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

Geologic units in Adams county, Idaho

[Additional scientific data in this geographic area]

Silt, clay, sand, and gravel; Quaternary-Tertiary alluvial and lacustrine deposits; western Snake River Plain (Early Pleistocene and Late Pliocene) at surface, covers < 0.1 % of this area

Pleistocene and Pliocene stream and lake deposits.

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

Clastic debris; Quaternary colluvium, fanglomerate, talus, and glacial deposits; upland-valley margins (Quaternary) at surface, covers 2 % of this area

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

Lithology: alluvium; glacial drift; colluvium

Intermediate intrusions; mostly Late Cretaceous dioritic to granodioritic plutons of the Idaho batholithic assemblage (Cretaceous) at surface, covers 0.6 % of this area

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

Lithology: tonalite; granodiorite; quartz diorite; trondhjemite

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 9 % 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

Basalt lava flows; Middle to Late Miocene local basalt flows of subunit 3b; Columbia Plateau (Late Miocene) at surface, covers 0.2 % 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 < 0.1 % 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

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

Limestone, slate; Upper Triassic greenschist-facies metamorphic rocks; western Idaho, Blue Mountains island-arc complex; (Late Triassic) at surface, covers 0.4 % 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

Metavolcanic and metasedimentary rocks; Jurassic greenschist-facies metamorphic rocks; western Idaho, Blue Mountains island-arc complex (Jurassic) at surface, covers 0.4 % of this area

Jurassic mixed marine detrital and volcanic rocks of western Idaho.

Lithology: greenstone; metasedimentary rock; keratophyre; meta-argillite; graywache; meta-conglomerate; meta-rhyolite; marble; evaporite

Basalt lava flows; Middle Miocene flood-basalt flows of subunit 2b; Columbia Plateau (Miocene) at surface, covers 39 % 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 0.2 % of this area

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

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

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 4 % of this area

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

Lithology: basalt; latite; lava flow

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 3 % 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)

Marine sedimentary rocks (Upper Triassic? and Upper and Middle Triassic) (Early Triassic) at surface, covers < 0.1 % of this area

Black, green, and gray argillite, mudstone, and shale; graywacke, sandy limestone, tuff, and some coarse volcaniclastic rocks; chert, sandstone comprised of chert clasts, and chert pebble conglomerate; thin-bedded and massive limestone. Locally contains some interbedded lava flows, mostly spilite or keratophyre. In places metamorphosed. Invertebrate marine fauna indicates unit mostly of Late Triassic (Karnian and Norian) age. Includes the Begg and Brisbois Formations of Dickinson and Vigrass (1965; Vester Formation of Brown and Thayer, 1966) and the Rail Cabin Argillite of Dickinson and Vigrass (1965); Fields Creek Formation and Laycock and Murderers Creek Graywackes of Brown and Thayer (1966); Martin Bridge Formation and lower sedimentary series in and near the Wallowa Mountains (Prostka, 1962; Nolf, 1966); and Doyle Creek and Wild Sheep Creek Formations (Vallier, 1977). Probably partly age correlative with rocks of the Applegate Group (Wells and Peck, 1961) of southwestern Oregon

Lithology: argillite; shale; graywacke; limestone; tuff; chert; sandstone; lava flow

Tuff, arkose, claystone, siltstone, conglomerate, lignite; Miocene alluvial and lacustrine deposits (Miocene) at surface, covers 2 % 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

Metasedimentary and metavolcanic rocks; Permian greenschist-facies rocks; western Idaho, Blue Mountains island-arc complex (Late Permian) at surface, covers 0.7 % of this area

Upper Permian submarine volcanic complex in the Snake Canyon of western Idaho.

Lithology: intermediate metavolcanic rock; quartzite; meta-conglomerate; meta-argillite; marble

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 2 % of this area

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

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

Metamorphosed granodiorite, quartz monzonitek tonalite, quartz diorite; mostly Cretaceous orthogneiss and migmatite; northern and Atlanta batholith; margins of Bitterroot and Atlanta batholiths (Cretaceous) at surface, covers 3 % of this area

Metamorphosed granitic intrusive rock; associated with pluton margins and stress areas.

Lithology: granodiorite; quartz monzonite; tonalite; quartz diorite; orthogneiss; migmatite

Quartz diorite, metasedimentary rock, metavolcanic rock, and migmatite; Cretaceous to Jurassic plutons in Triassic to Permian metamorphic host rocks, undivided; western Idaho (Cretaceous to Permian) at surface, covers 3 % of this area

Mixed, highly altered and migmatitic rocks; derived from imbrication and dynamic events

Lithology: quartz diorite; metasedimentary rock; metavolcanic rock; trondhjemite; quartz monzonite; migmatite

Glacial debris; Late Pleistocene till, outwash, and alluvium of valley glaciers; high mountain valleys (Late Pleistocene ) at surface, covers 0.9 % of this area

Pleistocene upland valley deposits; commonly derived from alpine glaciation.

Lithology: till; outwash; alluvium

Conglomerate, sandstone, and siltstone; Eocene to Late Cretaceous alluvial-fan deposits; east-central Idaho, Cordilleran fold-thrust belt, piggyback basins (Eocene to Late Cretaceous ) at surface, covers < 0.1 % of this area

Lower Tertiary to Upper Mesozoic breccia, conglomerate and sandstone; syntectonic in part.

Lithology: conglomerate; arkose; siltstone; limestone

Basalt lava flows; Early Miocene valley-filling basalt flows of subunit 1b; Columbia Plateau (Miocene) at surface, covers 21 % of this area

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

Lithology: tholeiite; lava flow

Metavolcanic and metasedimentary rocks, diorite, trondhjemite, and migmatite; Cretaceous to Jurassic quartz dioritic plutons in Mesozoic to Permian greenschist-facies rocks; western Idaho, Blue Mountains island-arc complex (Cretaceous to Permian) at surface, covers 2 % of this area

Triassic and possibly Permian submarine metavolcanic rocks of west-central Idaho.

Lithology: metavolcanic rock; meta-argillite; migmatite; amphibolite; serpentinite

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

Lakes and streams

Lithology: water

Imnaha Basalt (lower Miocene) (Early Miocene) at surface, covers < 0.1 % of this area

Mostly coarse-grained, plagioclase porphyritic basalt; flows commonly contain zeolite amygdules and montmorillonitic alteration is widespread. Potassium-argon ages mostly 16 to 17 Ma (McKee and others, 1981)

Lithology: basalt

Sedimentary and volcanic rocks, partly metamorphosed (Permian and Permian?) (Permian) at surface, covers < 0.1 % of this area

Epiclastic and volcaniclastic rocks, chert, limestone, and lava flows of mid- or Early Permian(?) age that are moderately to intensely metamorphosed. Includes part of Hunsaker Creek Formation of Vallier (1977), in the eastern Blue Mountains province, composed mostly of keratophyre flows, keratophyric volcaniclastic rocks and minor spilite, mudstone, and limestone. In Wheeler County, includes phyllite, chert, and fusulinid-bearing crystalline limestone of probable Early Permian (Wolfcampian?) age (Oles and Enlows, 1971), associated with phyllite, chlorite, and muscovite schist, and lawsonite-crossite blueschist (Swanson, 1969b)

Lithology: fine-grained mixed clastic; sandstone; chert