IDAHO GEOLOGICAL SURVEY DIGITAL WEB MAP 166 MOSCOW-BOISE-POCATELLO IDAHOGEOLOGY.ORG PHILLIPS, GARWOOD, AND FEENEY

CORRELATION OF MAP UNITS GEOLOGIC MAP OF THE LAMONT QUADRANGLE, FREMONT AND TETON COUNTIES, IDAHO Artificial Alluvial Sediments Glacial Mass Wasting Eolian Volcanic Rocks and Fill Deposits Deposits Sediments Sediments

m Qas Qac Qab Qabi HOLOCENE William M. Phillips, Dean L. Garwood, and Dennis M. Feeney Qls Qt Qafbn Qgo Qel 2014 ? Qd ? ? QUATERNARY PLEISTOCENE Qgo Qgo/Qyh Qba Qyh Qgo/Qyh Qbbc Qgo/Qyh Qgo/Qyh Qyh Qac Qyh Qgo/Qyh 395686 Qgo/Qbbc Qas Tb SYMBOLS Ts PLIOCENE

Qas TERTIARY Qyh Qas ? Qas Contact: dashed where approximately located. Thr Qac MIOCENE Normal fault: ball and bar on downthrown side; dashed where approximately located; dotted where concealed. ?

Qgo/Qbbc Monocline, arrow shows direction of dip. Qgo/Qyh Qyh Basaltic volcanic vent, concealed by loess. Qas present. In Bitch Creek canyon (center, sec. 18, T. 7 N., R. 45 E.), consists of nantly a bedrock-floored creek; the only significant alluvial reach is 405619 Qyh Flow line: Linear flow feature in basalt, concealed by loess; arrow shows >45 m (150 ft) of blocky pink eutaxitic rhyolite capped with a lithophysal 405619 flow direction. between the Highway 33 bridge and the Ashton-Tetonia railroad trestle. zone, a platy zone, a black vitrophyre, and a thin red vitric tuff. Maximum Qac Alluvium of Conant Creek (Holocene-Late Pleistocene)—Cobbles and exposed thickness in map is about 150 m (490 ft) in Bitch Creek canyon Strike and dip of eutaxitic foliation in welded tuff. 3 boulders up to 1.5 m (4.9 ft) in length; contained in braided channels and (SE/4 sec. 10, T. 7 N., R. 44 E.). At the Highway 33 bridge over Bitch Creek (NW 1/4 sec. 17, T. 7 N., R. 45 E.), > 30 m (100 ft) of Member A is exposed Qas Landslide scarp. two levels of terraces; well-rounded, crudely parallel bedded and imbri- cated. Clasts are composed of sandstone, quartzite, diorite, basalt, welded in the canyon and overlain by blocky pinkish-gray densely welded rhyolite 72513-21 Geochemical sample. tuff, granite, gabbro, and hornblende porphyry. Largest boulders consist of of Member B at road level. A normal fault places Member C in contact with Qas Member B. Member C consists of altered reddish to yellow unwelded Qas very hard, gray aphyric basalt with quartz xenocrysts, and lithophysal rhyo- 13P05 Qgo/Qyh Paleomagnetic sample. lite. Thickness ranges from 3 to 5 m (10 to 16 ft). air-fall deposits and altered orange to yellow low density welded tuff with abundant cavities, capped with a black vitrophyre (Wilson, personal R Fluxgate measurement site showing magnetic polarity. Qt Terrace deposits (Holocene-Late Pleistocene)—Silt and fine sand; thinly communication, 2014). Qas bedded with nearly horizontal tops. Incised by active channels. May repre- 374593 Water well showing Well ID number. sent reworked loess trapped in temporary lake created by landslide block- age of lower Swanner Creek in sec. 18, T. 7 N., R. 45 E. Thickness is about Tb Basalt (Pliocene?)—Not exposed in the map area; known only from subsurface 3 m (10 ft). information. Basalt encountered in water well logs stratigraphically below Qgo/Qbbc METHODS AND PREVIOUS WORK the Huckleberry Ridge Tuff. For example, well 358104 in sec. 24, T. 7 N., R. Qgo Glacial outwash deposits (Late-Middle Pleistocene)—Boulders, cobbles, 44 E. penetrates 96 m (316 ft) of basalt below Qyh. This basalt may be pebbles, and sand; generally well-rounded; composed dominantly of basalt correlative to basalts lying below Qyh that are exposed in the Teton River with lesser gneiss, sandstone, and quartzite derived from the Teton Range. Qgo/Qyh This map depicts the bedrock and surficial geology of the Lamont quad- canyon in the Newdale quadrangle (Phillips, and others, 2011). Qas Qgo Water wells indicate thickness of about 8 to 9 m (25 to 30 ft). Best rangle. Previous work by Prostka and Hackman (1974), Mitchell and Ts Sediments (Pliocene?)