USGS Home
Contact USGS
Search USGS

Mineral Resources > Online Spatial Data > Geology > by state > Idaho Geology

Geologic units in Camas county, Idaho

[Additional scientific data in this geographic area]

Basalt flows, basaltic pyroclastic and clastic debris; Middle Pleistocene canyon-filling and plateau lava flows, pyroclastic debris, alluvium, and colluvium; Snake River Plain (Middle Pleistocene) at surface, covers 8 % of this area

Middle Pleistocene plateau and canyon-filling basalt in and near Snake Plain.

Lithology: tholeiite; lava flow; pyroclastic; alluvium; colluvium

Intrusive rocks: mostly Late Cretaceous granodioritic to granitic plutons of the Idaho batholithic assemblage, but including some Eocene intrusions; northern Idaho and Atlanta batholith (Cretaceous to Eocene) at surface, covers 41 % of this area

Cretaceous plutons; probably includes unmapped older and younger crystalline bodies.

Lithology: granodiorite; peraluminous granite; quartz monzonite; quartz diorite; tonalite; trondhjemite; pegmatite; alkali-granite (alaskite)

Trachyandesite, latite, trachybasalt flows, dikes, and volcaniclastic debris; Eocene intermediate volcanics; central Idaho, southern Challis volcanic field (Eocene) at surface, covers 11 % of this area

Eocene mixed silicic and basaltic volcanic ejecta, flows and reworked debris.

Lithology: trachyandesite; latite; trachybasalt; dacite; trachyte; lava flow; volcanic breccia (agglomerate)

Monzogranite, syenogranite, and syenite; Eocene phaneritic to porphro-aphanitic intrusions of the pink monzogranite suite; Challis magmatic belt (Eocene) at surface, covers 0.3 % of this area

Eocene intrusions of predominantly felsic (pink granite) composition

Lithology: granite; quartz syenite

Gravel, sand, and silt; Quaternary; alluvium (Quaternary) at surface, covers 17 % of this area

Quaternary alluvium; may contain some glacial deposits and colluvium in uplands

Lithology: alluvium; alluvial terrace; floodplain; alluvial fan; colluvium

Black argillite, quartzite, siltite, marble, chert, and syngenetic silver-lead-zinc deposits; Devonian euxinic marine-basin deposits; central Idaho (Devonian) at surface, covers 0.3 % of this area

Devonian thrusted, deep-water siliceous argillite and quartzite of central Idaho.

Lithology: meta-argillite; quartzite; marble; calc-silicate rock; siltstone; chert

Gravel, sand, and silt; glacial outburst flood deposits, outwash, fanglomerate, and alluvium, undivided; Pleistocene (Pleistocene) at surface, covers 0.4 % of this area

Pleistocene outwash, fanglomerate, flood and terrace gravels; sudivisions are: (Qpug, Qpmg, and Qplg).

Lithology: stratified glacial sediment; alluvium; outwash; alluvial fan; alluvial terrace

Intermediate intrusions; mostly Late Cretaceous dioritic to granodioritic plutons of the Idaho batholithic assemblage (Cretaceous) at surface, covers 4 % of this area

Cretaceous plutons; intermediate; as granodiorite or diorite; probably includes unmapped older and younger crystalline bodies.

Lithology: tonalite; granodiorite; quartz diorite; trondhjemite

Sandstone, limestone, siltstone, shale, and conglomerate; Lower Permian to Middle Pennsylvanian deltaic turbidites; central Idaho; (Early Permian) at surface, covers 2 % of this area

Lower Permian to Middle Pennsylvanian thrusted, marine detritus of central Idaho.

Lithology: sandstone; limestone; siltstone; conglomerate; shale

Clastic debris; Quaternary colluvium, fanglomerate, talus, and glacial deposits; upland-valley margins (Quaternary) at surface, covers 0.4 % of this area

Quaternary colluvium, fanglomerate, and talus plus some glacial debris in upland valleys.

Lithology: alluvium; glacial drift; colluvium

Open Water (Holocene) at surface, covers 0.4 % of this area

Lakes and streams

Lithology: water

Rhyolite, quartz latite, and latite ignimbrites and flows; Miocene felsic volcanics; Owyhee Plateau; (Miocene) at surface, covers 7 % of this area

Miocene silicic flows, tuffs; most common in southwestern Idaho.

Lithology: rhyolite; latite; quartz latite; ignimbrite; lava flow

Basalt flows, pyroclastic debris, clastic sediments, and diatomite; Pliocene basaltic volcanics and clastic sediments; Snake River Plain and vicinity (Pliocene) at surface, covers 3 % of this area

Pliocene olivine basalt flows and associated tuff and detritus of southern Idaho.

Lithology: basalt; lava flow; tuff; mixed clastic/volcanic

Basalt, pumice; Holocene basaltic lava flows and cinder cones; Snake River Plain and vicinity (Holocene) at surface, covers < 0.1 % of this area

Recent, relatively unweathered Snake Plain basalt flows and cinder cones.

Lithology: tholeiite; lava flow; pumice

Basalt, clay, and gravel; Late Pleistocene basalt flows with interlayered alluvial and lacustrine sediments; Snake River Plain and vicinity (subunits are Qpu1b, Qpu2b, Qpu3b, and Qpu4b) (Late Pleistocene) at surface, covers 0.1 % of this area

Upper Pleistocene Snake Plain lava flows; local stratigraphic position shown by (Qpu4b, Qpu3b, Qpu2b, Qpu1b).

Lithology: tholeiite; lava flow; clay or mud; gravel

Gravel and sand; Middle Pleistocene alluvial pediment gravel (Pleistocene ) at surface, covers 2 % of this area

Middle Pleistocene deposits; outwash, fanglomerate, flood and terrace gravels.

Lithology: alluvium; gravel; sand

Quartz monzodiorite, monzogranite, granodiorite, monzonite, diorite; Eocene phaneritic to porphyro-aphanitic intrusions of the quartz monzodiorite suite; Challis magmatic belt (Eocene) at surface, covers 3 % of this area

Eocene intrusions of intermediate (mafic to felsic) composition

Lithology: quartz monzodiorite; monzogranite; granodiorite; quartz monzonite; quartz diorite