Paleoenvironmental implications of the calcium isotope characteristics in the MD81349 from the Nintyeast Ridge in the Indian Ocean  

作　　者：WANG Feng FANG Nianqiao HU Chaoyong GOLDSMITH Sarah XU Yonghang DING Xuan WANG Aijun CHEN Ping BAO Rui 

机构地区：[1]Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China [2]Institute of Marine Geology and Geophysics, China University of Geosciences (Beijing), Beijing 100083, China [3]School of Earth Sciences, China University of Geosciences, Wuhan 430074, China [4]Demo Laboratory, Ctd. MicroMass, Mantchestt M139PL, United Kingdom [5]School of Earth Science Environmental Engineering, Anhui University of Science and Technology, Huainan 232001, China [6]Climate and Environment Sciences Laboratory of the institute Pierre Simon Laplace (LSCE), Gif sur Yvette 75000, France

出　　处：《Acta Oceanologica Sinica》2018年第9期59-66,共8页海洋学报（英文版）

基　　金：The National Programme on Global Change and Air-sea Interaction under contract Nos GASI-03-04-01-03 and GASI-GEOGE-03;the Research Grant of Third Institute of Oceanography,State Oceanic Administration under contract No.2015015

摘　　要：A δ^（44） Ca curve from shells of the planktonic foraminifera Globigerinoides sacculifer in calcareous biogenic oozes has been extracted from the Nintyeast Ridge in the Indian Ocean since 300 ka. By combining terrigenous inputs（e.g., grain size, magnetic susceptibility, and turbidite frequency） with the oceanic productivity（e.g., biogenic content and Neogloboquadrina dutertrei content）, it is found that the curve＇s variations are closely related to the historical evolution of the oceanic calcium cycle. The δ^（44）Ca value is in lower tendency and has small oscillation during Marine Isotope Stage（MIS） 6, when the supply of terrigenous detrital is highest. In contrast, during MIS 3,5 and 7, the δ^（44） Ca values are in higher tendency, and their fluctuations are consistent with the variations of the productivity proxies. These results suggest that the calcium isotopes are mainly influenced by the input of the Himalayan erosion products to the northern Indian Ocean. In addition, the developmental stages of calcareous planktons may have a secondary impact on the fluctuations of the calcium isotope ratio of sea water.A δ^（44） Ca curve from shells of the planktonic foraminifera Globigerinoides sacculifer in calcareous biogenic oozes has been extracted from the Nintyeast Ridge in the Indian Ocean since 300 ka. By combining terrigenous inputs（e.g., grain size, magnetic susceptibility, and turbidite frequency） with the oceanic productivity（e.g., biogenic content and Neogloboquadrina dutertrei content）, it is found that the curve＇s variations are closely related to the historical evolution of the oceanic calcium cycle. The δ^（44）Ca value is in lower tendency and has small oscillation during Marine Isotope Stage（MIS） 6, when the supply of terrigenous detrital is highest. In contrast, during MIS 3,5 and 7, the δ^（44） Ca values are in higher tendency, and their fluctuations are consistent with the variations of the productivity proxies. These results suggest that the calcium isotopes are mainly influenced by the input of the Himalayan erosion products to the northern Indian Ocean. In addition, the developmental stages of calcareous planktons may have a secondary impact on the fluctuations of the calcium isotope ratio of sea water.

关 键 词：Nintyeast Ridge calcium isotope paleoceanography Indian Ocean 

分 类 号：P736.4[天文地球—海洋地质]