raft River respectively (McDougall and Harrison, 1999). Detrital potas- Mountains, and the range morphology probably results from sium feldspar from the Elba Quartzite was analyzed follow- doming rather than block-faulting typical of other ranges in ing the multiple-diffusion-domain analysis methods of the Basin and Range Province. Lovera and others (1989, 1991) (see Wells and others, 2000, for details). The potassium feldspar is affected by excess argon and yielded a saddle-shaped age spectrum, with an age GEOCHRONOLOGY gradient from 10.58 ± 0.40 Ma at 10.3 percent 39Ar release, to 70.23 ± 0.27 Ma. The low-temperature portion of the age The upper and lower plate rocks in the Raft River Moun- spectrum was modeled to determine a cooling history (figure tains experienced similar peak metamorphic conditions of 5), which is cautiously interpreted as a minimum cooling rate upper greenschist to lower amphibolite facies, most likely in due to the potential complication of excess argon in this por- the mid-Cretaceous (Wells and others, 2000), but their timing tion of the gas release. The fission-track age of detrital zir- of cooling (a probable proxy for unroofing) differs signifi- con from the Elba Quartzite is 9.4 ± 0.73 Ma. At average cantly. Muscovite 40Ar/39Ar ages from the upper plate are geologic cooling rates, zircon has a closure temperature of Late Cretaceous, whereas muscovite (as well as biotite and approximately 210°C ± 20°C (Zaun and Wagner, 1985). potassium feldspar) 40Ar/39Ar ages from the lower plate are Apatite from the metamorphosed adamellite unit, collected late early to early late Miocene (table 2). on the eastern side of Indian Creek canyon (1.5 miles [2.2 Wells and others (1990) described four muscovite km] to the east of the Ten Mile Creek canyon locality) 40Ar/39Ar age determinations from four samples of marble records a cooling age of 7.42 ± 0.99 Ma. At geologic cooling and schist from the lower allochthon in the eastern Raft River rates (1-100°C/m.y.), fission-track annealing in apatite Mountains (table 2). Muscovite separates from the Garden occurs between approximately 60° and 120°C (for example, City Formation (Ogc) containing D1 fabrics yielded a total Gleadow and Duddy, 1981; Gleadow and others, 1983). The gas age of 81.3 ± 0.2 Ma (MWRR59-88) and plateau ages of muscovite, biotite, and potassium feldspar 40Ar/39Ar ages 87.8 ± 0.3 Ma (MWRR41-88) and 90.4 ± 0.3 Ma and the apatite and zircon fission-track ages detail a cooling (MWRR40-88); a muscovite separate from Pennsylvanian(?) curve for the lower plate to the Raft River detachment fault * marble tectonite ( ot) adjacent to the D2 Emigrant Spring (figure 5). fault yielded a similar plateau age of 88.5 ± 0.3 Ma The D6 mylonite zone was previously interpreted as a (MWRR12-89). The similarity in age and in morphology of Mesozoic thrust-sense (Malavieille and Cobb, 1986; Snoke age spectra from muscovite defining D1 and D2 fabrics indi- and Miller, 1988) and Cenozoic normal-sense shear zone cates that both fabrics developed prior to or synchronous (Malavieille, 1987a; Wells, 1992, 1997). Plastic shearing Geologic map of the Kelton Pass quadrangle, Box Elder County, Utah, and Cassia County, Idaho 17 Table 2. Geochronologic data from the Kelton Pass quadrangle area, eastern Raft River Mountains; all age reported at 1-sigma analytical uncertainty. 40Ar/39Ar analyses from Lower Allochthon (Ordovician strata and unit IPot) were performed in the laboratory of R.D. Dallmeyer at the University of Georgia (Wells and others, 1990). 40Ar/39Ar analyses from Parautochthon (Precambrian rocks) were done at the U.S. Geological Survey in Denver, Colorado (Wells and others, 2000). Plateau ages marked with an asterisk (*) are not true plateau ages, but rather are weighted mean ages (preferred ages) of selected contiguous gas increments, and most likely represent the cooling age. Fission track analyses were performed by A.E. Blythe at Uni- versity of Southern California. NA=Not applicable, sample from just outside quadrangle. PARAUTOCHTHON Map Sample Sample site Sample site Mineral Unit Total Gas Plateau Age Fission Track # Number Latitude Longitude Symbol Age (Ma) (Ma) Age (Ma) 1 MWRR100-89 41° 54' 46" 113° 14' 22" Muscovite LOWER ALLOCHTHON Map Sample Number Sample site Sample site Mineral Unit Total Gas Plateau Age Fission Track # Latitude Longitude Symbol Age (Ma) (Ma) Age (Ma) 6 MWRR12-89 41° 55' 44" 113° 10' 55" Muscovite IPot 88.0 ± 0.3 88.5 ± 0.3 7 MWRR40-88 41° 54' 48" 113° 11' 25" Muscovite Ogc 88.7 ± 0.3 90.4 ± 0.3 8 MWRR41-88 41° 54' 18" 113° 12' 21" Muscovite Ogc 87.1 ± 0.4 87.8 ± 0.3 9 MWRR59-88 41° 54' 03" 113° 12' 07" Muscovite Ogc 81.3 ± 0.2 10 MWRR58-88 41° 56' 15" 113° 10' 08" Whole Rock Ock 65.0 ± 0.6 11 MWRR92-89 41° 53' 8" 113° 12' 35" Muscovite 500 Figure 5. Time-temperature plot derived from thermochronometric 400 data for the Ten Mile Creek canyon locality. Darker shaded area rep- resents cooling path envelope (envelope bounding permissive cooling Mu paths); boxes indicate cooling ages with range of closure temperature Deformation and 1-sigma errors in age; vertical bars indicate temperature condi- Bt Between hbl & Mu conditions tions bracketed between thermochronometers. The apatite fission- 300 Ar closure track age is projected from age-versus-distance regression of Wells and ZFT others (2000). The approximate deformation conditions for late plastic (ductile) shearing in quartz are indicated by lighter shaded area. Note K-spar 200 that the D extensional shearing took place during rapid cooling, indi- MDD model 6 cating a Miocene age for shearing. Letter symbols on figure are: AFT, 40 39 Temperature (°C) apatite fission track; ZFT, zircon fission track; Bt, biotite Ar/ Ar; 40 39 40 39 100 Mu, muscovite Ar/ Ar; Hbl, hornblende Ar/ Ar; Kspar MDD AFT model, multiple diffusion domain thermal model for potassium Age of ductile shearing feldspar. 