New Mexico Geological Society
Fall Field Conference Guidebook - 32
Western Slope (Western Colorado and Eastern Utah)
Rudy C. Epis and Jonathan F. Callender, eds, 1981, 337 pages.
Since the days of the Hayden Survey more than a century ago, the part of Colorado west of the continental divide generally has been referred to as the western slope. Together with adjoining parts of eastern Utah and southwestern Wyoming, the western slope of Colorado long has been known to contain vast deposits of uranium, vanadium, coal, oil and gas, and oil shale. Equally well-known and documented in the literature are base and precious metal deposits related to volcanic and subvolcanic environments of Laramide and middle to late Tertiary age.The western mountainous slope of Colorado and adjacent province of plateaus and Canyonlands of eastern Utah, which merge imperceptibly, are endowed with some of the most spectacular physiography and scenery in the nation. They are the result of repeated tectonic uplift and volcanism, and attendant erosion by the Colorado River and its major tributaries such as the Gunnison, Uncompahgre, Dolores and San Miguel Rivers, including of course, the renowned abandoned river valley of Unaweep Canyon atop the Uncompahgre Plateau, and the Black Canyon of the Gunnison River National Monument. The several papers in the geomorphology section of this volume are intended to decipher and explain the impressive landscapes we will enjoy during the field conference. The first day road log is from Grand Junction to Whitewater, Unaweep Canyon, Uravan, Paradox Valley, La Sal, Arches National Park, and return to Grand Junction via Crescent Junction, Utah. This trip will traverse part of the Uncompahgre uplift and the fold and fault belt of the Paradox Basin. We will see the western flank of the uplift and on the third day the eastern flank. The second day road log is from Grand Junction to Glenwood Canyon and return to Grand Junction. This trip will cover the stratigraphy and structure of west-central Colorado. The stratigraphic sequence covered ranges in age from Proterozoic to Eocene in age and includes a wide variety of depositional environments. The major structural elements crossed include the east flank of the Uncopahgre uplift, the Piceance Basin and the White River uplift. The third day road log is from Grand Junction to Crested Butte via Delta, Montrose and Gunnison. This route leads southeast from Whitewater, Colorado, through the desolate Mancos Shale deserts surrounding Grand Junction to the alpine meadows of Crested Butte. The first 100 or so kilometers will traverse Creteceous sedimentary rocks flanked on the east and west by Jurassic to Precambrian rocks. These older rocks constitute cores of the Uncompahgre and Gunnison uplifts. Most of the softer sedimentary rocks between Whitewater and Montrose are veneered by Pleistocene terrace and pediment gravels.
Papers from this guidebook are available for download from the NMGS website.
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