Possible origins of till-like deposits near the summit of the Front Range in north-central Colorado

Geomorphic inferences from regolith thickness, chemical denudation and CRN erosion rates near the glacial limit, Boulder Creek catchment and vicinity, Colorado

“…The interpolated data do not distinguish different rock types nor, at the scale of measurement, unglaciated ridges above glaciated valleys nor canyons incised into unweathered rock. Within the glacial and periglacial zone, field observations show that erosion has stripped the weathered regolith in valley areas west of the glacial limit, but weathered bedrock and unconsolidated deposits (Madole, 1982) persist locally between glaciated valleys at elevations as high as 3500 m. The clipped IDW pattern suggests, as do field observations and well records, that highly weathered regolith is preserved in the vicinity of the glacial limit. Because the Clayton values east of the glaciated area are based mainly on roadcut measurements, they underestimate the degree of weathering in the flatter, soil and grus-surfaced areas between roadcuts.…”

The Landscape Continuum: A Model for High-Elevation Ecosystems

“…The rocks underlying this area are of similar origin and are extremely old (Peterman et al 1968, Madole 1982. Variations in the rock's chemical content and weathering rates, especially in the cold alpine environment, are unlikely to produce the differences seen in figure 10.…”

“…The intermediate site in the valley bottom shown in figure 10 was glaciated in the most recent event (Caine 2001), and thus the soils there are unlikely to be any older than approximately 12,000 years. Because the other two sites were not glaciated (Madole 1982), it is possible that the alpine soils at these sites may be extremely old. In fact, the suggestions of phosphorus limitations to plant growth in the saddle region (Theodose and Bowman 1997) initially led us to hypothesize that relatively low phosphorus availability might be a product of very old soils, as in the pattern described by Walker and Syers (1976).…”

Alpine debris flows triggered by a 28 July 1999 thunderstorm in the central Front Range, Colorado

“…The terrain is characterized by glaciated valleys and unglaciated interfluves (Barsch and Caine, 1984;Madole et al, 1998). The unglaciated interfluves are generally either bedrock arêtes or low-relief ridges capped by a bouldery diamicton that may be remnants of Tertiary-age alluvium and debris flow deposits (Madole, 1982). The area was glaciated several times during the Pleistocene, but only three ages of glacial deposits can be distinguished.…”