IDAHO GEOLOGICAL SURVEY DIGITAL WEB MAP 179 MOSCOW-BOISE-POCATELLO IDAHOGEOLOGY.ORG FEENEY AND PHILLIPS

GEOLOGIC MAP OF THE MIDVALE QUADRANGLE, WASHINGTON COUNTY, City of Midvale Well SW 1/4 SW 1/4 sec. 8, T. 13 N., R. 3 W.

Well logs 364619 and 398035 Dennis M. Feeney and William M. Phillips Feet Below Ground Surface 0 Gravel and Overburden 2016 CORRELATION OF MAP UNITS Sand and Gravel Artificial Alluvial Deposits Sedimentary Deposits Deposits Qafo QTs? Qt1 100 QTs? Qaw m Qt Qlp Qaw Qas QTs? Ts Qaw Qaf Qaw 1 Holocene Qaf Ts Qt1 Qaf 0.01 ka Ts QUATERNARY Qt Qt ? 1 2 423902 Qt Twb 2 Ts 2 ª Pleistocene 200 Qas QTs? Qas Qafo QTs QTs? Qaw Blue Clay Qt 1 Qas 2.6 Ma Qaf ? 300 Qt1 Ts Qafo Qt1 Pliocene m Qaw ? Qaw Qas 5.3 Ma Volcanic Rocks 400 Qaw Qaw Rhyolite and Basaltic Basalt Qaf andesite andesite TERTIARY Qaw 436355 Weiser volcanics ª 367711 Qas BX6031* ª Twb 500 Basalt 288654 2 427441 Qaf Ts Ts ª Twb Miocene A 376249 ª 1 359569 ª 14.9 ± 0.57 Ma* Shale and Rock Stringers ª 289163 Twba 600 ª 15.1 ± 0.16 Ma* Basalt m Ts Green Shale Qaw 289500 367717 Tmv Columbia River Qaw m ª ª Basalt Group Basalt (very hard) Broken Basalt with Water Tgr1 700 Qaw ? Basalt (very hard) Qaf Gray Shale *Richard Gaschnig, personal comm., 2015. BX6032 Basalt Shale Qt Basalt 1 800 Qafo ª 364619 424042 Shale Qas ª 365834 Basalt Ts Blue Shale Qas ª Twb Qaf 2 Brown Shale and Sand 424657 Qt1 Qaw ª SYMBOLS 900 ALLUVIAL DEPOSITS Qaf Contact: dashed where approximately located. Basalt Qlp Lake and playa deposits (Holocene and Pleistocene)—Fine sand, silt, and clay sorted into thin laminar beds deposited during periodic floods around small Qt Normal fault: ball and bar on downthrown side; dashed where approxi- TD 990 feet 1 man-made reservoirs. Figure 1. Photograph looking southwest of QTs ª Qaf mately located; dotted where concealed. sediments as they appear at lat. 44.4414˚ N. long. 1000 337894 Qt1 Qas Alluvium of side streams (Holocene)—Clayey sand, silt, and fragments of shale 116.7402˚ W. The perspective is from the banks of the Weiser River looking up at the sequence. Estimated strike and dip direction of volcanic flows. in small channels draining landscapes underlain by Tertiary sedimentary Figure 2. Log of water well drilled for the City of Midvale based Qaf Qt2 deposits (Ts). In streams draining basaltic landscapes such as Sage Creek upon records filed with the Idaho Department of Water Resources. Qt1 367711 Water well showing Well ID number. Selected water wells shown with and Dry Creek south of Midvale, deposits are predominantly well-rounded The well was drilled to a depth of 963 feet below ground surface 288686 Idaho Department of Water Resources WellID number. Water well logs on June 15, 1962. At that time, the well had artesian closed-in Qt basaltic cobbles. In Dutch Flat, unit includes broad unchanneled areas 1 QTs pressure of 175 psi, flow rate of 2000 gpm, and water temperature ª m can be found at underlain by thin re-worked eolian sediments. Thicknesses range from <1 http://www.idwr.idaho.gov/apps/appswell/RelatedDocs.asp? to 2 m (<3 to 6.5 ft). Many tributary streams are ephemeral. Subject to VOLCANIC ROCKS of about 80°F. The well was deepened to 990 feet on November 25, 1983. At that time, well had artesian closed-in pressure of 158 WellID=xxxxxx where “xxxxxx” is the six-digit WellID. seasonal flooding during spring snowmelt and summer thunderstorms. psi, flow rate of 800 gpm, and temperature of 81°F. Original well Weiser volcanics logs are available at http://www.idwr.idaho.gov/apps/appsWell/ Qaw 14DF303 Geochemical sample location. Qaw Alluvium of Weiser River (Holocene)—Well-rounded cobbles and coarse- to m Twb RelatedDocs.asp?WellID=364619 and http://www.idwr.idaho. 2 Weiser basalt 2 (Miocene)—Medium- to dark-gray with shades of purple, fine- Qaf medium-grained subrounded sand; cobbles dominated by dark-gray to gov/apps/appsWell/Related Docs.asp?WellID=398035. Ts m R Fluxgate magnetometer reading location (R - reverse, N - normal). black mafic volcanic rocks, with rare light-gray to yellowish tuffs and to medium-grained basalt. Phenocrysts and microphenocrysts compose 15 QTs granitic rocks. Sand consists of quartz, feldspar, and black and orange-gray percent; phenocrysts are plagioclase as long as 3 mm, iddingsite up to 2 Ts Patterned ground: Circular to elongate silty mounds separated by gravelly lithic fragments. Micas are absent. Forms cobble point bars with braided mm, olivine, and augite; the remaining 85 percent is groundmass. Normal Qt1 Qt1 zones form a pattern of contrasting soil characteristics and vegetation channels 1 to 1.5 m (3 to 5 ft) deep. Islands and tops of some bars have thin magnetic polarity as determined in the field (fluxgate magnetometer) and Qt Qaf REFERENCES 2 that are readily mappable from aerial images. The mounds average 9 to deposits of arkosic sand. Thickness estimated at 2 to 3 m (6.5 to 10 ft). by laboratory paleomagnetic analysis (Feeney and others, 2014; Garwood Qt 2 29 m (30 to 95 ft) in diameter and 0.3 to 2 m (1 to 6 ft) in height. They Inundated during spring snowmelt or during winter rain-on-snow events in and others, 2014). Formerly mapped as the Star Butte member of Weiser Qaw 14DF303 are associated with a grain size contrast that varies from silt and clay in headwaters. Basalt by Fitzgerald (1982). Consists of up to four flows ranging from about Feeney, D.M., D.L. Garwood, and W.M. Phillips, 2014, Geologic map of the Qt1 m QTs N the mounds to gravel in the intermounds. The patterned ground occurs 3 to 9 m (5 to 30 ft) in thickness (Fitzgerald, 1982). Outcrops are long ridges Mann Creek SE quadrangle, Washington County, Idaho: Idaho Geological Qt Lower terrace alluvium of Weiser River (Holocene)—Predominantly well- on surfaces of gravel terraces, alluvial fans, and basalt flows with 1 with rare colonnades, or blocky well-vesiculated flow tops in gullies or Survey Digital Web Map 169, scale 1:24,000. BX6041 