Geologic Map of the Goodwin Meadows Quadrangle, Idaho

IDAHO GEOLOGICAL SURVEY DIGITAL WEB MAP 97 MOSCOW-BOISE-POCATELLO WWW.IDAHOGEOLOGY.ORG KAUFFMAN AND OTHERS

CORRELATION OF MAP UNITS

Alluvial Mass Movement Volcanic Rocks Intrusive Island-Arc Metavolcanic Amphibolite-Facies Metamorphic GEOLOGIC MAP OF THE GOODWIN MEADOWS QUADRANGLE, IDAHO COUNTY, IDAHO Deposits Deposits Rocks and Metasedimentary Rocks Rocks of Unknown Affinity rounded ridges within the KPgs unit. Bonnichsen and Godchaux (1994) studied the ultramafic rocks northeast of Corduroy Meadows (NE¼, sec. 1, Qam Qas Qaf Holocene T. 28 N., R. 3 E.) and reported anthophyllite, chlorite, tremolite, and talc, Qls QUATERNARY Disclaimer: This Digital Web Map is an informal report and may be Pleistocene with minor amounts of opaque oxides and serpentine. They also report revised and formally published at a later time. Its content and format hornblende-garnet ("blackwall zone") rock with ilmenite and spinel. An John D. Kauffman, Reed S. Lewis, David E. Stewart, and Keegan L. Schmidt may not conform to agency standards. Ts Pliocene exposure about 1 mile to the east-northeast (southern part of sec. 31, T. 29 N., R. 4 E.) was studied by Hoover (1986) and Bonnichsen and Godchaux Columbia River Basalt Group (1994) who reported talc-olivine-anthophyllite rock and pyroxenite. Two 2008 Latah Formation additional pyroxenite-bearing (orthopyroxene) bodies were discovered Sediments Grande Ronde Basalt A during our mapping west of Twin Cabins Creek in the southwest part of Tgr2 map. 65 Miocene TERTIARY Tgn1 CENOZOIC TRPc Tgr1 50 75 Tgr1 KPgs Gneiss and schist (Permian to Cretaceous)—Fine- to medium-grained 34 Tim 36 Tli Tgr Qls Qls 52 1 plagioclase-hornblende gneiss that grades into hornblende ± biotite ± 79 chlorite schist and muscovite-plagioclase-quartz ± biotite ± zoisite schist. Tgn Imnaha Basalt KPgs 1 Qam Also includes calc-silicate rocks and zoisite-plagioclase quartzite. Light Tim gray or green to black, weathers to a fine gray brown soil. Calc-silicate Tgr Tim 1 Qls rocks contain zoisite, epidote, chlorite, plagioclase, quartz, pyroxene, and 75 sphene. Garnet is common. Although some plagioclase-amphibole gneiss Qaf may be metavolcanic in origin, most (if not all) of the unit is probably Tgr Kto CRETACEOUS 1 Tgr1 metasedimentary.

