THE COLORADO FRONT RANGE - MAPPING IN RESPONSE TO GROWING URBAN PRESSURE

The Colorado Front Range region includes the prominent mountain front west of Denver, Colorado, with peaks rising to over 14,000’ (4,250 m). This area is one of the fastest-growing regions in the western U.S., with a population growth of more than 30 percent since 1990. To help meet the resultant pressures on water, mineral, industrial, and recreational resources, the U.S. Geological Survey has just completed mapping four 30’ x 60’ (1:100,000-scale) digital geological maps: Fort Collins, Estes Park, Denver West, and Bailey. Estes Park and Denver West are published, and the other two will be published soon. This mapping effort involved evaluation of existing maps and new mapping of more poorly understood regions. Several new 7 ½’ (1:24,000-scale) maps in the area have also been published.

These maps provide both the geologic framework and discussions to help understand a variety of geologic, resource, and land-use issues that include (1) surficial processes, especially those related to changing climate over time, (2) geologic hazards, such as landsliding and stream flooding, (3) quantity and quality of both ground and surface waters in mountain-recharge environments, (4) the Precambrian and Phanerozoic basement framework and its relationship to mineral deposits, augmented by new U-Pb and Sm-Nd isotopic studies, and (5) industrial and mineral resources, including aggregate, ornamental stone, limestone, coal, oil, and natural gas. These maps also provide information critical to the management of our National Forests, in particular to understanding (1) the effects of increased recreational land use in the Front Range region, such as erosion of roads and trails, (2) the long-term effects of forest fires (the danger of which is amplified by the recent pine-bark beetle infestation) on erosion and sedimentation, and (3) mitigation of abandoned mine lands.