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

Geologic units in Bannock county, Idaho

[Additional scientific data in this geographic area]

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

Limestone, arenite, shale, dolostone, and siltstone; Upper Proterozoic to Cambrian marine continental-shelf deposits; southeastern Idaho (Cambrian) at surface, covers 5 % of this area

Cambrian marine dolomite, limestone, claystone, and quartzite; grades into Precambrian.

Lithology: limestone; arenite; shale; dolostone (dolomite); siltstone

Basalt flows, pumice, and tuff; Early Pleistocene to Pliocene basaltic volcanics; Snake River Plain (Early Pleistocene) at surface, covers 0.3 % of this area

Lower Pleistocene to Pliocene basalts with associated tuffs and volcanic detritus.

Lithology: tholeiite; lava flow; pumice; tuff

Surficial sediments; Quaternary alluvial, lacustrine, eolian, and glacial-outwash deposits, undivided; Snake River Plain, and Basin-and-Range provinces (Quaternary) at surface, covers 3 % of this area

Quaternary surficial cover; Snake Plain stream, lake, wind and glacial-flood mantle.

Lithology: loess; colluvium

Open Water (Holocene) at surface, covers 3 % of this area

Lakes and streams

Lithology: water

Dolostone, limestone, arenite, chert, and conglomerate; Ordovician marine continental-shelf deposits; southeastern Idaho (Ordovician) at surface, covers 4 % of this area

Ordovician marine dolomite, quartzite, and limestone; subdivisions are (Ou and Ol).

Lithology: dolostone (dolomite); limestone; arenite; chert; conglomerate

Clay, silt, sand, and gravel; Late Pleistocene glacial-lake sediments; Basin and Range province (Late Pleistocene) at surface, covers 1 % of this area

Pleistocene glacial-lake, ponded-water, and shoreline sediments.

Lithology: glaciolacustrine; silt; sand; gravel

Gravel, sand, and silt; Quaternary basin-filling alluvium; Snake River Plain, Basin and Range provinces (Quaternary) at surface, covers 7 % of this area

Quaternary detritus; generally basin-filling deposits of central and southern Idaho.

Lithology: alluvium; alluvial fan; alluvial terrace

Quartzite, argillite, carbonate, meta-conglomerate, siltite, intermediate volcanic rock; Late Proterozoic rifted continental margin; southeastern Idaho (Late Proterozoic) at surface, covers 4 % of this area

Younger Precambrian detrital units of central and southeastern Idaho; subdivisions are (Z2s and Z1s).

Lithology: quartzite; argillite; carbonate; conglomerate; siltstone; intermediate volcanic rock

Silt; Quaternary wind-blown loess; eastern Snake River Plain and Basin and Range provinces (Quaternary) at surface, covers 16 % of this area

Quaternary wind-blown deposits; most commonly a loess mantle east of the Snake Plain.

Lithology: loess

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 17 % 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

Limestone, dolostone, arenite, shale, and siltstone; Lower Paleozoic marine continental-shelf deposits; southeastern Idaho; (Early Paleozoic) at surface, covers 4 % of this area

Lower Paleozoic marine carbonate and clastic units southeast of the Snake Plain.

Lithology: limestone; dolostone (dolomite); arenite; shale; siltstone

Dolostone, limestone, sandstone, shale, and conglomerate; Devonian marine continental-shelf deposits; east-central and southeastern Idaho (Devonian) at surface, covers < 0.1 % of this area

Devonian bedded dolomite and limestone interval of eastern and southern Idaho.

Lithology: dolostone (dolomite); limestone; sandstone; shale; conglomerate

Basalt and gravel; Late Pleistocene basalt flows and interlayered gravel of subunit 2b; Snake River Plain (Late Pleistocene) at surface, covers 2 % of this area

Upper Pleistocene Snake Plain basaltic lava flows, unit 2.

Lithology: tholeiite; lava flow; gravel

Shale, arenite, conglomerate, intermediate and felsic volcanic rocks; Late Proterozoic rifted continental margin; southeastern Idaho (Late Proterozoic) at surface, covers 3 % of this area

Younger Precambrian volcanic and diamictic units of central and southeastern Idaho.

