[B-PT04] 地球生命史

[BPT04-P03] 白亜紀後期北西大西洋における浮遊性有孔虫の多様性変動と有機炭素埋没

*守屋 和佳¹、古屋 俊和¹、宮倉 寧子¹ (1.早稲田大学 教育・総合科学学術院 地球科学専修)

キーワード：白亜紀、浮遊性有孔虫、多様性変動、有機炭素埋没

Abundance and diversity of planktic foraminifers in the late Cretaceous north-western Atlantic show distinctive decrease at the Cenomanian/Turonian boundary (CTB) and the Santonian/Campanian boundary (SCB). Both boundaries are marked by positive excursions in stable carbon isotopes, known as the Cenomanian Turonian Boundary Event and the Santonian Campanian Boundary Event. Planktic foraminiferal assemblages recovered by IODP Exp. 342 at Newfoundland Ridge indicate sudden decrease in abundance. Abundances became less than 1 individual/cm^2/kyr at both boundaries. After these boundary crises, abundances have not been reached to pre-boundary levels. While total organic carbon content (TOC) at CTB become more than 10 wt%, the highest TOC at SCB is less than 1 wt% throughout the boundary event.