0 10 20 30 40 Age (Ma) 18 Utah Geological Survey occurred within the temperature window spanned by represents an important and well-established industry. This Miocene rapid cooling, as indicated by the deformation con- flagstone industry has been studied and described by Tripp ditions recorded in microstructures (Wells and others, 2000), (1994). The quality of flagstone in the region is primarily a and confirms a Miocene age. Rapid cooling during the function of mica content in quartzite and magnitude of defor- Miocene probably resulted from footwall uplift related to mation related to Tertiary extensional shear zones. Principal- both displacement along the Raft River detachment fault and ly, mylonitic quartzite is quarried; the mylonitic foliation, extension of the upper plate. along which mica is commonly concentrated, acts as prom- inent folia along which the quartzite is split. The quartzite of Clarks Basin, quartzite of Yost, and Elba Quartzite are the ECONOMIC GEOLOGY principal rock units in the region that are currently quarried, and these units have the greatest potential for economic flag- Metals stone. Within the Kelton Pass 7.5' quadrangle, the quartzite of No mining prospects were observed within the Kelton Yost is not present, and the quartzite of Clarks Basin is not Pass 7.5' quadrangle. However, in the nearby Black Pine well-enough foliated and generally too jointed and fractured Mountains, five separate “Carlin type” gold ore bodies have to be of economic interest for flagstone. The low quality of been identified and produced gold (Brady, 1984; Willden and the quartzite of Clarks Basin as flagstone (in the quadrangle) Adair, 1984; Hefner and others, 1991). Gold deposits in the is due in part to its position in the upper plate of the Raft Black Pine mining district are generally hosted within the River detachment fault and resultant brittle deformation Oquirrh Formation. These rocks are of similar metamorphic (indicated by common closely spaced joints and fractures). grade, and are probably in an equivalent structural position to Additionally, the quartzite of Clarks Basin in the quadrangle the Oquirrh Formation in the middle allochthon in the eastern has not experienced Tertiary (foliation-producing) myloniti- Raft River Mountains (Wells and others, 1990; Wells and zation, in contrast to quarried localities in the Grouse Creek Allmendinger, 1990). Two detachment faults may localize and western Raft River Mountains described by Tripp mineralization in the Raft River Mountains: the Raft River (1994). There, the quartzite of Clarks Basin crops out within detachment and the middle detachment. The carbonate rocks an Eocene-Oligocene top-to-the-west shear zone (Wells and above the Raft River detachment, including Ordovician and others, 1997, 2000a). The Elba Quartzite has potential for Permian-Pennsylvanian rocks, may be hosts for detachment- flagstone, but its quality is not as high, due to jointing and related mineralization, such as the well-documented exam- fracturing, as in areas to the west along the south flank of the ples in the lower Colorado River extensional corridor (for range that are currently quarried. example, Spencer and Welty, 1982). Locally, extensive iron- oxide and pyrite mineralization is related to both high-angle faults above the Raft River detachment and the Raft River Broken or Crushed Stone detachment fault. About 1.6 miles (2.5 km) west of the Highly fractured rocks of the Eureka Quartzite have quadrangle, in the Clear Creek mining district (principally 1 been mined at the head of Emigrant Spring Canyon (NE ⁄4 section 12, T. 14 N., R. 13 W.), several adits and numerous 1 NE ⁄4 section 23, T. 13 N., R. 12 W.) for fire insolation mat- surface pits indicate mining activity for copper, silver, and erial or possibly for road or railroad gravel. No other locali- lead (Doelling, 1980). ties with easy access to fractured quartzite are present. Sand and Gravel Water Resources Deposits of well-sorted gravel and subordinate sand are The principal uses for groundwater in the quadrangle are found in lacustrine beach and barrier bar deposits along the for livestock and limited agricultural use. Given that the eastern edge of the quadrangle. The principal accumulations ranching industry in the area is relatively well established, of gravel are mapped as lacustrine gravel (Qlg), but many and no commercial or residential development is currently other small shoreline gravel deposits exist. Some gravel ac- taking place, no significantly large demands on groundwater cumulations close to State Highway 42 were previously are foreseeable in the near future. Published reports on the inventoried by the Utah State Department of Highways, in- 1 1 water resources of this region include Baker (1974) and cluding accumulations at locations SE ⁄4SE ⁄4 section 1, T. 14 1 1 Batty and others (1993). N., R. 12 W. (Qlg); SW ⁄4NW ⁄4 section 6, T. 14 N., R. 11 W. 1 1 1 1 Two distinct groundwater flow systems are present with- (Qlg); and NE ⁄4SE ⁄4 section 6 and NE ⁄4SW ⁄4 section 5, T. 14 in the quadrangle. The first is within Cenozoic deposits in the N., R. 11 W. (Qla) (Utah Department of Highways, 1965). Raft River Valley; the second lies in westernmost Curlew Deposits of sand are also found along the eastern edge of the Valley and was referred to as the Kelton flow system by quadrangle. Lacustrine sand is present as sand sheets (Qls) Baker (1974). The two flow systems are separated by a and also beneath gravel barrier beaches, and fine sand and silt occurs in relatively thin eolian deposits (Qe). bedrock ridge of nearly continuous outcrops of Oquirrh For- mation that connects the southern Black Pine Mountains to the northeastern Raft River Mountains. Building Stone (Flagstone) The eastern boundary of the Kelton flow system, as indi- cated by gravity studies (Baker, 1974), is a ridge of locally Ornamental flagstone is quarried at many localities with- exposed Oquirrh Formation and volcanic rocks associated in the Raft River, Grouse Creek, and Albion Mountains, and with the Wildcat Hills (approximately 5 miles [8 km] east of Geologic map of the Kelton Pass quadrangle, Box Elder County, Utah, and Cassia County, Idaho 19 the quadrangle) that more typically is shallowly buried by Flooding Cenozoic deposits. This bedrock ridge probably marks the trace of a high-angle fault with east-side-up displacement. Flooding is a potential hazard within the narrow canyons Water that enters the Curlew Valley from the eastern Raft that cut into the Raft River Mountains, and flooding, debris