Interim Geologic Map of the West Part of - Utah Geological Survey

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distal part of either the Midway Creek or Horse Pasture lava flows; the lavaflowed from west to east down the ancestral Duck Creek drainage and continuednortheastward to at least the Bowers Flat area at the west edge of the Asay Benchquadrangle; contains a long, open lava tube near Aspen Mirror Lake, just west ofDuck Creek village (U.S. Forest Service restricts access); lava flow is typicallypartly concealed by a veneer of unmapped surficial deposits of alluvial, colluvial,and eolian origin; age unknown, but it locally covers the Bowers Knoll lava flow(Qbbk) and in turn is locally covered by the Henrie Knolls lava flow (Qbhk), thusis probably late to middle Pleistocene; however, Johnson and others (2010)suggested that the distal end of the Bowers Knoll flow as mapped here, includingthe part that contains Mammoth Cave, may be the Duck Creek flow―if so,incision there suggests that the Duck Creek flow is about 500,000 years old, farolder than the degree of incision suggests along the upstream part of the flow;maximum exposed thickness is about 15 feet (5 m) near Aspen Mirror Lake, butlikely several tens of feet thick where it fills paleotopography in the Duck Creekdrainage.Qbsk, QbskcStrawberry Knolls lava flows and cinder cones (Pleistocene) – Medium- todark-gray potassic trachybasalt that contains clusters of olivine and clinopyroxenephenocrysts in an aphanitic to fine-grained groundmass; lava flows (Qbsk)erupted from Strawberry Knolls (Qbskc), two cinder cones located about 2 miles(3 km) east of Duck Creek village, and flowed mostly northeast along StrawberryCreek to Uinta Flat; age unknown, but cinder cones are well vegetated and flow isincised by Strawberry Creek as much as 40 feet (12 m) at its downstream end andso is probably middle Pleistocene; lava flows are typically 20 to 30 feet (6-9 m)thick, but doubtless many tens of feet thick near vent areas.Qblhc Lake Hollow cinder cone (Pleistocene) – Forms a small, partly eroded cindercone about 1.5 miles (3 km) north of Mammoth Creek and east of Black RockValley, with a small lava flow (not differentiated on this map) at the base of thecone of medium- to dark-gray hawaiite (sodium-rich trachybasalt) that containsclusters of olivine and clinopyroxene phenocrysts in an aphanitic to fine-grainedgroundmass; vent is on-trend with the Henrie Knolls lava flows, to which it maybe related; age unknown, but likely late to middle Pleistocene based on position inlandscape; lava flow is less than about 20 feet (6 m) thick.Qbef, QbefcEast Fork Deep Creek lava flow and cinder cone (Pleistocene) – Medium- todark-gray, fine-grained olivine basalt lava flow (Qbef) west of Navajo Lake;cinder cone (Qbefc) is deeply eroded due to its location just below the westernescarpment of the Markagunt Plateau, just west of Navajo Lake; the distalsouthern end of this flow was called the Three Creeks lava flow by Biek andHylland (2007), which they estimated to be less than 300,000 years old based ondegree of incision and comparison with nearby dated lava flows; lava flow isprobably 20 to 40 feet (6-12 m) thick.17
Qbw, QbwcWater Canyon lava flow and cinder cone (middle Pleistocene) – Dark-graypotassic trachybasalt and shoshonite (potassium-rich basaltic trachyandesite) thatcontains clusters of olivine and clinopyroxene phenocrysts in an aphanitic to finegrainedgroundmass; quartz xenocrysts common; lava flow (Qbw) erupted fromcinder cone (Qbwc) in Water Canyon about 3 miles (5 km) southeast ofParagonah (Maldonado and Moore, 1995); Fleck and others (1975) reported a K-Ar age of 0.44 ± 0.04 Ma for this flow; lava flow is as much as 200 feet (60 m)thick where it partly fills Water Canyon.Qbbk, QbbkcBowers Knoll lava flow and cinder cones (middle Pleistocene) – Medium-graymugearite (sodium-rich basaltic trachyandesite) containing abundant clusters ofolivine, plagioclase, and clinopyroxene phenocrysts in a fine-grained groundmass;lava flow erupted from Bowers Knoll, a cinder cone (Qbbkc) about 3 miles (5km) northeast of Duck Creek village; forms rugged, heavily vegetated, blockysurface having steep flow fronts 40 feet (12 m) or more high; as