—Not exposed in the map; known only from subsurface Qas Qas Bennett (1979), and Scott (1982) were consulted and compiled. The map of exposures are at Highway 33 bridge over Bitch Creek where about 1.5 m (5 Qas information. Silt, clay, and gravel encountered in water well logs Love and others (1992) was used to infer sources for gravels derived from ft) of sandy gravel overlies a reddish paleosol, and in road cuts along Highway 33 between Bitch Creek and Lamont. Overlain in most exposures stratigraphically below the Huckleberry Ridge Tuff. For example, well 327679 the Teton Range. Water well logs from the Idaho Department of Water 358104 in sec. 24, T. 7 N., R. 44 E. penetrates 13 m (42 ft) of silt, clay, and Resources (IDWR, 2014) were used, where possible, to trace bedrock units by >1 m (>3 ft) of loess. Age and correlation with regional glacial periods Qel are uncertain. Lobes of the Yellowstone ice cap lay just north of the map gravel about 91 m (300 ft) below Qyh. The sediments may be correlative to concealed beneath surficial deposits. Soil maps (Soil Survey Staff, 2014) tuffaceous laucustrine deposits exposed in the Teton River canyon (Phillips were helpful in characterizing some surficial units. Field work for new during at least three glaciations: Sacagawea Ridge, Bull Lake, and Pinedale (Richmond, 1973; Scott, 1982). Large volumes of outwash from Bull Lake and others, 2011) and in geothermal test well logs (Phillips, 2010) near geologic mapping was conducted in 2013 at a scale of 1:24,000. Basalts Newdale. 326636 were correlated with major and trace element analyses by wavelength and Pinedale glaciers were directed down the Falls River – Conant Creek drainages rather than south onto the map. The map likely received Yellow- dispersive x-ray fluorescence, and by paleomagnetic analyses using drilled Thr Rhyolitic Rocks of Heise Volcanic Field, undivided (Pliocene-Miocene)— Qas stone ice cap outwash only during Sacagawea Ridge glaciation during cores, spinner magnetometer, and alternating field demagnetization. Rhyolitic ignimbrites, lava flows, and pyroclastic deposits (Morgan and Qgo Marine Isotope Stage 16, at approximately 660 ka (Pierce, 2003). Most Fluxgate magnetometer determinations of basalt polarity were also used. McIntosh, 2005); shown in the cross section; not exposed in the map. Heise Qgo/Qbbc Qgo/Qbbc outwash in the map was derived from the western flank of the Teton Range. Qas Qyh Qyh units are exposed in the adjacent Tetonia (Phillips and others, 2013a) and Packsaddle Lake (Phillips, and others, 2013b) quadrangles, and were Qyh 430888 Qas STRATIGRAPHY suggested by Christiansen (2001) and Morgan and McIntosh (2005) to be MASS WASTING DEPOSITS present in the subsurface of the Lamont map. Qyh Qls Landslides (Holocene-Late Pleistocene)—Along the south rim of Bitch Creek Qas Qas Exposed bedrock consists of the early Pleistocene Huckleberry Ridge Tuff of canyon, deposits consist of topples and falls of basalt blocks ranging in size Qgo/Qyh the Yellowstone Group (Christiansen, 2001), overlain in many places by Qgo/Qyh between 1 to >2 m (3 to >6.5 ft). Tension cracks are locally present parallel REFERENCES Qyh Pleistocene basalt lava flows. Vents for the basalts are obscured by thick to the rim. Elsewhere, consists of hummocky earth flows composed of Qgo/Qyh loess deposits; their location was inferred using geomorphic criteria. reworked loess along