Reconstruction of paleoinsolation and paleoenvironmental changes during the Middle Holocene

2015 Fiscal Year Final Research Report

• Project/Area Number: 26887005
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Stratigraphy/Paleontology
• Research Institution: Tohoku University
• Principal Investigator: Takayanagi Hideko 東北大学, 理学(系)研究科(研究院), 助教 (40729208)
• Project Period (FY): 2014-08-29 – 2016-03-31
• Keywords: シャコガイ / 炭素同位体比 / 酸素同位体比 / 微量金属元素濃度 / 日射量変化

Outline of Final Research Achievements

The sclerochronology and geochemistry of a giant clam Tridacna gigas shell collected from the South Ryukyus, Japan has been investigated for reconstructing paleoinsolation and paleoenvironmental changes during the Middle Holocene. Black and light growth bands were clearly confirmed in the T. gigs shell. Since growth variation in the Tridacna shell showed the seasonality, we inferred that such growth bands are probably daily increments. Oxygen isotope composition of the Tridacna shell showed secular changes in sea surface temperature (SST) during the Middle Holocene. Seasonal amplitude of the SST in the Middle Holocene was close to that of recent SST variation. The oxygen isotope profile indicate long-lasting warming during the Middle Holocene.

Free Research Field

炭酸塩堆積学・地球化学