Talk by Simon Brocklehurst on Thursday September 11th in the QRC library at 12pm. Please come and join! Details below:
"Geomorphological controls on the current and future topography of the High Himalaya"
Simon Brocklehurst, University of Manchester
Abstract: The Himalayan orogen is a consequence of convergence between India and Eurasia, but its topographic expression is strongly influenced by surface processes. Landscapes of the High Himalaya are broadly characterised by shallow glacial valleys and steep, tall bedrock hillslopes. The highest peaks are usually glacial horns surrounded by cirques, with peak height determined by the spacing between the cirques. However, many glaciers do not conform to the typical case of ice accumulating in a cirque and spilling out to form a valley glacier. These exceptions include “beheaded” glaciers lacking cirques at their heads (e.g., the Barun Glacier), and “reconstituted” glaciers whose upper and lower portions are separated by bare rock slopes (e.g., the Langshisha and Yebokangal glaciers). In extreme cases these features can combine to form isolated, low-relief, ice-covered surfaces far above the rest of the glacial valley network (e.g., the Sakyetang Glacier, >6,600m, above the Kazhen Glacier, <5,400m). The ice on low-relief surfaces > 6,000m will be frozen to the bed and move very slowly. Thus subglacial erosion rates will also be very low, and outpaced by both rock uplift and rockwall retreat. Given ongoing tectonic uplift, these low-relief surfaces will continue to rise to higher elevations, raising the possibility that remnants of low-relief surfaces may end up as high as, or even higher than, the current highest peaks.