Estimation of the ice thickness of cirque glaciers by the gravimetric survey at the Yamato Mountains, East Antarctica

• Main Authors: Toshiyasu Nagao, Yoshio Yoshida
• Format: Report
• Language: English
• Published: Earthquake Research Institute, University of Tokyo 1984
• Subjects: Antarctic; East Antarctica; Yamato; Nizi-no-kubo; Antarc*; Antarctica; Ice Sheet; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1634; http://id.nii.ac.jp/1291/00001634/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1634&item_no=1&attribute_id=18&file_no=1

As part of geophysical investigations by the 22nd Japanese Antarctic Research Expedition (JARE-22), the gravity measurements were carried out along the inland traverse route and in the Yamato Mountains region in 1981. In the latter area, the depth of subglacial rock surfaces under two peculiar cirque glaciers and one outlet glacier was estimated by gravity measurements, in addition to the investigation of the gravity field in ice-free areas. The results are as follows : 1) On the west side of Massif B, the bedrock height decreases steeply with a gradient of 300m/1000m from the shallow cirque glacier bottom to the west, 2) the deepest bedrock in the cross profile near the terminal part of the Nizi-no-kubo cirque glacier in Massif D reaches 265m, 3) the relationship among depth of cirque bottom, depth of the neighboring ice sheet, and surface features of cirque glaciers and the ice sheet suggest that the cirques were formed mainly prior to the ice sheet cover, and that the tectonic displacement might have been responsible for the deep subglacial bottom of the surrounding area, 4) the subglacial bedrock topography suggests that the fault line runs along the southern foot of Massif G, and the surface configuration of the outlet glacier between Massifs F and G seems to be influenced not only by snow accumulation controlled by surface topography but also by subglacial rock topography.