rounded basaltic cobbles and brown silty sand and clayey sand; water wells varying degrees of weathering. Malde (1964) noted that patterned flats. Generally a capping unit; however, preexisting structures and eleva- Feeney, D.M., R.S. Lewis, W.M. Phillips, D.L. Garwood, and S.W. Cooley, Twb2 indicate thickness of about 1.8 to 6 m (6 to 20 ft). Subject to flooding during tion around Star Butte (a possible vent) apparently caused Twb to flow Twb ? Qt ground of soil mounds and stone pavements is common in southern 2 2016, Geologic map of the Hog Creek Butte quadrangle, Washington and 1 1 spring snowmelt or during winter rain-on-snow events in headwaters. around older Twb . Source areas are uncertain. Chemical analyses from 14DF302 Idaho on gravel fans, basaltic lava flows, and rocky colluvium. His 1 Adams counties, Idaho: Idaho Geological Survey Digital Web Map 174, Qas Separated from Qt2 by a 3 to 6 m (10 to 20 ft) scarp. this quadrangle and adjacent quadrangles shows Twb with a SiO content Qas description is aptly applied to the best-developed patterned ground 2 2 scale 1:24,000. QTs ranging from 46.29 to 48.94 percent, TiO content ranging from 1.60 to observed in this quadrangle: “Soil mounds in flat areas are closely Qt Higher terrace alluvium of Weiser River (late Pleistocene)—Water wells 2 Fitzgerald, J.F., 1981, Geology and basalt stratigraphy of the Weiser embay- 2 2.64 percent, and P O content ranging from 0.56 to 0.95 percent (Table 1; Qt packed, monotonously uniform circular heaps 50-60 feet across and 3 (427657, 424042, 436355) indicate 4.9 to 6 m (16 to 20 ft) of cobble gravel 2 5 ment, west-central Idaho: University of Idaho Ph.D. dissertation, 121 p. Qaw 1 Feeney and others, 2014; Feeney and others, 2016; Garwood and others, Qaw feet high, but on slopes they are elliptical and lie in rows along paths of topped with about 1.5 m (5 ft) of brown silty sand or silty clay. Gravel pit in Fitzgerald, J.F., 1982, Geology and basalt stratigraphy of the Weiser embay- Qaf BX6040 2014); differences in composition may reflect separate flows. Interbeds of soil that trend downhill. Each mound is composed of a lens-shaped cap sec. 7, T. 14 N., R. 3 W. is developed in this unit. ment, west-central Idaho, in Bill Bonnichsen and R.M. Breckenridge, eds., of silt about 18 inches thick, abruptly underlain by 1-2 feet of brown tuffaceous material, ash, breccia, or Ts are present locally between Cenozoic Geology of Idaho: Idaho Bureau of Mines and Geology Bulletin Qaw BX6043 14DF330 clay” (Malde, 1964: p. 191). It is likely that the patterned ground Qaf Alluvial fan deposits (Holocene and late Pleistocene)—In Middle Valley, individual flows and above or below the unit; no attempt was made to 26, p. 103-128. m formed through periglacial processes during times of colder climate in consists of crudely bedded, poorly sorted, gray to brown sand, silt, and clay show the interbeds unless mappable at 1:24,000 scale. Fitzgerald, J.F., 1984, Geology and basalt stratigraphy of the Weiser embay- Ts m the Pleistocene. These processes are investigated and modeled by derived from Tertiary sedimentary deposits (Ts). These fans have coalesced Twb ment, west-central Idaho: Rockwell International Corp., Richland, WA, Twb N 1 Weiser basalt 1 (Miocene)—Purplish-gray to dark-gray, fine- to coarse-grained 1 N Kessler and Werner (2003), who attribute the resulting landform to into semi-continuous fan aprons that interfinger with gravels and sands of Rockwell Hanford Operations, RHO-BW-SA-217P, 121 p. basalt. Phenocrysts and microphenocrysts compose 70 percent; pheno- BX6044* Ts freeze-thaw cycles that sort stones and soil. Qt . Apparent thickness from topography and water wells (423902, Garwood, D.L., D.M. Feeney, and W.M. Phillips, 2014, Geologic map of the 2 crysts are interlocking plagioclase as long as 8 mm, corroded augite, 5 365834, 367711, 367717, 289500) is 3 to 12 m (10 to 40 ft). Nutmeg Flat quadrangle, Washington County, Idaho: Idaho Geological 14DF30 iddingsite, olivine, and trace interstitial hornblende; the remaining 30 Survey Digital Web Map 168, scale 1:24,000. Twb2 percent is groundmass. Voids are common among the interlocking crystals. Qafo Older alluvial fan deposits (Pleistocene)—Sand, silt, and clay over gravel; Garwood, D.L., K.L. Othberg, and J.D. Kauffman, 2010, Geologic map of the Reverse magnetic polarity as determined in the field (fluxgate magnetom- comprises surface deposits on the Shoe Peg Valley alluvial fan. Water wells Indian Valley quadrangle, Adams County, Idaho: Idaho Geological Survey INTRODUCTION eter) and by laboratory paleomagnetic analysis (Feeney and others, 2014; Twb (288654, 289163, 359569, 376249, 427441) indicate from 1.5 to 6.4 m (5 Digital Web Map 121, scale 1:24,000. 1 Garwood and others, 2014). Formerly mapped as the Sugarloaf member of to 21 ft) of fine-grained sediments over 1.2 to 3 m (4 to 10 ft) of gravel. These Idaho Department of Water Resources (IDWR, 2015, Water Well data. Weiser Basalt by Fitzgerald (1981 and 1982). Consists of up to nine flows R Ts The geologic map of the Midvale 7.5’ quadrangle depicts the rock units deposits are best exposed on the incised edge of the fan adjacent to Available at: http://www.idwr.idaho.gov/GeographicInfo/gisdata/gis_data. 14DF306 ranging from about 9 to 18 m (30 to 60 ft) in thickness (Fitzgerald, 1982). Qas exposed at the surface or underlying a thin cover of soil or colluvium; Highway 95 north of Midvale. htm (accessed January 20, 2015). BX6046 Vent location is unknown. Outcrops are long ridges with partial colon- alluvial and man-made surficial deposits are also depicted where they form Kessler, M.A., and B.T. Werner, 2003, Self-organization of sorted patterned BX6047 nades or well-vesiculated blocky flow tops. Chemical analyses from this BX6048 significant mappable units. This map is a result of fieldwork conducted in ground: Science, v. 299, p. 380-383. Qas quadrangle and