Glacio-Geomorphological Observations in and around Ice-Free Areas in the Vicinity of Syowa Station, Antarctica

Abstract

Geomorphological survey of ice-free areas, observation on ablation in a marginal zone of the ice sheet, and measurement of earth temperature were conducted by the author in the austral summer of 1971/1972 and during the period from January 1974 to February 1975. Directions of the former ice flow inferred from glacial striae in the ice-free areas were perpendicular to the present coast on the whole. Directions of glacial striae on the valley wall of the Langhovde Glacier differ greatly from the direction of present glacier flow. This seems to suggest that the direction of movement of the upper part of ice was different from that of the lower part of ice when the ice sheet was thicker than the present. The amount of deposits forming moraine ridges at the fringe of the ice sheet is considerably small. These moraines are evidently caused by thrusting of active ice on stagnant bottom ice. Therefore, glacial till in the ice sheet may be small in amount at least in the vicinity of Syowa Station. Earth temperature in summer on East Ongul Island rarely rises and falls beyond the freezing point. Once it exceeds 0℃ at the beginning of summer, it remains above 0℃ till the end of that summer. This may be one of the causes for poor development of sorted polygon on East Ongul Island. Raised beaches are widely distributed on the east coast of Lutzow-Holm Bay and Prince Olav Coast. The upper limit of the marine-boulder pavement is measured to be 35m in height at Cape Hinode. Chemical analysis of the water of Lake Akebi suggests that the uplift of over 50m relative to the present sea level did not take place in this area after the retreat of the ice sheet. In summer, meltwater streams seem to play an important part in wastage of the marginal part of the ice sheet. Measurements of meltwater and evaporation at Cape Hinode have amounted to 46.6×l0^3t/km/day and 0.14-0.25g/cm^2/day, respectively. The movement of the marginal part of the ice sheet behind Cape Hinode was 0.5-6m/year (mean value : 2m/year) from January 1972 to January 1974.