長崎県橘湾および唐比低地の堆積物による古環境解析

概要

論文の詳細を見る
Tachinana Bay is a circular inner bay opening to the East China Sea on the west side of Nagasaki Prefecture. Karako Lowland is situated at the northern end of Tachinana Bay and extends westward from the Chijiwa Fault that lies at the northern part of Unzen Volcano. The samples from the No.2 drilling core of Karako Lowland were analyzed for fossil diatom and pollen. The environmental conditions in the bay throughout a period of 250 thousand years evolved from fresh water to marine. The vegetation during this age consisted of Pinus, Picea and abies accompanied by cryptomeria under the cool temperate conditions of MIS 6. In this age, it is considered that the area was depressed under a cool but marine condition. In the MIS 5, the existence of markers such as Cyclobalanopsis and Castanopsis pollen suggest a warmer climate. Fossil diatom assemblage indicates the condition of a river mouth. After the Last Glacial Age, Karako lowland changed through a complex condition of rise and depression of both sea level and land area. The samples of cores from the eastern Tachibana Bay coast were clarified through diatom and pollen assemblage analysis. Sedimentation started at the Last Glacial Age and continued to the Post Glacial Age. The climate became cool to warm and sedimentation continued under conditions from fresh to marine.
熊本大学の論文
2007-03-30