Climate Change and Mountain Topographic Evolution in the Central Karakoram, Pakistan.

Mountain geodynamics represent highly scale-dependent interactions involving climate, tectonic, and surface processes. The central Karakoram in Pakistan exhibit strong climate-tectonic feedbacks, although the detailed tectonic and topographic responses to climate perturbations need to be systematically explored. This study focuses on understanding climate variations in relation to glacier erosion and relief production. Field data, climate modeling, remote sensing, geomorphometry, geochronology, glaciology, and geomorphological assessment are utilized to characterize climate change and geomorphic response. Climate simulations suggest that the region has experienced significant climate change due to radiative forcing over at least the past million years due to changes in Earth's orbital configuration, as well as more temporally rapid climate dynamics related to the El Nino Southern Oscillation. Paleoclimate simulations support geomorphological evidence of multiple glaciations and long-term glacier retreat. Mesoscale relief patterns clearly depict erosion zones that are spatially coincident with high peaks and rapid exhumation. These patterns depict extreme spatial and temporal variability of the influence of glacier erosion in the topographic evolution of the region. Results support the interpretation of high-magnitude glacial erosion as a significant denudational agent in the exhumation of the central Karakoram. Consequently, a strong linkage is seen to occur between global, or at least hemispheric, climate change and the topographic evolution of the Karakoram and the western Himalaya. [ABSTRACT FROM AUTHOR]