Neoglacial Facies in the Colorado Front Range

A variety of surficial deposits related to three intervals of Neoglaciation occur in valley heads above timberline in the Colorado Front Range. These deposits may be treated as facies, each representing a distinct and separate depositional environment. Frost-riving and rockfall produce detritus over a broad area, but depending upon the environment, it becomes part of either talus, a lobate rock glacier, a tongue-shaped rock glacier, or moraine. No two facies develop simultaneously in the same place. Oscillation of climate causes horizontal shifting and overlapping of facies just as does marine transgression and regression. Thus, geologic and in part climatic history can be inferred from vertical sections, or altitudinal succession can be used as a guide to stratigraphic succession. Differences in topoclimate strongly influence the distribution pattern of the facies as well as some of their sedimentary characteristics. Consequently, these diverse surficial deposits become indicators of topoclimate and microenvironment, past and present.