Age determinations on ODP Hole 117-723A in the Arabian Sea

Planktonic foraminiferal abundances, fluxes, test sizes, and coiling properties are influenced in various ways by the southwest monsoon winds and associated upwelling in the western Arabian Sea. To determine the short-term changes in the southwest monsoon, we have carried out a high-resolution time-series analysis of three upwelling indices (total flux of planktonic foraminiferal tests and flux and relative abundance of the planktonic foraminiferal species Globigerina bulloides) from Ocean Drilling Program (ODP) Site 723A (Oman Margin, western Arabian Sea) spanning the last 19 kyr. In addition, we have determined the relationships between upwelling intensity and the relative abundance, fluxes, and shell concentrations of various planktonic foraminiferal species. Upwelling indices suggest that from 19 to 16 ka (22 to 18.2 cal kyr B.P.) the SW monsoon was relatively strong compared to the period 15.8 to 12.5 ka (17.8 to 13.8 cal kyr B.P.). […]

浮游有孔虫的丰度、通量、壳体大小以及旋卷特性，受到西南季风及其在阿拉伯海西部的上升流以多种方式的影响。为确定西南季风的短期变化，我们对来自海洋钻探计划（Ocean Drilling Program，简称ODP）723A站位（阿曼边缘，阿拉伯海西部）的三个上升流指数（浮游有孔虫测试的总通量以及浮游有孔虫物种Globigerina bulloides的通量和相对丰度）进行了高分辨率的时间序列分析，分析时间跨度为过去19千年前。此外，我们还确定了上升流强度与多种浮游有孔虫物种的相对丰度、通量和壳体浓度之间的关系。上升流指数表明，在19至16千年前（22至18.2千年前碳纪年B.P.）期间，与15.8至12.5千年前（17.8至13.8千年前碳纪年B.P.）相比，西南季风相对较强。 [...]