COLLABORATIVE RESEARCH: Relief Evolution at the Fluvial-Glacial Transition

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9980419GrangerMost mid- and high-latitude mountain ranges have been sculpted dramaticallyby glacial erosion. The isolated spires, narrow ridges, long bare-rockhillslopes, and broad valleys of alpine terrain immediately give aqualitative impression that glaciers are highly efficient erosive agentsand that glacial erosion produces considerable relief. However, little isknown quantitatively about the rates and patterns of glacial erosion, thefactors that control them, nor even the morphological consequences of ashift from fluvial (non-glacial) to glacial erosion. We propose to exploitnatural laboratories at the southern limit of glaciation where adjacentfully-, partially-, and un-glaciated, but otherwise similar, basins can bestudied. We identify two field settings in the eastern Sierra Nevada,California, and the northern Sangre de Cristo range, Colorado, where onemay estimate quantitatively the amount and pattern of topographic changeattributable to glacial erosion alone as a function of the intensity ofglaciation. We propose a research program in these two field settingscombining field mapping, DEM analysis, and cosmogenic isotope dating totest quantitatively 5 hypotheses developed during a preliminaryinvestigation of glacial landforms and erosion