page_title: Colorado Mineral Belt
hierarchical_section_title: Colorado Mineral Belt
caption_attribution_description: English: Outline of state of Colorado (USA) with approximate reproductions of the two versions of the Colorado Mineral Belt that were suggested by Tweto and Sims (Precambrian Ancestry of the Colorado Mineral Belt, Geological Society of America Bulletin 74, p. 991-1014, 1963). The principal mining districts of Laramide age are in the inner area bounded by solid lines and in a darker color. The "Maximum boundary" is shown by the dashed lines.
context_page_description: The Colorado Mineral Belt is an area of ore deposits from the La Plata Mountains in Southwestern Colorado to near the middle of the state at Boulder, Colorado and from which over 25 million troy ounces of gold were extracted beginning in 1858. The belt is a "northeast-striking zone defined by: a Proterozoic shear zone system; a suite of Laramide-aged plutons and related ore deposits; a major gravity low; low-crustal velocities; and high heat flow." Mining districts include:
  Central City-Idaho Springs district
  Leadville mining district, named for Leadville, Colorado
  Sneffels-Red Mountain-Telluride district
  The belt lies within a zone that has been geologically active at intervals beginning from near the time of crustal accretion in central Colorado at least 1.6 billion years ago until the present. Parts of the CMB follow shear zones of Precambrian age and the Paleozoic and Mesozoic. Igneous rocks intruded about 60 to 70 million years ago during the Laramide orogeny are associated with the belt and once were thought to be responsible for most of the ore deposits.
context_section_description: The Colorado Mineral Belt (CMB) is an area of ore deposits from the La Plata Mountains in Southwestern Colorado to near the middle of the state at Boulder, Colorado and from which over 25 million troy ounces (778 t) of gold were extracted beginning in 1858.  The belt is a "northeast-striking zone defined by: a Proterozoic shear zone system (McCoy, 2001); a suite of Laramide-aged plutons and related ore deposits (Tweto and Sims, 1963); a major gravity low (Isaacson and Smithson, 1976); low-crustal velocities; and high heat flow (Decker et al., 1988)."  Mining districts include:
  Central City-Idaho Springs district
  Leadville mining district, named for Leadville, Colorado
  Sneffels-Red Mountain-Telluride district
  The belt lies within a zone that has been geologically active at intervals beginning from near the time of crustal accretion in central Colorado at least 1.6 billion years ago until the present. Parts of the CMB follow shear zones of Precambrian age and the Paleozoic and Mesozoic. Igneous rocks intruded about 60 to 70 million years ago during the Laramide orogeny are associated with the belt and once were thought to be responsible for most of the ore deposits.  Now many of the important ore deposits are thought to be genetically related to younger magmatism, some at least as young as about 25 million years.
caption: Approximate boundaries of the Colorado Mineral Belt with inner area having principal mining districts.[1]
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