Kto JURASSIC MESOZOIC 02JB042 Kto STRUCTURE Tgr1 KPgs KPum 06JK139 6 1 TRIASSIC MOUNT IDAHO STRUCTURE TRPsd TRPc Tgn1 PERMIAN PALEOZOIC Faults and folds of the southwest-northeast-trending Mount Idaho structure 81 (Schmidt and Lewis, 2007) cross the northwest corner of the map and ? 80 probably extend at depth under the northern part of the map (see cross 02JB041 section A-A'). The structure has a poorly understood, complex and lengthy 5 Qls history of deformation. Included in this feature are the Mount Idaho shear zone, a sheared, mylonitized zone as much as 1.2 miles wide within the 75 INTRODUCTION basement metamorphic rocks, and the Mount Idaho fault, which offsets 55 The geologic map of the Goodwin Meadows quadrangle depicts rock magnetic polarity, although field magnetometer readings commonly give both basement rocks and the overlying Columbia River basalts. The units exposed at the surface or underlying thin surficial cover of soil and weak normal or conflicting results, particularly near the top of the R2 Miocene and younger Mount Idaho fault, whose trace is interpreted to be colluvium. Thicker surficial deposits of alluvium and landslides are also 86 section. Consists of one or two flows in the central and southwest parts of just north of the quadrangle, represents south-side-up displacement on a depicted where they mask or modify the underlying rock units or form 70 the quadrangle. Unit thickness generally less than 100 feet. Local fault connected at depth to the Cretaceous-Paleogene Hammer Creek 80 62 significant mappable units. The map is the result of field work conducted thickening and thinning may result from structures developed on earlier thrust, which is the basal fault of the Mount Idaho shear zone. Monoclinal Tgr1 Kto in 2003, 2006, and 2007 by the authors. Previous work includes that of Grande Ronde Basalt or from erosion on the earlier basalt surface. to synclinal flexures that flank the south and east side of Mount Idaho in Tim? Bond (1963), reconnaissance mapping and sampling in the area from Ts the northwest part of the map are related to development of the Mount 1978 to 1980 (Camp, 1981; Swanson and others, 1981), mapping and Tgn1 Grande Ronde Basalt, N1 magnetostratigraphic unit (Miocene)—Dark Idaho fault. Tim geochemical analysis near the eastern edge of the map (Hoover, 1986), gray, fine-grained generally aphyric to plagioclase-microphyric basalt. unpublished mapping by Paul Myers (1977-1982), and reconnaissance Normal magnetic polarity. Number of flows not determined, but estimated Southeast of the Mount Idaho shear zone, higher-grade, hornblende- 64 73 sampling by John Bush in 2002. at three to five. Flows near the top of the sequence are commonly 50-70 dominated gneiss and schist occur in the basement window in the Qls Qam feet thick and typically sugary textured with scarce small plagioclase northwest corner of the map. On the adjacent Grangeville East Much of the northern and central parts of the quadrangle are underlain by phenocrysts 1-3 mm in length. Flows lower in the sequence are typically quadrangle, these rocks show mylonite fabrics adjacent to the Mount Ts? Miocene basalt flows of the Columbia River Basalt Group. Basement rocks thicker, generally 100-200 feet. Colonnades of thin flows and entablatures Idaho shear zone that do not persist for more than 30-100 feet from the Qls are exposed in the eastern and southern parts and in two drainages in the VC79-454 of thick flows tend to form tiered cliffs on steep canyon slopes. Thickness contact and are replaced by northeast-striking, southeast-dipping gneissic northwest corner. Permian to Triassic island-arc rocks of the Seven Devils of the unit ranges from 400 to 600 feet. and schistose banding and foliation (Schmidt and others, 2007). Group are exposed in a window through the basalt in the northwest Ts corner of the map. Permian to Cretaceous amphibolite facies Tgr1 Grande Ronde Basalt, R1 magnetostratigraphic unit (Miocene)—Mostly

