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Data Series 906

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Database for the Preliminary Geologic Map of the Mount Hood 30- by 60-minute Quadrangle, Northern Cascade Range, Oregon

By Lina Ma, David Sherrod, and William Scott

Table 1. Projection and datum.

Element Definition
Projection Lambert conformal conic
Grid coordinate system Oregon Lambert projection
UTM zone number 10
Unit International foot (0.3048 m)
1st standard parallel 43
2nd standard parallel 45.5
Central meridian -120.5
Latitude of projection’s origin 41.75
False Easting 1,312,335.958 ft (400,000 m)
False Northing 0
Horizontal datum name North American datum 1983
Vertical datum NAVD 1988
Ellipsoid name GRS 1980
EPSG code 2992


Table 2. Files used to produce GIS version of geologic map.

  Filename File Format
1 MH_Geopoly ESRI shp and Mapinfo TAB
2 MH_Patterns ESRI shp and Mapinfo TAB
3 MH_Contacts ESRI shp and Mapinfo TAB
4 MH_Structure ESRI shp and Mapinfo TAB
5 MH_Dikes ESRI shp and Mapinfo TAB
6 MH_Strikedip MS xls
7 MH_Ventsymbols MS xls
8 MH_Drillholes MS xls
9 MH_Magpolarity MS xls
10 MH_KARages MS xls
11 MH_Geogrnames MS xls


Table 3. Numeric code values and map-unit symbols and names for stratigraphic units. Table is also included as a separate file in the folder of spreadsheets for this publication.

