48ka以来日本海古生产力和古氧化还原环境变化的地球化学记录

The geochemical records of paleoproductivity and paleoredox in the Sea of Japan since 48ka

通过对日本海Ulleung盆地KCES-1孔元素地球化学分析,探讨了过去48 ka以来日本海古生产力和古氧化还原环境的变化规律和影响因素。多种替代指标质量累积速率（总有机碳、CaCO3,磷、过剩钡、镉含量）显示日本海古生产力自48 ka以来发生了显著的变化。在48~18 ka低海平面和有限的水体交换导致表层水古生产力相对较低。在18~11 ka随着海平面的上升,富营养盐水团（亲潮和东海沿岸流水团）的流入导致古生产力逐渐增大,在12.6~11.5 ka古生产力达到最大值。在全新世对马暖流成为影响古生产力变化的重要因素,并且自5 ka以来古生产力保持相对稳定。古氧化还原替代指标（总有机碳、钼、铀、锰、碳与硫含量之比、自生铀、自生钼含量）显示在12~9 ka日本海底层水可能为无氧环境。古生产力高和底层水体有限的交换是诱发底层水缺氧的主要因素,而这又与全球气候变化和海平面变化有关。

The paleoproductivity and paleoredox history in the Sea of Japan since 48 ka have been reconstructed using element geochemical data,and factors controlling the change are determined.The mass accumulations of multiproxies[total organic carbon（TOC）,CaCO3,phosphorus,cadmium,excess barium content]show that the paleoprodutivity has varied greatly since 48 ka.At 48~18 ka,a relative lower sea-level and a limited water mass exchange resulted in the lower paleoproductivity.At 18~11 ka,the higher paleoproductivity was resulted from the rich-nutrients water mass（the Oyasio and the East China Sea coastal water） inflowing into the Sea of Japan with relative sea-level rise,and the maximum value was observed at 12.6~11.5 ka.In the Holocene,the Tsushima Warm Current was a main factor that controlled the distribution of paleoproductivity,and since 5 ka the paleoproductivity had remained relative stability.the proxies about the paleoredox（TOC,molybdenum,uranium and manganese,the ratio of carbon to sulfur content,authigenic uranium and molybdenum contents） indicate that at 12~9 ka,the bottom water is anoxic.Both enhanced paleoproductivity and restricted bottom-water advection triggered the bottom water anoxic and it was also related to the global climate change and the sea-level change.