未固結堆積物上に噴出した新第三紀海底火山の一例(<特集>水底における火山活動とその噴出物)

概要

論文の詳細を見る
Neogene siliceous shales are widely distributed in the southwestern part of the Shiretoko Peninsula, Northeast Hokkaido, Japan. These shales have been intruded by many basaltic dykes and sills, and some of these intrusive rocks erupted in submarine environments. In this paper, I describe the dykes, subaqueous flow deposits, massive lavas, lava lobes, and hyaloclastites in the Onnebetsu River in this district, to reconstruct a submarine volcano which intruded and erupted on the wet sediments. The dyke which intruded into the wet sediments formed peperites, and deformed the sediments. The magma exploded in the wet sediments and produced subaqueous pyroclastric flow deposits. It was probably due to phreatomagmatic explosion by contact-surface steam explosivity. Finally, several lavas grading into lava lobes and hyaloclastites flowed on the deposits. These volcanic rocks made up a monogenetic submarine volcano.
地学団体研究会の論文
1990-11-25