晚第四纪普里兹湾北部陆坡岩心沉积学记录及古海洋学意义

LATE QUATERNARY SEDIMENTARY RECORDS AND PALEOCEANOGRAPHIC IMPLICATIONS FROM THE CORE ON CONTINENTAL SLOPE OFF THE PRYDZ BAY, EAST ANTARCTIC

摘要: 通过对普里兹湾北部陆坡P1-03岩心沉积物敏感粒级组分的提取和年代学分析,发现:大于>63 μm的砂砾级组分可作为冰筏碎屑的指示粒级,过去52万年以来该地区共发生了8次较大的冰筏碎屑事件,出现在冰期及间冰期中相对较冷的阶段。分选级粉砂和黏土组分的含量可指示底流强弱,其旋回变化显示冰期底流较弱,有利于黏土沉降;间冰期南极绕极流主轴南移,陆架-陆坡水体交换加强,底流增大,对沉积物的搬运和簸选加强。

Abstract: Environment sensitive grain size components of the sediments of the core P1-03, recovered from the continental slope off the Prydz Bay, were analyzed. Eight events of ice-rafted debris were identified for the past 520 ka, which mostly occurred in the glacials and the relatively cold periods in interglacials. The amount of sorted silt and clay fractions reflect the strength of bottom currents. Their cyclic variations suggest that the bottom currents were relatively weak during ice ages, which is favorable for clay deposition, while intensive during interglacial stages, together with the southward shift of the main axis of the Antarctic Circumpolar Current, and the increase in water exchange between shelf and slope.