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

Geologic units in Payette county, Idaho

Basalt flows and incidental andesite, and latite flows; Miocene mafic to intermediate volcanics; subunits are Tmib, Tm1b, Tm2b, Tm3b; Columbia Plateau, Owyhee Plateau (Miocene) at surface, covers 10 % of this area

Miocene plateau basalt flows of western Idaho; subdivisions are (Tm3b, Tm2b, Tm1b).

Lithology: basalt; latite; lava flow

Clay, silt, and minor sand; Late Pleistocene distal glacial-flood deposits; western Snake River Plain (Late Pleistocene) at surface, covers 15 % of this area

Pleistocene waterlaid detritus; may be distal deposits of glacial floods and outwash.

Lithology: stratified glacial sediment; outwash; glaciolacustrine

Tuff, arkose, claystone, siltstone, conglomerate, lignite; Miocene alluvial and lacustrine deposits (Miocene) at surface, covers 0.7 % of this area

Miocene stream and lake deposits; generally associated with volcanic episodes.

Lithology: tuff; arkose; claystone; conglomerate; siltstone; mixed clastic/coal

Open Water (Holocene) at surface, covers < 0.1 % of this area

water

Lithology: water

Gravel, sand, and silt; Quaternary; alluvium (Quaternary) at surface, covers 16 % of this area

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

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

Gravel, sand, and silt; glacial outburst flood deposits, outwash, fanglomerate, and alluvium, undivided; Pleistocene (Pleistocene) at surface, covers 10 % 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

Open Water (Holocene) at surface, covers 0.3 % of this area

Lakes and streams

Lithology: water

Alluvial deposits (Holocene) (Holocene) at surface, covers < 0.1 % of this area

Sand, gravel, and silt forming flood plains and filling channels of present streams. In places includes talus and slope wash. Locally includes soils containing abundant organic material, and thin peat beds

Lithology: sand; gravel; silt; peat

Sandstone, conglomerate, siltstone, tuff, claystone, limestone, and diatomite; Pliocene tuffaceous alluvial and lacustrine deposits; Snake River Plain and vicinity, southeastern Idaho (Pliocene ) at surface, covers 49 % of this area

Pliocene stream and lake deposits; may be due to volcanic and block-faulting events.

Lithology: sandstone; conglomerate; siltstone; tuff; claystone; shale; limestone