image area (including reg marks) trim size guides center of image area text box for cooperator note always is centered image area (without reg marks) within entire image area (but text box should minimum 0.50” space not overlap any other map elements – allow 0.40” space at least 0.5” space on either side)

Map Series Headnote Open-File Report 95-219 0.275” space U.S. Department of the Interior DBID Prepared in cooperation with the Prepared In Cooperation Note Sheet X of Y Headnote U.S. Geological Survey DBID National Park Service and Bureau of Land Management Cooperator Note Pamphlet Accompanies Headnote Pamphlet accompanies map Lat/Long Value Tcwpr Tcwf Tcgn Tcgn 2 Tcwf Ts Trh Along Top & Bottom 2 Tcwf 122°00' Tcwpr QTb Tb Taop Tcgn2 121°30' 122°00' 45°30' Trh 45°30' Trh Qls Tazm Tb Tcwf Tvs QTa LIST OF MAP UNITS Tbbu Basalt of Bull Run Watershed and other ridge-capping basalt [NW] Qls Tvmf Tcgn2 Tcgn2 Qg Tvmf QTb Tcwf 44 Td Lost Qbp 0.05” space Tazm Qbal [Arranged alphabetically by map-unit symbol except within stratigraphic Tcwpr Lake Tbg Basalt near Ghost Creek [SW] Taef groupings, where shown by age. See Description of Map Units (in pamphlet) for Tbbu QTb Tcwf Qca Qbr Qca Qal Tcwf Td unit descriptions, where volcanic units are arranged into sections according to Qg QTs Tbj Basalt of Juniper Flat [SE] Tbbu Qv Tvmf QTa QTb Qg Qca Taef quadrants on the map. Bracketed letters following unit names in this list QTb Qall Taef QTb Tcgn Taop indicate corresponding section in Description of Map Units] 2 Qal 72 Qbdr Columbia River Basalt Group Qhc 20 Tcwf Tbbu Taef Qls Tb Qap QTs Qabl Andesite of Boulder Lake [SE] Qls Taop Qall Qv Qt Taef QTs Tcwpr Wanapum Basalt, Priest Rapids Member [NW] Qap 350 Tcgn2 Qal Tia 3582 Tazm Qt Laurence Qbac Qv Qt Lake 3 Andesite of Cabin Creek [SW] QTb B Qbr Qt Qha Td 3431 Qac Tcwf Wanapum Basalt, Frenchman Springs Member [NW] ull R Td Qbdr QTs un Qca QTb Qah L Qca Taop Qt Qca 1 Tbbu ak Qal QTa Qacl e Qall Qal Taft Andesite west of Clear Lake [SW] Tcgn2 Grande Ronde Basalt, normal-polarity unit 2 [NW] Qt Qbac? Taef Qg Qv Qg Qbap Qt Tcwf QTb 49 Td Qg Qal Tb Tdm Trh Qv Qall Qae Andesite of Enola Hill [NW] Tcgr Taop Tvmf? 2 Grande Ronde Basalt, reversed-polarity unit 2 [NW] Qls Qget Qget Qoe 28 Tcwf QTba Qhc 10 QTb QTb Td Qha Qget Taef Qah Andesite of Hiyu Mountain [NW] Qbr Qha Td Dalles Formation [NE] Taop? Qal 8 Qal 163 Tvmf? Qbap Qbac Qbdr Qbaa Qha Qbas Tcwf QTb Qt Qahr Andesite of Horseshoe Ridge [NW] Tdb Dacite of Beaver Butte [SW] 15 Qv Qt 23 Qget 21 Qbdr Qg Qha Qv Tazm 11 26 Qal Alluvium Taop? Qhpc Tdgb Dacite of Graveyard Butte [SE] Qg QTba Qbac QTb Tcgn2 Qls 25 Taop? Qhpc Tlmd? QTb 230 157 Qha 7 ? Tazm Taop Qget 339 Qall Andesite of Laurance Lake [NW] Dacite north of Long Ridge [SW] QTb Qal Tafv Tdl Qg Qha QTb N ? 