adjacent quadrangles shows Twb with a SiO content BX6049 the summer and autumn of 2014 by the authors. Previous work in the area SEDIMENTARY DEPOSITS 1 2 Kirkham, V.R., 1931, Revision of the Payette and Idaho formations, Journal of ranging from 49.64 to 51.65 percent, TiO content ranging from 1.19 to includes the surficial geology map of Othberg (1982), and geology of the 2 Geology, v. 39, no. 3, p. 193-239. QTs 1.64 percent, and P O content ranging from 0.33 to 0.61 percent (Table 1; (Lund, 2004). The field maps, field notes, fluxgate Quaternary-Tertiary sedimentary deposits (Pleistocene and Pliocene)—Silt, 2 5 LeBas, M.J., and A.L. Streckeisen, 1991, The IUGS systematics of igneous rocks: Twb1 Feeney and others, 2014; Feeney and others, 2016; Garwood and others, magnetometer data, XRF analytical chemistry, and posthumous Ph.D. by clay, fine-grained sand, and lesser gravel; best exposed along east side of Journal of the Geological Society, London, v. 148, p. 825-833. m 2014); differences in composition may reflect separate flows. The absence James Fitzgerald (1981, 1982, and 1984) were consulted and incorporated the Weiser River in sec. 19, T. 13 N., R. 3 W. where about 7 m (23 ft) of gray Lindgren, W., 1898, Description of the Boise quadrangle, Idaho: U. S. Geologi- of Twb in the southeast corner of the map indicates an unconformity where appropriate. to light-brown, laminated to very thinly bedded clayey silts are interbedded 1 cal Survey Geologic Atlas, Folio 103, 7 p. between Twb and Twba. Abundant ash, breccia, tuffaceous material, or Ts with about 4.5 m (15 ft) of well-rounded cobbles (Figure 1). In the City of 2 Lund, K.L., 2004, Geology of the Payette National Forest and vicinity, west- form interbeds between individual flows and below and above the unit. On The basement rocks of the Midvale 7.5’ quadrangle are Miocene composi- Midvale water well (364619; Figure 2), about 27 m (90 ft) of sand and central, Idaho: U.S. Geological Survey Professional Paper 1666-A, 89 p. m the far eastern edge of cross-section B-B' we have depicted the reemer- tionally diverse flows of the Weiser volcanics. The Weiser volcanics were gravel are correlated with this unit. Other water wells (424657, 424042, Malde, H.E., 1964, Patterned ground in the western Plain, Idaho, Twb2 likely erupted along north-northwest trending linear vents that followed gence of a thinner Twb unit east of Camp Creek; though its appearance is ª 365834) show the unit to consist of as much as 45 m (147 ft) of interbedded 1 and its possible cold-climate origin: Geological Society of America Bulle- 414999 regional structures and flowed over older Columbia River Basalt Group speculative, it correlates to Twb seen in the geology of northeastern sand, sandy clay, and gravel. The laminated deposits in this unit are 1 tin, v. 75, p. 191-208. volcanics. We use stratigraphy, whole-rock XRF geochemistry, paleomag- interpreted to be lake beds. Unit age range is uncertain. Large landslides are Nutmeg Flat quadrangle (Garwood and others, 2014). 432540 McIntyre, D.H., 1976, Reconnaissance map of the Weiser geothermal area, netic data, and morphology to differentiate volcanic units. When evaluating present in the upper Weiser River canyon. These landslides may have Twba Washington County, Idaho: U.S. Geological Survey Miscellaneous Field ª the rock types we use the total alkalis versus silica chemical classification dammed the Weiser River several times, creating lakes in the Middle Valley. Weiser basaltic andesite (Miocene)—Purplish-gray to dark-gray, fine- to Ts medium-textured basaltic andesite. Phenocrysts and microphenocrysts Studies Map MF-745, scale 1:62,500. of volcanic rocks from the International Union of Geological Sciences Based upon soil development on the youngest dam-break deposits in the Nakai, T.S., 1979, Stratigraphy of the Payette Formation, Washington County, Twb compose 40 percent; needle-like plagioclase as long as 5 mm, subhedral 2 (LeBas and Streckeisen, 1991). The Midvale quadrangle contains the three lower Weiser River canyon (Feeney and others, 2014), the youngest Idaho: University of Idaho M.S. thesis, 187 p. largest volume members of the Weiser volcanics (Twba, Twb , and Twb ). Midvale lake was probably in existence during the late Pleistocene. Older augite, and the remaining 60 percent is groundmass; samples can appear 1 2 aphyric. Voids and vesicles are common and locally filled with secondary Othberg, K.L., 1982, Surficial geologic map of the Baker quadrangle, Idaho: Though there are local variations in strike and dip, the general dip of the lake deposits could date the initial incision of the lower Weiser River Idaho Geological Survey Surficial Geologic Map 2, scale 1:250,000. volcanic flows are towards Middle Valley. Exposure of Weiser volcanics to canyon in the Pliocene. minerals. Reverse magnetic polarity as determined in the field (fluxgate Twb2 Shah, S.M.I., 1968, Stratigraphic paleobotany of the Weiser area, Idaho: the west and north indicate that Middle Valley and Shoe Peg Valley are magnetometer) and laboratory paleomagnetic analysis (Feeney and others, Ts Tertiary sedimentary deposits (Pliocene and Miocene)—Primarily flat lying to 2014; Garwood and others, 2014). Formerly mapped as the Cambridge University of Idaho Ph.D. dissertation, 189 p. Twb2 underlain by some portion of the Weiser volcanics. A' gently dipping fluvial arkosic sand with components of silty sand, and member of Weiser Basalt by Fitzgerald (1981 and 1982). Consists of up to Smiley, C.J., S.M.I. Shah, and R.W. Jones, 1975, Later Tertiary stratigraphy and Fluvial and lacustrine Tertiary sediments (Ts) were deposited prior to, clayey silt. Arkosic sand is medium to coarse grained, subangular to fourteen flows ranging from about 9 to 12 m (30 to 45 ft) thick (Fitzgerald, paleobotany of the Weiser area, Idaho: Idaho Bureau of Mines and Geology Qas contemporaneous with, and subsequent to Weiser