南海北部陆坡晚第四纪有机壁浮游藻类记录及其古环境意义  

LATE QUATERNARY ORGANIC-WALL PHYTOPLANKTON RECORD IN NORTHERN SLOPE OF SOUTH CHINA SEA AND ITS PALEOENVIRONMENTAL SIGNIFICANCE

作　　者：吴国瑄[1] 孙湘君[2] 

机构地区：[1]同济大学海洋地质教育部重点实验室,上海200092 [2]中国科学院植物研究所,北京100093

出　　处：《海洋地质与第四纪地质》2000年第2期57-63,共7页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金重点资助项目!( 4 973 2 0 60 )

摘　　要：通过 92个样品分析 ,发现南海北部陆坡末次冰期以来沉积物中有机壁浮游藻类输入通量在新仙女木期和早全新世明显高于其它时期 ,新仙女木期的输入通量峰值及不同于 Spiniferites spp.组合 (较暖期 )和Protoperidinioid类孢囊组合 (较冷期 )的 Operculodinium cetrocarpum组合 ,表明当时表层海水环境较为特殊 ,可能是水温偏低且较富营养的条件 ,早全新世的有机壁浮游藻类高输入通量期持续约达 40 0 0 a,Spiniferites spp.为优势的孢囊组合和较高的淡水绿藻输入通量反映了早全新世夏季风强盛及表层海水较暖 ,Spiniferites spp.含量低值段对应于末次盛冰期和新仙女木期 ,而高值段对应于夏季风强盛的早全新世 ,Protoperidinioid类孢囊显示了与Spiniferites spp.相反的变化趋势 ,其含量在末次盛冰期最高 ,新仙女木期又现高值 ,而 8～ 5 ka B.P.的全新世暖期降至最低。L ingoludinium machaerophorm和 Polysphaeridium zoharyi的含量变化记录了末次冰期以来南海北部海水盐度由低到高的变化趋势 ,末次冰期海水盐度低 ,冰消期开始升高 。A high resoluton depositional sequence of late Quaternary has been obtained in core 17940 got from northern slope of the South China Sea.This paper presents the organic wall phytoplankton record from core 17940.Based on the analytical results,including organic wall phytoplankton influx and assemblages from total 92 samples,environmental change of late Quaternary in the northern South China Sea was discussed.Two periods of high organic wall phytoplankton influx can be identified.They are respectively in Younger Dryas,from 11 300 10 000 aB.P.,and the early Holocene,ca.10 000～6 000 aBP.Younger Dryas is characterised by increased dinocyst influx and Operculodinium cetrocarpum content. O.cetrocarpum assemblage should be indicative of the cool and nutrient surface seawater,different from Spiniferites spp.assemblage or Protoperidinioid cyst assemblage reflecting respectively warm and cold sea surface conditions.The period of high influx in early Holocene,nearly 4 000 years long,is characterised by high relative abundance of Spiniferites spp.and influx of freshwater green algae,indicative of warm condition in the northern South China Sea and coast resulting from the rising intensity of the summer monsoon.The percentage of Spiniferites spp.is low in the sediments of the Last Glaciation and Younger Dryas and highest in the early Holocene.Change in the content of Protoperidinioid cysts shows a contrary trend to that of Spiniferites spp.The low percentage of Protoperidinioid cysts corresponds to the warm period of Holocene(ca.8 000～5 000 aB.P.),whereas the high percentage to the Last Glaciation and Younger Dryas.Variations in the relative abundance of Lingoludinium machaerophorm and Polysphaeridium zoharyi indicate the change in sea surface salinity of northern

关 键 词：古环境 有机壁浮游藻类 南海北部陆坡 晚第四纪 

分 类 号：P736.22[天文地球—海洋地质] Q914.663[天文地球—海洋科学]