fault scarps. Many small topples and falls of rhyolite Christiansen, R.L., 2001, The Quaternary and Pliocene Yellowstone Plateau Regional relationships suggest that these units are underlain by Pliocene- Qas (not mapped) are also present on steep slopes of Bitch Creek and Badger volcanic field of Wyoming, Idaho, and Montana, U.S. Geological Survey Qas Miocene rhyolitic rocks, and associated basalts and tuffaceous sediments of Qgo/Qbbc Qyh Creek canyons. Professional Paper 729-G. 145 p. the Heise volcanic field (Morgan and McIntosh, 2005; Christiansen, 2001; Qas Qabi Dauteuil, O., J. Angelier, F. Bergerat, S. Verrier, and T. Villemin, 2001, Deforma- Qbbc Phillips and others, 2011; Phillips, 2010). This stratigraphy is characteristic EOLIAN SEDIMENTS tion partitioning inside a fissure swarm of the northern Icelandic rift: Journal Qabi of the uplands bordering the southeastern Snake River Plain from Ririe to Qas of Structural Geology, v. 23, p. 1359-1372. Qbbc Qyh this map. Qel Loess (Late-Middle Pleistocene)—Massive, light gray to light brownish gray silt, Qyh Ellis, B.S., D.F. Mark, C.J. Pritchard, and J.A. Wolff, 2012, Temporal dissection clay, and very fine sand; locally crudely bedded where reworked on hill 40 39 72713-13 of the Huckleberry Ridge Tuff using the Ar/ Ar dating technique: Quater- Qbbc Surficial units are dominated by late Pleistocene loess deposits. Economi- slopes. Thickness in water wells averages 8 m (25 ft), with range of 2 to 14 m Qas Qyh cally important potato and grain crops are grown on soils derived from the nary Geochronology, v. 9, p. 34-41. (7 to 46 ft). Cut along Ashton-Tetonia railroad grade in NW 1/4 sec. 6, T. 7 N, Feeney, D.M., D.L., Garwood, and W.M. Phillips, in press, Geology of the R loess. The areas north of Bitch Creek and along the eastern edge of the map Qyh R. 45 E. exposes about 4.5 m (15 ft) of loess. Landforms covered with thick Drummond quadrangle, Teton and Fremont counties, Idaho: Idaho Qbbc Qgo/Qyh received deposits of glacial outwash derived from the Teton Range. Most of loess display prominent linear geomorphic patterns that trend northeast, 73013-5 Qyh Qas Qgo/Qyh Geological Survey Digital Web Map. R the outwash appears to be older than the loess deposits. parallel to prevailing winds. Derived from deflation of outwash deposits Qbbc Qbbc Idaho Department of Water Resources (IDWR), 2014, All Permitted Wells, in Qabi Qyh during glaciations of the Yellowstone Plateau and Teton Range (Scott, 1982; Qyh Qyh Qls GIS Data, Maps and Spatial Data, Idaho Department of Water Resources. Qyh m Pierce and others, 2011). Several depositional units separated by buried soils Available at: http://www.idwr.idaho.gov/GeographicInfo/GISdata/wells. Qel/Qbbc Qyh Qas are present in correlative deposits in the eastern Snake River Plain (Pierce Qbbc? STRUCTURE htm (accessed 7 February 2014). Qls Qas and others, 1982; Scott, 1982; Pierce and others, 2011). Not dated in the Qgo/Qyh Qyh Idaho Transportation Department (ITD), 2013, Unpublished logs of hollow stem Qyh map; regional ages range between 15-25 ka, 35-51 ka, 69-76 ka, and auger holes for Badger Creek Bridge project, Teton County, Idaho: Idaho The map lies on the edge of the west-dipping Teton Range block, and south Qabi 141-154 ka (Phillips and others, 2009; Pierce and others, 2011). Transportation Department, Key Number 13399, Project number A013(399), Qls Qyh 337168 of the Big Bend Ridge Caldera (source of the Huckleberry Ridge Tuff). The holes TH B3 and TH B4, drilled 7/13/2013, logged by Shawn Enright. Qyh m Teton Range block is cut by an array of north-trending normal faults to form 72513-21 Love, J.D., J.C. Reed, and A.C. Christiansen, 1992, Geologic map