南海东北部末次冰期以来的沉积环境演变

利用南海东北部上陆坡处所取的D孔柱样进行硅藻分析,结合粒度与碎屑矿物分析结果,探讨该海域末次冰期以来沉积环境演变过程.结果表明：粒度与硅藻分析结果较为吻合,共同显示D孔柱样可分为上下两层.上表层（0～2 cm）的砂质沉积层为冰后期海进过程改造的晚更新世残留沉积层,即变余沉积;下层（2～130 cm）主要是末次冰期形成的浅海沉积.整个柱样可反映出海洋同位素MIS 4期海退至MIS 3期海进与MIS 2期海退至冰后期海进的沉积变化韵律.

PRELIMINARY STUDY ON SEDIMENTARY ENVIRONMENTAL DEVELOPMENT OF THE NORTHEASTERN SOUTH CHINA SEA SINCE LAST GLACIAL STAGE

The process of sedimentary environmental change in the northeastern South China Sea since the last glacial stage was studied by using core D(water depth 405 m,core length 130 cm)sampled from the upper slope in this sea area to carry out diatom,grain size and detrital mineral analyses.The results of grain size and diatom analyses matched with each other perfectly by which core D could be divided into surface and lower layers.The surface sand layer(0~2 cm) consists of residual or palimpsest sediments which were formed in the late Pleistocene and transformed in the post glacial transgression.The lower layer (2~130 cm) was mainly formed in a neritic sedimentary environment in the last glacial stage.Two sedimentary rhythms can be detected in core D: MIS 4 regression to MIS 3 transgression and MIS 2 regression to the post glacial transgression.