南海北部早—中中新世钙质超微化石群落与大洋碳储库关系初探  

EARLY AND MIDDLE MIOCENE CALCAREOUS NANNOFOSSILS AND OCEAN CARBON RESERVOIR RESEARCH IN THE NORTHERN SOUTH CHINA SEA

作　　者：林冠宇 金晓波[1] 刘传联[1] LIN Guanyu;JIN Xiaobo;LIU Chuanlian(State Key Laboratry of Marine Geology,Tongji University,Shanghai 200092)

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092

出　　处：《微体古生物学报》2021年第2期197-208,共12页Acta Micropalaeontologica Sinica

基　　金：国家自然科学基金项目(41876046,41930536)资助。

摘　　要：本文对南海北部大洋发现计划IODP 1501站早—中中新世(21—12Ma)深海沉积物进行了钙质超微化石群落分析,初步探讨了钙质超微化石演化与大洋碳储库的关系。结果显示:在~16Ma,钙质超微化石组合反映海水由高生产力环境向低生产力环境过渡,而与之对应的是大洋海水碳同位素由变重转为变轻;而在~14.2Ma,钙质超微化石组合揭示海水由低生产力环境向高生产力环境过渡,与之对应的是大洋海水碳同位素从变轻转为变重。这些现象说明钙质超微化石群落演化与大洋碳储库具有明显的相关性。推测主要是由于生物光合作用优先吸收12 C,合成有机质埋藏到海底,导致海水碳同位素变重。另外在~13.8Ma,由于东南极冰盖扩张引起中中新世气候转型,陆源输入和洋流重组等因素可能会导致大洋碳同位素变轻。We studied the Early and Middle Miocene(21—12Ma)calcareous nannofossil assemblages of the deep-sea sediments from the International Ocean Discovery Program(IODP)Site 1501in the northern South China Sea,China.This study aims to explore the relationship between calcareous nannofossil assemblages and oceanic carbon isotope.At~16Ma,calcareous nannofossil assemblages indicated that the high productivity environment changed to a low productivity environment,where the oceanic carbon isotope became negative.At~14.2Ma,calcareous nannofossil assemblages indicated that the low productivity environment changed to a high productivity environment,where the oceanic carbon isotope became positive.It showed that the correlation of productivity and carbon isotope was negative.We inferred that phytoplankton prioritized to absorb 12 C and extracted orgnic carbon into deep-ocean deposites,which caused the carbon shift.At~13.8Ma,East Antarctic Ice-sheet Expansion led to the Middle Miocene Climate Transtion.The excursion of carbon isotope probably related to terrestrial input and ocean current reorganization.

关 键 词：钙质超微化石 IODP1501站 大洋碳储库 早—中中新世 南海北部 

分 类 号：Q915.2[天文地球—古生物学与地层学]