东海陆架泥质沉积区全新世有孔虫和介形虫及其古环境应用

HOLOCENE BENTHIC FORAMINIFERA AND OSTRACODA FROM THE SHELF MUD AREA OF THE EAST CHINA SEA AND THEIR PALEOENVIRONMENTAL IMPLICATIONS

浙江岸外东海内陆架MD06-3040柱状样完整保存有10.6cal.kaPB以来的全新世沉积记录,采取257个沉积物样品进行了有孔虫和介形虫定量分析。依据丰度上的优势成分和特征种的分布,识别出6个底栖有孔虫组合和4个介形虫组合。应用属种组合和不同生态(表生/内生、内陆架/中—内陆架、暖水)种的丰度,探讨了研究区全新世以来的古环境变迁。分析结果揭示了研究区全新世早期海面快速上升,沉积环境由滨岸内陆架(10.6—9.8cal.kaBP)、内陆架外缘(9.8—7.8cal.kaBP)转变至中陆架内侧并达全新世最高海面(7.8—3.4cal.kaBP)。台湾暖流在8.0cal.kaBP起开始发育,并在5.7—2.8和0.7—0cal.kaBP二个时期派生出明显的上升流。台湾暖流及其所派生的上升流是造成东海陆架泥质快速沉积的最主要原因。依据浮游有孔虫Globigerina bulloides的丰度变化,推测浙闽沿岸流在4.9—3.2cal.kaBP时期最为强盛。

Core MD06-3040 was taken from the mud area off the Zhejiang-Fujian coast of the East China Sea （27°43. 3663′N, 121°46. 8822′E, water depth 47 m,core length 19.36 m）. A total of 257 samples were quantitatively analyzed for paleontological study of planktonic, benthic foramini-fera and ostracods as well as their paleoenvironmen- tal implications. Holocene paleoenvironmental evolution since 10.6 cal. kaBP has been discussed by benthic foramini- feral and ostracod assemblages and some important ecological indicators （infaunal/epifaunal, inner-shelf/inner-middle shelf, warm-water species groups）. Results show a rapid sea-level rise during the early Holocene from the inner in- ner-shelf （10.6--9.8 cal. kaBP）, outer inner-shelf （9.8--7.8 cal. kaBP） to the middle shelf with the highest sea-level （7.8--3.4 cal. kaBP）. The Taiwan Warm Current is suggested to be developed since 8.0 cal. kaBP and its derived upwelling appeared during the periods of 5.7--2.8 and 0.7--0 cal. kaBP respectively, resulting in the rapid mud depo- sition on the shelf of the East China Sea. The marked increase in abundance of planktonic foraminifera Globigerina bulloides is referred to the enhancement of the Zhejiang-Fujian Coast Current during 4.9--3.2 cal. kaBP.