The fluctuations of Nd and Pb isotopic compositions of ferromanganese crusts collected from four different depths of the Takuyo-Daigo Seamount

Abstract

We determined time-series Nd and Pb isotopic compositions data of four ferromanganese crusts collected from different water depths of Takuyo-Daigo seamount in the Northwest Pacific, which aims to reconstruct paleoceanic circulation in the area. The sample collected from the deepest depths, 5373 m, shows a negative shift of Nd isotopic composition in 8 million years ago, suggesting an intensified inflow of the Antarctic Bottom Water. Contrastingly, the Pb isotopic composition of the deepest depths sample does not show the negative shift, but keeps a constant value, resembling with the previously reported data. Nd isotopic record of the past ocean seems to be controlled by ocean circulation pattern. Meanwhile, Pb isotopic record may be regulated by some additional factors.