Colorado Gold Production Summary
The mineral belt of Colorado trends obliquely to the mountain ranges and crosses the San Juan Mountains in the southwestern part of the State and the Sawatch, Mosquito, Gore-Tenmile, and Front Ranges in the central and north-central parts of the State. This belt is coincident with a belt of intrusive stocks, dikes, and sills of porphyritic acidic igneous rocks of Late Cretaceous or Tertiary age. Gold, silver, and lead-zinc ore deposits occur throughout this belt, in rocks of various types and ages. In the San Juan Mountains the deposits are chiefly in volcanic rocks of Tertiary age; in the Sawatch, Mosquito, and Gore-Tenmile Ranges they are in sedimentary rocks of Paleozoic age; and in the Front Range they are in the metamorphic and igneous rocks of Precambrian and Tertiary age. In Colorado, 44 districts—scattered in 24 counties— each have produced more than 10,000 ounces of gold.