? metamorphic rocks crop out in the eastern and southern parts of the dark gray, fine-grained aphyric to microphyric basalt. Uncommon GOODWIN MEADOWS FAULT quadrangle and in thrust contact with the Seven Devils Group rocks in the plagioclase phenocrysts 2-4 mm in length in one or more flows. Reverse The Goodwin Meadows fault, which appears to be a minor vertical fault, 06JK141 northwest. Cretaceous intrusive rocks are found in the canyon of the South magnetic polarity, although flows near the R -N boundary commonly 1 1 offsets Grande Ronde Basalt units in the vicinity of Goodwin Meadows. Fork Clearwater River, in a window through the basalt on the western side have inconsistent and weak field magnetometer polarity readings; The fault trends northeast through Goodwin Meadows, then bends ? of the quadrangle, and in intrusive contact with the metamorphic rocks in therefore the mapped contact is poorly constrained. Outcrop northward along the South Fork Clearwater River. Maximum displacement the south and east. The basalt flows invaded ancestral drainages and characteristics of flows are similar to those in the Grande Ronde N unit. Kto 1 in the basalt is about 300 feet. The fault appears to die out southwest of flooded the paleotopography. Structural warping of the basalt occurred Exposed thickness is about 700 to 800 feet. Goodwin Meadows and also just north of the quadrangle boundary. both during and after emplacement, in part controlling the distribution of ? younger basalt units, stream development, and the cutting of the South Tim Imnaha Basalt (Miocene)—Medium- to coarse-grained, sparsely to abun- Fork Clearwater River canyon. Major landslides are associated with the dantly plagioclase-phyric basalt; olivine common; plagioclase phenocrysts generally 0.5-2 cm but some are as large as 3 cm. Flows examined in the KPgs contact between basalt and basement rocks. A saprolite surface produced by deep weathering is noted at many localities. Alluvial deposits are found field have normal polarity. Poorly exposed along Forest Service Road 2022 57 within the canyon of the South Fork Clearwater River 1,000 feet above below Cove Road in the northeast part of the quadrangle. Also found as SYMBOLS present river level and may represent a terrace remnant of an older regime float fragments at elevations as high as 5,200 feet on the north slope of Tgn1 65 Contact: dashed where approximately located. 60 of the river. A similar high gravel deposit at an elevation of 5,000 feet in Mount Idaho. Imnaha in the northeast corner of the quadrangle on the east side of the South Fork Clearwater River is from mapping by V.E. Camp the southwest corner of the map is of unknown origin, but may be related Fault: bar and ball on downthrown side; dashed where (Swanson and others, 1981). to early development of the White Bird Creek drainage system. approximately located; dotted where concealed. A/T on cross-section indicates strike-slip direction on fault: A = away from observer; T = toward observer. 73 Kto INTRUSIVE ROCKS 30 DESCRIPTION OF MAP UNITS Tgr1 73 Kto Tonalite and trondhjemite (Cretaceous)—Light gray biotite- and hornblende- Thrust fault: dashed were approximately located; dotted ? Throughout the following descriptions and later discussion of structure, 1 80 biotite tonalite cut in the northern part of map by dikes and pods of light where concealed; teeth on upper plate. 60 we use the metric system for sizes of mineral or clast constituents of units. gray, fine-grained to pegmatitic, muscovite-bearing trondhjemite. Tonalite However, we use English system for thickness and distance measurements characterized by a distinctive mottling due to the presence of large biotite Qls? because that system is used on the base map. 45 plates; weathers to micaceous light tan grus. Generally medium grained, KPgs with plagioclase comprising approximately 65-70 percent and quartz 16- SEDIMENTARY AND MASS MOVEMENT DEPOSITS 20 percent of the rock. Biotite plates, locally as large as 2 cm, comprise Estimated strike and dip of basalt flows. 