青森県西津軽地域に分布する鮮新統軽石凝灰岩の対比

概要

論文の詳細を見る
Chemical components and heavy mineral compositions were analyzed for the pumice tuffs in the lower to middle parts of the Pliocene Taiaki Formation and the middle part of the Maido Formation in the Nishitsugaru district, Aomori Prefecture, Northeast Japan. Because the chemical composition of volcanic glass in these pumice tuffs resemble each other and these tuffs contain large amount of biotite, these are correlatable each other. The age of these pumice tuffs is inferred 3.6Ma on the basis of microbiochronology and radiometric age. These pumice tuffs are also correlative with the Nihonmatsu Tuff Member of the Misogasawa Formation in the middle part of the Tsugaru Peninsula, Northeast Japan. This implies that the pumice tuffs originated from the Yunosawa Caldera in the southern part of Tsugaru region are intercalated in bathyal deposits in the Nishitsugaru district.
2008-11-25