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

Geologic units in Nez Perce county, Idaho

[Additional scientific data in this geographic area]

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 < 0.1 % 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

Silt; Pleistocene wind-blown loess dunes; northwestern Idaho, Palouse Hills (Pleistocene) at surface, covers 36 % of this area

Pleistocene wind-blown loess of northern Idaho.

Lithology: loess

Sedimentary and volcanic rocks (Upper? Triassic) (Late Triassic) at surface, covers < 0.1 % of this area

Undifferentiated marine sedimentary rocks and volcanic rocks, locally slightly to moderately metamorphosed, of Late(?) Triassic age, exposed principally in Hells Canyon of Snake River, locally in tributary canyons of Imnaha River, and in several areas marginal to the Wallowa Mountains

Lithology: mixed clastic/volcanic

Open Water (Holocene) at surface, covers 1 % of this area

Lakes and streams

Lithology: water

Basalt lava flows; Early Miocene valley-filling basalt flows of subunit 1b; Columbia Plateau (Miocene) at surface, covers 4 % of this area

Miocene basalt flows of western Idaho; commonly porphyritic and exposed on lower slopes.

Lithology: tholeiite; lava flow

Mica schist, quartzite, and calc-silcicate rock; Proterozoic high-grade metasedimentary rocks; trans-Idaho metamorphic province (Proterozoic) at surface, covers 0.5 % of this area

Precambrian high-grade metamorphic rock; metasediment; kyanite-sillimanite calc-silicate schist and gneiss, scapolite common

Lithology: mica schist; quartzite; calc-silicate rock

Basalt lava flows; Middle to Late Miocene local basalt flows of subunit 3b; Columbia Plateau (Late Miocene) at surface, covers 0.5 % of this area

Upper Miocene valley-filling basalt flows of western Idaho.

Lithology: basalt; lava flow

Gravel, sand, and silt; glacial outburst flood deposits, outwash, fanglomerate, and alluvium, undivided; Pleistocene (Pleistocene) at surface, covers 1 % 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

Metavolcanic and metasedimentary rocks; Middle to Lower Triassic greenschist-facies metamorphic rocks; western Idaho, Blue Mountains island-arc complex (Middle and Early Triassic) at surface, covers 3 % of this area

Middle and Lower Triassic metabasalt and submarine volcaniclastics of western Idaho

Lithology: mafic metavolcanic rock; metasedimentary rock; quartzite; meta-conglomerate; meta-argillite; marble; keratophyre

Shale, limestone, and sandstone; Triassic marine to non-marine epicontinental deposits (subunits are TRl and TRu) (Triassic) at surface, covers < 0.1 % of this area

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

Lithology: shale; limestone; sandstone; chert; conglomerate

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

water

Lithology: water

Quartz diorite, tonalite, granodiorite, orthogneiss, migmatite; Cretaceous to Jurassic quartz dioritic plutons; western Idaho, Blue Mountains island-arc complex (Early Cretaceous to Late Jurassic) at surface, covers 0.5 % of this area

Lower Cretaceous to Upper Jurassic intrusions in west-central Idaho.

Lithology: quartz diorite; tonalite; granodiorite; orthogneiss; migmatite; gabbro; trondhjemite; aplite

Sedimentary rocks (Jurassic) (Jurassic) at surface, covers < 0.1 % of this area

Black and gray mudstone, shale, siltstone, graywacke, andesitic to dacitic water-laid tuff, porcelaneous tuff, and minor interlayers and lenses of limestone and fine-grained sediments metamorphosed to phyllite or slate. Locally includes some felsite, andesite and basalt flows, breccia, and agglomerate. Marine invertebrate fauna indicates age range from Early Jurassic (Hettangian) to early Late Jurassic (Oxfordian). In northeast Oregon, includes Graylock Formation, Mowich Group, and Shaw Member (of Snowshoe Formation) of Dickinson and Vigrass (1965); Keller Creek Shale of Brown and Thayer (1966); Weberg, Warm Springs, Snowshoe, Trowbridge, and Lonesome Formations of Lupher (1941); the Coon Hollow Formation of Morrison (1964); and unnamed Jurassic rocks near Juniper Mountain in northern Malheur County (Wagner and others, 1963)

Lithology: shale; siltstone; graywacke

Basalt lava flows; Middle Miocene flood-basalt flows of subunit 2b; Columbia Plateau (Miocene) at surface, covers 50 % of this area

Miocene basalt flows of western Idaho; commonly finely crystalline and exposed on upper slopes.

Lithology: basalt; lava flow

Diorite, gabbro, and granite; Jurassic to Triassic plutons; western Idaho, Blue Mountains island-arc complex (Jurassic to Triassic) at surface, covers < 0.1 % of this area

Lower Mesozoic intrusions; localized near the Snake Canyon of western Idaho.

Lithology: diorite; quartz diorite; gabbro; norite; alkali-granite (alaskite); greenschist

Gravel, sand, and silt; Quaternary; alluvium (Quaternary) at surface, covers 0.4 % of this area

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

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

Limestone, slate; Upper Triassic greenschist-facies metamorphic rocks; western Idaho, Blue Mountains island-arc complex; (Late Triassic) at surface, covers 3 % of this area

Upper Triassic shale overlying reefal limestone and dolomite in west-central Idaho.

Lithology: limestone; slate; shale; dolostone (dolomite); phyllite; marble; skarn (tactite); amphibolite schist; greenschist