Lithology: shale; arenite; conglomerate; bimodal suite; intermediate metavolcanic rock; meta-rhyolite; lava flow; pyroclastic

Limestone, sandstone, dolostone, and chert; Permian to Pennsylvanian marine epicontinental-basin deposits; southeastern Idaho; (Early Permian to Early Pennsylvanian) at surface, covers 0.3 % of this area

Lower Permian to Lower Pennsylvanian chert, limestone, and sandstone of southern Idaho; subdivisions are (Ps, and PNs).

Lithology: limestone; sandstone; dolostone (dolomite); chert; siltstone; shale

Dolostone, shale, and chert; Silurian marine inner continental-shelf deposits (Late and Middle Silurian) at surface, covers 1.0 % of this area

Upper and Middle Silurian fossiliferous dolomite; clay, silt and sand near base.

Lithology: dolostone (dolomite); shale; chert

Gravel, sand, and silt; Quaternary; alluvium (Quaternary) at surface, covers 7 % of this area

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

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

Limestone, dolostone, shale, and arenite; Ordovician and Cambrian shallow marine inner continental-shelf deposits; southeastern Idaho (Ordovician and Cambrian) at surface, covers 3 % of this area

Ordovician, commonly Lower, and Cambrian marine sediments of eastern and southern Idaho.

Lithology: limestone; dolostone (dolomite); shale; arenite

Arenite, carbonate, conglomerate, and shale; Late Proterozoic rifted continental margin; southeastern Idaho (Late Proterozoic) at surface, covers 11 % of this area

Uppermost Younger Precambrian massive quartzite with carbonate beds of central and southeastern Idaho; overlies (Z1s).

Lithology: arenite; carbonate; conglomerate; shale

Clay, silt, and minor sand; Late Pleistocene distal glacial-flood deposits; western Snake River Plain (Late Pleistocene) at surface, covers 1 % of this area

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

Lithology: stratified glacial sediment; outwash; glaciolacustrine

Limestone, sandstone, shale, and chert; Pennsylvanian marine epicontinental-basin deposits; southeastern Idaho (Pennsylvanian) at surface, covers < 0.1 % of this area

Pennsylvanian beds; lowermost portion of the southern Idaho sequence (PPNs).

Lithology: limestone; sandstone; shale; chert

Clastic debris; Quaternary colluvium, fanglomerate, talus, and glacial deposits; upland-valley margins (Quaternary) at surface, covers 3 % of this area

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

Lithology: alluvium; glacial drift; colluvium

Rhyolitic tuffs, ignimbrites, and flows, basaltic flows, conglomerate and marlstone; Pliocene to Miocene volcano-sedimentary deposits; eastern Snake River Plain and southeastern Idaho (Pliocene-Miocene) at surface, covers 1 % of this area

Pliocene volcanic units, generally air-fall or pyroclastic in origin; grade into (Tpd).

Lithology: rhyolite; tuff; ignimbrite; tholeiite; conglomerate; marlstone

Gravel, sand, silt, clay; Late Pleistocene glacio-alluvial and lacustrine deposits; Basin and Range, and Snake River Plain (Late Pleistocene) at surface, covers 2 % of this area

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

Lithology: outwash; alluvium; lake or marine deposit (non-glacial); gravel; sand; silt; clay or mud

Shale, limestone, and sandstone; Triassic marine to non-marine epicontinental deposits (subunits are TRl and TRu) (Triassic) at surface, covers 0.2 % of this area

Triassic shallow-marine to non-marine sediments of eastern Idaho; subdivisions are (TRu and TRl).

Lithology: shale; limestone; sandstone; chert; conglomerate

Sand; Holocene dunes; Snake River Plain (Holocene) at surface, covers 0.2 % of this area

Recent active sand dunes and eolian deposits.

Lithology: dune sand; eolian

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

Limestone, arenite, dolostone, chert, siltstone, shale; Upper Paleozoic marine continental-shelf deposits; southeastern Idaho (Late Paleozoic) at surface, covers 0.1 % of this area

Upper Paleozoic marine sediments in southern Idaho.

Lithology: limestone; arenite; dolostone (dolomite); chert; siltstone; shale