SURFICIAL LANDFORMS AND GEOMORPHOLOGY OF THE WESTERN SAN JUAN MOUNTAINS, COLORADO

Mass movement is a recurrent phenomenon in the rugged topography of the western San Juan Mountains, Colorado. Debris flows, landslides, and snow avalanches pose a significant threat to human life and infrastructure in the area. In this study, the surficial geomorphology of the western San Juan Mountains was mapped at a scale of 1:3,000 to determine the spatial distribution of phenomena, which potentially pose hazards from slope failures.

The study area encompasses the USGS quadrangles: Ridgway, Dallas, Mount Sneffels, Ouray, Telluride, Ironton, Ophir, and Silverton covering an area of approximately 1,615 km². Mapped surficial landforms were categorized as 1) glacial landforms; 2) glaciofluvial landforms; 3) fluvial and water; 4) gravitational landforms; 5) morphological components; 6) outcrop geology; and 7) periglacial landforms. Mapping was completed using a combination of field mapping and air-photo interpretation. Talus and landslide deposits are the dominant landforms in the area. This map provides a detailed understanding of the landscape evolution of the San Juan Mountains. Furthermore, this valuable resource will assist in future geomorphological studies and land-use planning.