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

Geologic units in Chaffee county, Colorado

[Additional scientific data in this geographic area]

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

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

Lithology: gravel; alluvium

Landslide deposits (Phanerozoic | Cenozoic | Quaternary) at surface, covers 0.4 % of this area

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

Lithology: landslide; talus; colluvium

Dry Union Fm (Phanerozoic | Cenozoic | Tertiary) at surface, covers 9 % of this area

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

Lithology: siltstone; sandstone; conglomerate; tuff

Felsic and hornblendic gneisses, either separate or interlayered (Proterozoic | Paleoproterozoic) at surface, covers 10 % 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

Leadville Limestone, Williams Canyon Limestone , Manitou Limestone, and Sawatch Quartzite (Phanerozoic | Paleozoic | Cambrian Ordovician(?) Silurian(?) Devonian(?) Carboniferous) at surface, covers 0.3 % of this area

Lithology: limestone; quartzite

Mafic rocks of 1700-m.y. age group (Proterozoic | Paleoproterozoic) at surface, covers 0.1 % of this area

Gabbro and mafic diorite and monzonite

Lithology: gabbro; diorite; monzonite

Older glacial drift (Phanerozoic | Cenozoic | Quaternary) at surface, covers 0.5 % of this area

Lithology: glacial drift

Biotitic gneiss, schist, and migmatite (Proterozoic | Paleoproterozoic) at surface, covers 4 % 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 5 % of this area

Mainly intermediate to felsic compositions; some mafic

Lithology: granitoid

Granitic rocks of 1700-m.y. age group (Proterozoic | Paleoproterozoic) at surface, covers 23 % 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

Glacial drift (Phanerozoic | Cenozoic | Quaternary) at surface, covers 8 % of this area

Includes some unclassified glacial deposits

Lithology: glacial drift

Rhyolitic intrusive rocks and flows of late-volcanic bimodal suite (Phanerozoic | Cenozoic | Tertiary) at surface, covers 0.1 % of this area

Lithology: rhyolite

Evaporitic facies of Minturn And Belden Fms in South Park and southward (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian) at surface, covers 0.9 % of this area

Gypsum, siltstone, and shale

Lithology: siltstone; shale; evaporite

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 4 % 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

Pre-ash-flow andesitic lavas, breccias, tuffs, and conglomerates (Phanerozoic | Cenozoic | Tertiary) at surface, covers 1 % of this area

Includes several named units

Lithology: andesite; tuff; volcanic breccia (agglomerate)

Gravels and alluviums (Phanerozoic | Cenozoic | Quaternary) at surface, covers 9 % of this area

Includes Broadway and Louviers Alluviums

Lithology: gravel; alluvium

Intra-ash flow andesitic lavas (Phanerozoic | Cenozoic | Tertiary) at surface, covers < 0.1 % of this area

Lithology: andesite

Basalt flows and associated tuff, breccia, and conglomerate of late-volcanic bimodal suite (Phanerozoic | Cenozoic | Tertiary) at surface, covers 0.1 % of this area

Includes basalts of Hinsdale Fm in San Juan Mountains - Servilleta Fm in San Luis Valley and many other occurrences

Lithology: basalt; tuff; volcanic breccia (agglomerate); conglomerate

Ash-flow tuff of main volcanic sequence (Phanerozoic | Cenozoic | Tertiary) at surface, covers 2 % of this area

Includes many named units

Lithology: ash-flow tuff

Minturn and Belden Fms (Phanerozoic | Paleozoic | Carboniferous Pennsylvanian) at surface, covers 2 % of this area

Lithology: sandstone; shale; limestone; conglomerate

Leadville Limestone, Williams Canyon Limestone, and one or more of: Fremont Limestone, Harding Sandstone, and Manitou Limestone (Phanerozoic | Paleozoic | Ordovician Silurian(?) Devonian(?) Carboniferous Mississippia) at surface, covers 3 % of this area

Lithology: limestone; sandstone

Wall Mountain Tuff (Phanerozoic | Cenozoic | Tertiary) at surface, covers 0.8 % of this area

Early ash-flow tuff of Sawatch Range provenance

Lithology: ash-flow tuff

Middle Tertiary intrusive rocks (Phanerozoic | Cenozoic | Tertiary) at surface, covers 13 % of this area

Intermediate to felsic compositions

Lithology: plutonic rock (phanerit