The change in redox condition of the Japan Sea since its birth based on trace element geochemistry of sediment cores and sulfur isotope ratio of framboidal pyrite.

从日本海日本海盆的KH 77 -3-L4 '活塞岩心的高硫层中分离出框架状黄铁矿球粒，测定了黄铁矿-硫的硫同位素比值。硫同位素比值低至-50 ~*，表明贫氧沃茨下的硫黄铁矿是同生形成的，它对区分贫氧沃茨下硫黄铁矿的形成是有效的，对区分贫氧沃茨下硫黄铁矿的同生形成和成岩硫酸盐还原作用下硫黄铁矿的形成也是有效的。用加速器质谱法测定了岩芯高有机碳层的有机碳碳~（14）C年龄。除有机碳、氮和硫外，还通过中子活化分析测定了岩心中27种主要和微量元素的含量。根据这些化学参数，特别是氧化还原敏感元素的精确垂直剖面，估算了日本海深水35000年来的氧化还原条件变化，分析了123个深海钻孔岩心（127航次795岩心）的有机碳、氮、总硫和27种常量和微量元素，并对这些化学参数进行了分析。来自日本海的日本盆地。还分离出了框架状黄铁矿球粒，并测定了它们的硫同位素比值。根据这些化学参数，氧化还原条件的变化，因为日本海的诞生，约。15马前，估计。根据这些结果，高氧和高还原条件之间的周期性变化已经变得显着，因为2.4 Ma前。

Framboidal pyrite spherules were isolated from high sulfur layrs of a piston core (KH77-3-L4') sample collected from the Japan Basin of the Japan Sea and sulfur isotope ratios of the pyrite-sulfur was measured. The sulfur isotope ratios show as low as-50* indicating the syngenetic formation of framboidal pyrite under euxinic bottom waters and its validity to distinguish the formation of framboidal pyrite under euxinic bottom waters and its validity to distingnish the formation of framboidal pyrite between syngenetic formation under euxinic bottom waters and diagenetic formation through diagenetic sulfate reduction. The C-14 ages of organic carbon were measured at high organic carbon layrs of the core by accelerator mass spectrometry. Twenty seven major and trace element contents were also measured for the core by neutron activation analysis in addition to organic carbon, nitrogen and sulfur. Based on the precise vertical profiles of these chemical parameters, especially of those of redox sensitive elements, the changes of redox conditions of the deep water of the Japan Sea were estimated for the last 35000 years.Organic carbon, nitrogen, total sulfur and 27 major and trace elements were analyzed for 123 samples from and Deep-sea Drilling Core, Leg 127 Site 795 Core, from the Japan Basin of the Japan Sea. Framboidal pyrite spherules were also isolated and the their sulfur isotope ratios were measured. Based on these chemical parameters, the changes in redox conditions of the deep water since the birth of the Japan Sea, ca.15 Ma ago, were estimated. According to these results, the cyclic changes between highly oxic and highly reducing conditions have become significant since 2.4 Ma ago.