River and southern Black Pine Mountains probably flows to flows, and seasonal high-energy deposition may occur on the south, between the Raft River Mountains and the bedrock active alluvial fans near the flanks of the mountain range. ridge to the east (Baker, 1974). The Cenozoic deposits in the These hazards are mostly restricted to areas underlain by Kelton Pass 7.5' quadrangle, as estimated from gravity stud- map units Qal and Qaf1. ies, are as much as 2000 feet (600 m) thick in the southeast- ern part of the quadrangle, but are greater than 3000 feet (900 Gullying m) thick east of the quadrangle (Baker, 1974). No test wells have been reported in the quadrangle, Gullying has occurred in many areas underlain by Terti- although two sites nearby do have groundwater monitoring ary tuffaceous deposits (part of Ts) and finer grained Quater- wells (Baker, 1973; Batty and others, 1993). Monitoring of nary lacustrine deposits. Gullying is especially pronounced wells near Kelton (9 miles [14.4 km] south of the southeast within washes crossing the Cedar Creek Road. corner of the quadrangle) shows a slow decline in water table depths between 1935 and 1982 (about 7 feet [2.1 m] of with- drawal), a rapid increase of about 4 feet (1.2 m) between Landsliding 1982 and 1985, and a steady rapid decline of 6 to 7 feet (1.8- 2.1 m) between 1985 and 1993. A well about 2 miles (3.2 Landsliding is a potential hazard along the canyons that km) southeast of the southeast corner of the quadrangle, for dissect the Precambrian basement, and along the steeper dip- which data is limited, recorded up to 2 feet (0.6 m) of slopes to the range-scale anticline defined by Precambrian groundwater-depth increase from 1963 to 1993 (Batty and lithologies. The canyons are typically steep-walled within others, 1993). Archean rocks due to the high resistance to erosion of the overlying Elba Quartzite. Landslides are mapped on plate 1 as Qms. GEOLOGIC HAZARDS ACKNOWLEDGMENTS Earthquakes K. Tilman, K.M. Merchant, and T.T. Cladouhous provid- Surficial geologic mapping shows no Quaternary fault ed invaluable field assistance. R.W. Allmendinger and D.M. scarps in the Kelton Pass 7.5' quadrangle. The only mapped Miller provided continuing interest and support throughout Quaternary faults in northwesternmost Utah are: (1) a single 1-mile (1.6-km) long fault mapped by Compton (1975) about this project. This work was principally supported by Nation- 3 miles (5 km) to the west of the northwest corner of the al Science Foundation Grant EAR-8720952 to R.W. All- quadrangle, interpreted by Hecker (1993) as cutting middle mendinger and M.L. Wells, and a National Research Council to late Pleistocene deposits; and (2) a N-S trending belt of Postdoctoral Fellowship at the Branch of Western Regional inferred faults along the eastern margin of the Grouse Creek Geology, U.S. Geological Survey (USGS). Additional sup- Mountains, interpreted by Hecker (1993) to be of middle to port was provided by the Utah Geological Survey (UGS). late Pleistocene age. No range-bounding faults have been Much of this map area is private land; I thank the local ranch- identified along the northern, southern, and eastern margins ers and landowners for granting access and for their hospital- of the Raft River Mountains, and the range morphology ity, especially R. Bronson, J. Flinders, L. Kempton and fam- probably results from doming rather than block-faulting typ- ily, R. Morris, D. Dorius, and Ten Mile ranch foreman W. ical of other ranges in the Basin and Range Province. How- Pugsley. J.E. Repetski (USGS) is gratefully acknowledged ever, this part of northwestern Utah lies near the Intermoun- for conodont identification and color-alteration indexing. tain seismic belt, a north-south zone of historic earthquake R.D. Dallmeyer (University of Georgia) provided the activity that bisects Utah (Smith and Arabasz, 1991). Historic 40Ar/39Ar geochronological analyses from Ordovician rocks, earthquakes such as that in Hansel Valley in 1934 show that L.W. Snee is thanked for access to the USGS 40Ar/39Ar facil- a significant seismic potential exists in the region (Smith and ity in Denver, Colorado, and for interpretive assistance, and Arabasz, 1991). Possible earthquake hazards include surface A.E. Blythe (University of Southern California) performed fault rupture, ground shaking (causing rockfalls and slope the fission-track analyses. Constructive reviews by D.M. failures within steep-walled canyons), and liquefaction with- Miller and R. Tosdal (USGS), and B. Black, R. Biek, J.K. in the unconsolidated basinal sediments where shallow King, D. Sprinkel, and G. 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Miller, D.M., 1983, Allochthonous quartzite sequence in the Smith, J.F., 1983, Paleozoic rocks in the Black Pine Mountains, Albion Mountains, Idaho, and proposed Proterozoic Z and Cassia County, Idaho: U.S. Geological Survey Bulletin Cambrian correlatives in the Pilot Range, Utah and Nevada, 1536, 36 p. in Miller, D.M., Todd, V.R., and Howard, K.A., editors, Smith, L.H., Kaufman, A.J., Knoll, A.H., and Link, P.K., 1994, Tectonic and stratigraphic studies in the eastern Great Chemostratigraphy of predominantly siliciclastic Neopro- Basin: Geological Society of America Memoir 157, p. 191- terozoic successions—A case study of the Pocatello Forma- 213. tion and Lower Brigham Group, Idaho, USA: Geological Miller, D.M., 1985, Geologic map of the Lucin quadrangle, Box Magazine, v. 131, p. 301-314. Elder County, Utah: Utah Geological Survey Map 78, 10 p., Smith, R.B., and Arabasz, W.J., 1991, Seismicity of the Inter- 2 plates, scale 1:24,000. mountain seismic belt, in Slemmons, D.B., Engdahl, R.R., Miller, D.M., Armstrong, R.L., Compton, R.R., and Todd, V.R., Zoback, M.D., and Blackwell, D.D., editors, Neotectonics 1983, Geology of the Albion-Raft River-Grouse Creek of North America: Geological Society of America, DNAG Mountains area, northwestern Utah and southern Idaho: map volume 1, p. 185-228. Utah Geological and Mineral Survey Special Studies 59, p. Snoke, A.W., and Miller, D.M., 1988, Metamorphic and tectonic 1-59. history of the northeastern Great Basin, in Ernst, W.G., edi- Miller, D.M., Hillhouse, W.C., Zartman, R.E., and