of Grand a complex graben in the center of the map. The graben has a general north- VOLCANIC ROCKS AND SEDIMENTS 13P05 Teton National Park, Teton County, Wyoming: U.S. Geological Survey, R Qas ward tilt that may reflect post-eruption subsidence into the Big Bend Ridge Qel/Qyh Qbbc Qbbc Miscellaneous Investigations Series Map I-2031, scale 1:62,500. Qls Qgo/Qbbc Caldera. Basaltic lava flows partially fill the graben. Vents for the flows Qel Basalt of Ard Farms (early? or Middle? Pleistocene)—Light to medium gray 421145 393282 Qba Mitchell, V.E., and E.H. Bennett, 1979, Geologic map of the Driggs quadrangle, Qyh Qbbc Qyh appear to be contained within or immediately adjacent to the graben. Fault fine-grained basalt with rare plagioclase phenocrysts <2 mm and patchy Qba Idaho: Idaho Geological Survey Geologic Map 6, scale 1:250,000. 328247 displacements based upon topographic profiles are generally <5 m (16 ft) areas of diktytaxitic texture; about 3 to 17 m (10 to 55 ft) in thickness. Qls Morgan, L.A., and W.C. McIntosh, 2005, Timing and development of the Heise Qel/Qyh Qgo/Qyh except for fault segments along the eastern side of the map where displace- Normal magnetic polarity (Table 1). Shown as Qel/Qba where covered by Qyh volcanic field, Snake River Plain, Idaho, western USA: Geological Society ments on the order of 45 m (150 ft) are present. Visible fault segments are loess. Vent concealed by loess. Probably erupted from a 3.3 km (2.1 mi) Qyh Qls Qls of America Bulletin v. 117, p. 288-306. m generally short, only 5 to 10 km (3 to 6 miles). This may reflect cover by long, north-trending ridge with a series of ~6220 ft high points centered at Phillips, W.M., 2010, Well logs for the Union Oil UNST-7 and UNST-8 geother- Qgo/Qyh loess, partial burial of fault traces by basalt flows, and displacements by lat 43.8819° N, long 111.2996° W in the adjacent Drummond quadrangle. 13DG704 Qt mal test wells, Newdale 7.5-minute quadrangle, Idaho: Idaho Geological Qt E-W normal faults. The faults resemble arrays produced in basalt flows by Correlated on the basis of paleomagnetism (Table 1) and geochemistry Survey Staff Report 10-9. Qyh Qt shallow dike injection (cf. Blackfoot lava field, Idaho (Polun, 2011) and (Table 2); also see data in Phillips and others (2013a and 2013b). Age is Phillips, W.M., T.M. Rittenour, and Glenn Hoffmann, 2009, OSL chronology of northern Icelandic rift, Dauteuil and others (2001)). uncertain. The thick loess cover away from canyon edges and presence on Qab 377523 late Pleistocene glacial outwash and loess deposits near Idaho Falls, Idaho: Qbbc both sides of the Teton River canyon in sec. 3, T. 6 N., R. 44 E., suggests Qas eruption prior to major stream incision during the Olduvai normal Geological Society of America Abstracts with Programs, v. 41, no. 6, p.12. Qyh Qas subchron at 1.79-1.95 Ma, rather than during the Brunhes chron after 0.78 Phillips, W.M., G.F. Embree, and J.A. Welhan, 2011, Geologic map of the Qas Qt UNIT DESCRIPTIONS Qel/Qbbc ka. The name “Ard Farms” was first applied to this unit by Prostka and Newdale Quadrangle, Fremont and Madison Counties, Idaho: Idaho 72913-2 357393 Geological Survey Digital Web Map 122, scale 1:24,000. Qel/Qyh Qel/Qyh Embree (1978); it does not appear on U.S Geological Survey 1:24,000- R Qas scale topographic maps. Phillips, W.M., G.F. Embree, and D.L. Garwood, 2013a, Geologic map of the 375304 Qgo/Qyh ARTIFICIAL FILL Tetonia quadrangle, Teton County, Idaho: Idaho Geological Survey Digital Qas Qt Web Map 157, scale 1:24,000. m Man-made fill (Holocene)—Blocks of Huckleberry Ridge Tuff and basalt Basalt of Bitch Creek (early Pleistocene)— Dark gray basalt with sparse olivine Qel Qgo