PORTER, KAREN W., and EDMOND G. DEAL
Montana Bureau of Mines and Geology, Montana Tech, Butte, MT

Abstract: Geologic Mapping Program for Montana: Status Report

The first priority of Montana Bureau of Mines and,Geology?s (MBMG) geologic mapping program is the completion of a 1:100,000-scale geologic base, in digital form, for the State. Two other objectives are completion of 1:48,000-scale maps for areas experiencing significant demographic and land-use pressures, and a new Geologic Map of Montana at 1:500,000 scale.

Prior to 1986, significant parts of Montana were, inadequately mapped even at 1:500,000. Since then, through cooperative programs with the U.S. Geological Survey (USGS), 1:100,000-scale maps have been published by MBMG for 81%, of eastern Montana, east of 108° west longitude, and for 52% of central Montana, between 108° and 112° west longitude. About 90% of western Montana, west of 112° west longitude, has been mapped, including 1:250,000-scale (USGS) and 1:100,000-scale (MBMG) work. The program has produced a significant amount of new mapping and incorporates all appropriate published maps, to date. Generally, two or more field seasons are required for each 1:100,000-scale quadrangle map, depending upon the complexity of the geology, the number and quality of previously, published maps, and the availability of funding.

Completed MBMG maps are available as (1) blueline paper copy of geology on a topographic base; (2) color geology on a topographic base (digitally produced hard copy); or (3) digital geologic map data (available for electronic transfer). USGS 1:250,000-scale maps are available in hard copy from the USGS or from MBMG. Currently, digital geologic map coverage is available for approximately 15% of the State at the 1:100,000 scale.

AAPG Search and Discovery Article #90919©1999 AAPG Rocky Mountain Section Meeting, Bozeman, Montana