Lanphere, tor, Metamorphism and crustal evolution of the western M.A., 1987, Geochronology of intrusive and metamorphic United States, Rubey Volume VII: Englewood Cliffs, New rocks in the Pilot Range, Utah and Nevada, and comparison Jersey, Prentice Hall, p. 606-648. with regional patterns: Geological Society of America Bul- Spear, F.S, and Cheney, J.T., 1989, A petrogenetic grid for letin, v. 99, p. 880-885. pelitic schists in the system SiO2-Al2O3-FeO-MgO-K2O- Miller, D.M., and Hoisch, T.D., 1992, Mesozoic structure, meta- H2O: Contributions to Mineralogy and Petrology, v. 101, p. morphism, and magmatism in the Pilot Range and the 149-164. Toano Range, in Wilson, J.R., editor, Field guide to geolog- Spencer, J.E., and Welty, J.W., 1982, Geology of mineral ic excursions in Utah and adjacent areas of Nevada, Idaho, deposits in the Buckskin and Rawhide Mountains, in Geol- 22 Utah Geological Survey ogy and mineral resources of the Buckskin and Rawhide Wells, M.L., 1997, Alternating contraction and extension in the Mountains, west-central Arizona: Arizona Geological Sur- hinterlands of orogenic belts—An example from the Raft vey Bulletin 198, p. 223-254. River Mountains, Utah: Geological Society of America Sullivan, W.A., 2008, Significance of transport-parallel strain Bulletin, v. 109, p. 107-126. variations in part of the Raft River shear zone, Raft River Wells, M.L., 2001, Rheological control on the initial geometry Mountains, Utah, USA: Journal of Structural Geology, v. of the Raft River detachment fault and shear zone, Basin 30, p. 138-158. and Range, western United States: Tectonics, v. 20, p. 435- Todd, V.R., 1980, Structure and petrology of a Tertiary gneiss 457. complex in northwestern Utah, in Crittenden, M.D., Jr., Wells, M.L., and Allmendinger, R.W., 1990, An early history of Coney, P.J., and Davis, G.H., editors, Cordilleran metamor- pure shear in the upper plate of the Raft River metamorphic phic core complexes: Geological Society of America Mem- core complex, Black Pine Mountains, southern Idaho: Jour- oir 153, p. 349-383. nal of Structural Geology, v. 12, p. 851-868. Todd, V.R., 1983, Late Miocene displacement of pre-Tertiary Wells, M.L., Dallmeyer, R.D., and Allmendinger, R.W., 1990, and Tertiary rocks in the Matlin Mountains, northwestern Late Cretaceous extension in the hinterland of the Sevier Utah, in Miller, D.M., Todd, V.R., and Howard, K.A., edi- thrust belt, northwestern Utah and southern Idaho: Geolo- tors, Tectonic and stratigraphic studies in the eastern Great gy, v. 18, p. 929-933. Basin: Geological Society of America Memoir 157, p. 239- Wells, M.L., Hoisch, T.D., Hanson, L., Struthers, J. and Wolff, 270. E., 1997, Large magnitude thickening and repeated exten- Tripp, B.T., 1994, The quartzite building stone industry of the sional exhumation in the Raft River, Grouse Creek, and Raft River and Grouse Creek Mountains, Box Elder Coun- Albion Mountains: Brigham Young University Geology ty, Utah: Utah Geological Survey Special Study 84, 19 p. Studies, v. 42, p. 325-340. Utah Department of Highways, 1965, Materials Inventory - Box Wells, M.L., Hoisch, T.D., Peters, M.P., Miller, D.M., Wolff, Elder County: Utah State Department of Highways, 17 p., E.W., and Hanson, L.W., 1998, The Mahogany Peaks fault, 7 plates, scale ~1:200,000. a Late Cretaceous-Paleocene(?) normal fault in the hinter- Veizer, J., and Hoefs, J., 1976, The nature of 18O/16O and land of the Sevier orogen: Journal of Geology, v. 106, p. 13C/12C secular trends in sedimentary carbonate rocks: 623-634. Geochimica et Cosmochimica Acta, v. 40, p. 1387-1395. Wells, M.L., Snee, L.W., and Blythe, A.E., 2000, Dating of Veizer, J., Clayton, R.N., and Hinton, R.W., 1992a, Geochem- major normal fault systems using thermochronology—An istry of Precambrian carbonates - IV, Early Paleoprotero- example from the Raft River detachment, Basin and Range, zoic (2.25 ± 0.25 Ga) seawater: Geochimica et Cosmo- western United States: Journal of Geophysical Research, v. chimica Acta, v. 56, p. 875-885. 105, p. 16,303-16,327. Wells, M.L., Spell, T.L., Hoisch, T.D., Zanetti, K.A., 2008, Veizer, J., Holser, W.T., and Wilgus, C.K., 1980, Correlation of 40 39 13C/12C and 34S/32S secular variation: Geochimica et Cos- Laserprobe Ar/ Ar dating of strain fringes—Mid- mochimica Acta, v. 44, p. 579-587. Cretaceous orogen-parallel extension in the interior of the Sevier orogen: Tectonics, v. 27, TC3012, doi:10.1029 Veizer, J., Plumb, K.A., Clayton, R.N., Hinton, R.W., and /2007TC002153. Grotzinger, J.P., 1992b, Geochemistry of Precambrian car- 13 bonates - V, Late Paleoproterozoic seawater: Geochimica et Wickham, S.M., and Peters, M.T., 1993, High δ C Neoprotero- Cosmochimica Acta, v. 56, p. 2487-2501. zoic carbonate rocks in western North America: Geology, v. 21, p. 165-168. Wells, M.L., 1991, Kinematics and timing of Mesozoic and Cenozoic deformations in the Raft River and Black Pine Willden, R., and Adair, D.H., 1984, The Tallman disseminated Mountains, northwestern Utah and southern Idaho: Ithaca, gold deposit, Cassia Country, Idaho: Utah Geological Asso- New York, Cornell University, Ph.D dissertation, 287 p., ciation Publication 13, p. 215-26. scale 1:12,000. Wolff, E.D., 1997, Geothermometry and thermal evolution of Wells, M.L., 1992, Kinematics and timing of sequential defor- the Raft River Mountains, Utah: Flagstaff, Northern Ari- mations in the eastern Raft River Mountains, in Wilson, zona University, M.S. thesis, 156 p. J.R., editor, Field guide to geologic excursions in Utah and Zaun, P.E., and Wagner, G.A., 1985, Fission track stability in adjacent areas of Nevada, Idaho, and Wyoming: Utah Geo- zircons under geological conditions: Nuclear Tracks, v. 10, logical Survey Miscellaneous Publication 92-3, p. 59-78. p. 303-307. UTAH GEOLOGICAL SURVEY Plate 1 a division of Utah Geological Survey Miscellaneous Publication 09-3 Utah Department of Natural Resources Geologic Map of the Kelton Pass Quadrangle Qal Ts P*o Ts Qal Qal Qal 34 Ts P*o Ts 25 Qal Ts Qaf2(P*) 24 Qal Qaf2(P*) Qaf2(=) 29 Qaf2(=) B B P*o Qal B Qal Qal B Ts QTaf P*o B P*o Qal 25 26 QTaf Qlg 36 B P*o Qla 47 Qlg QTaf 45 Qaf2(=) B QllQll Qlg Qll 60 P*o Qal Ts Ts 35 Ts B Qlg P*o Qal Ts 47 P*o Qal Ts P*o P*o Qal P*o P*o Qaf2(=) Qlg B P*o Ts 59 Qal Qla Ts Qal Qal Qal 65 Area of detailed bedrock mapping B Qla Ts 25 2(=) Qaf Qaf3 P*o Qal Qaf2(=) Ts 50 P*o 55 Ts Qal Qaf2(=) B Qaf2(=) Qal Qal Ts ! B ! ! ! ! ! ! Qal Qal ! ! ! ! ! ! Qaf3 ! ! ! Qls ! Qal ? ! ! ! ! Qlg ! ! ! ! ! Ts ! ! P*o SOd ! ! ! ! ! ! ! ! ! ! ! ! Ock ! ! ! A ! ! ! ! Ts ! 