論説
沿岸の海の基本図「猿払」の測量成果について
1989 年 1 巻 2 号 p. 1_1-1_8
詳細
1989 年 1 巻 2 号 p. 1_1-1_8
In this paper, some geomorphological and geological explanations on the survey results of "Basic Map of the Sea (1:50,000)" carried out in coastal water off Saruhutu in June-July 1987, are shown.
Flat planation surfaces are widely distributed on the sea floor except around banks and shoals. Very flat planation surfaces reflecting the ancient water levels are observed at the depths from 15 m to 25 m and from 50 m to 70 m.
Conglomeraric sediments with a very small amount of fine-grained sediments are distinguished in the bottom material under the influence of strong current in the coastal waters.
Seven beds from Is to VIIs are identified in the subbottom geological sections. We suppose many valleys were formed during the last glacial regression age at the basement of Is bed.
Many folds in the north-south direction are distributed at subbottom geological structure. However, tectonic movement during the Quaternary, was not confirmed.
South-easterly current is dominant in the coastal waters.
