Geologic units in Clear Creek county, Colorado

Additional scientific data in this geographic area

Biotitic gneiss, schist, and migmatite (Early Proterozoic) at surface, covers 33 % of this area

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

Granitic rocks of 1400-m.y. age group (Middle Proterozoic) at surface, covers 25 % 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

Granitic rocks of 1700-m.y. age group (Early Proterozoic) at surface, covers 20 % 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; also, unnamed granitic rocks

Felsic and hornblendic gneisses, either separate or interlayered (Early Proterozoic) at surface, covers 10 % of this area

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

Glacial drift (Quaternary) at surface, covers 9 % of this area

Includes some unclassified glacial deposits

Laramide intrusive rocks (Tertiary-Cretaceous) at surface, covers 0.8 % of this area

Mainly intermediate to felsic compositions; some mafic

Rocks of Pikes Peak Batholith (1000-m.y. age group) (Middle Proterozoic) at surface, covers 0.3 % of this area

Includes Pikes Peak, Mount Rosa, Windy Point, and Redskin Granites and unnamed rocks

Landslide deposits (Quaternary) at surface, covers 0.2 % of this area

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

Middle Tertiary intrusive rocks (Tertiary) at surface, covers 0.2 % of this area

Intermediate to felsic compositions

Bouldery gravel on old erosion surfaces in Front Range and Never Summer Mountains (Tertiary) at surface, covers 0.2 % of this area

Bouldery gravel on old erosion surfaces in Front Range and Never Summer Mountains