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

Geologic units in Lake county, Colorado

[Additional scientific data in this geographic area]

Ash-flow tuff of main volcanic sequence (Phanerozoic | Cenozoic | Tertiary) at surface, covers 0.7 % of this area

Includes many named units

Lithology: ash-flow tuff

Middle Tertiary intrusive rocks (Phanerozoic | Cenozoic | Tertiary) at surface, covers 0.7 % of this area

Intermediate to felsic compositions

Lithology: plutonic rock (phanerit

Minturn and Belden Fms (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian) at surface, covers 0.8 % of this area

Lithology: sandstone; shale; limestone; conglomerate

Glacial drift (Phanerozoic | Cenozoic | Quaternary) at surface, covers 16 % of this area

Includes some unclassified glacial deposits

Lithology: glacial drift

Gravels and alluviums (Phanerozoic | Cenozoic | Quaternary) at surface, covers 5 % of this area

Includes Broadway and Louviers Alluviums

Lithology: gravel; alluvium

Pre-ash-flow andesitic lavas, breccias, tuffs, and conglomerates (Phanerozoic | Cenozoic | Tertiary) at surface, covers 0.6 % of this area

Includes several named units

Lithology: andesite; tuff; volcanic breccia (agglomerate)

Granitic rocks of 1400- and 1700-m.y. age groups, undivided, or, in Taylor River region, rocks with characteristics of Xg but U-Th-Pb zircon ages of Yg (Proterozoic | Paleoproterozoic Mesoproterozoic) at surface, covers 0.3 % of this area

Granitic rocks of 1400- and 1700-m.y. age groups, undivided, or, in Taylor River region, rocks with characteristics of Xg but U-Th-Pb zircon ages of Yg

Lithology: granitoid

Older glacial drift (Phanerozoic | Cenozoic | Quaternary) at surface, covers 3 % of this area

Lithology: glacial drift

Modern alluvium (Phanerozoic | Cenozoic | Quaternary) at surface, covers 1 % of this area

Includes Piney Creek Alluvium and younger deposits

Lithology: alluvium

Granitic rocks of 1700-m.y. age group (Proterozoic | Paleoproterozoic) at surface, covers 17 % of this area

Includes Boulder Creek -M.Y. AGE GROUP (AGE 1650-1730 M.Y.)--Includes Boulder Creek, Cross Creek, Denny Creek, Kroenke, Browns Pass, Powderhorn, Pitts Meadow, Bakers Bridge, and Tenmile Granites, Quartz Monzonites, or Granodiorites;

Lithology: granite; granodiorite; quartz monzonite

Biotitic gneiss, schist, and migmatite (Proterozoic | Paleoproterozoic) at surface, covers 11 % of this area

Locally contains minor hornblende gneiss, calc-silicate rock, quartzite, and marble. Derived principally from sedimentary rocks

Lithology: biotite gneiss; schist; migmatite; quartzite; marble

Laramide intrusive rocks (Phanerozoic | Mesozoic Cenozoic | Cretaceous Tertiary) at surface, covers 8 % of this area

Mainly intermediate to felsic compositions; some mafic

Lithology: granitoid

Older gravels and alluviums (Phanerozoic | Cenozoic | Quaternary) at surface, covers 4 % of this area

Includes Slocum, Verdos, Rocky Flats, and Nussbaum Alluviums in east, and Florida, Bridgetimber, and Bayfield Gravels in southwest

Lithology: gravel; alluvium

Dry Union Fm (Phanerozoic | Cenozoic | Tertiary) at surface, covers 4 % of this area

Siltstone, sandstone, and conglomerate. Includes Wagontongue Fm (Miocene) in South Park

Lithology: siltstone; sandstone; conglomerate; tuff

Landslide deposits (Phanerozoic | Cenozoic | Quaternary) at surface, covers 2 % of this area

Locally includes talus, rock-glacier, and thick colluvial deposits

Lithology: landslide; talus; colluvium

Leadville Limestone, Williams Canyon Limestone , Manitou Limestone, and Sawatch Quartzite (Phanerozoic | Paleozoic | Cambrian Ordovician(?) Silurian(?) Devonian(?) Carboniferous) at surface, covers 4 % of this area

Lithology: limestone; quartzite

Felsic and hornblendic gneisses, either separate or interlayered (Proterozoic | Paleoproterozoic) at surface, covers 0.1 % of this area

Includes metabasalt, metatuff, and interbedded metagraywacke; locally contains interlayered biotite gneiss. Derived principally from volcanic rocks

Lithology: felsic gneiss; mafic gneiss; meta-basalt; meta-graywacke

Minturn Fm in west-central and south-central and other units (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian) at surface, covers 6 % of this area

Arkosic sandstone, conglomerate, shale, and limestone. Includes Madera Fm and Sharpsdale Fm of Chronic (1958) in Sangre de Cristo Range and Gothic Fm of Langenheim (1952) in Elk Mountains. Other units of Middle Pennsylvanian age.

Lithology: sandstone; conglomerate; shale; limestone

Granitic rocks of 1400-m.y. age group (Proterozoic | Mesoproterozoic) at surface, covers 14 % of this area

Includes Silver Plume, Sherman, Cripple Creek, St. Kevin, Vernal Mesa, Curecanti, Eolus, and Trimble Granites or Quartz Monzonites; also, San Isabel Granite of Boyer (1962) and unnamed granitic rocks

Lithology: granite; granodiorite; quartz monzonite