pentane

CORRELATION OF MAP UNTTS

* ] 7 TA LAVA FLOWS (MROCENT)--Chiefily lwen flows and interflew
a Haiiteene brectia cones of basaltic aspect. Unit conpelna
ol | Ge > QUATERNARY beswit of Calumbia River Gr: 3; ney dee contain
Pletatecene andesitie or other ‘more je racks of unknown
band Op provenance. Also included are minor aile- and
, ‘ONO! i. elay-cich sedimentary unite Interstratified with
Be meet > teva flewe; twe prominent occurrences are eset of
"Ah the dam that impounds Ben Ress Reserveir and on
—— south-facing «lope in NW 1/4 wee. 29, T. 15 4.,
a, TH ts! R. 2M. Cantaert with pl in Cuddy Mountain modt-
ad | Miocene filed from me
emery TERTIARY Te RHYOLITE DIKES ?)--Aphanitde recke with phenc-
wee erysts of quartz, alkali feldspar, plagieriase,
mum and biotite; dikes cut pre-Tertiury recke on south
URCANFORMTTY flank of Cuddy Moentwins. Dike ffret noted by
an | King (1971), whe believed them to be related te
et a } onemedei J emplacement of the Creteceous Iduho Bathelith.
UNCONFORMITY A welded aeh-Clew tuff exposed in Long Gulch,
pt PRE-SERTOARY believed by King (L971) to be generically related
CTRTASSIC®) ty the dikes, haw yielded an Eocene k-Ar age
(A7.742.4 m.ys; Armstrong, 1975, p. 2%), Whieh
. diken,
DESCRIPTION OF MAP UNE'TS ae a dee oe outed aotal
differs somewhat from that King,
SURFICTAL DEPOSITS (HOLOCENE AND PLETSTOCENE)--Chief ly igen a
sand and gravel of floodplain and terrace depowite PRESPERFIARY GRYSTALLINE ROCKS (FRIASSEC?)-- Exposed
ace Opal aioe; Spe Enda Biiny of on south flank of the Cuddy Moumteins; includes

fan depesiite at mouths of streams that enter the i
wujeo Ould gabbro, quart® diorite, and perphyritie grane—

LANDSLIDE, EARTHFLOW, AND RELATED DRPOSTYS (HOLOGENE

detail 971), whe notes that the
AND PLEESTOCENE)--Only Larger examples shown _ ages pA > ng te Re rocks elsewhere
\ANDSLIDE DEPOSTTS AND MORATNES (HOLOCENE AND PL#TS- in the Guddy Mountains eluster around 200 m.¥.
TOCENE)--Area around Calamity Meadows in the Cuddy Contact with Tl in Cuddy Neuntsine modified fram
Mountsine may be underlain by « cemplex ef morainal Kang (1972)
material and landslide debris as suggested by :
aerial Taps
OUDER SURP'ECTAL S (PLEESTOCENE)--Sand aad gravel REFERENCES
of older erosion surface separated by scarp from
lewer-lying surface of Qs. od only in Anmstreng, R. L., 1975, The gesehromometry of Tiwhw:
Indian Valley; an occurrence q agwigned ‘Weochron/Weat, no. 14, p. 1-50.
te thie unit occurs in a strip along Highway 95 King, J. R., 2972, The gealogy of the southeastern
beginning about 2? mi (3.2 km) east of Cambridge Guddy Mountain district, western Ideho: M.S.
PEWIMENT GRAVEL (PLEISTOCENE)--Relict pediment eravel Thesiw, Oregen State Unir., 78 p.
mantle that overlies Te near southwest corner of D. H., 1976, Reconnaissance geologic map
map. The remnant within the map ares is northward of Welser geothermal area, Wastiington County,
extension of much larger gravel-mantled ares seuth Idaho: U.S. Gem). Survey Mize, Field Studies
of map area Map MF-745 -

--Interstratified with sedimentary recks

Rese from U.S. Geslogical Survey,
Cambridge, 1957, Counct), 1954

Lava flows--Dark-gray nonporous te light-gray ? CONTACT--1 ’
id a se. Dashed approximately located; queried
P } Temembles rock of dike expesed about - nian a
22 mi (35 km) to the southwest thet has been chemi- tt? FAULT--Daghed whete approximately lewsted; queried
cally enalyeed and that has @ K-Ar age of 10.0+0.6 . where uncertain; dutted where cen-
n.y. (Melntyre, 1976, Table 1, anwlysis H) coaled younger depowftm. Bar and ball
Dikes of basaltic andesite(?) within cinder cone-- on downthrown «ide, Half-errowe indieate sense
Rock from that of adjacent non- of inferred Arrow indieetew
lava direction of dip of fault
Pyrodlastie recks of cinder cone--Crudely layered am ‘
arayish-brow and yeliowksh-brown altered fine tuft  ——}— WFICHA. SHOWIN CRESTHINE--Dashed where spprent
with sbundent basaltic andesite(?) rw
scoria — SYNCLINE, SHOWING TROUGHLINE--Dashe@ where approx i-
SEDIMENTARY ROCKS (MIOCENE)--Chiefly arkewie sandstone mately located
with variable amounts of coarser and finer mate- STRIKE AND DIP OF BEDS OR LAVA FLOWS
rial. mere ¢ommon toward the northewst; am inatiived < anak of , -
outerope nesr Mess contain bede ef cobble and aaemieaiin fin ali, eae areeenatl
jer gravel with clasts of basaltic rock folt- e Apptentibentally ‘ hestingpanaiias

i
'
i
|
iF

suiiiion, @ winvme, Sesipaite af Ghibe kit t in the
Weiser area (McIntyre, 1976), ft» not present tn
this eres

os HYDR@FHERMALLY ALTERED ZON®--Poorly expownd; suth
ef Thorn Greek at North end of Indian Valley

U.S. Geological Survey
OPEN FILE REPORT
Thie wap is preliminary and has not :
been edived er reviewed for eenformity
with Geological Survey standards.