42 Ts ! ! ! ! B ! ! ! ! ! ! ! ! *Mcd ! ! ! ! ! ! ! Oe ! ! 40 ! ! ! 2 ! 43 (=) ! ! Qaf ! ! ! ! ! ! % ! ! ! ! ! ! ! ! ! ! ! ! ! % % % % ! P*o ? ! ! % ! ! % ! ! 45 ! ! ! % ! ! % ! ! ! ! % % ! ! % ! ! % ! 70 ! ! ! ! ! ! ! % ! ! Qal ! ! ! ! P*o ! ! ! ! ! 45 ! ! ! % ! ! ! ! ! ! 2 50 % ! ! (=) Qaf ! ! 3 ! Ts ! Qaf ! % ! ? ! Ock ! ! ! ! ! 60 ! ! ! Qms ! % Ogc ! ! ! % Qc ! ! ! ! ! % 3 ! Qaf ! % ! ! ! ! % ! P*o ! ! % % ! 55 ! ! 60 Qaf1 ! ! ! ! ! ! ! % ! ! % ! ! 55 ! ! *Mcd P*o 50 3 % Ock % Qaf ! 60 ! ! ! % ! % ! % ! ! % ! % ! % ! Ock ! P*o % ! % ! ! % ! ! % % ! ! % ! % 15 ! P*o P*o % ! ! ! 25 40 B ! ! Qls ! $ ! ! % % 12 % Oe % ! SOd % $ ! % % ! % % % ! % % ! % % SOd ! %Ock % $ % ! % ! % % Ock $ ! $ 3 ! ! Ogc % ! $ ! % Qc Qls ! % % 50 ! 10 % $ $ ! ! ! Ts ! ! % ! ! ! 70 % $ ! ! 3 ! $ % Qaf 50 ! ! $ ! ! ! ! Qla ! 60 % % ! ! % % % % $ Ç ! ! ! SOd Ç % ! $ %Ç % $ % ! Ogc 45 % %% ! $ ! ! $ ! 55 *ot$ % ! % % % ! $ ! % $ % % 80 % ! Qal $ Oe % Oe ! % % $ % SOd ! Qc ! % Ock % $ % ! % SOd $ % % ? % % P*o % % % ! % % $ 1 Qal % Qaf ! Qla % *ot 30 % % % 30 Ogc % Oe ! 10 % $ % % ! 40 $ 26 Qlg $ ! % $ $ Ts $ ! % 30 30% 20 ! Oe 10 $ % Qc ! SOd 40 20 % ! 2(=) % % Qaf $ 70 $ % 80 % % ! ! Ock % % $ 20 ! % $ ! % $ Ami Qc % Ami Oe % Ogc % 10 P*o $ ! % P*o 35 30 % 25% ! % 15 4 % ! ! % $ ! $ % ! % % $ % ! ! Qc 50 $ % Ock $ 10 ! ! ! SOd $ $ % % % $ % ! $ % % ! % ! $ % ! Ogc 47 % Ogc$ $ % ! 45 ! 15 SOd $ $ % ! % ! $ $ 15 ! % $ $ % $ 35 ! % ! % 15 % % % $ *ot % ! Qms $ ! % % Aos ! % Oe % % % ! ! $ 40$ $ $ % $ $ 8 ! $ *ot ! % % $ Ami % ! $ % % % Oe ! ! ! % $ $ 22 ! $ SOd $ % ! $! $ $ 22 ! ! 15 % ! $ % Qc 30 % 2 ! $ *ot 65 25 % ! $ $ % ! *ot $ $ B ! $ Ogc % % % ! $ SOd $ % $ % % $ $ ! 55 $ $ Ock $ $ 15 ! % $ % 40 *ot $ 20 Ock $ $ Ami ! % $ % $ ! % $ 40 % $ % $ Oe% 20 $ $ ! $ $ Oe Oe Aos % % $ % Oe % 10 % $ $ % Qc 25 % %%$ SOd $ $ 55 % % $ 0 SOd % % % % 75 % $ % % % % 25 $ % % Ogc % % % % 15 12 % 40 30 % % $ $ $ % P*o % $ % % $ % ! Oe % 35 % Ogc SOd % ! 55 $ % 10 $ ! $ 10 % % % % ! Ogc % 6 $ $ % Aos ! % % 50 25 Ogc % % 10 % % ! % % 50 % $ Oe 5 $ ! ! ! ! ! ! ! 55 Ock ! % ! ! ! *ot % ! % SOd ! ! ! $ % ! P*o % % ! 12 Ogc% $ % ! % SOd ! % ! % % $ % Ogc % ! Ock ! Ami Ock % % 40 Qc ! Qal ! 25 $ % % Ami % ! % % % % Ock % % $ ! $ 25 % % % ! % 60 % Ogc $ % Qal % $ 35 % % Qal Ock % P*o % % % % % % % % % $ ! % % % 36 % % % % ! % % $ 28 15 ! % $ % % % Qc 50 Qc % Oe $ ! % 4 11 % % Ogc % % Ogc % % 10 Qc Ogc % % Qc % % 50 15 $ 15 $ % % % Ogc 25 $ Ock % % % $ % 30 % % % % % % % 1 % 4 $ Ogc % Qaf % $ *ot Osd 50 Ock Ock % $ % 30 ! $ % % % $ % % % $ 10 15 % Qc % % ! $ % % % % % % Oe % Oe Ami Qc ! % $ % SOd % % % 28 % ! % % % % SOd $ $ % $ % Ock % % ! % % Ock $ 36 ! 20 % ! ! % % Oe % ! $ % % Ock Ogc % % $ % ! ! % ! % % ! 25 ! ! % % $ $ $ ! % 50 $ ! % Ock $ ! ! $ % Aos $ % ! 14 *Mcd Ogc 40 % % ! Oe 24 $ % ! % ! $ ! % ! % ! Ogc *ot ! $ % ! % % ! Ç % Ock ! $ $ % % ! $ $ % $ ! $ % 30% Ç ! 10 40 ! $ $ % Ç 15 % ! $ Qal ! % % % 32 Aos ! Qms $ Qc % SOd ! % % % ! 20 % % % % $ Ock % ! % $ $ ! $ Oe 40 % ! % $ $ P*o SOd 3 $ % % % % *ot 10 Qaf % 30 % ! Ami % % % 40 % %Oe % *ot ! % % 40 $ $ % $ % Oe % $ $ $ % $ % % ! 30 % $ $ % % ! P*o % % % % $ ! % ! ! ! % ! ! ! 20 Ogc 35 35 ! ! ! ! % % $ $ % % ! % Ock % % ! $ $ % B $ ! $ $ 15 % 40 % ! $ % SOd $ % % ! Ogc ! 20 % % % % ! % $ % $ ! ! % % % % % % $ ! $ ! % % ! % % % Ogc Oe 12 Qms % % % % ! Ock % Qc % Qc % % % ! $ ! 40 $ % $ 20 % % % % ! % ! % ! % $ $ % % ! SOd 20% 17 ! % 15 53 $ ! Ogc $ 20 % $ ! % % % % Ock % % % $ $ Ock % % $ ! % ! ! $ $ % % % % % % Qc % Ock % % % % % % ! 52 Ock Qc ! ! $ % % % % ! % % $ % ! % $ 40 ! $ % $ $ % % % 55 % % ! % %Oe SOd % 72 % ! $ % *ot % ! % 25 $ 4 % % % % % Oe 60 % $ ! % % % $ Oe 60 % Ogc ! $ $ SOd $ % % $ 35 % *ot % % % ! Ogc $ 20 $ % % % $ % $ $ ! $ % % % 50 50 $ $ ! $ 25 $ Ock 15 45 % % Oe ! % $ $ $ % $ $ % % 46 % % $ 35 % 25 Oe% % 45 *ot % % % Ogc % 13 6 % $ % 28 Qms $ 15$ 13 $ $ 40 $ Ogc $ % % $ *Mcd $ % Ami $ % $ % 35 $ % % 25 ! % Ogc ! ! % % $ $ % % ! $ 30 ! ! ! ! % % ! ! $ % ! ! % ! ! $ ! ! 35 ! 28 ! ! $ % % SOd ! Ami ! Qc % ! 50 $ % ! % *ot % ! % $ % ! ! % % $ ! ! Oe ! 25 50 SOd % 69% % *ot 40 $ ! $ % ! *ot $ ! ! % 45 % % ! 18 $ ! 30 $ % % ! $ % ! $ ! Ogc $ $ ! $ 10 $ ! $ $ ! $ ! % ! Ock ! ! $ ! ! % ! % ! ! ! ! ! ! Ock ! ! 20 $ % 23 *Mcd $ Qc ! ! $ % % Ock $ ! ! ! ! ! ! Qms % ! $ % Ogc ! $ 16 ! ! ! ! % SOd ! ! ! ! ! 32 ! ! % % ! ! 45 ! $ $ 20 $ % % ! ! $ % 40 ! *ot % ! % ! ! ! 15 ! ! ! 10 25 % ! Qc ! 20 ! % % 15 50 ! ! ! Qc % Ock $ Oe % 27 ! % % $ $ ! % ! % ! % 4 ! % ! ! 21 8 ! 15 SOd % ! ! P*o 55 ! Oe $ ! % 6 ! % Qlg $ $ ! ! ! Ogc % ! % % 20 ! 50 ! Ock 22 % 24 ! % % 35 $ ! % % $ ! ! 35 % % Ogc ! 3 % Qaf ! Ock ! $ $ % % 65 $ ! % Qc 40 % % SOd% ! $ % % % % % ! $ $ % Ts Oe % ! % ! ! $ Oe % $ % ! 60 $ % $ % % ! $ $ ! % *ot % 30 % P*o $ % $ % ! ! 6 40 % 35 15 % Ami 6 ! % Oe 36 % ! 40 45 % % % $ 20 $ 28 ! $ Oe % $ % % % Ock 20 ! $ % $ 40 ! % % % ! % % 35 $ Ç ! ! $ Ç % % % Ç ! SOd % % ! % ! % $ ! Ock Ç $ % % ! Ç % Ogc ! $ % % ! $ ! % Ç $ ! SOd Aos $ Ç 20 ! % $ % ! Ç % % % ! ! % Ç 20 % 25 ! 12 % % 35 ! $ ! Aos *ot %Ç $ % % 37 ! % % 40 Ç % % Oe % ! 70 Ogc % Ock 50 ! Ç ! 3 ! ! %Ç % Qaf ! Qal ! % ! $ % $ ! 25 % ! % % Ç % $ Ogc % % ! ! P*o % % 30 % ! ! % % ! 40 % SOd ! % 25 % ! ! ! % % % Ami ! % P*o ! $ % ! ! ! ! ! ! 3 ! ! ! ! ! ! ! ! Oe $ 35 ! Qaf ! ! ! ! % ! % % ! Qc ! ! % Qc % ! 3 % ! ! % % % % % Qaf % % ! ! ! % ! % % $ ! $ Ock Oe ! ! ! % ! 30 Ç % % Ç % Ami % ! ! ! % % $ % ! ! $ Qal 3 % $ % % ! ! Qaf ! % % % ! ! ! ! ! ! ! ! ! ! % ! 60 ! ! Ts $ 20 ! $ ! % Ç % ! ! % % $ % ! Ogc % ! ! % 30 $ % ! Ock *ot SOd % 20 % ! ! ! Qal % % 33 ! Oe ! % % $ Ç Qaf ! % % ! % % ! % ! % $ ! ! ! ! 30 % % % % $ SOd $ ! ! SOd % Qal 25 % ! Ts % 55 ! $ *ot $ % 50 ! % ! 30 % ! $ % % ! % % ! Oe 36 % Ts 33 $ ! Oe ! P*o % $ % $ ! ! % $ $ % % P*o 25 ! ! % $ % % % ! % SOd ! % $ ! % % % 55 ! A' % % ! 25 % $ ! % Ts % ! % ! 20 % % ! 20 ! 