北部湾东南部末次冰期以来环境演化与驱动机制

Environmental evolution and its driving mechanisms of southeastern Beibu Gulf since the Last glacial period

应用单道浅层地震、等离子体质谱仪(ICP-MS)和X射线衍射(XRD)等测试技术对地层结构及主微量元素地球化学、黏土矿物组成和结晶学特征等气候代用指标进行分析,高精度刻画了北部湾东南部末次间冰期以来的气候演化及驱动机制。指标变化显示南海西北部75千年(75 ka)以来物源供给受气候及海平面变化的协同控制。晚更新世受海因里希(Heinrich)全球气候变冷事件及青藏高原巨大高度和纬度效应的调控导致56ka、41ka和28ka东亚季风的冬季风较夏季风阶段性增强,步入全新世以来,北部湾东南部历经多次干湿交替性升温过程,逐步演化到现今气候阶段。

The stratigraphic structure,the geochemistry of major and trace elements,and the composition of clay minerals and the crystallographic characteristics have been analyzed by single-channel shallow seismic,ICP-MS,EDS,and XRD.The climate evolution and its driving mechanisms since the last interglacial period in the southeastern Beibu Gulf have been accurately characterized.The variation of indices shows that the provenance supply of the northwest South China Sea has been controlled by climate and sea level changes since 75 thousand years(75 ka)ago.In the late Pleistocene,the Heinrich event and the differential uplift of the Qinghai-Tibet Plateau caused the East Asian monsoon,especially the winter monsoon,to gradually increase at 56 ka,41 ka,and 28 ka.Since the Holocene(11.5 ka ago),the southeastern part of the Beibu Gulf has experienced several drying-humid warming processes,which gradually evolved into the current climate stage.