85 from 8-11 percent and define a foliation that is locally strong. Hornblende Alluvial Deposits is subordinate to biotite (5 percent or less) and locally absent. Garnet is 80 Tgn1 common. Epidote is conspicuous in hand specimens (locally up to 7 80 Qam 85 Alluvium of the South Fork Clearwater River (late Holocene)—Channel and percent) and interpreted to be primary on the basis of textural relations 39 flood-plain deposits that are part of the present river system. Two grain- with other minerals. Body in the northeast part of map referred to as 80 60 Fold axis. Kto 75 size suites are typically present: well-sorted and rounded pebble to Qls trondhjemite of the Blacktail pluton by Myers (1982). However, normative 74 boulder gravel in river bars and islands, and coarse sand in thin shoreline 65 values plot in the tonalite field on an Ab-An-Or diagram (after Barker, Syncline. deposits. Gravel clasts include granitic, basaltic, and metamorphic rocks. 1979). Muscovite trondhjemite, present as dikes and pods in the tonalite, 78 63 was only noted near the northern map boundary. Weathers to a Monocline. 58 Qas Alluvial deposits in local drainages (Holocene)—Stratified silt, sand, and clay. micaceous light tan fine grus. The trondhjemite is commonly more Thickness 5-20 feet. Monocline: synclinal flexure; shorter arrow on steeper limb. Tgr1 resistant to weathering than the tonalite and can mask the presence of 50 82 67 80 Qaf Alluvial-fan deposits (Holocene)—Crudely bedded, poorly sorted brown tonalite where float is abundant. Unit belongs to a suite of trondhjemite Strike of vertical foliation. 85 84 and tonalite plutons that occur along and west of (outboard) the Salmon Qls 54 muddy gravel deposited by tributaries to the South Fork Clearwater River. 61 Fan deposit clasts are predominantly tonalite and trondhjemite from Kto River suture and which contain primary epidote indicative of high Strike and dip of foliation. VC79-464 35 unit. Thickness 5-20 feet. pressure (_8> kb) crystallization (Zen and Hammerstrom, 1984). U-Pb 60 Kto Tgn ? KPum Tgn1 1 zircon dating of a tonalite sample collected immediately north of the map T 60 07JK230 Ts Sediment, undivided (Miocene or Pliocene)—Gravel deposits at 3,000 to yielded a 111.0 ± 1.6 Ma age (McClelland and Oldow, 2007). U-Pb 88 KPgs Bearing and plunge of lineation, type unknown. Kto 3,300 feet elevation above the South Fork Clearwater River near the zircon dating has yielded 116-119 Ma ages in tonalite and trondhjemite F A U L Tgr 2? eastern edge of the map lie 1,000 feet above the present river level. of the Sixmile Creek pluton to the north near Orofino (Lee, 2004) and an Bearing and plunge of mineral lineation. Deposit includes well-rounded cobbles of biotite tonalite as large as 15 Tli age of about 118 Ma in tonalite in the Hazard Creek complex to the south Kto KPum cm. Location and elevation suggest they represent an alluvial channel near McCall (Manduca and others, 1993). Qls gravel associated with the cutting of the South Fork Clearwater River 07JK227 canyon. Several of these gravel deposits were placered for gold (Lorain and Metzger, 1938) and recent placer activity was noted at one location. ISLAND-ARC METAVOLCANIC AND Bearing and plunge of small fold axis. Another gravel deposit in the southwest corner of the map lies at an METASEDIMENTARY ROCKS KPum Tgr2 elevation of 5,000 feet and contains primarily basalt clasts as large as 15 Fault breccia. Qls? cm, but also contains a few quartzite and porphyritic volcanic rock clasts. These metamorphosed volcanic, volcaniclastic, and sedimentary rocks are interpreted to belong to the Wallowa accreted terrane assemblage Latah Formation Sediments (Silberling and others, 1984; Vallier, 1995). In this quadrangle, they are 82 79 either poorly exposed in the northwest corner of the map or are S 84 Sediments within the basalt sequence are stratigraphically equivalent to interpreted to occur at depth as shown in the cross section. 65 the Ellensburg Formation (Swanson and others, 1979) in Washington. Sample location and number. 