7 Qhdl QTb Trh Tlma? Qha Qget 51 Qam Andesite of McCubbins Gulch [SE] Qls Trh Qhc Qha 53 Tdm Dacite of Mill Creek Buttes [NE] Qhc Qhdl Qgnt Qha 30 6 Taft Tiba Qha Tatc QTb 284 Tbbu 35a 34 Taop Qha Qhpl Qgnt 1 Qap Andesite of Perry Lake [NW] Dacite of Plaza Lake [SW] 32 Qls Qls 16 Tcgn2 Tdp Tbbu Tia Qget Qget Qha 12 Qhc? Tlma 38 31 Qca G Tlma QTb l Ladd Gl. OMF-7A Taop is Lat/Long Value Qal a Qgnt Qgnt R Qas OMF-1 Qha Qhc Qal n Taft Tcwf Andesite of Skyline Road [SW] Fine-grained andesite [SW] Along Left Side Qget Qls 5220 Tfa 3 Coe Gl. 1 Tcwf Qhpc Qsg R 36 18 Qgnt Qha r Qca Qv Qaw Tazm e Tcgn2 Andesite of Wapinitia Pass [SW] Hornblende-bearing andesite [SW] Qca ci Qt Tha Trh 9 Sandy Qgnt la Qhpc Qha Qls Qal Qha Glacier ot G Tlma Tcwf Tcwf 27 Qhc Qhoc Eli Qha Qhpl Qbaa Basaltic andesite of Aschoff Buttes [NW] Tia Intrusive andesite Qhoc Qhol Qget Newton Qae? Qls Qahr Tazm Qsg Reid Gl. Qgnt Ttvp Clark Qha Qha Qbac Basaltic andesite of Cloud Cap [NW] Qal QTb Tiba Intrusive basalt or basaltic andesite Qca Qv Qhpc Qls Qhtc Qhtc Glacier Tlmd Tlmd Qv 185

Trh Qha 3 Zigzag W Qbc Qhoc Taj Trgx Ttvp Qhc Qgnt Gl h Tcgn2 Qbal

i Qhpl Tlma Basaltic andesite of Lost Lake Butte [NW]

t Tilh Intrusive rocks of Laurel Hill [NW] Qhoc Qhtc Palmer e Qhpl QTb R Taef Qg Qal Ts Qhtc Gl. Qha Qha Trgx i Qv Qv Tazm v Taj Qg Tbbu Qha e Qhpc R QTb QTb Qhpc r Qbap Tcwf Tcwf Basaltic andesite of The Pinnacle [NW] Lookout Mountain volcanic sequence Qhpc 24 14 G Taft Taft Tazm l 0 Y Ts Ts Tlmb Tcgn2 Qt Taj Td 22 Qhpl Y Qhpc Ttvp Tcwf 0 R Qt Trh Trh 5 Qhpl Tcgr2 Qbas Basaltic andesite of Stump Creek [NW] Qhpc Qal Qg Tlma Andesite [NW] 7 Tbbu Tlma 33 13 Qhoc Tcwf 17 48 22 Qhtc Qbdc 2 Qhtc Qha 45 Tcwf Qls Tbbu Qhpc Qv Tcwf 2 Tcgn2 347 Qha R Qal Trgx Qbc Basalt of Crutcher Bench [NW] Tlmb Basalt [NW] 337 Qal Tlmb QTb Taj 43 Trh Qls Trgd QTs Tcwf 42 Qha Qhpc 0 Trgd QTb Taef Tcwf Tcwf Qal Qhpc QTa Y Qls Td Qbdc Basaltic andesite of Devil Canyon [NW] Tlmd Dacite [NW] Qls QTat Qget Qget Qg Ttvp Tcgn2 Qv Taef Tbas Tcwf 40 Qal Tcwf Trgd Tcgn2 Tcwf Qhpc Qha Qhpc Trbg Qbdr Trh Qha Qal Qls Tbas Basaltic andesite of Dog River [NE] Tma Andesite of middle and late Miocene age [SW] Trh Qhpc Tcgn2 Ttvp Tcgr2 Qls Pucci Tcgn Tcgn2 Tcwf Qae Qhpc Qg 2 Trgd 0 Qbdc 19 Qv Ttvp Qbp Tma Qha Qhpc Qget Qls Trgx Basaltic andesite of Parkdale [NW] Toa Older andesite [SW] Qls 98 Tcwf Tbbu Qhpc QTa 3289 Laurel Hill Tma Qhpc Qha 4 Qhoc n Tcgn Qca Trgd Tcwf Tcwf 54 Qbr intrusio Qhpc 2 Tcgn Tcgr Basaltic andesite of Blue Ridge [NW] Volcanic rocks of the Mutton Mountains Qhpc 2 Qls Qt Tcwf 26 6 Qhtc Tcgn 240 UNMAPPED Trbg Tcgn 2 29 QTat Qhpc Qt 2 Trgx QTat Qal Qt 35 Qca Colluvial