巽他海峡BAR9442岩心30 kaBP以来的沉积记录与古季风活动

为重建巽他海峡区古季风活动历史，通过对BAR9442岩心氧同位素、AMS14C测年、陆源碎屑标准偏差区间粒径分布，以及上升流种Globigerina bulloides等变化特点分析，并结合前人对该岩心粘土矿物的研究，获得如下认识:末次冰期30~17 kaBP，海平面下降，陆源粉砂物质输入增加; 南半球夏季日照率高，然而受冰期热带辐聚带位置影响，西北季风受阻，东南信风持续吹过研究海域形成类似东南季风的效应，气候冷干; 受印度东北季风影响，伊利石含量最高，上升流活动不发育, 古生产力降低.17~8 kaBP，海平面迅速上升，出现较强的表层穿越流活动，粘土物质成为沉积物的主要组分; 此时东南与西北季风都有增强，说明当时研究区气候有着更强的季节性.全新世8 kaBP以来，全球海平面上升使穿越流活动加强，沉积物粘土组分含量最大，西北季风带来温暖湿润的气候条件. 

Sedimentary Record and Monsoon Activity of Core BAR9442 in Sunda Strait during 30 kaBP

Core BAR9442 (6°04.56′S and 102°25.08′E; 2 542 m water depth) is obtained below the present South Java Current, offshore the southern portion of Sumatra in the eastern Indian Ocean. Based on analyses of δ18O, AMS14C ages, grain-size distribution of standard deviation stages and relative abundance of Globigerina bulloides which commonly encountered in upwelling areas, as well as the record of clay mineral in Gingele et al.(2002), we come to the following conclusion: during the last glacial period 30-17 kaBP, when sea level was lower, terrigenous sands supply increased. Even the austral summer insulations strengthened, though the southward shift of the ITCZ in the austral summer may have been considerably restricted, where the northwest monsoon did not operate, and this would create a situation analogous to the southeast monsoon operating throughout the year, because the trade winds would blow continually across the study area. The climate was cold and dry. Under the influence of Indian northeastern monsoon, the percentage content of illite was the highest, and upwelling activity was absent and induced a low productivity. Rapid rise of sea level at the deglaciation 17-8 kaBP, the shallow connections re-opened, Makassar Strait and Lombok Strait were wider, leading to intensified surface ITF, and clay mineral became the dominated terrigenous material. The SE monsoon and NW monsoon seem to be strengthened in Early Holocene, indicating that the biannual monsoonal system was mostly intense at this time. During the Holocene (about 8 kaBP), with the sea level rising, the throughflow enhanced, and the clay minerals of the terrigenous sediments have a maximum influx while intensified NW monsoon generated a warm and wet climate.