| 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 |
|
| 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 |
| |
|
|
|