and alluvial slope deposits Tilh Td Tcwf 56 Toma Andesite [SE] Qal Qg Qha Qal Tcgn2 4 26240 80 Qal Qt 238 239 Tilh QTat QTab 23 70 QTbme Trbg 8757 Tcwf Trh 54 Qdf Dacite of Frog Lake Buttes [SW] Tomr Rhyolite [SE] UNMAPPED QTbme 50 28 Trbg Qca Td Trgx Talb Tcgr2 255 QTat Tbah Trgx Tvs Tcgn2 Qg Glacial deposits Qget Qget 20 Trgd Tomt Tuff and tuffaceous sedimentary rocks [SE] QTat Qhtc Ttvp Tcgr2 Ttvp 60 Tcwf Trh 68 0 Trbg Tcwf Qls Trbg Qt 67 75 0 Qgnt Glacial deposits, till of neoglacial age Tos Older sedimentary rocks Qal QTtlb 67 N 82 71 67 Tilh Tma 11 66 37 Talb Tb N Tvs Qg Ttvp Talb Tcwf 95 55 22 22 S on QTbme Tv Qg Ttvp Qget Glacial deposits, till of Evans Creek age Rhyolite [SW] Tcgn till rusi Qg Talb 90 Tcgn2 Tr 2 Creek int Qls Tb Trbg Tb N Qt Tvs 82 Tbbu Tcgn2 Qls 102 41 Tcwf Tcwf Trbg Qls Tb Qt Qv Tv Pre-Polallie andesitic and dacitic rocks of QTtlb Qabl Tb 110 Trbg Rocks of Barlow Ridge and Gunsight Butte [NW] Tb QTbg Ttvp Tb Qal 45 Tcwf Tcwf Tb 55 UNMAPPED Qt Tbah 40 Tcgn2 Qob QTbg Tbah Qls Ttvp Tvs Qha Andesite and dacite lava [NW] 5 Rhyodacite of Gordon Butte Tcwf Ttv 15' QTtla2 Tbg R 164 Tb 15' Tcgn2 QTat R QTab Tbah Qg 2 Trbg Qv QTs R Qt N 47 Qal Tcwf Qhc Pyroclastic-flow and debris-flow deposits [NW] Trgd Domes and flows [NE] R Qls Qt Tcwf R R Trh Tcwf QTtlb N R Tbj Qob Ttla1 N Qal Qhdl Debris-avalanche deposit of Ladd Creek [NW] Qca Tbj Tcwf Trgx Tuff breccia [NE] Qt R N Tcgn2 N R QTs Qls Tfa Qal Products of Old Maid eruptive period Qt Qaw Tb Qaw Qls Trh Rhododendron Formation [NW] Qca N Ttv Tdp QTtla2 Qg R Tcwf Qt Tcgn Qal Qob Rock Creek Qg Tcwf Qt Tcwf Qhop Tas Tfa R N R Reservoir Pyroclastic-flow and debris-flow deposits [NW] Ts Sedimentary rocks [NW] Tas Trh Qob Ttla1 Tas Tbj Tcgn2 Tcwf Tbam Tbam Qg Qdf R N Tbao Tiba Tfa Qob Qg N Qhol Lava flows [NW] Ttla1 Volcanic rocks in Trillium Lake area, andesite [SW] 218 R R Tb 87 Qt Qal Tcgn2 Tvs Trh Tbao Tv Tfa N R Qdf R Products of Polallie eruptive period Tfa Tma Ttv Tygh Valley Formation [NE] Qt Trh Tma R Qaw Tas Tiba Qal Tbj Tcwf Qt Tbao Qt Qg Tvs Qhpc Pyroclastic-flow and debris-flow deposits [NW] Ttvp Pyroclastic and sedimentary rocks [NE] Trh Qls Tas Qt R Qt Qls Tbj Qls Trh Tbao R Qg Qg Tbao Qiba R Qhpl Lava [NW] Qv R QTbg Tv Cinder cone or small volcano Qt Qacl Qacl Qv Qg R Qaw Tbao C Qhtc Timberline eruptive period, pyroclastic-flow and debris-flow Tvmf Volcaniclastic rocks of Middle Fork of Hood River [NW] Qg Qv Qob le Tcwf deposits [NW] ar Tbj N L Qls Qg Tiba Tha ak R Tvs Volcaniclastic rocks [NE] e R Tdgb Qls Tcwf R Tdgb Qiba Intrusive basalt and basaltic andesite Qg Qt R Tiba QTb Tbao Qt QTb Tys Younger sedimentary rocks [SW] Qt R Qaw R Tbj Tcwf Qls Landslide deposits Tbao Tiba Tcwf Tcgn2 Tbj Tdgb Tcgn2 