渤海晚冰期以来环境变化的化石介形类证据

EVIDENCE OF FOSSIL OSTRACODES FOR ENVIRONMENTAL CHANGES OF BOHAI SEA SINCE LATE GLACIAL PERIOD

对渤海中央盆地Ｂ９２－３孔（芯长４２０ｃｍ）、Ｂ９２－１孔（芯长４２０ｃｍ）以及莱州湾Ｂ９２－２孔（芯长３３０ｃｍ）柱状样进行了介形类属种、丰度和分异度分析，并将Ｂ９２－３孔和Ｂ９２－１孔的介形类划分出６个组合带。根据渤、黄海地区不同沉积环境中现代介形类的分布，将剖面中的介形类分成滨岸－河口区的Ｓｉｎｏｃｙｔｈｅｒｉｄｅａ组合和近岸区的Ｍｕｎｓｅｙｅｌｌａ组合。按照地层１４Ｃ年代以及剖面中Ｓｉｎｏｃｙｔｈｅｒｉｄｅａ组合分子和Ｍｕｎｓｅｙｅｌｌａ组合分子的相对丰度变化，讨论了渤海晚冰期后期以来的古环境演化历史：晚冰期为河流、湖沼环境；大约１００００ａＢ．Ｐ．开始海侵，早全新世属滨岸－河口沉积；８７００ａＢ．Ｐ．前后开始水深加大，盐度提高；２４００ａＢＰ以后水深逐渐降低。

Species, abundance and diversity of ostracodes from 3 cores in the Bobai Sea were analysized;among them, Core B92-3 (420cm in length) and Core B92-1 (420cm) were obtained from the Central Basin and Core B92-2(330cm)from the Laizhou Bay. Based on the relative abundance of ostracode species, 6 assemblages were recognized in the profiles of Core B92-3 and Core B92-1.