昭和基地付近の露岩地域の地形と大陸氷縁辺部の地学的観察

• Main Authors: 森脇 喜一, Kiichi MORIWAKI
• Format: Report
• Language: Japanese
• Published: 研究論文 1976
• Subjects: 551.1/.4:552; Austral; Syowa Station; Ongul; Ongul Island; Langhovde; Prince Olav Coast; East Ongul Island; Cape Hinode; Langhovde Glacier; Boulder Pavement; Ice Sheet
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=7878; http://id.nii.ac.jp/1291/00007878/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=7878&item_no=1&attribute_id=18&file_no=1

昭和基地付近の露岩地域の地形調査と地温測定,および大陸氷縁辺部の消耗量測定を行い,次の結果を得た.過去の氷の流動方向は,現海岸線とほぼ直交するものであったが,氷の流動は必ずしも一様ではなく,ラングホブデ氷河付近では,氷体の上部と下部とが異方向の流動をした可能性がある.昭和基地付近では,氷床がもたらす氷河性堆積物は少量である.日の出岬の隆起汀線は海抜35m以下にみられ,明るい岬の9.5mの隆起汀線からは,7,730±110年B.P.を示す貝化石が得られた.ラングホブデの池の化学分析から,氷床後退後の相対的な地盤上昇は,50m以下であることが示唆される.昭和基地では50cm以浅の地温は,夏季に一度氷点を上回ると,その夏の終りまで氷点下に下がらない.日の出岬背後の大陸氷の夏季の消耗は融解水流による量が46.6×10^3t/km/day,昇華による量が0.14-0.25g/cm^2/dayと測定された.また同地点での氷の流動量は0.5-6m/年(平均2m/年)と測定された. 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 ...