84 Tgn1 VC79-461 Tli Latah Formation, sedimentary interbed (Miocene)—Clay, silt, sand, pebble, Seven Devils Group M E A D O W and cobble deposits interbedded between basalt flows or at the basement TRPsd KPgs 33 rock-basalt contact. Sands are typically arkosic. Pebbles and cobbles are Seven Devils Group, undivided (Permian to Triassic)—shown only in cross- section A-A'. Projected into the quadrangle on the basis of exposures to 65 KPum usually well rounded; composition varies depending on source area. 60 the northeast on the Grangeville East 7.5-minute quadrangle. See Schmidt Kto Interbeds are probably more extensive than mapped. Deposited by Tgn1 ? 55 streams as a result of repeated damming of drainages by basalt flows. and others (2007) for unit description. ? 50 Interbeds are mostly restricted to marginal areas near prebasalt basement 60 Tgn1 65 55 rocks. Seven Devils Group(?) REFERENCES N Tgr2 I Kto 80 R 30 60 W T Pc Chlorite-epidote-actinolite schist and gneiss (Permian to Triassic)—Medium Anderson, A.L., 1930, The geology and mineral resources of the region about D 85 Mass Movement Deposits ? KPgs ? O to dark green chlorite-epidote-actinolite schist and gneiss with Orofino, Idaho: Idaho Geological Survey Pamphlet 34, 63 p. O Barker, F., 1979, Trondhjemite: definition, environment, and hypotheses of KPum G Qls Landslide deposits (Pleistocene and Holocene)—Poorly sorted and poorly subordinate intrusive rocks. Light to medium green on weathered surfaces; KPgs origin, in F. Barker, ed., Trondhjemites, Dacites, and Related Rocks: Kto stratified angular pebbles, cobbles, and boulders mixed with silt and clay. weathers easily to fine, dark gray to brownish gray soil. Poorly exposed in Elsevier, New York, p. 1-12. Deposited by slumps, slides, and debris flows. Location of landslide window through the basalt in northwest corner of map, but better KPgs exposures occur on adjacent Grangeville East quadrangle to the north. Bond, J.G., 1963, Geology of the Clearwater embayment: Idaho Bureau of Tgr2 19 deposits is typically controlled by the presence of sedimentary interbeds ? 65 Mines and Geology Pamphlet 128, 83 p. and the interface between basalt units and underlying basement rocks. There the unit has ubiquitous greenschist-grade metamorphism; mylonitic 40 70 80 70 80 and brittle shearing heavily overprint the original texture and mineralogy. Bonnichsen, Bill, and M.M. Godchaux, 1994, Geology of the western Idaho 70 67 Landslides range in age from ancient, relatively stable features, to those 70 85 ultramafic belt: Idaho Geological Survey Staff Report 94-3, 75 p. that have been active within the past few years. Epidote veins and stringers are common. Commonly contains plagioclase porphyroclasts in fine-grained matrix of greenschist metamorphic Camp, V.E., 1981, Geologic studies of the Columbia Plateau: Part II. Upper Tgr 1? 10 minerals. Intrusive rocks also typically mylonitic and include fine-grained Miocene basalt distribution, reflecting source locations, tectonism, and 50 60 70 VC79-458 KPgs Kto VOLCANIC ROCKS porphyritic granite with 3-6 mm bluish quartz phenocrysts. Unit occupies drainage history in the Clearwater embayment, Idaho: Geological Society Kto 35 Qls of America Bulletin, Part I, v. 92, p. 669-678. 40 65 a position between low-grade (lower greenschist grade) metamorphic 10 50 Columbia River Basalt Group assemblages in the Wallowa terrane to the northwest and considerably Hamilton, Warren, 1963, Metamorphism in the Riggins region, western Idaho: KPgs U.S. Geological Survey Professional Paper 436, 95 p. 65 KPgs higher grade (amphibolite grade) metamorphic assemblages in the Riggins 30 60 Tgn1 The stratigraphic nomenclature for the Columbia River Basalt Group Kto Group rocks to the southeast. Interpreted to be primarily igneous in origin Hietanen, Anna, 1962, Metasomatic metamorphism in western Clearwater Kto follows that of Swanson and others (1979). In Idaho, the group is divided Kto KPum and equivalent to the Seven Devils Group. County, Idaho: U.S. Geological Survey Professional Paper 344-A, 116 p. into four formations. From oldest to youngest, these are Imnaha Basalt, Hoover, A.L., 1986, Transect across the Salmon River suture, South Fork of the Kto Grande Ronde Basalt, Wanapum Basalt, and Saddle Mountains Basalt. Clearwater River, western Idaho: Rare earth element