[B-PT27] 原生代末／顕生代生物多様性変遷：絶滅と多様化

[BPT27-P02] 北欧エストニアにおけるオルドビス紀中後期動物多様化と環境変動

*島塚 桃子¹、磯崎 行雄²、可児 智美³、石川 晃⁴ (1.東京大学大学院理学系研究科地球惑星科学専攻、2.東京大学大学院総合文化研究科広域科学専攻広域システム科学系、3.熊本大学大学院自然科学研究科（理学）、4.東京大学大学院総合文化研究科)

Following up the 'Cambrian explosion' , marine biodiversity increased dramatically during the Ordovician, as known as the 'Great Ordovician Biodiversification Event' (GOBE). Estonia in central Batoscandia provides excellently continuous Ordovician sedimentary package for detailed analysis. We are analyzing the drilled core samples of the Middle-Upper Ordovician strata (ca. 150 m-thick) collected from Velise in central Estonia, in order to clarify litho-, bio-, and isotope stratigraphy of C and Sr, and to reveal the cause and processes of the GOBE. We will report on our preliminary results.