南海南部末次冰期以来的沉积物特点及其古环境意义  

CHARACTERISTICS OF SEDIMENTS IN THE SOUTHERN SOUTH CHINA SEA SINCE THE LAST GLACIATION AND THEIR PALEOENVIRONMENTAL SIGNIFICANCE

作　　者：乔培军[1] 邵磊[1] 

机构地区：[1]同济大学海洋地质教育部重点实验室,上海200092

出　　处：《海洋地质与第四纪地质》2003年第2期73-78,共6页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金资助项目(49999560;40276019);国家重点基础研究发展规划项目(G2000078500)

摘　　要：对南海南部接近湄公河三角洲中陆坡上的MD01 2392站样品进行了地球化学和粒度分析,揭示出该站位上部12 8m地层包含了完整的末次冰期约7万年以来的沉积旋回。其MIS4期以来的沉积速率是南海南部已知站位柱状样中最高的,呈现冰期高而间冰期低的特征;并发现沉积物中Ti、Si、Fe和Al等元素含量在冰期时高,推测与低海面时期具较高的陆源物质输入有关。元素Sr、Ba、Ca的含量分布与CaCO3的相似,冰期低、间冰期和全新世高;推测冰期低值是陆源和非CaCO3物质稀释作用的结果。粒度分析表明粉砂(2～63μm)是该站陆源物质的主要成分,粗组分(>63μm)主要出现在MIS2的早、晚期,指示有浊流沉积存在。Analysis of the geochemistry and granularity has been performed on samples from core MD012392 at middle slope near the Mekong delta, southern South China Sea. The results reveal a whole depositional cycle of the last glaciation since the last 70 ka in the upper 128 m section. The sedimentation rate is found the highest in the known sites of the southern SCS since MIS 4, with a general trend that it is higher in the glaciations and lower in the interglaciation and postglaciation. Geochemical data show generally higher Ti, Si, Fe,and Al contents in the glaciations due to the higher terrigenous influx during the lower sea level. Similar to CaCO3, contents of Sr, Ba and Ca are found lower in the glaciations and higher in the interglaciation and Holocene. Their lower contents in the glaciations are considered to be the result of the terrigenous and nonCaCO3 dilution. Size data show that silt sizes (2～63 μm) dominate the terrigenous sediment of core MD012392. High content of coarser sizes (>63 μm) occur mainly in the early and late intervals of the MIS 2, indicating the occurrence of the turbidite deposition.

关 键 词：末次冰期 沉积物 古环境 地球化学 粒度 沉积速率 南海 

分 类 号：P736.22[天文地球—海洋地质]