mapped, containsMammoth and Bower caves, large open lava tubes, but this part of the flow maybelong to the Duck Creek flow (Johnson and others, 2010); age unknown, butlocally underlies the Duck Creek lava flow (Qbdc), so is probably middlePleistocene; Best and others (1980) reported a K-Ar age of 0.52 ± 0.05 Ma for thenearby Asay Knoll lava flow (Qbak), which exhibits a similar degree of incisionand weathering; typically 40 feet (12 m) or more thick near flow margins, butmay exceed 100 feet (30 m) thick near the central part of the flow.Qbak, QbakcAsay Knoll lava flow and cinder cone (middle Pleistocene) – Medium- to darkgraypotassic trachybasalt and shoshonite (potassium-rich basaltic trachyandesite)that contains clusters of olivine and clinopyroxene phenocrysts in an aphanitic tofine-grained groundmass; lava flow (Qbak) erupted from Asay Knoll cinder cone(Qbakc) and covers Asay Bench; Best and others (1980) reported a K-Ar age of0.52 ± 0.05 Ma for this flow; lava flow is typically 20 to 30 feet (6-9 m) thick, butis doubtless many tens of feet thick near vent area.Qbck, QbckcCooper Knoll lava flow and cinder cone (middle Pleistocene) – Medium-graybasalt that contains clusters of olivine, plagioclase, and clinopyroxenephenocrysts in a fine-grained groundmass; lava flow (Qbck) erupted from a ventat a cinder cone (Qbckc) on the south flank of Cooper Knoll, about 1 mile (1.6km) southeast of Panguitch Lake; overlies stream gravels containing roundedpebbles and cobbles of the Isom Formation, mafic and intermediate volcanicrocks of the Mount Dutton Formation, chalcedony, and minor quartzite; ageuncertain, but may be about 500,000 years old based on comparison with thesimilarly incised Asay Bench lava flow (Qbak) for which Best and others (1980)18
Page 1 and 2: ! !! !!! ! ! !! ! ! ! !! ! !! !! !
Page 3 and 4: MAP UNIT DESCRIPTIONSQUATERNARYAllu
Page 5 and 6: Qafc Coalesced fan alluvium of Paro
Page 7 and 8: glacial deposits and features that
Page 9 and 10: (Tbhv) and Dakota (Kd and Ktd) Form
Page 11 and 12: typically mapped where lava flows d
Page 13 and 14: that range in age from Miocene to H
Page 15 and 16: fronts (except at Dry Valley, immed
Page 17: the quadrangle; no fault that postd
Page 21 and 22: others, 2007); lava flow is typical
Page 23 and 24: Mahogany Hill, about 500 feet (150
Page 25 and 26: lava flow (Tbbm) that conceal the u
Page 27 and 28: TERTIARYpreserved in down-dropped b
Page 29 and 30: and Rowley and others (in preparati
Page 31 and 32: field (or possibly coeval batholith
Page 33 and 34: hidden by shadow; we tentatively as
Page 35 and 36: esistant crystal-poor rhyolite tuff
Page 37 and 38: thickness uncertain but outcrop pat
Page 39 and 40: divide between Red Creek and Little
Page 41 and 42: pyroxene (5%), and sanidine (trace)
Page 43 and 44: unconformityThe Leach Canyon Format
Page 45 and 46: unconformityMa (Best and others, 19
Page 47 and 48: interval, and a lower limestone int
Page 49 and 50: Figure 3. View northwest to North V
Page 51 and 52: dark-yellowish-orange, grayish-pink
Page 53 and 54: TKgc Grand Castle Formation, undivi
Page 55 and 56: track (the latter found by Eric Rob
Page 57 and 58: noted by Moore and Straub (2001) an
Page 59 and 60: shoreface, beach, lagoonal, and est
Page 61 and 62: water deposits of Cenomanian age (N
Page 63 and 64: 62Figure 7. Cedar Mountain Formatio
Page 65 and 66: leached white under the Cretaceous
Page 67 and 68: ACKNOWLEDGMENTSThis geologic map is
Page 69 and 70:
Anderson, R.E., and Christenson, G.
Page 71 and 72:
Biek, R.F., Rowley, P.D., Hayden, J
Page 73 and 74:
field guide (The Mackin Volume): Ut
Page 75 and 76:
2001, Cretaceous and early Tertiary
Page 77 and 78:
Hacker, D.B., Rowley, P.D., Blank,
Page 79 and 80:
Kurlich, R.A., III, 1990, Geology o
Page 81 and 82:
Maldonado, F., and Moore, R.C., 199
Page 83 and 84:
Flagstaff-Green River basins [abs.]
Page 85 and 86:
elation to other igneous centers in
Page 87 and 88:
Schulman, E., 1956, Dendroclimatic
Page 89:
Van Kooten, G.K., 1988, Structure a
Page 92:
113°00'112°00'15BV20R i v e rCCNP
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Interim Geologic Map of the West Part of - Utah Geological Survey

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