Japan Sea oxygen isotope stratigraphy and global sea-level changes for the last 50,000 years recorded in sediment cores from the Oki Ridge
Japan Sea oxygen isotope stratigraphy and global sea-level changes for the last 50,000 years recorded in sediment cores from the Oki Ridge
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DOI：
10.1016/j.palaeo.2006.11.018
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发表时间：
2007-04
期刊：
影响因子：
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通讯作者：
Y. Yokoyama;Y. Kido;R. Tada;Ikue Minami;R. Finkel;H. Matsuzaki
中科院分区：
文献类型：
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作者：
Y. Yokoyama;Y. Kido;R. Tada;Ikue Minami;R. Finkel;H. Matsuzaki
我们获得了20个AMS（加速器质谱）放射性碳测年，2火山灰层年表，和一个南极有孔虫δ 18 O地层在过去的50,000年从日本海的核心冲木海岭。在本文中，我们报告AMS 14 C的结果，使我们能够重建一个高分辨率的年表的核心和讨论千年尺度的气候变化记录在日本海沉积物。从冰期到全新世，由于冰川消退和全球海平面上升带来的重大水文变化，该遗址的沉积速率急剧增加。末次盛冰期（LGM）时，浮游有孔虫的δ 18 O异常较轻。这一变化对应于日本海表面沃茨的淡化，主要是由于全球海平面下降，而不是像以前报道的那样，异常温暖的SST（海表面温度）。我们的记录结合全球海平面数据表明，LGM开始于大约3万年前，日本海的盐度变得比现在更新鲜。MIS（海洋氧同位素阶段）第3期海表温度相对稳定，全球海平面不低于约1000米。-80米。日本海的表层水在新仙女木冷事件之后达到了“正常”的含盐水平，并在7 kyr前达到了现在的δ 18 O值。
We obtained twenty AMS (Accelerator Mass Spectrometry) radiocarbon dates, 2 tephra layer chronologies, and a planktonic foraminiferal δ18O stratigraphy for the last 50,000 years from Japan Sea cores from the Oki Ridge. In this paper we report AMS14C results that allow us to reconstruct a high-resolution chronology of the cores and discuss millennial scale climate changes recorded in Japan Sea sediments. The sedimentation rate for the site increased dramatically from the glacial stage to the Holocene as a result of significant hydrological changes associated with deglaciation and global sea-level rise. A lighter δ18O anomaly for the planktonic foraminifers was found during the LGM (Last Glacial Maximum). This shift corresponds to a freshening of the Japan Sea surface waters, and is mainly due to a global sea-level drop rather than anomalously warm SSTs (sea-surface temperatures) as previously reported. Our record combined with the global sea-level data suggests that the LGM started about 30 kyr ago and that the salinity of the Japan Sea became fresher than at present. The SSTs during MIS (Marine Oxygen Isotope Stage) 3 were relatively stable and global sea-level was not lower than ca. −80 m. The surface water of the Japan Sea attained “normal” saline levels following the Younger Dryas cold event and reached the present-day δ18O values 7 kyr ago.