volcanics, but their 1982). Outcrops appear as colonnades and brecciated flows. Abundant Information Circular 28, 12 p. N ª subrounded grains of quartz, potassium feldspar, plagioclase feldspar, and 288148 distribution across the area is largely controlled by north-northwest trend- in places trace amounts of biotite, muscovite, tuffaceous material, and ash, breccia, tuffaceous material, or Ts may form interbeds between ing normal faults and preexisting topography. The majority of Ts exposed in volcanic ash. Laminar beds, thin (<5 cm) organic beds, and frequent sets of individual flows. Source area is unknown. Chemical analyses from this quadrangle and adjacent quadrangles shows Twba with a SiO content this map is subsequent to Weiser basalt 2 (Twb 2). Ts lies conformably climbing ripples and cross-cutting beds are present locally. Unit generally 2 ranging from 52.57 to 57.01 percent and TiO content ranging from 0.76 to BX6071 beneath Twb 1 on the south side of Star Butte (Garwood and others, 2014), does not crop out in Midvale quadrangle; exposures include road cuts and 2 and in the southeast corner of the map Ts underlies Twb ; however, the a small slump in SW ¼ SW ¼ sec. 6, T. 13 N., R. 2 W. Appears as knolls 61 1.48 percent (Table 1; Feeney and others, 2014; Feeney and others, 2016; Qas 2 Qas units are too thin to be mapped at 1:24,000 scale. Middle Valley, which to 91.5 m (200 to 300 ft) tall across the center part of the map but also Garwood and others, 2014); differences in composition may reflect R hosts most of the Quaternary fluvial deposits, also hosts a significant lacus- appears as interbeds between flows which may range from < 1 meter to separate flows. Two samples taken from two separate flows within Twba 14DF314 trine deposit (QTs) (Figure 1). The age constraints on the lacustrine environ- several meters thick. Consists of undifferentiated Idaho Group and Payette provide 40Ar/39Ar ages of 14.49 ± 0.57 Ma and 15.1 ± 0.16 Ma (Richard ment are still to be determined; however, the lakes were likely caused by Formation. The unconsolidated sediments and sedimentary rocks of the Gaschnig, personal communication, 2015). N 14DF324 landslides down river in the Weiser River canyon, and older lacustrine Payette Formation and Idaho Group have been well described (Lindgren, deposits might be caused by volcanic events (Twa ) also found down the 1898; Kirkham, 1931; Shah, 1968; McIntyre, 1976; Nakai, 1979; and 3 Other volcanic rocks Weiser River canyon (Feeney and others, 2014). Smiley and others, 1975). The most definitive paper is a literature review ACKNOWLEDGMENTS Ts and interpretation by Kirkham (1931). Kirkham describes the Payette Faults are generally north-northwest trending normal faults. These fault Formation as Miocene sediments interbedded between Columbia River Tmv Mixed volcanics (Miocene)—Appears in cross-section only. Projected from N Thanks to Stanley Mertzman and Karen Mertzman at the X-Ray Laboratory structures are poorly exposed and are primarily mapped based on geomor- basalt flows and the Idaho formation (later redefined as Idaho Group) as unit mapped on the Hog Creek Butte quadrangle to the east (Feeney and at Franklin and Marshall College for their high-quality XRF analyses and phic expression and stratigraphy. Faulting and warping occurred prior to, nearly flat lying Pliocene sediments on top of Columbia River basalts. others, 2016). quick turnaround time. Thanks to Barbara Marvin, The Soulen Ranch, Twb2 during, and after emplacement of the basalts, in part controlling the distribu- However, due to the poor exposure of Ts and a dearth of fossils, constrain- 14DF318 Daniel Cesaro, Aimee Wolfe, Joy Faerber and her farm managers, Jerry tion of younger Tertiary and Quaternary deposits, and the Weiser River. ing the age is difficult. Our work leads us to believe that some flat-lying 14DF325 Twb 14DF319 Widner, and all other landowners ranchers and farmers who allowed us 14DF332 2 sediments are concurrent with the later phases of Weiser volcanics and are Columbia River Basalt Group access to their land to map the geology; your spirit of cooperation is to be Twb1 thus older than the proposed Pliocene age. We have mapped Ts as undiffer- 14DF333 m commended. Thanks to Richard Gaschnig and Vic Camp for additional DESCRIPTION OF MAP UNITS entiated until we can resolve a more definitive stratigraphic break. Tgr Grande Ronde Basalt R1? magnetostratigraphic unit (Miocene)—Appears in 1 analytical data and dates. Thanks to Reed Lewis for field reviews, editing, Twb cross-section only. Unit is projected from the Indian Valley quadrangle to Qlp 2 and valuable geology discussions. Thanks to Dean Garwood and John the east-northeast (Garwood and others, 2010). Kauffman for additional geologic discussions. m ARTIFICIAL DEPOSITS 14DF317 m N Man-made land (Holocene)—Boulder, sand, and gravel fill. Makes up the Twb1 abandoned Pacific and Idaho Northern railroad grade along the Weiser 14DF326 BX6062 Table 1. Major oxide and trace element chemistry of samples collected in the Midvale quadrangle. River, portions of Highway 95 at Midvale, and small stock-water dams in N the hills south, east, and southeast of Midvale. Thickness is generally less Major elements in weight percent Trace elements in parts per million 14DF307 than 2 m (6.5 ft). Sample Map Qlp number Longitude Unit name # ## 14DF315 Latitude unit SiO2 TiO2 Al2O3 Fe2O3 FeO MnO MgO CaO Na2O K2O P2O5 Total LOI Ni Cr Sc V Ba Rb Sr Zr Y Nb Ga Cu Zn Pb La Ce Th Nd Co U 14DF327 14DF302 44.4425 -116.6298 Weiser basalt 2 Twb 48.22 2.11 15.58 13.44 0.19 6.65 9.74 2.52 0.51 0.80 99.76 4.06 132 243 30 265 487 4.7 550 110 31.4 11.6 18.6 93 117 1 16 34 <0.5 54 0.7 15DF387 14DF334 14DF335 14DF323 2 Twba 14DF303 44.4469 -116.6463 Weiser basalt 2 Twb 48.20 2.16 15.04 14.21 0.23 7.11 9.41 2.42 0.55 0.76 100.09 3.33 138 211 30 253 558 5.5 554 102 35.4 10.7 18.4 77 124 <1 19 40 <0.5 59 1.7 Twba B' 2