geochemical, structural, Imnaha Basalt is inferred from float fragments to be present on the north AMPHIBOLITE-FACIES METAMORPHIC ROCKS OF and metamorphic study: Oregon State University M.S. thesis, 138 p. Kto Qas Qas KPgs face of Mount Idaho at the north edge of the quadrangle; it also is poorly UNKNOWN AFFINITY Lee, R.G., 2004, The geochemistry, stable isotopic composition, and U-Pb Kto exposed east of Cove Road on the slope above the South Fork Clearwater Tgn1 geochronology of tonalite trondhjemites within the accreted terrane, near 55 River. Grande Ronde Basalt, from oldest to youngest, has been subdivided Amphibolite-facies metasedimentary (and metavolcanic?) rocks that are Greer, north-central Idaho: Washington State University M.S. thesis, 132 p. 07JK223 80 into the informal R1, N1, R2, and N2 magnetostratigraphic units (Swanson east of and structurally above the Wallowa accreted terrane assemblage, Lorain, S.H., and O.H. Metzger, 1938, Reconnaissance of placer mining and others, 1979). Of these units, flows of the R1, N1 and R2 are exposed but are west of continental North American rocks (Myers, 1982; Hoover, districts in Idaho County, Idaho: U.S. Bureau of Mines Information ? in the quadrangle. Grande Ronde Basalt forms the upland surface or caps 1986). May be equivalent to the Orofino series exposed 36 miles to the Qls Circular 7023, 93 p. Tgr 1 basement rock exposures over much of the area. Wanapum Basalt and northwest (Anderson, 1930; Hietanen, 1962) or to the Riggins Group of Lund, K., W.F. McCollough, and E.H. Price, 1993, Geologic map of the Slate 72 Saddle Mountains Basalt do not occur in the quadrangle. Representative Hamilton (1963) exposed 40 miles to the south. Onasch (1977) and Creek-John Day area, Idaho County, Idaho: U.S. Geological Survey 60 samples were collected for chemical analysis. These samples supplement McCollough (1984) interpreted the Riggins Group as lateral equivalents of Tgr2 Miscellaneous Investigations Series Map I-2299, scale 1:50,000. previous ones collected by V. E. Camp (written commun., 2002). Our the Seven Devils Group and Martin Bridge Formation (Limestone). Lund Manduca, C.A., M.A. Kuntz, and L.T. Silver, 1993, Emplacement and KPum KPgs KPgs A' sample locations and those of Camp are identified on the map. Analytical and others (1993) mapped similar rocks in the Slate Creek area 30 miles 60 deformation history of the western margin of the Idaho batholith near KPgs results are listed in Table 1. Samples were analyzed at Washington State to the south as "rocks of the North Fork block". In the map area, we Tgr ? McCall, Idaho: Influence of a major terrane boundary: Geological Society Ts 2 University's GeoAnalytical Laboratory. interpret these rocks to be thrust over the TRPc unit. of America Bulletin, v. 105, p. 749-765. Tgr2 66 Grande Ronde Basalt McClelland, W.C., and J.S. Oldow, 2007, Late Cretaceous truncation of the 07JK213 70 Tgr2 60 western Idaho shear zone in the central north American Cordillera: Tgr1 68 70 Tgr2 Grande Ronde Basalt, R2 magnetostratigraphic unit (Miocene)—Medium KPum Ultramafic rocks (Permian to Cretaceous)—Metamorphosed pyroxenite or Geology, v. 35, no. 8, p. 723-726. Tgn 75 1 Kto to dark gray, fine-grained basalt, commonly with a sugary texture. peridotite with clusters of radiating amphiboles (anthophyllite), talc, and McCollough, W.F., 1984, Stratigraphy, structure, and metamorphism of Permo- Uncommon to common 1-2 mm plagioclase phenocrysts. Reverse chlorite. Light green to orange on fresh surfaces, gray where weathered. Triassic rocks along the western margin of the Idaho batholith, John Day These rocks are found as elongate, discontinuous bodies forming low Creek, Idaho: Pennsylvania State University M.S. thesis, 141 p. Tgn1 Kto Myers, P.E., 1982, Geology of the Harpster area, Idaho County, Idaho: Idaho Bureau of Mines and Geology Bulletin 25, 46 p. Onasch, C.M., 1977, Structural evolution of the western margin of the Idaho Base map scanned from USGS film positive, 1963. Field work conducted 2003, 2006, and 2007. batholith in the Riggins, Idaho area: Pennsylvania State University Ph.D.

