2010 Fiscal Year Final Research Report

Foraminiferal assemblage and isotope studies of diatomaceous deposits collected under the subarctic convergence in the North Atlantic

Research Project

Project/Area Number	21740361
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	Geology
Research Institution	Akita University
Principal Investigator	YAMASAKI Makoto Akita University, 工学資源学研究科, 准教授 (40344650)
Project Period (FY)	2009 – 2010
Keywords	地球史 / 浮遊性有孔虫 / 海洋前線 / 北大西洋 / 酸素同位体
Research Abstract	Stratigraphic variation in foraminiferal assemblage and oxygen isotope was examined using the late Pleistocene diatomaceous deposits collected under the subarctic convergence in the North Atlantic. Oxygen isotope from surface and subsurface dwelling planktic foraminifers (Globigerina quinqueloba and Neogloboquadrina pachyderma sinistral) revealed that mat-forming diatom, Thalassiothrix longissima, occurred extremely abundant under cooler surface water condition, while it occurred commonly under warmer surface water one. The evidence suggests that deposition of the diatom mats is closely related to the surface water conditions.