70 % % 10 % % 25 % ! P*o % % *ot % 50 ! % 40 % Ts % 35 $ ! Oe % % Qaf3 SOd % % Oe % 45 % ! % 38 ! % % Ts % % *ot $ ! % % % Ogc Ts ! % % % % 42 30 % % % % % % $ % % % $ % % 50 % Ogc % % 35 $ % %29 Ts % Ç % 45 % % 25 % 45 19 % 30 % Ç % ! % 30 % Ç Oe Ç ! Qal $ ! Ç 20 SOd Ç % Qls 45 % ! % $ 15 % % $ P*o Ç % % Ç % % % ! % 35 Ç Ç ! $ $ % % Ock % ! Ç $ ! 60 ! 15 % % ! ! Ç ! % % % Ogc ! ! Ç % ! $ 20 $ Ç Oe ! ! Qla ! Aos Ç Qal ! % % ! 12 ! B' % % Qal SOd Ç $ 50 8 ! ! % ! % ! $ Ç % 3 $ ! Ts ! ! Qaf 30 P*o % Ç 3 B % 58 ! ! ! Qaf % Ç $ 30 35 % 35 ! 45 Ock % ! ! % % Ç ! $ % ! ! % % % ! $ % % 50 % ! % ! ! % $ % ! $ ! 50 ! B ! % ! $ % % 35 % Ock % % ! % $ % % % 25 ! % $ Ogc $ 20 ! P*o Qal Ts 42 % ! % % Aad % $ % ! % Ogc % $ 85 Oe Qal ! 75 % Qal % $ Ock ! $ % % Oe % Ogc % % ! % % 45 % Qc % ! $ ! $ Ts ! ! Oe % $ ! % ! % ! $ 7 ! % % % % ! % B ! Qc % ! % $ % ! % Qc ! $ $ ! ! % 40 % $ SOd ! % % ! $ 50 ! ! % % ! ! ! % ! ! % 15 $ % $ Ts ! Oe ! $ $ ! 45 ! % 3 ! % ! 20 Qc % Oe ! $ Ock Qaf % % ! $ ! 7 4 $ % % $ ! ! ! % ! $ $ % ! 8 % ! 3 50 % ! Qaf 1 ! ! 28 % % % ! 8 ! $ Ogc SOd % ! *ot % Ogc ! ! ! Ock $ % $ % % $ ! ! 60 Ogc % 35 $ 35 % $ B ! ! $ ! ! *ot % % $ ! % 30 Ogc ! 35 % % % ! $ ! Ock SOd % ! % ! % % $ ! % $ Ts $ % % % ! ! $ Ogc $ Ts % $ % % SOd $ $ $ $ % ! % $ $ $ ! ! *ot 35 30 % ! Ts % Oe ! Ock Ock % ! % % % % 30 ! 75 % % % % % ! % P*o P*o % ! % % % Ts 45 *Ola % ! % Ç Ç % Ock ! 45 % % % % Ç % Qal ! % ! % Ç ! % ! % % 30 ! 30 ! ! Qal Ç ! % Oe ? 30 ! % % % ! % ! Ç ! ! 30 10 % ! ! ! % % ! ! % % ! 30 ! Qal ! ! ! ! 8 % % % 47 ! 32 *ot ! 10 ! 45 ! 30 35 ! ! % Qc ! % 30 ! 20 $ % *ot ! ! ! Ock % $ Ts % 60 Ts ! Ock ! $ ! Ogc ! 25 ! 10 % ! ! % ! ! ! % $ ! Ts % ! % ! ! 6 15 % ! 45 2 ! $ % ! ! 75 ! ! ! ! Ogc ! P*o ! ! 50 ! ! Qal ! 20 Ami 10 % ! % ! 45 Ock ! Qe Oe ! Aos % ! % ! % 45 ! 15 B ! 55 Ock ! ! Qms ! % ! Qal ! ! % 45 8 ! 3 ! Qc Qaf ! ! ! Qal 18 ! ! Aos Qc ! ! Ogc P*o ! ! ! 35 Ts ! ! ! ! ! ! ! 3 ! Qla ! ! ! 31 ! Qc Ogc ! 20 ! ! ! ! Ami 5 12 20 ! ! ! ! ! ! ! 15 25 20 ! Ts 13 25 ! ! ! ! ! Ami % Ogc ! $ 9 4 ! ! IPot ! 7 Aos ! ! ! ! % $ 15 ! 7 Qc ! ! SOd 15 % ! 25 ! Aos $ ! ! ! ! Aos ! % Ts ! ^ $ ^ ^ ! ^ 36 13 27 ! ! % Qaf3 ! 80 10 Ami ! ! % ! Ts ! 30% 15 ! Ami ! B'' ! Aos ! ! ! Qc ! ! 15 ! ! ! Qal ! ! ! ! Qal Ami ! ! ! 3 15 10 ! ! 35 ! ! *Ola ! 30 10 ! ! 15 ! ! ! 10 34 ! ! ! Ami ! ! *Ola Ts 28 ? Qc *Ola ! ! ! ! Aos ! ! ! ! ! 7 ! ! 10 7 ! Qla ! ! P*o Qaf3 ! 24 ! Qc Aos Ts ! Ami Area of detailed bedrock mapping ! ! ! 28 ! ! 15 ! 8 ! ! Ts ! ! ! P 15 ! ! ! ! ! ! ! 35 B Qlg ! ! ! ! ! ! 0 ! 35 ! ! ! ! Qc! ! ! 12 ! P*o % Qla % Ts ! ! ! Qal Ts ! ! % Ock ! ! 3 ! ! Ts 26 % % 12 % 6 % Ts % Qc % 25 % % % ! % Aos ! 27 % % Ock % % % ! ! % 20 % ! % Qc % Aos ! % % ! % 1 % % % ! Qc 31 % Oe Qaf ! Ami % Ts ! % % % ! % % % ! % ! Ts % % Qal ! Osd Qe ! ! 30 30 % ! ! % ! % SOd % Ts ! Aos ! % ! ! ! 39 ! % ! Ogc ! % Ogc % 35 P ! ! Oe % ! 40 ! % 40 % ! % % ! % Ock ! ! Ock % % % 22 ! 12 ! % Qal 25 % % ! 5 ! % ! Qc % % % B ! 30 ! % ! % % ! Ami ! % ! % ! ! ! ! % ! ! % % % ! % ! % $ ! ! ! ! ! ! ! ! % % ! % ! Ock $ % ! % ! ! % % 30 % ! ! ! Oe ! ! SOd ! 8 ! ! ! Ts ! ! ! 35 ! *Ola ! 2(=) P ! Qaf ! ! % ! 0 ! % ! ! 45 ! ! Oe ! ! Qe Qms ! 22 ! Ts ! 27 %Oe % ! Qaf3 ! 20 12 Qc ! 10 16 ! Ts ! % ! ! ! Ogc ! 15 ! ! ! ! ! 10 P*o ! Qal ! ! 15 ! Qaf3 12 2 13 30 3 ! Qaf ! ! Qaf3 Qaf2(=) Qc 28 The Miscellaneous Publication series provides non-UGS Base from USGS Kelton Pass 7.5’ Quadrangle (1990) authors with a high-quality format for documents concerning SCALE 1:24,000 Projection: UTM Zone 12 Utah geology. Although review comments have been 1 0.5 0 1 MILE Datum: NAD 1927 incorporated, this publication does not necessarily conform to Spheroid: Clarke 1886 UGS technical, editorial, or policy standards. The Utah 12° Department of Natural Resources, Utah Geological Survey, 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET Project Manager: Jon King makes no warranty, expressed or implied, regarding the GIS and Cartography: J. Buck Ehler, Darryl Greer suitability of this product for a particular use. The Utah and Angela Wadman Department of Natural Resources, Utah Geological Survey, 1 0.5 0 1 KILOMETER shall not be liable under any circumstances for any direct, Utah Geological Survey indirect, special, incidental, or consequential damages with 1594 West North Temple, Suite 3110 respect to claims by users of this product. CONTOUR INTERVAL 40 FEET TRUE NORTH P.O. Box 146100 UTAH MAGNETIC NORTH Salt Lake City, UT 84114-6100 For use at 1:24,000 scale only. The Utah Geological Survey (801) 537-3300 (UGS) does not guarantee accuracy or completeness of data. QUADRANGLE APPROXIMATE MEAN geology.utah.gov LOCATION GEOLOGIC MAP OF THE KELTON PASS QUADRANGLE, DECLINATION, 2008 1. Naf 1 2 3 2. Strevell BOX ELDER COUNTY, UTAH, AND CASSIA COUNTY, IDAHO 3. Black Pine Peak 4. Rosevere Point 4 5 by 5. Curlew Junction 6. Park Valley 6 7 8 7. Black Butte Michael L. Wells 8. Kelton Pass SE Department of Geoscience, University of Nevada, Las Vegas ADJOINING 7.5' QUADRANGLE NAMES 4505 S. Maryland Parkway, Las Vegas, NV 89154 -4010 2009 UTAH GEOLOGICAL SURVEY P*o Plate 2 a division of Qaf2(=) Utah Geological Survey Miscellaneous Publication 09-3 Qlg Utah Department of Natural Resources Geologic Map of the KeltonB Pass Quadrangle P*o 113°15'0"W 113°13'30"W Ts 113°12'0"W 113°10'30"W 59 Qal Qla Ts Qal Qal Qal 65 Area of detailed bedrock mapping B Ts 25 2(=) Qaf Qaf3 P*o Qal Qaf2(=) Ts 50 P*o 55 Ts Qal Qaf2(=) B Qaf2(=) Qal Qal Ts ! ! B ! ! ! ! ! ! ! ! ! ! ! ! ! ! Qal Qal ! ! ! ! ! ! ! ! 3 ! ! ! Qaf ! ! ! ! ! ! ! ! Qal ! ! ? ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! SOd ! ! ! ! P*o ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! Ock ! ! ! ! A ! ! ! ! ! ! ! ! ! Ts ! ! 42 ! ! ! Ts ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! *Mcd ! ! ! ! ! ! ! ! ! ! ! ! ! ! Oe ! ! ! ! 40 ! ! ! ! ! 2 ! ! (=) ! ! 43 ! Qaf ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! % ! ! ! ! ! ! ! ! ! ! ! ! % ! ! ! % ! ! ! ! ! ! ! ! % ! ! % % ! ? % ! P*o ! % % ! ! ! ! % ! ! % 45 ! % ! ! ! ! % ! ! ! ! ! ! ! ! % ! % ! 41°57'0"N ! ! ! 41°57'0"N ! % % ! % ! ! % ! ! % % ! ! % ! ! ! ! % ! % 70 ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! % ! ! ! Qal ! ! ! ! P*o ! ! ! ! ! ! ! ! ! ! Qal ! ! Ock ! ! P*o ! ! % ! ! P*o ! ! ! ! ! ! ! ! ! ! 45 % ! ! ! ! ! ! ! ! ! ! % ! ! ! ! ! ! ! % ! ! ! 2 50 ! (=) % ! ! Qaf ! ! 3 ! ! % ! Ts ! Qaf ! ! ! ! ! ! % ! ! ! ? ! Ock ! ! ! ! ! ! ! ! % 60 ! ! ! ! ! ! ! Qms ! Ogc ! ! % ! ! ! % ! ! ! Qc % ! ! ! ! % ! ! ! 