N 14DF321 14DF305 44.4342 -116.7264 Weiser basalt 2 Twb 47.96 2.21 15.28 13.27 0.18 7.66 9.28 2.37 0.69 0.79 99.69 3.8 116 187 28 246 428 7.6 510 83 33.3 11.4 18.4 71 120 <1 12 35 4.9 53 1.4 BX6069 BX6061 14DF320 2 B m R 14DF328 14DF306 44.4281 -116.6944 Weiser basalt 2 Twb2 47.60 2.20 15.64 14.11 0.23 6.04 9.69 2.61 0.63 0.89 99.64 2.34 136 255 29 257 470 5.4 577 105 32 11.5 18.2 93 125 <1 15 34 4.8 57 0.6 Twb2 14DF316 Twb Twb2 14DF322 14DF307 44.3830 -116.6289 Weiser basalt 2 Twb 47.76 2.20 14.97 14.16 0.22 6.99 9.56 2.37 0.58 0.78 99.59 2.78 131 200 29 260 529 5.6 547 99 35.4 11.5 17.9 70 123 <1 21 40 3.7 57 1.6 1 BX6070 2 Twb1 R

14DF310 44.4119 -116.7517 Weiser basalt 2 Twb2 47.55 2.25 14.65 13.59 0.18 7.89 9.25 2.55 0.74 0.81 99.46 1.69 124 255 30 272 433 9.5 466 120 33.5 10.8 17.9 105 111 4 18 35 0.5 54 <0.5