Qt Tbao Qoba 13 UNMAPPED Unmapped [NW] Qg 56 72 Tcwf Qo Outwash Tiba R Qv R QTs Qt 41 R Qg QTb Qaw Qls Tiba Tbao QTb Tbj Qob Olivine basalt [SW] Contact—Approximately located. Short dashed where inferred; shown R R Tcgn 2 dotted where enclosing a zone of propylitic alteration between Qal Tv Qoba Older basaltic andesite [SW] Qg Qls Salmon River and Still Creek as mapped by Wise (1969) Qca R Tcwf Qv N Qal Qyba Qv Qoe Outwash of Evans Creek age Contact—Separating sequentially younger deposits of Polallie eruptive N QTs Y N Qv period in and adjacent to Newton Creek east of Mount Hood (unit N Tcwf O Qg N Qsg Rocks of Sandy Glacier volcano [NW] Qhpc). Contact labeled to show relative age of deposits: Y, Tbao Qg Tcwf N Tbj Tcwf younger; O, older Tbao Tiba Qt QTb Qv Qam N Tcgn2 Qt Talus Timothy Lake QTs QTs Tv Contact—Bounding unmapped area in Salmon River drainage and Qg Qaw QTa Andesite [NE] poorly mapped area in Mutton Mountains Tcgn2 Qg Tiba Tar Qyba Tv N Qoba Andesite of Badger Butte [NE] N QTab Fault—Showing dip locally; dashed where approsimately located or R Qas Qal Tbao Tha R Tcwf Tcwf Tcwf Tbao N Qoba inferred, dotted where concealed. Ball and bar on downthrown Qg Tbao Qal R Tcgn2 QTat Andesite of Tom Dick and Harry Mountain [NW] side Tcgn2 Qt Qg Qg Tcwf Qyba QTb Tcgn2 Qca Tos Tbao QTb N R Tcgr2 R QTb Basalt [SE] Qt N Tcgr2 Tcwf Reverse or thrust fault—Dashed where approximately located or Tcwf Qls Qls Qo Tomt Tcgn2 inferred, dotted where concealed. Teeth on upper plate Toa R QTba Basaltic andesite [SW] Toa Tbao Tys Qyba Tar Qt Qal N Anticline—Showing crestline and locally showing plunge Tcgn2 Qt Qo Qg QTb Qg Tar QTbg Basaltic andesite of Grasshopper Point [SE] Tcwf QTb Qg Tdb Tcgn Qo N QTb Tcgr2 2 Tcgn2 Toa Tys Tr Syncline—Showing troughline N Tcwf Tys R Tcwf QTbme Basaltic andesite of Mirror Lake and Eureka Peak [NW] N Tar Tcgn2 Qls Tbao Qv Qoba 59 Toma 42 Monocline—Shown only on Columbia Plateau and on east wall of Qyba Qg N QTs Tcgr2 Tcwf Sedimentary rocks and deposits [SE] Hood River escarpment Toa R Qls QTb Qls N Tcgn2 Abrupt decrease of dip in direction of arrows Tma QTs Tcwf Tbao QTs Toma Tcgn2 Volcanic rocks in Trillium Lake area Qas QTb Abrupt increase of dip in direction of arrows Qt Tar QTb Tdb Tr Tomt QTtla2 Andesite [SW] Qls N Lineament—Interpreted from aerial photographs QTs Qls Qt R Tar Basalt [SW] Tma Qas Qyba N Qls QTtlb Qv Moraine crest—Shown in glacial deposits (unit Qg) Tma Qls Qal Qca Qal 43 N N Qv Cinder cone or small volcano Qt 39 Qca Qal Tomt Strike and dip of clastic strata or layering in basalt flows Qt QTb Qas R Tdl Tcgr2 Tomr Toa Qyba Younger basaltic andesite [SW] Inclined Ta Qv Tomr Qca Qiba Qoba R QTs 26 Tma Tma Qca Tiba Horizontal Tv N Ta