Central Colorado Assessment Project—Application of Integrated Geologic, Geochemical, Biologic, and Mineral Resource Studies

Central Colorado is one of the fastest-growing regions in the Western United States. Population along the Front Range increased more than 30 percent between 1990 and 2000 (http://www.demographia. com/db-metro3newworld.htm) with some counties within the study area such as Park County experiencing greater than 100 percent growth (http:// www.censusscope.org/us/s8/rank_popl_growth.html). This growth has caused tremendous demand for natural resources and has created challenging landmanagement issues related to the interface between wilderness and urban expansion. Management of this wilderness/urban interface will benefit from current digital geoscience information collected by the U.S. Geological Survey (USGS) Central Colorado Assessment Project that began in 2003. Approximately 20,800 square miles (53,800 km) of land divided almost equally between the public and private sectors were part of the assessment (fig. 1). The study area includes much of the Colorado Mineral Belt, a northeast-trending zone that contains 30 economically significant metal deposits. Historically, the area provided much of Colorado’s metal production. The only active gold and molybdenum mines in Colorado lie within the study area. Recently, metal and uranium exploration activity has increased sharply in response to record prices for metals and uranium. This further underscores the need for up-to-date geoscience information presented in compatible GIS databases in order to facilitate rapid land-management decisions. Cooperative studies by USDA Forest Service, National Park Service supported by the USGS Mineral Resources (MRP), and National Cooperative Geologic Mapping Programs (NCGMP) contributed to the mineral-resource assessment and included regional geologic mapping at the scale 1:100,000, collection and geochemical studies of stream sediments, surface water, and bedrock samples, macroinvertebrate and biofilm studies in the riparian environment, remote-sensing studies and geochronology. Geoscience information available as GIS layers has improved understanding of the distribution of metallic, industrial, and aggregate resources, location of areas that have potential for their discovery or development, helped to understand the relationship of tectonics, magmatism, and paleohydrology to the genesis of the metal deposits in the region, and provided insight on Figure 1. Location of Central Colorado Assessment Project study area. The thick black line in the larger figure is the outline of the study area. Red lines are major highways. Blue shading is water. White fill represents private lands and green fill represents public lands, managed mainly by the U.S. Department of Agriculture Forest Service, the National Park Service, and the Bureau of Land Management. Vail