14DF314 44.3997 -116.6622 Weiser basalt 2 Twb 47.80 2.27 14.76 13.69 0.20 7.72 9.46 2.64 0.61 0.84 99.99 1.77 118 251 29 282 424 6.7 538 125 32.1 11.8 17.2 67 112 7 15 35 5.8 55 1.5 Base Map Credit Field work conducted 2014. 2 Base digitally scanned from 24,000-scale USGS film separates, MN This geologic map was funded in part by the U.S. Geological 14DF315 44.3808 -116.6615 Weiser basaltic andesite Twba 54.91 0.95 16.99 8.98 0.17 4.51 7.72 3.35 1.62 0.46 99.66 2.32 95 142 21 183 767 17.6 620 177 32.4 10.6 18.8 66 96 2 31 52 <0.5 32 <0.5

HOPPER 1986. CREEK EAST OF Survey National Cooperative Geologic Mapping Program, CAMBRIDGE SCALE 1:24,000 CAMBRIDGE 14DF316 44.3753 -116.6901 Weiser basalt 1 Twb 50.24 1.33 17.55 10.37 0.18 5.10 10.97 2.97 0.79 0.34 99.84 1.38 103 281 29 253 475 8 665 108 28.8 7.2 17.8 75 71 6 19 33 <0.5 45 0.8 GN 1 Shaded elevation from 10 m DEM. 1 0.5 0 1 USGS award no. G14AC00164. 0o 35 14.03o MILE 14DF317 44.3853 -116.6932 Weiser basalt 2 Twb2 47.5 2.22 15.25 14.63 0.26 6.02 9.74 2.75 0.68 0.82 99.87 1.36 133 242 32 286 940 7.2 518 123 35.7 11.1 17.2 73 111 <1 22 36 2.5 58 <0.5 Topography by photogrammetric methods from aerial Digital cartography by Jane S. Freed at the Idaho Geological FEET Survey’s Digital Mapping Lab. HILL photographs taken 1980. Field checked 1982. MIDVALE MIDVALE BUTTE 14DF318 44.3918 -116.6915 Weiser basalt 2 Twb2 47.16 2.23 15.28 14.29 0.22 7.07 9.68 2.54 0.62 0.83 99.92 2 135 260 30 282 625 6 573 123 33 10.8 17.5 80 111 <1 17 29 2.8 54 <0.5 1000 0 1000 2000 3000 4000 5000 6000 7000 HOG CREEK Technical review status: Authors only. Map edited 1986. 14DF319 44.3911 -116.6820 Weiser basalt 2 Twb 47.68 2.14 15.02 13.80 0.19 7.30 9.39 2.60 0.78 0.82 99.72 2.6 163 284 28 269 430 8.1 519 115 32.9 10.7 17.2 71 123 <1 12 28 3.3 59 0.6 KILOMETER 2 Projection: Idaho coordinate system, west zone (Transverse UTM Grid and Map version 4-7-2016. 2014 Magnetic North 1 0.5 0 1 14DF320 44.3770 -116.6280 Weiser basaltic andesite Twba 55.95 1.04 17.35 8.52 0.14 2.96 8.19 3.52 1.55 0.46 99.68 4.71 107 142 22 189 725 16.7 598 182 26.3 11.2 19.2 48 103 <1 24 50 0.5 36 <0.5 Mercator). 1927 North American Datum. IDAHO PDF (Acrobat Reader) map may be viewed online at Declination at Center of Map SE NUTMEGFLAT MANN CREEK 10,000-foot grid ticks based on Idaho coordinate system, west Contour interval 20 feet CRANERESERVOIR CREEK www.idahogeology.org. 14DF321 44.3769 -116.6286 Weiser basaltic andesite Twba 54.67 0.93 16.94 9.07 0.15 4.89 7.77 3.32 1.54 0.43 99.71 1.91 86 134 22 178 745 16.1 641 168 26.6 9.4 18.3 60 91 <1 26 50 3.8 33 <0.5 Supplemental contour interval 10 feet zone. The IGS does not guarantee this map or digital data to be free of errors nor 14DF322 44.3763 -116.6309 Weiser basalt 2 Twb 48.02 1.60 15.69 12.76 0.21 8.12 9.73 2.60 0.49 0.57 99.79 2.75 134 248 28 241 401 3.3 460 122 30.5 10.1 16.9 109 97 <1 19 32 0.6 49 <0.5 QUADRANGLE LOCATION ADJOINING QUADRANGLES 2 1000-meter Universal Transverse Mercator grid ticks, zone 11. assume liability for interpretations made from this map or digital data, or A’ 14DF323 44.3792 -116.6282 Weiser basalt 2 Twb 48.62 1.98 15.59 12.91 0.22 6.96 9.31 2.72 0.64 0.76 99.71 1.54 115 186 30 285 660 6.1 511 146 32.1 14.5 17.4 84 113 6 21 37 5.8 51 1.5 2 Declination from NOAA National Geophysical Data Center. decisions based thereon. 4,000