Andesite [SW] Tbao Qca Qv Tma R Overturned—Found in lava flows of Columbia River Basalt Group Tos Qal Qv Tcgn 80 0.30” space QTba Tbao QTb N Tv QTb Taef Andesite of East Fork Hood River [NE] on Tygh Ridge Qt Ta R Qas Tdl Qal Tomr Qv QTb Tma Qac Qas Tba Qca 45°00' Tbao Qal Qas 45°00' Dike—Tick marks indicate composition; two ticks, basalt or basaltic 122°00' Qv 12'30" 10' 121°00' Taft Andesite of Fifteenmile Creek [NE] 121°30' andesite; three ticks, andesite or dacite

1 SCALE 1:100,000 Base from U.S. Geological Survey, 1983 15 /2° Geology mapped by D.R. Sherrod, 1985 and 1987–94; and Tafv Andesite of Fivemile Butte [NE] Universal Transverse Mercator projection, zone 10, North American 1 0 1 2 3 4 5 6 7 8 MILES W.E. Scott, 1989–94. Distribution of Columbia River Basalt Intermediate-size volcano—Showing central buildup of basalt or Group compiled from published and unpublished sources of datum of 1927 Taj Andesite of Jordan Butte [NE] basaltic andesite shield volcanoes. Many occurrences interpreted 1 0 1 2 3 4 5 6 7 8 9 10 KILOMETERS mapping Base, intended for visual reference only, was fitted to map neatline by on basis of landform, owing to lack of dissection inspection. River-reach GIS layer (Oregon Geospatial Enterprise This map sheet presents legacy mapping that was available TRUE NORT H Office website, http://www.oregon.gov/DAS/CIO/GEO/), digitized from MAGNETIC NORTH previously only in paper print-on-demand format, published Talb Andesite of Little Badger Creek [NE] 1995. GIS database by Lina Ma, 2006; digital cartography by 1:24,000- and 1:62,500-scale maps, is also fitted by inspection and APPROXIMATE MEAN CONTOUR INTERVAL 50 METERS Thermal remanent magnetization (TRM) measurement—N, normal D.R. Sherrod, 2013 R varies slightly in its coincidence with base map DECLINATION, 2013 MAP LOCATION Andesite of Lolo Pass [NW] polarity; R, reversed polarity Manuscript approved for publication December 15 , 2014 Taop

Tar Andesite of Rocky Point [SW] Potassium-argon sample locality—Showing map number (table 1) 59 Samples from bedrock exposures except No. 31, which is from drill core. Nos. 46, 57, and 58 are from outside map area and not CORRELATION OF MAP UNITS APPROXIMATE AGE, IN Tas Andesite of Salmon Butte [SW] plotted on map. Thermal remanent magnetization indicated by R MILLIONS OF YEARS AGO SURFICIAL DEPOSITS, VENT DEPOSITS AND INTRUSIVE ROCKS NORTHEASTERN PART SOUTHEASTERN PART Tatc Andesite of Tumble Creek [NW] (reversed polarity) or N (normal polarity) where known ALL PARTS OF MAP AREA ALL PARTS OF MAP AREA NORTHWESTERN PART OF MAP AREA SOUTHWESTERN PART OF MAP AREA OF MAP AREA OF MAP AREA (Nonlinear scale) ** Drill hole locality—Showing name and number for holes deeper than 1 