3 ! % % ! % ! Qaf ! ! ! % ! ! ! ! % % ! ! ! % ! P*o ! % ! ! ! 55 ! ! ! 60 ! ! % % ! ! ! ! ! ! ! ! ! % ! ! ! % ! ! ! ! ! % % ! ! ! ! ! % ! 55 ! ! ! *Mcd P*o 50 3 ! % Ock ! 60 ! ! % Qaf ! % ! % ! ! ! % % % ! ! % ! % ! ! % ! % ! ! ! ! % ! ! % ! % ! ! Ock% ! ! P*o ! ! ! ! % ! ! % ! ! % ! % ! ! % ! ! % ! % ! ! % ! ! ! % % ! 15 ! % P*o ! P*o % ! % ! % ! 25 ! ! % 40 ! ! ! % % ! $ ! ! % ! % ! % ! % % 12 % ! ! Oe $ ! % % % % SOd $ ! ! % % % ! % ! % % % ! % $ ! ! % % % % $ ! % % % % Ock % SOd % ! % ! % ! % % ! $ ! % Ock % ! % % % % $ ! ! 3 ! $ $ ! % $ ! ! ! % $ % % ! % % ! ! $ Ogc $ !Qc ! % 50 ! 10 ! ! ! % ! ! ! % ! ! % $ Ts ! ! $ % $ ! ! % $ ! ! $ ! ! ! ! ! $ ! % 3 70 ! ! % ! ! 50 ! Qaf ! ! ! ! ! ! ! ! ! % ! ! $ % ! % % ! 60 $ % % % ! $ Ç ! % Ç Ç % % % % ! ! $ Ç% ! ! ! % SOd % % Ç ! $ % ! Ç % % % $ $ ! % $ % % ! % ! $ % % % $ 45 ! ! Ogc % ! ! ! $ % ! ! $ % ! $ % % 55 % ! % % % *ot ! % ! $ % $ ! $ ! % $ % ! $ % % % $ $ ! 80 % % % ! % ! Qal % % $ % Oe Oe $ ! % ! % % SOd ! $ Qc ! % % % % % ! $ $ Ock % % ! % % % SOd % ! % $ % ? % % % % % % ! % % $ % % P*o % ! % % % % $ % ! % % % Qal % ! % % *ot 30 $ % % $ ! % % 30 Ogc Oe % 10 % ! % % $ % $ % ! $ % 26 ! $ $ 40 % ! $ % ! % $ % $ % ! % $ $ ! $ 30 $ 30 % ! 20 % % % 10 % ! % ! Oe $ ! 40 20 $ Qc % ! 2 SOd ! $ Qaf (=) 70 % ! % % ! $ % 80 % % ! ! $ % % Ock % % 20 $ % ! % % ! $ $ ! $ $ ! % ! % Ami % Qc % % % % $ Oe Ami % % % P*o ! Ogc % 10 $ % % ! % % 25 $ ! P*o % $ 35 30 % % $ 15 !! ! ! ! 4 % ! % ! % $ % ! % % ! ! % % % % % ! $ % % $ $ Qc % ! $ ! ! $ Ock 50 % ! $ 10 % ! % ! $ % ! $ $ SOd % ! ! % % $ % $ % % ! $ ! $ $ $ ! $ % % $ % ! ! ! Ogc $ % 47 % $ % % $ % % Ogc ! ! ! $ $ 45 % % % $ 15 SOd ! ! ! $ $ % ! % % ! ! % $ % $ % % 15 ! ! $ $ % $ ! $ 35 % % % ! % $ ! % % % % ! 15 ! *ot % ! $ % % % % ! $ % ! $ Qms $ $ % $ ! % % % ! $ $ Aos Oe % % % ! ! % % $ % $ % ! $ $ % 40 ! $ $ % ! $ 8 % $ ! $ ! *ot % $ Ami $ % ! % ! % $ % % % ! $ $ % ! % $ % Oe ! ! ! $ ! ! ! $ $ $ 22 ! ! ! % $ % % $ $! % ! $ $ % SOd % ! ! % ! ! ! $ $ 22 ! ! $ $ 15 % ! $ $ $ ! % ! % % $ % 30 % ! ! Qc ! $ 2 $ ! Qaf $ $ ! % $ 25 ! *ot % $ 65 $ ! ! $ % $ % ! *ot % % % $ $ % $ ! $ % $ $ $ Ogc ! SOd % % ! % % $ $ % $ % ! $ $ $ SOd $ $ $ $ % % ! $ 55 $ $ % Ock ! % $ % 15 $ $ ! $ $ % $ $ $ $ ! $ % $ $ % % *ot ! 40 $ 20 Ock Ami $ $ ! $ $ $ $ % % % % ! % $ SOd $ 40 ! $ Oe % $ ! $ $ % 20 % $ % ! $ $ % $ % $ Oe Aos $ Oe % $ $ $ $ $ % % Oe $ Oe % % 10 % $ $ 25 Qc % $ $ $ % % % % %$ % % % $ 55 % $ % % SOd % % SOd% % % % % $ $ % % % 0 % $ 75 % % % % % 25 % % % % $ $ % % $ Ogc % $ % 12 % % % % % 40 % 15 % % 30 % $ % % % $ $ % % $ % $ % $ $ P*o % % ! % $ % % 35 $ % ! Oe % SOd % % % % Ogc % % ! 55% $ $ 10 ! ! $ % ! $ 10 $ 40 % ! % % ! $ % % % $ 6 Ogc $ Aos ! $ % $ ! 50 10 % % 25 Ogc % % % ! % % % % % % % $ % $ ! 50 % ! ! ! Oe ! ! ! ! $ ! ! ! ! 5 ! % ! ! ! ! ! Ock % 55 ! $ ! ! ! ! ! % ! *ot % ! % % ! ! $ % % ! ! $ SOd % % ! ! ! P*o ! % % 12 % $ % ! Ogc ! % % $ % % ! ! % SOd % % ! % ! % ! $ ! % ! % % Ogc % Ock % $ ! Ami ! ! % Ock % % ! % 40 ! % % $ Qc 25 Qal ! % ! % % % Ami % ! ! $ % % % SOd % ! $ % % $ ! % Ock % % % $ % % ! % 25 % % ! % % % $ $ $ % ! % % % % % % 60 % ! Ogc 35 % Qal % % % % Ock $ % % % P*o % % Qal % % $ % % $ % % % % % % % % % % % % % % % % ! % % % % $ 36 ! % % % $ % ! % % % % % ! % 28 15 % % % % % % ! $ % % % Qc Oe Qc 50 ! $ 4 % $ % % 11 % ! % % % % % % Ogc % Ogc ! % 10 Ogc% % % % % % % Qc % Qc % 50 % % % 15 $ % % % % % % % $ % 15 % $ % $ % Ogc $ 25 Ock % % 30 $ $ $ % % $ % % % % % % % % % % 4 % % % % $ Ogc % % $ % Osd % *ot % % % $ $ % % 50 Ock $ % Ock 30 $ % ! $ % % % % % % % % $! % $ $ Qc % 10 % % 15 % ! % $ % % % % % % % % Oe ! % % $ % Oe % % % % ! Ami % $ % % $ % % Qc ! % $ % % % % % % % % SOd ! % $ 28 % % $ % ! SOd % % % % % !$ % % % % % Ock $ % % ! Ock $ 36 ! ! % % 20 % $ % % ! % % ! $ % ! % % Oe % ! ! % % % $ % ! Ock% % ! Ogc ! $ % % % % % ! $ $ ! % ! % % $ % ! 30 Aos % ! ! ! $ % ! 25 % % ! % ! ! % % $ % ! ! % % 50 $ $ ! % $ % $ ! ! Ock % $ % ! % $ ! ! % ! Aos % $ $ 14 ! *Mcd 40 $ 24 $ Ogc ! Oe $ ! ! % ! ! % % % ! $ ! $ % % ! ! % ! % $ ! Ogc % $ % % $ % ! Ç ! % $ ! % % ! *ot $ Ç ! $ Ock $ $ ! % ! % ! Ç % ! ! % % % ! Ç % % 30 % % ! ! $ % % $ % $ % 10 $ % $ ! $ Ç % % ! % ! 40 $ $ ! $ Ç Qal 15 $ ! % $ ! ! 32 % % ! % % Qms % % % ! $ $ Aos % % % ! % % $ $ SOd $ Qc ! % ! % % 20 $ $ ! ! % % % Ock % % ! % ! % % % % 40 $ % % $ $ ! $ ! Oe % P*o SOd $ 3 % $ ! % $ $ *ot % Qaf % 10 % % % % ! % % % % % % 30 % $ $ Ami % % % % $ ! $ 40 % $ *ot % ! % Oe $ % % $ % $ 40 $ $ $ % % ! $ $ $ $ Oe $ % $ % % % % % $ % % ! % % % $ % % 30 % % ! $ % % ! P*o % % % % $ $ % ! $ % ! % ! ! $ ! ! ! % % % ! $ $ ! % % ! ! ! ! ! ! % $ % ! Ogc ! ! ! ! 20 $ 35 % ! 35 % % % % % % $ ! % ! % % $ $ $ % % $ ! Ock % ! $ % % % ! % % % $ $ % % % % ! % 15 % $ ! $ $ 40 % $ % % SOd ! ! 20 $ Ogc $ % ! % % $ ! ! $ $ % % % % % % ! ! ! % % % % $ % % % % $ % % ! % % ! % $ ! % % % % ! ! % % ! % % $ $ ! % % % $ Oe 12 % % ! % Ogc % % Qms ! % % ! % % Ock % % ! Qc $ Qc % % % $ ! % ! % % % 40 % % % ! % $ % ! 20 % ! % % % ! % $ $ % % ! ! $ % % $ % % % ! ! % $ SOd $ 20 % % $ % ! $ % ! ! 17 % % % $ % $ % % 15 % % % 53 % $ 20 ! Ogc % % ! % ! $ $ % % $ ! % $ % % % % % $ ! Ock ! % Ock $ % % % ! % $ $ % % % % $ % ! % % ! $ % % % ! Qc $ % % % $ % Ock % ! % $ $ % % % $ ! % ! % % % % 52 Qc % Ock % % $ % ! ! % % % ! % % % ! % ! % % $ $ $ % ! % $ % % ! % 40 % % % % % $ % $ % ! % ! 55 % $ % $ % % % % % % Oe ! ! SOd 72 % % % $ $ % % $ % $ ! % ! % 25 *ot % % % 4 % % % % % ! % Oe 60 % ! $ % % $ % ! $ $ $ $ $ % Oe % % % $ % % ! % 60 $ % % % Ogc $ $ SOd % % % $ % ! % 30 35 $ % SOd % % % $ ! $ % $ *ot $ % Ogc % 20 $ ! $ % % % % % % $ % ! $ $ % $ % % $ $ % Ogc % % % $ % % $ % SOd $ $ % 50 ! 50 % $ $ $ $ $ ! $ % 15 % $ 25 Ock % % % % 45 ! $ $ % % $ % % % ! % Oe % % $ $ % $ $ % $ $ ! % 46 %Oe $ 35 25 45 *ot % % % $ % % 6 % % % % 13 % $ Ogc % % $ $ % $ 28 % % $ % 15$ Qms % $ $ $ $ $ 13 % % $ 40 % Ogc % $ % $ *Mcd $ % $ $ % $ % $ % $ $ $ % Ami % % 25 $ ! ! % $ % $ % ! $ Ogc $ ! ! % $ % ! % % $ ! 30 % ! $ % ! % % % $ ! % ! $ $ ! ! ! ! ! ! ! ! % ! % ! ! % ! ! % ! ! ! ! % $ 35 % ! ! ! % $ 28 ! ! ! % ! % ! % % ! ! SOd $ % $ ! % % ! ! Ami 50 % % % ! Qc ! % ! % ! *ot ! ! % $ $ $ ! % % % ! ! % ! % ! % $ ! ! ! Oe $ 25 % $ % % 50 ! $ % % 69 ! ! SOd $ ! *ot 40 % ! % $ $ % ! $ ! *ot ! % % $ ! ! 