南海北部陆坡SH1B孔MIS 6期以来古生产力和古环境变化的硅藻记录

PALEOPRODUCTIVITY AND PALEOENVIRONMENTAL CHANGES OF THE NORTHERN SLOPE OF SOUTH CHINA SEA SINCE MIS 6:EVIDENCE FROM DIATOM OF CORE SH1B

通过对神狐海域SH1B孔硅藻丰度和生态类群组成的研究,探讨了该海域MIS 6期以来古生产力及古环境变化特征。硅藻丰度变化表明MIS 6期以来古生产力具有显著的冰期高-间冰期低旋回特征。末次冰期(MIS2-4)和MIS 6时低海平面导致河流剥蚀作用增强,并可能存在季风驱动的上升流,使得营养物质输入增加引发高生产力。MIS 5和MIS 1期硅藻丰度低,与高海平面时期河流输入的营养物质相对减少,对表层生产力的影响减弱有关。MIS 6期热带远洋种含量偏高,反映硅藻分布主要受盐度控制。MIS 5期半咸水沿岸种含量增加,可能是由降雨量增加引起。

Based on the diatom distribution pattern of core SH1 Bin the Shenhu area,the variation in productivity and paleoenvironment of the northern slope of the South China Sea since the Marine Isotope Stages（MIS）6are discussed in this paper.The changes in diatom abundance represent conspicuous glacial/interglacial cycles,resulted from the nutrient input induced by sea level condition.Increasing nutrients supplies from both the intensified river runoffs and upwelling currents during the MIS 2-4and MIS 6had led to the high level of primary paleoproductivity.The distribution of the four different diatom ecological assemblages in the SH1 Bhas provided with useful information on paleoenvironment.High percentage of warm temperature species in the ice age of MIS 6reveals that diatoms are dominantly influenced by salinity.The increased rainfall in the MIS 5may cause the dominance of coastal brackish species.