Qas 14DF324 44.3989 -116.7439 Weiser basalt 1 Twb1 50.78 1.52 16.82 11.78 0.16 4.90 9.92 2.88 0.57 0.48 99.81 4.35 119 185 30 259 309 5.4 493 110 31.5 6.4 17.2 102 108 1 17 23 4 48 <0.5 432540 too thin 414999 14DF325 44.3911 -116.7410 Weiser basalt 1 Twb 49.74 1.27 16.30 11.02 0.17 6.95 10.68 2.62 0.68 0.37 99.8 2.23 138 341 32 258 882 6.9 647 104 27.7 8.5 15.9 101 89 3 17 28 <0.5 49 <0.5 to show 1 14DF326 44.3836 -116.7386 Weiser basalt 1 Twb 49.57 1.38 16.84 11.32 0.23 6.52 10.39 2.68 0.70 0.35 99.98 2.21 160 375 29 292 574 6.9 690 103 26.1 8.1 16.1 99 81 5 16 29 <0.5 55 <0.5 City of Midvale 1 Beaver 14DF327 44.3797 -116.7499 Weiser basalt 1 Twb 50.54 1.19 16.97 11.10 0.19 6.36 9.58 2.92 0.68 0.45 99.98 2.9 146 145 29 249 406 7.3 564 126 27.6 9.2 17.2 52 90 <1 19 34 2.4 45 <0.5 well Ts 1 A 427441 (See Fig. 2) Creek 288654 Weiser 387894 14DF328 44.3764 -116.7462 Weiser basalt 1 Twb1 50.06 1.31 17.39 10.90 0.21 5.51 10.52 2.75 0.62 0.34 99.61 1.89 118 301 29 248 511 6.8 639 107 25.2 9.8 17.2 85 81 1 16 23 <0.5 49 0.7 3,000 359569 3,000 Qafo 364619 River 424657 288686 Twb Twb2 2 14DF330 44.4369 -116.7379 Weiser basalt 2 Twb 46.98 2.16 14.93 13.72 0.19 8.40 9.16 2.58 0.77 0.79 99.68 1.92 144 251 29 266 413 7.7 498 115 32.9 10.3 17.5 210 115 2 15 32 4.8 55 0.8 Qaf Ts Ts 2 Qaf Qaw and Qt 1 Twb 14DF332 44.3906 -116.7310 Weiser basalt 2 Twb 47.96 2.25 15.37 13.78 0.21 6.56 9.67 2.52 0.61 0.84 99.77 1.19 117 222 31 287 594 6.4 537 36.3 36.3 12.2 17.7 85 110 <1 20 26 0.9 51 <0.5

1 FEET Twb1 2

QTs Twba Tmv? 14DF333 44.3892 -116.7292 Weiser basalt 2 Twb2 47.48 2.19 15.16 14.07 0.23 6.62 10.02 2.46 0.56 0.82 99.61 1.72 119 203 31 281 705 6.3 537 31.7 31.7 10.2 17.3 73 109 2 18 32 <0.5 52 0.5 Ts 14DF334 44.3796 -116.7231 Weiser basalt 2 Twb2 47.61 2.16 15.02 14.03 0.22 7.30 9.28 2.64 0.65 0.80 99.71 0.78 141 245 28 263 2001 6.6 677 58.6 58.6 10.9 16.6 63 109 23 26 42 <0.5 53 0.5 Twb 2 Ts 14DF335 44.3795 -116.7142 Weiser basalt 2 Twb 46.92 2.23 16.00 16.06 0.20 5.13 8.87 2.56 0.77 0.74 99.48 2.74 135 317 28 253 483 8.7 573 31.9 31.9 11.2 17.4 63 105 8 16 37 1.6 55 0.6

FEET Twba 2,000 2,000 2 Twb 1 Ts 15DF387 44.3797 -116.7436 Weiser basalt 1 Twb1 48.94 1.33 16.70 11.14 0.19 7.18 10.33 2.82 0.77 0.37 99.77 1.09 148 383 27 282 445 8.2 682 89 27.2 8.1 16.5 111 81 1 16 28 <0.5 44 0.9 Tgr1? BX6031 44.4837 -116.6617 Weiser basalt 2 Twb 48.44 2.302 15.44 12.68 0.217 6.76 9.50 2.63 0.80 0.892 99.65 123 248 33 285 551 9 520 111 31 13.0 17 65 126 4 23 50 29 1 Twba 2 Tgr1? BX6032 44.4720 -116.6702 Weiser basalt 2 Twb2 47.13 2.333 15.10 12.75 0.197 7.19 9.78 2.67 0.57 0.872 98.59 140 254 30 290 554 7 536 113 31 13.2 18 47 123 4 21 53 1 28