Label Code Name Age
ow 1 Open water Holocene
g 2 Glacier Holocene and Pleistocene
Qabl 252 Andesite of Boulder Lake Pleistocene
Qac 302 Andesite of Cabin Creek Pleistocene
Qacl 308 Andesite west of Clear Lake Pleistocene
Qae 224 Andesite of Enola Hill Pleistocene
Qah 233 Andesite of Hiyu Mountain Pleistocene
Qahr 221 Andesite of Horseshoe Ridge Pleistocene
Qal 31 Alluvium Holocene and Pleistocene
Qall 226 Andesite of Laurance Lake Pleistocene
Qam 251 Andesite of McCubbins Gulch Pleistocene
Qap 222 Andesite of Perry Lake Pleistocene
Qas 303 Andesite of Skyline Road Pleistocene
Qaw 306 Andesite of Wapinitia Pass Pleistocene
Qbaa 202 Basaltic andesite of Aschoff Buttes Pleistocene
Qbac 206 Basaltic andesite of Cloud Cap Pleistocene
Qbac? 207 Basaltic andesite of Cloud Cap Pleistocene
Qbal 203 Basaltic andesite of Lost Lake Butte Pleistocene
Qbap 205 Basaltic andesite of The Pinnacle Pleistocene
Qbas 204 Basaltic andesite of Stump Creek Pleistocene
Qbc 208 Basalt of Crutcher Bench Pleistocene
Qbdc 209 Basaltic andesite of Devil Canyon Pleistocene
Qbdr 241 Basaltic andesite of Dog River Pleistocene
Qbp 201 Basaltic andesite of Parkdale Holocene
Qbr 223 Basaltic andesite of Blue Ridge Pleistocene
Qca 32 Colluvial and alluvial slope deposits Holocene and Pleistocene
Qdf 307 Dacite of Frog Lake Buttes Pleistocene
Qg 41 Glacial deposits Holocene and Pleistocene
Qget 43 Glacial deposits, till of Evans Creek age Pleistocene
Qgnt 42 Glacial deposits, till of neoglacial age Holocene
Qha 133 Pre-Polallie rocks of Mount Hood, andesite and dacite lava Pleistocene
Qhc 131 Pre-Polallie rocks of Mount Hood, pyroclastic-flow and debris-flow deposits Pleistocene
Qhc? 132 Pre-Polallie rocks of Mount Hood, pyroclastic-flow and debris-flow deposits Pleistocene
Qhdl 111 Debris-avalanche deposit of Ladd Creek Holocene
Qhoc 102 Old Maid eruptive period, pyroclastic-flow and debris-flow deposits Holocene
Qhol 101 Old Maid eruptive period, lava flows Holocene
Qhpc 122 Polallie eruptive period, pyroclastic-flow and debris-flow deposits Pleistocene
Qhpl 121 Polallie eruptive period, lava Pleistocene
Qhtc 108 Timberline eruptive period, pyroclastic-flow and debris-flow deposits Holocene
Qiba 62 Intrusive basalt and basaltic andesite Pleistocene
Qls 34 Landslide deposits Holocene and Pleistocene
Qo 44 Outwash Pleistocene
Qob 304 Olivine basalt Pleistocene
Qoba 305 Older basaltic andesite Pleistocene
Qoe 45 Outwash of Evans Creek age Pleistocene
Qsg 231 Rocks of Sandy Glacier volcano Pleistocene
Qt 33 Talus Holocene and Pleistocene
QTa 242 Andesite Pleistocene or Pliocene
QTab 243 Andesite of Badger Butte Pleistocene or Pliocene
QTat 227 Andesite of Tom Dick and Harry Mountain Pleistocene or Pliocene
QTat? 228 Andesite of Tom Dick and Harry Mountain Pleistocene or Pliocene
QTb 225 Basalt Pleistocene or Pliocene(?
QTba 421 Basaltic andesite Pleistocene or Pliocene(?)
QTbg 256 Basaltic andesite of Grasshopper Point Pleistocene or Pliocene
QTbme 234 Basaltic andesite of Mirror Lake and Eureka Peak Pleistocene or Pliocene
QTs 601 Sedimentary rocks and deposits Pleistocene and Pliocene(?)
QTtla2 321 Volcanic rocks in Trillium Lake area, andesite Pleistocene or Pliocene
QTtlb 322 Volcanic rocks in Trillium Lake area, basalt Pleistocene or Pliocene
Qv 61 Cinder cone or small volcano Quaternary
Qyba 301 Younger basaltic andesite Pleistocene
Ta 427 Andesite Pliocene
Taef 482 Andesite of East Fork Hood River Miocene
Taft 435 Andesite of Fifteenmile Creek Pliocene
Tafv 483 Andesite of Fivemile Butte Miocene
Taj 438 Andesite of Jordan Butte Pliocene and Miocene
Talb 437 Andesite of Little Badger Creek Pliocene
Taop 561 Andesite of Lolo Pass Pliocene(?) and Miocene
Taop? 562 Andesite of Lolo Pass Pliocene(?) and Miocene
Tar 428 Andesite of Rocky Point Pliocene
Tas 593 Andesite of Salmon Butte Miocene
Tatc 547 Andesite of Tumble Creek Pliocene
Tazm 581 Andesite of Zigzag Mountain Miocene
Tb 548 Basalt Pliocene and (or) Miocene
Tba 426 Basaltic andesite Pliocene
Tbah 436 Basaltic andesite of Happy Ridge Pliocene
Tbam 595 Basaltic andesite of Mack Hall Creek Miocene
Tbao 423 Basaltic andesite of the Oak Grove Fork Pliocene
Tbas 439 Basaltic andesite of Sunset Spring Miocene
Tbbu 235 Basalt of Bull Run Watershed and other ridge-capping basalt Pliocene and Miocene(?)
Tbg 422 Basalt near Ghost Creek Pliocene or Miocene
Tbj 549 Basalt of Juniper Flat Pliocene
Tcgn2 1003 CRBG, Grande Ronde Basalt, normal-polarity unit 2 Miocene
Tcgr2 1004 CRBG, Grande Ronde Basalt, reversed-polarity unit 2 Miocene
Tcwf 1002 CRBG, Wanapum Basalt, Frenchman Springs Member Miocene
Tcwpr 1001 CRBG, Wanapum Basalt, Priest Rapids Member Miocene
Td 583 Dalles Formation Miocene
Tdb 425 Dacite of Beaver Butte Pliocene
Tdgb 491 Dacite of Graveyard Butte Pliocene(?) or Miocene
Tdl 429 Dacite north of Long Ridge Pliocene
Tdm 481 Dacite of Mill Creek Buttes Miocene
Tdp 594 Dacite of Plaza Lake Miocene
Tfa 592 Fine-grained andesite Miocene
Tha 424 Hornblende-bearing andesite Pliocene
Tia 533 Intrusive andesite Pliocene and Miocene
Tiba 532 Intrusive basalt or basaltic andesite Pliocene
Tilh 571 Intrusive rocks of Laurel Hill Miocene
Tlma 541 Lookout Mountain volcanic sequence, andesite Pliocene
Tlma? 542 Lookout Mountain volcanic sequence, andesite Pliocene
Tlmb 543 Lookout Mountain volcanic sequence, basalt Pliocene
Tlmd 544 Lookout Mountain volcanic sequence, dacite Pliocene
Tlmd? 545 Lookout Mountain volcanic sequence, dacite Pliocene
Tma 591 Andesite of middle and late Miocene age Miocene
Toa 431 Older andesite Miocene
Toma 1112 Volcanic rocks of the Mutton Mountains, andesite Miocene and Oligocene
Tomr 1113 Volcanic rocks of the Mutton Mountains, rhyolite Miocene and Oligocene
Tomt 1111 Volcanic rocks of the Mutton Mountains, tuff and tuffaceous sedimentary rocks Miocene and Oligocene
Tos 604 Older sedimentary rocks Miocene
Tr 449 Rhyolite Pliocene or Miocene
Trbg 546 Rocks of Barlow Ridge and Gunsight Butte Pliocene and Miocene
Trgd 442 Rhyodacite of Gordon Butte, domes and flows Pliocene
Trgx 441 Rhyodacite of Gordon Butte, tuff breccia Pliocene
Trh 582 Rhododendron Formation Miocene
Ts 602 Sedimentary rocks Miocene
Ttla1 323 Volcanic rocks in Trillium Lake area, andesite Pliocene and (or) Miocene
Ttv 451 Tygh Valley Formation Pliocene and Miocene(?)
Ttvp 452 Tygh Valley Formation, pyroclastic and sedimentary rocks Pliocene and Miocene(?)
Tv 531 Cinder cone or small volcano Tertiary
Tvmf 563 Volcaniclastic rocks of Middle Fork of Hood River Miocene
Tvmf? 564 Volcaniclastic rocks of Middle Fork of Hood River Miocene
Tvs 484 Volcaniclastic rocks Miocene
Tys 603 Younger sedimentary rocks Pliocene and Miocene(?)
u 2001 Unmapped  