Phillips, W.M., D.L. Garwood, and G.F. Embree, 2013b, Geologic map of the Qyh together with compacted clayey silt (loess) along former Ashton-Tetonia phenocrysts <0.5 mm and very fine-grained groundmass. Shown as Qt Qt Qbbc Qbbc Packsaddle Lake quadrangle, Teton County, Idaho: Idaho Geological Survey railroad. Blocks range in length from about 10 to >75 cm (4 to >30 in). Qel/Qbbc where covered by loess; as Qgo/Qbbc where covered by glacial Qel/Qbbc Digital Web Map 155, scale 1:24,000. Qas Thickness ranges from about 2 to 4 m (6.6 to 13 ft). outwash and loess. Reverse magnetic polarity. Named here for good Qbbc exposures along rims of Bitch Creek canyon and at the Highway 33 bridge Pierce, K.L., 2003, Pleistocene glaciations of the Rocky Mountains, in A.R. Qel/Qbbc Qt 358104 Gillespie, S.C. Porter, and B.F. Atwater, eds., The Quaternary Period in the Qt over Bitch Creek. Also well exposed along the Ashton-Tetonia (A-T) railroad Qas United States: Developments in Quaternary Science, v. 1, p. 63-76. Qel/Qbbc A' ALLUVIAL SEDIMENTS grade near Felt, and along the Teton River canyon in Drummond quad- A'' Qgo/Qyh rangle (Feeney and others, in press). Preliminary correlations of outcrops Pierce, K.L., M.A. Fosberg, W.E. Scott, G.C. Lewis, and S.M. Colman, 1982, Loess Qel/Qyh Qas Alluvium of side streams (Holocene)—Silt, sand, and lesser granule to pebble are based on paleomagnetism (Table 1) and geochemistry (Table 2); see also deposits of southeastern Idaho: Age and correlation of the upper two loess data in Feeney and others (in press). However, considerable variation of units, in Bill Bonnichsen and R. M. Breckenridge, eds., Cenozoic Geology of m Qyh gravel; thickness generally less than 1 m (3 ft) but may reach 3 m (10 ft) in Qel/Qyh geochemistry suggests that multiple flows are present. Thickness ranges Idaho: Idaho Bureau of Mines and Geology Bulletin 26, p. 717-725. Qls Bull Elk Creek and Swanner Creek. Many streams have intermittent flow; 393077 374593 subject to flooding during thunderstorms and rain-on-snow events. from <3 m (10 ft) at Bitch Creek bridge to as much as 23 m (75 ft) in wells Pierce K.L., D.R. Muhs, M.A. Fosberg, S.A. Mahan, J.G. Rosenbaum, J.M. Qas 389078 and 375351. Thicknesses over about 10 m (32 ft) may reflect Licciardi, and M.J. Pavich, 2011, A loess–paleosol record of climate and 130917-8 Qab Alluvium of Badger Creek floodplain (Holocene)—Light gray well-rounded, multiple flow lobes near the vent and ponding in grabens. Vent location glacial history over the past two glacial–interglacial cycles (~ 150 ka), Qas Qas Qbbc pebble- and cobble-sized gravel and sand. Planar to cross-bedded; clasts uncertain because of thick loess cover; topographic high point labeled southern Jackson Hole, Wyoming: Quaternary Research v. 76, p. 119-141. 353985 72413-2 357381 357390 are composed of rhyolite, granite, biotite gneiss, limestone, dolomite, and “6234” in SW/4 sec. 20, T. 7 N., R. 45 E. (lat 43.9148° N, long 111.1749° Polun, S.G., 2011, Kinematic analysis of late Pleistocene faulting in the Blackfoot Qyh A Qel/Qyh Qas sandstone. Thickness is about 3 m (10 ft). Locally subject to seasonal flood- W) seems most likely for flows south of Bitch Creek. Correlation with very lava field, Caribou County, Idaho: Idaho State University M.S. thesis, 86 p. Prostka, H.J., and R.J. Hackman, 1974, Preliminary geologic map of the NW Qbbc Qel/Qbbc ing. Badger Creek is dominantly a bedrock reach downstream of sec. 26, T. poorly exposed basalts north of Bitch Creek is much less certain. Large Qls Qas Qbbc 7 N., R. 44 E. boulders of basalt with abundant quartz and feldspar xenocrysts along A-T 1/4 Driggs 1[degree] by 2[degree] quadrangle, southeastern