Tgr1? BX6040 44.4388 -116.6745 Weiser basalt 2 Twb 47.11 2.129 15.34 12.24 0.203 7.73 9.58 2.54 0.57 0.801 98.24 148 276 30 267 540 6 544 102 28 12.3 18 60 120 5 22 46 1 28 2 1,200 1,200 2 Water wells shown with Idaho Department of Water Resources WellID number. Water well logs can be found at 2x vertical exaggeration. BX6041 44.4458 -116.6617 Weiser basalt 2 Twb2 47.48 2.225 15.64 11.75 0.186 7.29 9.66 2.71 0.63 0.822 98.40 146 261 30 271 609 7 549 110 33 13.0 17 58 120 3 21 50 2 30 1 http://www.idwr.idaho.gov/apps/appswell/RelatedDocs.asp?WellID=xxxxxx where “xxxxxx” is the six-digit WellID.

BX6043 44.4380 -116.7450 Weiser basalt 1 Twb1 49.90 1.649 16.70 10.19 0.178 7.39 9.56 2.99 0.85 0.467 99.88 108 185 31 276 397 11 479 96 24 9.6 19 68 99 5 14 34 1 20 0

BX6044* 44.4342 -116.7271 Weiser basalt 2 Twb2 48.38 2.210 16.37 11.77 0.24 6.78 10.09 2.49 0.80 0.880 112 212 30 260 496 10 554 114 29 14.8 59 112 18 48 0

BX6046+ 44.4278 -116.7457 Weiser basalt 1 Twb 49.77 1.677 16.67 10.55 0.185 6.97 9.98 3.15 0.66 0.494 100.11 119 183 32 277 401 8 501 106 26 9.0 17 99 132 103 16 40 1 19 2 B B’ 1 4,500 4,500 BX6047+ 44.4278 -116.7457 Weiser basalt 1 Twb 49.66 1.676 16.57 9.93 0.170 6.98 9.60 3.15 0.87 0.486 99.08 110 172 31 292 403 13 472 105 26 9.2 17 82 100 5 18 36 1 20 1 Little Crane Creek 1 BX6048+ 44.4278 -116.7457 Weiser basalt 1 Twb 49.66 1.582 16.60 9.75 0.163 6.98 9.49 3.16 0.89 0.479 98.75 132 185 31 261 410 13 483 108 26 8.8 18 89 95 4 15 37 2 22 1 Reservoir Camp 1

BX6049+ 44.4278 -116.7457 Weiser basalt 1 Twb1 49.31 1.643 16.45 10.26 0.157 7.74 9.74 3.08 0.75 0.476 99.32 139 196 31 269 380 8 487 104 27 9.8 17 90 98 6 13 37 1 20 1 4,000 Twb2 Creek 4,000 Twb2 Twb BX6061 44.3776 -116.6392 Weiser basalt 2 Twb 47.85 2.348 15.70 12.20 0.200 6.80 9.82 2.84 0.73 0.907 99.39 99 202 32 287 583 8 590 113 33 13.0 19 58 127 6 22 56 2 30 2 1 Qlp too thin to show. 2 Twb1 Twb1 BX6062 44.3837 -116.6540 Weiser basalt 2 Twb2 47.78 2.247 15.74 12.47 0.195 7.85 9.91 2.76 0.65 0.896 100.49 149 261 30 272 487 6 579 111 31 13.5 18 50 120 4 22 50 2 27 1 Twb Twb Ts FEET 1 2 BX6069 44.3772 -116.6826 Weiser basalt 1 Twb 49.39 1.377 16.67 9.86 0.143 6.56 10.21 2.94 0.80 0.345 98.29 129 357 30 281 410 9 635 87 23 9.2 16 89 86 3 12 34 1 19 Twba 1 Twba Twba Twb

FEET Twba Twba 2 Twba BX6070 44.3750 -116.6900 Weiser basalt 1 Twb1 49.69 1.344 16.96 9.68 0.181 6.82 10.39 2.99 0.82 0.357 99.22 155 367 29 257 486 9 665 87 22 9.6 16 84 88 5 11 25 1 14 1 Tmv? BX6071 44.4026 -116.7425 Weiser basalt 2 Twb 47.60 2.371 15.39 12.67 0.203 6.55 9.85 2.66 0.69 0.938 98.92 120 234 33 294 526 9 485 109 35 12.7 19 75 126 4 23 53 32 1 3,000 Twb1? 3,000 2 Tgr 1? Tgr 1? Tgr ? Twba? Samples with prefix 14 and 15 were analyzed by Stanley Mertzman at Franklin and Marshall College X-Ray Laboratory. Tgr Tgr ? 1 1 1 Tmv? Samples with prefix BX were sampled by James Fitzgerald in 1978 and 1979 and were reanalyzed at Washington State University’s Geoanalytical Laboratory in 2015. * indicates samples were reanalyzed for trace elements at WSU Geoanalytical Laboratory in 2008; only normalized major elements available. #Franklin and Marshall College reports total iron as Fe O . Tgr1? 2 3 ##WSU Geoanalytical Laboratory reports total iron as FeO. +Samples were collected in-section but are represented by one location on map. Notes indicate the smallest number corresponds to lowest flow. 2,100 2,100 2x vertical exaggeration.

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