45 ! ! % $ % % 18 % $ ! 30 $ $ ! ! % ! $ % $ $ ! $ $ % $ Ogc ! % ! $ % $ ! ! $ % $ $ % ! $ $ 10 ! ! $ ! ! % ! ! $ $ ! Ock % % $ ! ! ! $ ! ! $ ! $ ! ! ! % ! ! % ! ! $ ! $ $ ! ! % ! ! ! ! % ! ! % ! $ % ! Ock ! % 20 % ! 23 ! *Mcd ! ! ! Qc ! ! $ ! ! ! Ock % ! ! ! ! $ ! $ $ ! Qms ! ! ! $ % ! $ ! $ ! % 16 Ogc ! % % ! % % ! ! SOd % % ! ! ! ! $ ! % ! ! $ ! ! $ ! ! ! ! ! ! $ ! ! % ! $ % 45 % % ! % ! % ! ! % ! 20 ! ! *ot 40 ! $ ! ! ! % % ! $ ! ! 15 ! $ ! ! $ ! ! ! ! ! % % ! 10 ! ! ! 25 Qc % ! ! % ! % 20 % % 50 ! $ ! % 15 % ! ! % ! ! ! 27 $ $ Oe % % ! $ % Qc Ock % ! ! % % ! ! % % ! $ ! ! % ! ! % ! 4 % ! $ ! % 21 ! ! ! % % ! % 15 8 SOd % ! ! $ ! ! $ 55 % P*o ! % ! ! % Oe $ % ! 6 ! % ! % ! % ! $ % ! ! % Ogc ! ! $ ! % $ ! % ! % ! % 20 50 ! ! 22 24 % Ock $ $ % % ! % Qc ! ! Ock % 35 % $ % $ % ! ! ! 35 $ % % % ! % ! % ! % $ 3 $ $ % Ogc ! % ! % % % % % Qaf % $ ! % % ! % Ock $ $ % ! % $ $ 65 % ! % % SOd ! Qc 40 $ $ ! $ % ! % % % % % % % ! % % ! $ % Oe $ ! % ! $ % % % $ % ! % ! $ $ % % % % 41°55'30"N $ ! Oe % ! % ! 41°55'30"N ! 60 % $ $ % ! ! % % $ $ $ % % $ ! $ % $ *ot % 30 ! P*o $ % % $ % ! % ! 40 % 35 6 % ! % ! % $ % % % 15 $ Ami 6 % % % ! $ $ ! 36 % $ Oe % 40 $ 45 $ ! 20 % ! % % % % % % % ! 28 ! % $ $ Ock 20 Oe % % ! % ! % $ $ % % $ % ! % % $ 40 ! $ $ % % ! % 35 Ç ! % $ % % $ ! ! Ç Ç % ! $ % % % % ! ! ! Ç Ç % SOd ! % % % % $ ! $ % ! % ! % %Ç $ $ Ç % $ Ock % ! $ ! $ % ! ! Ç Ç Ogc ! $ % % ! % ! ! Ç Ç ! ! % % SOd $ $ % % ! % Ç $ ! Ç Aos ! % ! 20 % $ $ % $ % ! % $ Ç ! Ç % ! ! % % % % % % % ! ! Ç Ç 20 % ! % ! 25 $ % 35 12 % % ! ! Ç % Ç % ! % *ot 37 ! Aos % $ % % Ç 40 ! ! %Ç ! % Oe ! $ % % % 70 % 50 Ogc Ç ! % ! Ock Ç ! % ! % 3 % ! % % $ % % Ç % % ! ! $ Qaf ! ! % % % ! % Qal ! ! ! % Ç ! % % ! % ! % 25 % ! ! $ Ç Ogc ! % % ! ! % % % ! % % ! ! % P*o ! % $ 30 % ! % ! ! % ! $ 40 % ! ! % SOd ! ! % 25 % ! ! ! % $ % ! % ! $ % ! % % ! ! % % % Ami ! P*o ! % % ! % ! % ! % ! ! ! 3 % ! ! ! ! ! ! ! ! ! ! ! ! ! ! % ! ! ! Qaf 35 ! ! Oe ! ! ! ! ! ! ! % ! % $ ! % ! ! ! ! ! % % $ ! % ! ! % % ! % Qc ! % ! Qc ! ! ! 3 ! % % ! % % ! % % ! % ! Qaf ! % ! ! $ % % ! % % ! ! ! % % % $ ! ! % % % % ! ! ! % $ Oe ! Ock % ! ! ! % % % ! % $ % % % 30 ! % Ç % ! % ! % % Ç ! Ç $ Ami $ ! ! ! % % ! % ! % % $ ! ! 3 Qal % ! ! % $ ! % % % % ! ! % Qaf $ ! ! ! ! ! ! ! ! ! ! ! ! % ! % $ ! ! ! ! ! ! % ! % ! ! ! % ! ! ! % % ! % $ 60 ! 20 % ! % Ts $ % ! $ ! ! % Ç % $ Ç ! ! $ ! % % % ! % % ! ! ! $ Ogc % % ! % % 30 ! ! ! % % % ! ! Ock *ot ! % 20 SOd % $ ! % % ! % ! ! % % Qal 33 ! ! $ ! % ! ! ! Ç Ç % $ % ! ! % % ! % ! % % ! % ! ! % % % % ! $ % ! % ! % ! 30 ! ! $ ! % ! % ! $ ! % $ $ $ % ! $ SOd $ SOd ! % % ! Qal % $ % 25 ! ! % % $ 55 % ! $ ! % ! % *ot % 50 ! % ! % 30 $ % ! ! $ % % ! % ! $ % ! % % ! % Oe 36 % ! $ ! $ % Ts 33 $ ! P*o ! Oe $ % % % $ ! ! % % % ! ! % % $ % $ ! % ! ! $ % % P*o ! % % % 25 $ ! % $ ! % ! % % % % ! % ! % % % % $ SOd % $ % % $ ! ! % $ 55 ! % A' ! % ! % % 25 ! ! % % % % ! % % Ts ! % % % ! $ % % ! 20 ! ! % ! ! % 20 ! % % 70 ! 10 % % % 25 % % % ! P*o % % $ % % % 50 *ot ! % % 40 ! Ts % % % % % ! 35 % % 3 % % $ ! Oe % % Qaf SOd ! % % % 45 ! Oe % % % % ! % 38 % $ % ! % % ! % % % *ot % % ! % $ ! % % Ogc Ts ! % % % % % % % % % % % % $ 30 % % % % 42 % % % % % % % % $ % % % % % % % % 50 % Ogc $ % % % Ts % $ *ot % % % Ock % % % %30% % $ $ % % % % % % % % % %29 % $ % Ç Ts 35 Ç % % % % 45 Ç % 25 45 % % 19 % % 30 % Ç % ! $ Ç ! % Ç 30 ! Ç % % % Ç % Qal ! % % Ç Oe Ç ! % % % ! Ç 20 Ç % $ SOd % ! % Ç 45 Ç % $ 15 $ ! % % % % $ P*o % % Ç Ç % % ! % % $ Ç % % Ç % ! $ % % $ 35 Ç Ç % $ ! % % Ç ! ! % ! $ % Ç Ock ! $ ! % % ! % % % % ! 60 % ! 15 Ç ! % % $ ! ! ! ! ! $ Ç Ç % % ! $ Ogc ! Ç ! Ç % % ! % ! % ! ! Ç 20 Ç ! % % Oe $ ! ! $ ! Ç % ! $ Qal ! Aos % ! 12 ! Ç B' ! Qal! ! % Ç % SOd 50 % % ! ! ! 8 $ Ç % $ ! $ ! % ! % ! Ç ! % ! ! % ! Ç 3 % ! % Qaf 30 Ç ! P*o $ % $ $ % ! ! % ! 3 Ç 58 ! ! % % Qaf ! 30 ! Ç % ! 35 Ç ! % % 35 45 % ! Ock ! % $ % $ Ç $ % % ! % ! ! % ! % ! ! ! % % ! % % ! ! % % 50 $ % $ ! ! $ % $ % ! % % ! ! % ! % ! ! ! % % % ! % % 50 ! ! $ ! % $ % $ $ ! % % % B 35 ! % ! Ock % % ! % $ % % ! % $ % $ % % % 25 $ ! % % % % ! Ogc ! % % P*o % 20 ! % 42 $ $ $ % ! $ % ! Aad % % % ! % % % Oe % ! % 85 $ Qal $ Ogc % $ ! $ 75 % Qal % ! % % Ock % ! % % % % % ! % % $ Oe % $ $ % Ogc ! $ % 45 % ! % % % % ! Qc % % ! % ! ! $ ! ! $ % ! ! % $ Oe % ! % ! $ ! % ! % % % ! % ! % 7 % ! ! $ $ ! % ! % % % ! % $ Qc % $ ! ! % % ! ! % $ Qc ! $ ! % % % % % ! ! % $ % ! ! ! $ 40 % % SOd % ! ! ! ! $ % ! 50 $ ! ! ! % % ! % ! ! ! % % % ! % % ! ! $ ! 15 $ ! ! % $ 25 ! ! $ $ $ Oe % % ! ! % % ! $ ! % % ! 45 % ! % % 3 ! ! $ Qc $ 20 Oe ! ! 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Qal ! ! ! % % ! % % ! ! ! % ! ! 8 47 ! % % ! *ot % ! ! ! ! 10 30 % 45 % ! ! 35 Qc ! ! ! % % 30 ! ! 20 ! ! ! *ot $ % $ ! % ! ! % % ! Ock $ ! ! $ 60 Ts ! Ts ! % Ock ! $ ! % ! ! ! Ogc 25 ! % % ! % ! 10 ! % % $ ! ! $ ! ! ! ! ! % ! Ts ! % ! % $ ! !! ! $ ! 6 15 % $ ! % ! ! 2 % ! % ! ! ! ! ! ! 75 ! ! % % ! ! ! ! % Ogc ! ! ! % ! P*o 50 % ! ! ! ! ! ! ! ! % Qal 10 ! ! % ! 20 Ami ! ! 45 % % ! Ock ! % % ! ! ! Aos % Oe % ! % ! ! 45 ! ! % 15 ! ! ! 55 ! ! ! ! % % Ock ! ! Qms % ! ! ! ! ! % ! Qal 45 ! ! % ! ! % P*o ! ! ! ! 3 ! ! 8 ! ! ! Qc Qaf ! ! ! ! ! ! ! Qal ! ! 18 Qc ! ! ! P*o ! ! Ogc 35 ! ! ! ! ! Ts ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 3 ! ! ! ! ! ! ! Ogc ! ! ! Qc ! 20 ! ! ! ! ! 20 ! ! Ami ! ! ! ! 5 12 ! ! ! ! ! ! ! 15 ! ! ! ! 20 25 ! 13 ! ! 25 ! ! ! ! ! ! ! ! Ami ! Aos ! ! 15 B ! ! 30 ! % ! ! ! ! ! 62 Aos ! % ! 10 ! $ ! ! ! Ogc ! % 9 ! 4 ! $ ! ! ! IPot ! ! 7 % ! ! ! $ Aos ! ! ! ! $ ! Qc ! ! ! 15 ! % SOd ! $ ! ! ! ! 25 ! % Aos ! ! ! $ ! ! ! % ! ! ! ! $ ! Aos ! ! ! ^ ^ 36 $ ! ^ ^ ^ ^ ^ 13 27 ! ^ ! ! % ! 3 ! % Qaf ! ! ! 80% 10 ! ! Ami ! % ! ! % Ts 15 ! 30% ! Ami ! ! ! ! ! ! P*o 50 ! ! Aos ! ! ! ! ! ! Qc ! 41°54'0"N 15 ! 41°54'0"N ! ! ! ! Qal ! ! ! ! ! ! ! ! ! ! ! Qal ! ! Ami 15 ! 3 ! ! 10 ! ! ! ! ! 35 ! ! ! ! 30 ! *Ola ! 10 ! ! 15 ! ! ! ! 10 ! ! ! 34 ! ! ! ! ! Ami ! ! ! ! Ts Qc ! *Ola 28 ! *Ola ! ! ! ! Aos ! ! ! ! ! ! 7 ! ! ! ! ! ! ! 10 ! ! ! 7 ! Qla ! ! ! 3 ! P*o Qaf ! ! ! 24 Ts ! Aos ! Qc ! Ami Area of detailed bedrock mapping ! 64 ! ! ! ! ! ! ! ! ! 28 ! ! ! ! 15 ! ! 15 ! 8 ! Ts ! ! ! ! ! ! ! ! ! 15 ! ! ! ! ! ! ! ! ! ! ! ! 35 B ! ! ! Qlg ! ! ! ! ! ! ! ! 0 ! ! ! ! ! 35 ! ! ! ! ! ! ! ! Qc! ! 12 ! ! % ! ! P*o ! ! % Qla Qal % ! ! ! ! ! Ts ! ! ! ! ! Qal ! ! !