Idaho: U.S. Qel/Qba grade between the Bitch Creek bridge and Lamont suggest that another vent Geological Survey, Open-File Report OF-74-105, scale 1:125,000. Qyh A''' Qafbn Alluvial fan of Badger Creek North (Late Pleistocene)—Light gray well- Prostka, H.J., and G.F. Embree, 1978, Geology and geothermal resources of the Qba is present at a 6240 ft high point in NW 1/4 sec. 4, T. 7 N, R. 45 E. (lat rounded cobble- to pebble-sized gravel, planar bedded with local sandy 43.9687° N, long 111.1566° W). Landforms in this area suggest that flows Rexburg area, eastern Idaho: U.S. Geological Survey Open-File Report Qel/Qbbc 418924 Qas cross-beds. Clast composition is similar to Qab. Generally capped by as from the vent ponded eastward against a fault scarp and moved westward 78-1009, 14 p., 2 plates, scale 1:48,000. much as 64 cm (25 in) of silty loam soil. Thickness ranges from 6 to 12 m Reynolds, R.L., 1977, Paleomagnetism of welded tuffs of the Yellowstone Qls Qbbc almost to Conant Creek. 427049 (20 to 38 ft). Unit consists of glacial outwash formed during the last glacia- Group: Journal of Geophysical Research, v. 82, p. 3677-3693. Qel/Qyh tion (Pinedale) of the Teton Range. Huckleberry Ridge Tuff (early Pleistocene)—Crystal rich, densely welded Richmond, G.M., 1973, Surficial geologic map of the Warm River Butte quad- Qel/Qbbc Qel Qgo rhyolitic ignimbrite. Shown as Qel/Qyh where covered by loess, and rangle, Yellowstone National Park and adjoining area, Idaho and Wyoming: Qd Diamict and lake deposits of Badger Creek (Pleistocene)—Known only from Qyh Qyh Qls Qgo/Qyh where covered by glacial outwash and loess. Major phenocrysts U.S. Geological Survey, Miscellaneous Geologic Investigations Map I-645, 130917-5 Qas subsurface information; not exposed in the map area. Shown as Qab/Qd Qyh are sanidine and quartz, with lesser plagioclase and pyroxene. Erupted scale 1:62,500. Qbbc Qas 72913-1 and Qafbn/Qd where covered by alluvium. Water wells (IDWR, 2014) and from the Big Bend Ridge Caldera in the Yellowstone volcanic field, and Qbbc Qyh Scott, W.E., 1982, Surficial geologic map of the eastern Snake River plain and auger logs for Highway 33 Badger Creek bridge at lat 43.8650° N, long divided into three members A, B, and C (Christiansen, 2001). Only adjacent areas, 111 degree x 115 degree W., Idaho and Wyoming: U.S. Geologi- Qel/Qba Qab R 111.1804° W (ITD, 2013), penetrate 12 to 30 m (40 to 120 ft) of very dense Member B is present in the map area according to Christiansen (2001); cal Survey, Miscellaneous Investigations Series Map I-1372, scale 1:250,000. Qbbc 3 Qel/Qbbc 326982 Qbbc Qyh clayey gravel, clayey sand, and clay beneath units Qab and Qafbn. Gravels however Wilson (2009; personal communication, 2014) determined that 345325 Soil Survey Staff, 2014, Natural Resources Conservation Service, United States Qas are angular to subrounded, about 2 to 4 cm in length, and composed of members A, B, and C are present, that Member A is by far the thickest, and Department of Agriculture. Soil Survey Geographic (SSURGO) Database Qbbc rhyolite, gneiss, and quartzite. Gravels are mostly matrix supported, Qel/Qyh that almost all Qyh in the map appears to be Member A. Paleomagnetic for Teton and Fremont counties, Idaho. Available at: http://soildatamart. suggesting origin as glacial till or debris flow. Lake deposits consisting of inclination and declination are anomalous (Reynolds, 1977) and correlated nrcs.usda.gov (accessed 7 February 2014). well-bedded silt with thin organic layers (interpreted to be varves) are with the Reunion Normal-Polarity Subchron between 2.128-2.148 Ma. Wilson, C.J., 2009, Physical volcanology of the Huckleberry Ridge Tuff: Eos 4 Qyh locally present. Unit is an aquatard. Recent mean 40Ar/39Ar ages for the three members are 2.135 ± 0.006 Ma, Qls Qyh Transactions American Geophysical Union, 90(52), Fall Meeting Supple- Qyh 2.131 ± 0.008 Ma, and 2.113 ± 0.004 Ma, respectively (Ellis and others, Qbbc Qabi Alluvium of Bitch Creek (Holocene-Late Pleistocene)—Cobble gravel and ment, Abstract V23-C-2085. 