Table 4. Numeric code values for map-unit contacts.

Line Code Line Feature Line Symbol Explanation
10 Contact, precisely or approximately located Solid Contact exposed or can be estimated closely on basis of outcrops in adjacent units. In some places contact corresponds to abrupt break in slope and was placed on basis of air-photo mapping. Position has been determined by field work to within 100 m on the ground (1 mm on map at 1:100,000 scale)
       
11 Contact, inferred or imprecise Short-dashed Geologic relations or ground surface morphology suggest contact present but not exposed and too uncertain to determine position more precisely than 100-200 m with confidence (as much as 2 mm at 1:100,000 scale)
       
12 Contact, internal Dotted Separates sequentially younger deposits in Polallie eruptive episode
       
13 Limit of propyllitic alteration Dot-dash Encloses an area of propyllitic clay alteration (shown patterned) in west-central part of map area between Still Creek and Salmon River, as mapped by Wise (1969)
  >     
15 Contact, figurative Hachured Boundary of areas unmapped or poorly mapped
       
16 Neatline Solid Edge of geologic unit owing to position of map neatline
       
17 Open-water boundary Solid Blue stroke
       
19 Scratch contact None (no stroke) Marks uncertain limit of tuff breccia (area shown patterned) within unit Trby at south end of Barlow Ridge where traverses were limited
       
41 Moraine crest Chained circles Crestline of ridges that formed as lateral moraines. Location approximate; drawn from air photos and topographic maps


Table 5. Numeric code values and descriptions for structural features.

Line code Feature Line style Explanation
21 Normal fault, approximately or well located Solid, with ball and bar on downthrown side Fault exposed or displaced stratigraphic units sufficiently close that position has been determined by field work to within 100 m on the ground (1.0 mm at 1:100,000 scale)
       
22 Normal fault, inferred Short dashed  
       
24 Normal fault, concealed Dotted Trace of fault concealed by younger stratigraphic unit; positional accuracy uncertain but within 2 mm at 1:100,000 (200 m on the ground) and commonly within 1.0 mm (100 m on the ground)
       
25 Reverse or thrust fault Solid, sawteeth on upper plate Right-hand rule for sawteeth ornamentation
       
26 Reverse or thrust fault, concealed Dotted, sawteeth on upper plate Right-hand rule for sawteeth ornamentation
       
28 Fault, type not reported Solid From Swanson and others (1981); may be oblique, reverse, or normal fault
       
31 Anticline Solid, with opposing arrowheads Showing crestline and locally showing plunge; plunge arrowhead at end-node of polyline
       
32 Syncline Solid, with converging arrowheads Showing troughline
       
33 Monocline hinge, abrupt decrease in direction of arrow Solid Lower limb. Right-hand rule for ornamentation, with arrow symbols converging on hinge line
       
34 Monocline hinge, abrupt increase in direction of arrow Solid Upper limb. Right-hand rule for ornamentation, with arrowheads diverging from hinge line
       
35 Lineament Dash-dot Mapped from air photos. Origin most likely by small-offset faults or nowinfilled ground cracks
       

First posted December 23, 2014

For additional information, contact:
CVO, Volcano Science Center,
Cascades Volcano Observatory
U.S. Geological Survey
1300 SE Cardinal Court, Building 10, Suite 100
Vancouver, WA 98683-9589
http://volcanoes.usgs.gov/observatories/cvo/

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