Preliminary results of ice radar investigation along the traverse between Zhongshan and Dome A in East Antarctic ice sheet: Ice thickness and subglacial topography

Abstract

During the 24th Chinese National Antarctic Research Expedition (CHINARE 24, 2007/08), a ground-based ice radar was used to survey ice thickness and subglacial topography along the 1170 km traverse between Zhongshan and Dome A in East Antarctic ice sheet (EAIS). Ice-bedrock interface was detected along 82% of the traverse and data was collected at a horizontal resolution of <5.6 m. The data was processed to produce curves of ice thickness distribution and subglacial topography along the traverse. The results indicate that, along the traverse, the average ice thickness is 2037 m, smaller than the average ice thickness in EAIS; the thickest ice is at 730 km, and the thinnest ice (891 m) is at the edge of the ice sheet, but the slightly larger ice thickness (1078 m) in inland appears at 1020 km; the average subglacial topography elevation is 728 m, greatly larger than the average value in EAIS, and the largest elevation reaches up to 2650 m at 1034 km. The lowest terrain is located at 765 km. In further inland of 900–1170 km, the subglacial topography is relatively high due to the existence of the Gamburtsev Subglacial Mountains in the region. Generally, the influence of subglacial topography on ice surface is not significant, except at 900 km where great rise of subglacial topography causes evident uplift of ice surface. Where ice-bedrock interface was detected, the frequent and strong change of ice thickness and subglacial topography in small-scale means large bedrock roughness along the traverse, and is considered as the result of the integrated influence of ice flow, basal environments and geology. The segment where bedrock was not detected has very large ice thickness. The strong ice flow there also makes internal structure more complicated and induces serious attenuation of radar signals.