"Climate as the Great Equalizer of Continental-Scale Erosion". University of Arizona Geoscientists present their findings in the Geophysical Research Letters issue of October 2021.

Oct. 19, 2021

 Figure Caption:“Despite widespread seismic activity in response to the India-Asia collision (60-45 million years ago), much of the erosion across Central Asia remains far older. This map shows timing of erosion recorded across Central Asia, with cooler colours associated with older erosion and warmer colours associated with more recent erosion. This is useful as the timing of erosion informs us on the processes controlling the formation of the topography we observe today. In this study, the authors use this record of erosion to show that the India-Asia collision is not the dominate control on erosion. Rather, they suggest atmospheric circulation and the hydroclimate (i.e. orographic barriers) control the erosion observed, and that the modern- and paleo-climate plays an important role in controlling the present-day relief.”

 Modern topography represents the product of the relationships among climate, tectonics, and erosion through time. Central Asia is one of the most topographically diverse regions on Earth. However, the relative role of tectonics versus climate on erosion of continental Asia remains one of the major debates in Earth sciences. One way to investigate this is through the analysis of erosional proxies. In their study published in Geophysical Research Letters, University of Arizona Geoscientists Dr. Gilby Jepson, Prof. Barbara Carrapa and their collaborators, present the first regional-scale analysis of thermochronometric ages from Central Asia as a proxy of erosion. We compare these data to tectonic processes, climate proxies, and state-of-the-art paleoclimate simulations in order to constrain the relative influences of climate and tectonics on the topographic architecture and erosion of Central Asia. There is a first-order relationship between more recent erosion and active tectonic boundaries. However, more recent erosion is also associated with areas of high precipitation, whereas areas that have been sheltered from significant precipitation retain a signal of older erosional events. Thus, we suggest that climate plays a key role in enhancing erosion in areas with developed topography and high precipitation, whereas areas which experienced sustained aridity record less erosion and preserve a record of older erosion. The whole article appears at Geophysical Research Letters, Vol 48, Issue 20, October 2021.

Kiriaki Xiluri