Detailed surficial-geologic mapping and related stratigraphic and geomorphic analysis of debris-flow origin of high-level sloping surfaces on the northern flanks of Battlement Mesa. Includes surficial geology of parts of the North Mamm Peak, Rifle, and Rulison Quadrangles located in Garfield County. Highlights new interpretation of origin of high-level sloping surfaces. 34 pages. 22 figures. 2 tables. 1 plate (1:50,000). Digital PDF download. B-50D
Excerpts from the abstract and introduction
A diverse assemblage of surficial geologic deposits is present in the Colorado River valley near Rifle on the northern flanks of Battlement Mesa. These include alluvium, colluvium, landslide deposits, debris- flow deposits, and eolian deposits ranging in age from Late Pliocene to Holocene. The most significant discovery is the recognition that extensive high-level sloping surfaces, originally mapped and described as gravel-veneered pediments flanking Battlement Mesa, are instead the remnants of huge, ancient debris-flow fans. Field studies and stereoscopic-photogeologic interpretation were used to map the surficial geology of part of the northern slope of the mesa and adjacent river valley in order to develop a stratigraphic framework for interpretation of the debris-flow stratigraphic framework for interpretation of the debris-flow deposits, and the geologic and geomorphic processes which formed them.
The existence of several levels of debris-flow remnants associated with main-stream terrace-gravel deposits implies that this happened more than once, and suggests that there may have been a cyclicity to these events. This study was developed to investigate these deposits in more detail, and determine their role in the geomorphic development of the area.