Qhol Tazm Andesite of Zigzag Mountain [NW] OMF-1 Qhoc km. Two holes west of Mount Hood in upper reach of Old Maid Tb Basalt [NW] Flat (OMF-1 and OMF-7A) and one hole (Pucci) on south flank of Qhtc Holocene Mount Hood. Locations from Priest and others (1982) and Hook Qgnt Qal Qca Qt Qls Qhdl Tba Basaltic andesite [SW] (1982). Symbol for OMF-7A nearly filled by dot showing K-Ar sample locality No. 31 Qbp Tbah 0.010 Basaltic andesite of Happy Ridge [NE] Qget Qoe Qhpl Palmer Snow and ice—Showing extent of major glaciers. Limited to higher Qv Qhpc Gl. elevations of Mount Hood. Names of separate glaciers shown Qg Brunhes Normal- Tbam Basaltic andesite of Mack Hall Creek [SW] Qo Polarity Chron where space allows QUATERNARY Tbao Basaltic andesite of the Oak Grove Fork [SW] Pleistocene Qiba Qhc Qha Qyba Tbas Basaltic andesite of Sunset Spring [NE] Qbdc Qac Qas Qbdr Qbaa Qbal Qbas Qbap Qbac Qbc Qahr Qap Qae 0.78 Qbr ? 0.78 Qob Qam Qall Qsg Qah Qaw Qdf Qacl Matuyama Reversed- Qoba QTb QTa 1.76 QTb QTtla2 QTb Qabl Polarity Chron QTat QTba QTb QTba QTs 1.98 QTtlb QTs QTab QTbg 2 2.60 QTbme Tha Taft Tdb Gauss Normal - 3.05 Tba Tar Tdl Tbg Trgx Polarity Chron Tlmb Tbao Tlma Trgd ** Pliocene Tbbu Ta Tbah Tbj Tlmd Ttla1 Talb Pre-Gauss chrons Tv Tiba Trbg Tatc Tys Ttv Tb Tb Tr Ttvp 5 Taop ? Tvmf Taj Tdgb Tbas Tdm Taef Td Tilh Tfa Tas Taef Tafv Tia Ts Tma Tdp Tazm Tbam ? Trh Trh Tvs TERTIARY Miocene Tcwpr Tcwpr Preliminary Geologic Map of the Mount Hood 30- by 60-Minute Quadrangle, Tcwf Tcwf Tcwf Tcwf Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government Tcgn Tcgn Tcgn Tcgn 2 2 2 2 This map is published as an online-only version. If printed, then dimensional calibration may vary Tcgr Tcgr , North-Central Oregon between electronic plotters and between X and Y directions on the same plotter, and paper may 2 2 Tcgr2 change size due to atmospheric conditions; therefore, scale and proportions may not be true on Tos Tomt plots of this map. Toa Toma Tomr 24 By Digital files available at http://pubs.usgs.gov/ds/906 Suggested Citation: Ma, Lina, Sherrod, D.R., and Scott, W.E., 2014, Digital data for preliminary ** Normal polarity (black) and reversed geologic map of the Mount Hood 30- by 60-minute quadrangle, northern Cascade Range, Oregon: Oligocene David R. Sherrod and William E. Scott polarity (white) shown for major U.S. Geological Survey Data Series 906, pamphlet 36 p., scale 1:100,000 subchrons through end of Gauss [http://dx.doi.org/10.3133/ds906]. Printed on recycled paper time 1995 Recycled Paper Note Author Affiliation Footnote URL Character Style 1.0” Footnote # in Author Affiliation Footnote Character Style space center of image area

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