CLIMATE, TECTONICS, AND THE MORPHOLOGY OF THE ANDES
David R. Montgomery, Greg Balco, and Sean D. Willett
Geology: Vol. 29, No. 7, pp. 579-582 (2001)
Abstract
Large-scale topographic analyses show that hemisphere-scale climate
variations are a first-order control on the morphology of the Andes. Zonal
atmospheric circulation in the Southern Hemisphere creates strong latitudinal
precipitation gradients that, when incorporated in a generalized index
of erosion intensity, predict strong gradients in erosion rates both along
and across the Andes. Cross-range asymmetry, width, hypsometry, and maximum
elevation reflect gradients in both the erosion index and the relative
dominance of fluvial, glacial, and tectonic processes, and show that major
morphologic features correlate with climatic regimes. Latitudinal gradients
in inferred crustal thickening and structural shortening correspond to
variations in predicted erosion potential, indicating that, like tectonics,
nonuniform erosion due to large-scale climate patterns is a first-order
control on the topographic evolution of the Andes.
