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

Geologic units in Franklin county, Idaho

Clastic debris; Quaternary colluvium, fanglomerate, talus, and glacial deposits; upland-valley margins (Quaternary) at surface, covers 0.9 % of this area

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

Lithology: alluvium; glacial drift; colluvium

Dolostone, shale, and chert; Silurian marine inner continental-shelf deposits (Late and Middle Silurian) at surface, covers 2 % 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 5 % of this area

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

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

Mica schist, quartzite, gneiss, and amphibolite; Late to Early Proterozoic high-grade metasedimentary rocks (subunits are ZXmhs, ZXmhq, and ZXmhc); trans-Idaho metamorphic province (Proterozoic) at surface, covers 0.1 % of this area

Precambrian high-grade metamorphic rock; metasediment

Lithology: mica schist; quartzite; calc-silicate rock; paragneiss; amphiibolite

Arenite, carbonate, conglomerate, and shale; Late Proterozoic rifted continental margin; southeastern Idaho (Late Proterozoic) at surface, covers 9 % of this area

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

Lithology: arenite; carbonate; conglomerate; shale

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

Dolostone, limestone, sandstone, shale, and conglomerate; Devonian marine continental-shelf deposits; east-central and southeastern Idaho (Devonian) at surface, covers 0.4 % of this area

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

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

Limestone, dolostone, arenite, shale, and siltstone; Lower Paleozoic marine continental-shelf deposits; southeastern Idaho; (Early Paleozoic) at surface, covers 7 % of this area

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

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

Limestone, arenite, shale, dolostone, and siltstone; Upper Proterozoic to Cambrian marine continental-shelf deposits; southeastern Idaho (Cambrian) at surface, covers 13 % of this area

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

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

Glacial debris; Late Pleistocene till, outwash, and alluvium of valley glaciers; high mountain valleys (Late Pleistocene ) at surface, covers 4 % of this area

Pleistocene upland valley deposits; commonly derived from alpine glaciation.

Lithology: till; outwash; alluvium

Quartzite, argillite, carbonate, meta-conglomerate, siltite, intermediate volcanic rock; Late Proterozoic rifted continental margin; southeastern Idaho (Late Proterozoic) at surface, covers 2 % 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

Clay, silt, sand, and gravel; Late Pleistocene glacial-lake sediments; Basin and Range province (Late Pleistocene) at surface, covers 32 % of this area

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

Lithology: glaciolacustrine; silt; sand; gravel

Dolostone, limestone, arenite, chert, and conglomerate; Ordovician marine continental-shelf deposits; southeastern Idaho (Ordovician) at surface, covers 6 % of this area

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

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

Open Water (Holocene) at surface, covers 0.6 % of this area

Lakes and streams

Lithology: water