南海北部晚中新世以来颗石藻Reticulofenestra属碳酸钙通量变化及其影响因素

CARBONATE FLUX OF RETICULOFENESTRA AND ITS CONTROLLING FACTORS FROM THE LATE MIOCENE IN THE NORTHERN SOUTH CHINA SEA

对南海北部大洋发现计划(IODP)367/368航次的1501站位进行了钙质超微化石定量分析,讨论了晚中新世以来Reticulofenestra属碳酸钙通量变化及其影响因素。结果显示:上新世Reticulofenestra属碳酸钙通量最高,更新世次之,晚中新世最低。影响Reticulofenestra属碳酸钙通量主要因素是颗石数量累计速率和颗石重量,两者在不同阶段对Reticulofenestra属碳酸钙通量的影响力不同。晚中新世,二者共同影响碳酸钙通量;上新世期间,数量累计速率是主要因素;更新世期间则是颗石重量对碳酸钙通量变化影响更大。

We studied the calcareous nannofossil assemblages of the deep-sea sediments from the International Ocean Discovery Program(IODP) since the Late Miocene(~12 Ma) in the northern South China Sea, China. The carbonate flux and its controlling factors of Reticulofenestra were discussed. The fluxe is expressed as the mass accurate rate of Reticulofenestra. The results show that the carbonate flux of Reticulofenestra was highest in the Pliocene, followed by the Pleistocene and lowest in the Late Miocene, except for the bottommost samples. The highest one could reach up to about 50% of the sediment carbonate flux. The analysis concluded that the main controlling factors were the number accurate rate and the morphological evolution of Reticulofenestra. Both have different influences on Reticulofenestra carbonate fluxes at different stages. In the Late Miocene, they acted together to influence carbonate fluxes, and in the Pliocene, the rate of number accurate rate was the main factor, the mass of the coccolith had a greater influence on changes in carbonate fluxes during the Pleistocene.