2012). At the railroad trestle over Bitch Creek, (sec. 9, T. 7 N., R. 45 E.) Qel/Qyh Qyh Qas sand derived from the western Teton Range; includes clasts of basalt, Qas consists of >33 m (>100 ft) of gray to pink eutaxitic rhyolite that weathers Qas Qyh rhyolite, gneiss, quartzite, sandstone, and rare pieces of jade and petrified Qbbc into large rounded blocks; closely spaced 1 cm lithophysae are locally ACKNOWLEDGMENTS Qyh wood. Thickness generally less than 3 m (10 ft). Bitch Creek is predomi- Qbbc Qbbc Thanks to J. Fenn, G. Ricks, and E. Soyland for permission to conduct Qbbc Qas Qel/Qba Qel/Qyh mapping on their respective properties; to K. Fletcher (UI) for performing the Table 1. Paleomagnetic data for the Lamont quadrangle. 375351 338515 Qas paleomagnetic analyses; and to G. Embree (BYU-Idaho) for helpful discus- sions and insights into the regional geology of the Teton Basin. S. Enright R 130917-12 Qyh 72613-3 Sample Map α κ (Idaho Transportation Department) provided auger logs from Badger Creek. 130917-13 number unit Latitude Longitude n D I 95 R Polarity Treatment Qyh N C. Wilson shared his extensive knowledge of the Huckleberry Ridge Tuff. Qbbc Qas 13P04 Qbbc 43.87732 -111.17758 6/8 198 -51 7.1 5.945 90.9 R PCA Qba Qab/Qd 340254 Qyh 5 Qyh 13P05 Qbbc 43.93610 -111.17920 8/8 194 -54 2.5 7.986 504 R PCA Qas Qas Disclaimer: Although this map was compiled from digital data that was 389078 Qel/Qyh n = number of cores used / number of cores measured. 413709 D = site mean declination of characteristic remanent magnetization (ChRm). successfully processed on a computer system using AutoCAD and ESRI 327368 I = site mean inclination of ChRM. ArcGIS software at the Idaho Geological Survey (IGS), no warranty, expressed Qafbn/Qd α = confidence limit for the mean direction at the 95% level. 327074 13P04 95 or implied, is made by the IGS regarding the unity of the data on any other 407011 κ = precision parameter. Qel/Qba Qbbc Polarity: N = normal; R = reverse. system, nor shall the act of distribution constitute any such warranty. The IGS ChRM isolated by principal component analysis (PCA) of alternating field demagnetization. does not guarantee this map or digital data to be free of errors nor assume Qel/Qba All analyses performed in IGS paleomagnetism laboratory. liability for interpretations made from this map or digital data, or decisions based thereon.

Base Map Credit Field work conducted 2013. Base digitally scanned from 24,000-scale USGS film separates, 1965. MN This geologic map was funded in part by the U.S. Geological

WARM SHEEP RIVER LAKE FALLS Survey National Cooperative Geologic Mapping Program, Shaded elevation from 10 m DEM. SCALE 1:24,000 PORCUPINE Table 2. Major oxide and trace element chemistry of samples collected in the Lamont quadrangle. GN 1 0.5 0 1 USGS award no. G13AC00122. Topography by photogrammetric methods from aerial photographs o o 0 13 12.02 MILE Major elements in weight percent Trace elements in parts per million taken 1963. Field checked 1965. Digital cartography by Jane S. Freed at the FEET Idaho Geological Survey’s Digital Mapping Lab. Sample Map LAMONT McRENOLDS Projection: Idaho coordinate system, east zone (Transverse Mercator). 