E E Shaded elevation from 10 m DEM, vertically exagerated 2x. MN R This geologic map was funded in part by the U.S. Geological dissertation, 196 p. LL LL E VI T VI S E T E T S G S P Survey National Cooperative Geologic Mapping Program, To pography by photogrammetric methods from aerial SCALE 1:24,000 NG E N Schmidt, K.L., and R.S. Lewis, 2007, Role of NE-striking oblique dextral thrust A W EA Table 1. Major oxide and trace element chemistry of samples in the Goodwin Meadows quadrangle. HAR GN R RA photographs taken 1961. Field checked 1963. 1 0.5 0 1 G G USGS Award No. 07HQAG0070. faults in the development of the Wallowa terrane in the northern 0o 40 20o MILE Po lyconic projection. 1927 North American Datum. Digital cartography by Theresa A. Taylor and Loudon R. Major elements in weight percent Trace elements in parts per million Cordillera: Implications for terrane accretion and clockwise rotation: Y FEET IRD IN S R B E Stanford at the Idaho Geological Survey’s L E DW G T L OW 1000 0 1000 2000 3000 4000 5000 6000 7000 I D I Sample Map Geological Society of America Abstracts with Programs, v. 39, no. 6, ISSN 10,000-food grid ticks based on Idaho coordinate system, west HI HUNG H OO A DR W G E Digital Mapping Lab. M unit zone. number Latitude Longitude Unit name SiO2 TiO2 Al2O3 FeO* MnO MgO CaO Na2O K2O P2O5 Ni Cr Sc V Ba Rb Sr Zr Y Nb Ga Cu Zn Pb La Ce Th Nd 0016-7592, Paper 106-4. Note on printing: The map is reproduced at a high resolution UTM Grid and KILOMETER 1000-meter Universal Transverse Mercator grid ticks, zone 11. 1 0.5 0 1 02JB041 45.85752 -116.10603 Gn ra de Ronde N1 Tng 1 54.94 2.257 13.99 11.89 0.200 4.05 7.55 3.36 1.37 0.397 11 31 39 386 586 34 312 164 39 13.4 22 22 130 10 13 31 2 Schmidt, K.L., J.D. Kauffman, D.E. Stewart, K.L. Othberg, and R.S. Lewis, of 600 dots per inch. The inks are resistant to run and fading 1963 Magnetic North E N R Y I E R A Y INZI I T 2007, Geologic map of the Grangeville East quadrangle, Idaho County, E Declination at Center of Map A GE IDAHO K E N D 02JB042 45.86318 -116.12248 Gn ra de Ronde N Tng 1 55.63 2.199 14.58 10.43 0.209 3.89 7.99 3.19 1.49 0.398 12 19 43 363 705 34 341 189 44 12.9 23 39 132 7 13 39 3 C D AW I but will deteriorate with long-term exposure to light. 1 Contour interval 40 feet M S R K CR MOU Idaho: Idaho Geological Survey Digital Web Map 86, scale 1:24,000. Map version 9-5-2008. 06JK139 45.86315 -116.11824 Gn ra de Ronde N1 Tng 1 54.94 2.201 13.87 12.35 0.211 3.69 7.49 3.30 1.53 0.411 14 7 35 392 684 37 316 189 41 12.1 22 44 133 8 23 47 4 27 Siberling, N.J., D.L. Jones, M.C. Blake, Jr., and D.G. Howell, 1984, QUADRANGLE LOCATION ADJOINING QUADRANGLES PDF (Acrobat Reader) map may be viewed online at 06JK141 45.83805 -116.06627 Gn ra de Ronde N Tng 54.57 2.148 13.95 12.27 0.207 4.07 7.93 3.10 1.40 0.355 14 17 36 368 585 36 318 162 34 9.6 22 21 124 8 22 44 3 26 1 1 Lithotectonic terrane map of the western conterminous United States, Pt. www.idahogeology.org. Tr g 07JK213 45.75588 -116.10215 Gn ra de Ronde R2 2 56.56 2.226 14.15 10.47 0.190 3.47 7.31 3.17 2.00 0.451 5 11 34 353 929 44 331 197 43 11.7 21 16 137 7 21 53 5 31 C, in N.J. Siberling and D.L. Jones, eds., Litiotectonic Terrane Maps of the 07JK223 45.76431 -116.08826 Gn ra de Ronde N1 Tng 1 55.70 2.039 14.08 11.33 0.205 3.91 7.51 3.13 1.72 0.377 4 13 35 375 711 41 334 181 39 10.3 20 34 130 8 25 54 5 27 North American Cordillera: U.S. Geological Survey Open-File Report 84-

