Colorado Mineral Belt Revisited-An Analysis of New Data

by Anna Burack Wilson and P.K. Sims

The three accompanying plates were presented as a poster session at the Geological Society of America's National meeting, October 29, 2002, in Denver, Colorado.  The maps are based on digital data sets of geology, mining districts, and mineral deposits (extensively revised, edited, and corrected, unpublished data compiled by Wilson, 2002) overlain on the Proterozoic basement map of Colorado interpreted from aeromagnetic data by Sims and others (2001).  All the maps were created in MapInfo, a GIS software program, and images of the maps were exported to Adobe Illustrator v.10.  Adobe Acrobat Reader (downloadable free from www.adobe.com) is the only requirement for viewing the plates.  Open GSA_poster_all.pdf and select the plates using the bookmarks, thumbnails, or page selection.  To plot the maps at full-scale (3 ft X 4 ft) requires a large format plotter, but the plates may be resized to print on smaller paper.

Although much discussed in the literature, maps showing the detailed outline of the Colorado Mineral Belt are lacking.  Lovering and Goddard (1950) show the geology and mines associated with the "Front Range mineral belt", and Sims and Tweto (1963) published the outline of the Colorado mineral belt as page-size illustrations.  Based on detailed information on the location of the Tertiary intrusions and mineral deposits, and on the control provided by the Proterozoic structures, all superimposed using GIS data, a new outline of the Colorado Mineral Belt is proposed herein.

Plate 1 includes an index map showing the location of the Colorado Mineral Belt, the abstract text, and the map showing the Colorado Mineral Belt, Cretaceous-Tertiary intrusions and inferred batholiths, mineral districts, and metallic deposits that may be related to the Cretaceous-Tertiary intrusions.  
Plate 2 includes a simplifed geologic map, explanation for the map shown on plate 1, conclusions, and references.
Plate 3 shows two maps, each with the Proterozoic rock units stripped away to better display the relationships of the Proterozoic structures to the Cretaceous-Tertiary intrusions and mineralization.

Acknowledgements:
We are grateful to the following people, among many others, for their assistance in numerous ways.  Eric Anderson for converting the Proterozoic basement map from an unregistered image to a GIS-compatible file.  Bill Ferguson for retrieving a useable digital dataset from the mines and prospects databases.  Luke Kinch for checking and rechecking references, metadata, converting MapInfo files to ArcView and vice versa, cleaning up the bibliography in the MRDS data, and for suggesting that the poster might fit vertical panels, instead of horizontal ones, and still stay within the 36 in maximum paper width.  Terry Klein and Doug Stoeser each reviewed the final digital files.

REFERENCES and Selected Data Sources

Green, G.N., 1992, The digital geologic map of Colorado in ARC/INFO format:  U.S. Geological Survey Open-File Report 92-507.  
	http://pubs.usgs.gov/of/1992/ofr-92-0507/

Lovering, T.S., and Goddard, E.N., 1950, Geology and ore deposits of the Front Range, Colorado:  U.S. Geological Survey Professional Paper 223, 319 p.

McFaul, E.J., Mason, G.T., Jr., Ferguson, W.B., and Lipin, B.R., 2000, U.S. Geological Survey Mineral Databases-MRDS and MAS/MILS:  U.S. Geological Survey Digital Data Series DDS-52.

Plumlee, G.S., Streufert, R.K., Smith, K.S., Smith, S.M., Wallace, A.R., Toth, M.I., Nash, J.T., Roginson, R., Ficklin, W.H., and Lee, G.K., 1995, Map showing potential metal-mine drainage hazards in Colorado, based on mineral deposit geology:  U.S. Geological Survey Open-File Report 95-0026.

Sims, P.K., Bankey, Viki, and Finn, C.A., 2001, Preliminary Precambrian basement map of Colorado-A geologic interpretation of an aeromagnetic anomaly map:  U.S. Geological Survey Open-File Report 01-0364.  
	http://pubs.usgs.gov/of/2001/ofr-01-0364/

Steven, T.A., 1975, Middle Tertiary volcanic field in the southern Rocky Mountains, in Curtis, B.F., ed., Cenozoic history of the southern Rocky Mountains:  Geological Society of America Memoir 144, p. 75-94.

Tweto, Ogden, and Sims, P.K., 1963, Precambrian ancestry of the Colorado mineral belt:  Geological Society of America Bulletin, v. 74, no. 8, p. 991-1014.

Tweto, Ogden, 1979, Geologic map of Colorado:  U.S. Geological Survey Special Map, scale 1:500,000.

Wilson, A.B., Spanski, G.T., Crane, M.J., and Woodard, M.D., 2000, Databases and spatial data model for mineralized areas, mines, and prospects in the Grand Mesa, Uncompahgre, and Gunnison (GMUG) National Forests, Colorado:  U.S. Geological Survey Open-File Report 00-0298.  
	http://pubs.usgs.gov/of/2000/ofr-00-0298/