1000 0 1000 2000 3000 4000 5000 6000 7000 DRUMMOND RESERVOIR number Latitude Longitude Unit name unit SiO TiO Al O FeO* MnO MgO CaO Na O K O P O Sum LOI Ni Cr Sc V Ba Rb Sr Zr Y Nb Ga Cu Zn Pb La Ce Th Nd U 1927 North American Datum. Technical review status: Authors only. 2 2 2 3 2 2 2 5 KILOMETER 130917-5 43.89796 -111.22828 Basalt of Bitch Creek Qbbc 48.02 1.731 16.60 11.14 0.181 9.01 10.29 2.51 0.23 0.317 100.04 0.22 174 357 31 254 355 1 265 159 28 15.7 19 28 105 5 20 45 3 22 0 10,000-foot grid ticks based on Idaho coordinate system, east zone. UTM Grid and Editorial review by Alyson R. Kral. 2014 Magnetic North 1 0.5 0 1 IDAHO Map version 1-22-2015. Declination at Center of Map LAKE 130917-8 43.91079 -111.23843 Basalt of Bitch Creek Qbbc 49.18 1.731 16.03 10.83 0.173 7.38 10.52 2.63 0.53 0.433 99.43 0.26 128 293 29 256 475 11 272 164 31 15.5 19 54 104 4 23 44 3 24 1 1000-meter Universal Transverse Mercator grid ticks, zone 12. TETONIA CLAWSON Contour interval 10 feet PACKSADDLE PDF (Acrobat Reader) map may be viewed online at Declination from NOAA National Geophysical Data Center. 130917-12 43.88332 -111.24668 Basalt of Ard Farms Qba 45.34 2.290 15.46 13.68 0.199 7.19 9.15 2.82 0.43 0.450 97.01 1.79 96 62 28 296 316 6 257 202 35 18.5 22 66 128 3 22 45 1 25 2 www.idahogeology.org. QUADRANGLE LOCATION ADJOINING QUADRANGLES 130917-13 43.88379 -111.24753 Basalt of Bitch Creek Qbbc 49.01 1.533 15.79 10.53 0.164 8.69 10.57 2.53 0.52 0.277 99.61 0.37 163 337 28 231 426 11 267 145 26 13.3 17 52 95 3 22 40 2 20 2

72413-2 43.91064 -111.16137 Basalt of Bitch Creek Qbbc 45.47 2.335 16.28 11.94 0.181 6.62 11.86 2.55 0.25 0.458 97.96 1.59 92 210 29 282 370 3 336 165 30 17.1 20 31 113 5 21 54 2 28 1

72513-21 43.93651 -111.17741 Basalt of Bitch Creek Qbbc 44.57 1.990 17.27 13.10 0.797 6.13 7.86 2.36 0.21 0.304 94.59 3.87 168 173 29 253 1137 2 239 172 39 18.4 20 62 125 3 25 46 3 23 0

Hill "6234" 72613-3 43.88306 -111.16836 Basalt of Bitch Creek Qbbc 48.90 1.727 16.46 11.57 0.175 7.84 10.11 2.79 0.56 0.264 100.40 0.11 166 175 26 238 356 11 260 160 29 17 19 39 110 5 22 41 2 22 1 A A’ A’’ vent A’’’ 72713-13 43.94501 -111.20373 Basalt of Bitch Creek Qbbc 48.44 1.841 16.68 11.96 0.180 7.58 9.92 2.73 0.50 0.331 100.14 0.25 166 171 28 247 465 7 262 179 31 18.8 20 48 117 3 22 47 3 24 0 7,000 357393 374593 353985 Ashton-Tetonia 7,000 357390 356104 357381 Trail Badger 393077 72913-1 43.89711 -111.21475 Basalt of Bitch Creek Qbbc 47.58 1.548 14.94 10.11 0.159 8.30 12.01 2.42 0.53 0.283 97.88 1.95 154 320 28 226 357 11 280 147 25 13.9 17 42 92 4 16 38 2 17 1 Qbbc Qbbc Creek Qyh 72913-2 43.92351 -111.23527 Basalt of Bitch Creek Qbbc 46.57 1.760 15.39 11.31 0.174 7.40 11.03 2.50 0.49 0.288 96.92 2.32 150 154 27 227 485 9 272 168 30 17.6 20 64 109 3 19 45 2 24 0 6,000 Qbbc 6,000 FEET Qyh Qyh 13DG704 43.92950 -111.19971 Basalt of Bitch Creek Qbbc 48.75 2.676 15.55 12.63 0.194 6.71 9.87 2.74 0.61 0.556 100.28 -0.36 88 193 31 303 445 11 313 233 35 22 20 56 125 5 26 61 2 32 1 FEET Tb Qyh Qyh Tb Qyh Tb Qyh Ts Ts Thr 73013-5 43.94583 -111.23420 Basalt of Bitch Creek Qbbc 47.34 1.799 16.61 11.84 0.177 7.73 10.31 2.74 0.38 0.268 99.19 0.62 164 180 26 249 435 4 284 158 31 18.2 21 54 114 7 22 45 3 24 1 Thr Thr Ts Ts Thr Thr 5,000 ? ? ? ? ? ? ? ? ? 5,000 Major and trace elements are not normalized. *Total Fe expressed as FeO. 5,500 5,500 Water wells shown with Idaho Department of Water Resources WellID number. Water well logs can be found at Surficial units of loess and outwash are not shown. All analyses performed at Washington State University GeoAnalytical Laboratory, Pullman, Washington. http://www.idwr.idaho.gov/apps/appswell/RelatedDocs.asp?WellID=xxxxxx where “xxxxxx” is the six-digit WellID.

Published and sold by the Idaho Geological Survey University of Idaho, Moscow, Idaho 83844-3014