07JK227 45.79934 -116.07077 Gn ra de Ronde N1 Tng 1 54.87 2.338 13.80 12.03 0.211 3.84 7.60 3.13 1.74 0.439 6 8 34 384 678 40 336 180 40 10.4 20 20 134 7 20 49 5 27 523, 43 p. Swanson, D.A., J.L. Anderson, R.D. Bentley, G.R. Byerly, V.E. Camp, J.N. 07JK230 45.80409 -116.05584 Gn ra de Ronde R2 Tr g 2 53.79 2.653 15.75 10.88 0.185 3.75 7.85 3.30 1.37 0.472 6 9 38 401 856 27 371 200 44 11.4 23 15 157 9 26 55 5 37 Gardner, and T.L. Wright, 1981, Reconnaissance geologic map of the **VC79-454 45.84396 -116.04299 Gn ra de Ronde R Tr g 54.01 2.13 14.70 10.90 0.21 4.57 8.45 2.87 1.65 0.32 1 1 Columbia River Basalt Group, northern Oregon and western Idaho: U.S. Tng **VC79-458 45.77533 -116.01491 Gn ra de Ronde N1 1 54.13 2.19 14.71 12.50 0.22 3.23 7.86 2.95 1.61 0.39 Geological Survey Open-File Report 81-797, 32 p., sheet 3 of 5. Tr g **VC79-461 45.79014 -116.05075 Gn ra de Ronde R2 2 54.92 2.17 14.51 12.30 0.21 3.47 7.15 3.00 1.69 0.39 Swanson, D.A., T.L. Wright, P.R. Hooper, and R.D. Bentley, 1979, Revisions in Tr g **VC79-464 45.8052 -116.04097 Gn ra de Ronde R2 2 54.18 2.12 14.44 12.77 0.22 3.64 7.37 2.90 1.79 0.36 stratigraphic nomenclature of the Columbia River Basalt Group: U.S. Geological Survey Bulletin 1457-G, 59 p. * Major elements are normalized on a volatile-free basis, with total Fe expressed as FeO. ** Samples collected by V. Camp in 1979. Analytical results used with permission (Camp, written commun., 2002). Vallier, T.L., 1995, Pertology of pre-Tertiary igneous rocks in the Blue All analyses performed at Washington State University GeoAnalytical Laboratory, Pullman, Washington. Mountains region of Oregon, Idaho, and Washington: Implications fo the geologic evolution of a complex island arc, in T.L. Vallier and H.C. Brooks, eds., Geology of the Blue Mountains Region of Oregon, Goodwin Meadows Washington, and Idaho: Petrology and Tectonic Evolution of Pre-Tertiary Fault A A’ Rocks of the Blue Mountains Region: U.S. Geological Survey Professional 6,000 6,000 Paper 1438, p. 125-209. Tgr2 Tgr2 Tgn1 Zen, E-an, and J.M. Hammerstrom, 1984, Magmatic epidote and its petrologic significance: Geology, v. 12, p. 515-518.

5,000 Tgr Tgn 5,000 1 Tgn 1 KPgs 1 Tgn KPgs 1 KPum

Tim Tgr1 4,000 KPgs 4,000 T KPgs Tim KPgs KPgs FEET Tim KPgs 3,000 M O U N T 3,000 FEET TRPc ACKNOWLEDGMENTS I D A H O Mount Idaho Kto We thank the landowners in the area for access to their property. Efforts of 2,000 2,000 Fault Kto Kto our field assistants Eric Stewart and Travis Steel are greatly appreciated. S H E A R We thank V.E. Camp for providing copies of his field notes and maps of mylonitic foliation the area, and for permission to publish his sample analyses. Paul Myers TRPc 1,000 Z O N E 1,000 kindly provided us with field maps, notes, and thin sections from his reconnaissance work in the 1970s and 1980s, and Dean Garwood and TRPsd? John Bush provided basalt sample data from reconnaissance work in A Hammer Creek Thrust 0 0 2002.

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