2012 Fiscal Year Final Research Report

Radiolarian extinction event in the Middle Paleozoic

Research Project

Project/Area Number	23740376
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Geology
Research Institution	Niigata University
Principal Investigator	KURIHARA Toshiyuki 新潟大学, 自然科学系, 准教授 (10447617)
Project Period (FY)	2011 – 2012
Keywords	放散虫 / プランクトン / 中期古生代 / デボン紀 / 大量絶滅 / 堆積岩化学組成 / 黒瀬川帯 / モンゴル
Research Abstract	Radiolarian faunal transition and geochemistry of Upper Silurian to Middle Devonian siliceous rocks in Japan and Mongolia were investigated to understand a possible mass extinction event in Early Devonian time. The result of the present study indicates the following faunal transition process: (1) the decline and subsequent extinction of Inaniguttidae occurred in the middle Early Devonian, (2) Palaeoscenidiidae that is a typical opportunistic group occupied a late Early Devonian radiolarian fauna, and (3) subsequent diversification of Entactiniidae became pronounced in the Middle Devonian. Based on the results of geochemical analysis of chert, there is a possibility that this extinction event has a causal relationship with Early Devonian environmental change attributed to a large igneous activity.