OF-08-18 Climax Quadrangle Geologic Map, Lake and Park Counties, Colorado


The purpose of Open File Report OF-08-18 is to map and describe the geologic setting, structure, geologic hazards, and mineral resources of this 7.5-minute quadrangle. This product is superseded by OF-12-09 Geologic Map of the Climax Quadrangle, Lake and Park Counties, Colorado. Digital ZIP/PDF download. OF-08-14D

From the Introduction:

The Climax quadrangle is dominated by the Mosquito Range, a component range of the Southern Rocky Mountains composed mainly of Precambrian crystalline rocks. This range probably existed as a topographic high during the Laramide orogeny (late Cretaceous—early Tertiary), based on the presence of reverse faults of that age (London fault). However, the present topography of the range is the result of Neogene uplift along the west‐dipping Mosquito and Weston faults on the west side of the range, both normal faults related to the Rio Grande rift. Uplift of 9,000 ft along the Mosquito fault has juxtaposed the Precambrian rocks of the footwall against the Pennsylvanian Minturn Formation, which underlies most of the western half of the Climax quadrangle. Both the Precambrian and Permian rocks are laced by early Tertiary dikes, sills, and stocks, the source of mineralization in the Leadville, Climax, and Alma‐Horseshoe mining districts. In the eastern half of the quadrangle (east of the Mosquito fault), most terrain is composed of the Precambrian core of the Mosquito Range. However, in small areas strata of Cambrian through Pennsylvanian age are preserved atop the Precambrian unconformity.