Personnel:  Simon Brocklehurst (Ph.D.)  Katerina Spyropoulou (M.S.)

The overall aims of this 3-yr proposal are to (1) investigate quantitatively the roles of fluvial and glacial erosion in the evolution of relief in mountainous regions, and (2) test rigorously the quality and accuracy of SRTM topographic data in areas of rugged relief - both the most challenging and of greatest interest to geomorphic, neotectonic, and hazards applications. 

Although much has been learned about the evolution of fluvial landscapes in the past decade or so, there has been little quantitative investigation of glacial erosion processes at landscape scale 1-3. This is particularly surprising considering the dramatic sculpting of most mid- and high-latitude mountain ranges, the prodigious quantities of glacially-derived sediment in terrestrial and marine basins, and the current cross-disciplinary interest in the role of denudational processes in orogenesis and the evolution of topography in general 4. Moreover, the evolution of glaciated landscapes is not only a fundamental problem in geomorphology in its own right, but also is at the heart of the debate over Late Cenozoic linkages between climate and tectonics 5-9. 

Excellent natural laboratories for the study of glacial landscape evolution, and transitions from fluvial to glacial erosion, exist in both the western US and the Southern Alps of New Zealand. A two-pronged approach is proposed, incorporating: (1) morphometric study -- utilizing both existing and new (SRTM, RASCAL, ATM, TOPSAR) digital elevation data -- of the signature of glacial erosion, its dependence on rock uplift rate, precipitation, and initial conditions, as well as its role in the evolution of relief and consequent isostatic responses; and (2) field study of (a) the relation between ice thickness and glacial relief production, and (b) the rates, patterns, processes, and implications of post-glacial fluvial modification of recently deglaciated valleys.

The proposal to test the SRTM data is facilitated by the concurrent Pacific Rim Campaign, which affords an opportunity to obtain high-resolution airborne topographic data to supplement existing DEMs. Selected field sites are chosen to cover both glacial and fluvial landscapes, a range of vegetation covers, and a range of target latitudes from 35°N to 45°S. Data requirements for the proposed research include SRTM and, where possible, supporting airborne topographic data in: King Range, CA; San Gabriel Mountains, CA; Sierra Nevada, CA; Southern Alps, New Zealand; Central Highlands, Papua New Guinea; and Central Range, Taiwan.