High-resolution reconstruction of environmental change off the east coast of Japan since the last 50,000 years reconded in a marine sediment core.

西北太平洋是当今冷的潮和暖的黑潮交汇的地方，是北太平洋监测西部边界校正响应过去气候变化的最敏感区域。在2001年的IMAGES巡航中，从日本中部2224米的水深中发现了一个长45.82米的岩心。对该岩心进行了颜色、粒度、矿物组成、古地磁、δ^<18>O、δ^<13>C蛋白石、CaCO_3、硅藻种类、球石藻、放射虫、浮游有孔虫和底栖有孔虫、CaCO_3保存、Uk37′、TOC、C/N、δ^<13>C_<TOC>、δ^<15>N_<TOC>、生物标记物和花粉等研究。得到了以下主要结果。G.bulloides的δ^<18>O曲线与标准氧同位素曲线相似，表明其在145ka内连续沉积。4种微化石组合（硅藻、球藻、放射虫和浮游有孔虫）的温水指数均显示出在MIS 2和6阶段温度下降，而在MIS 5阶段温度上升，但它们之间的相关系数并不总是很高（在0.5 ~ 0.6之间）。核心顶部alkenon导出温度（19℃）与该地区目前年平均海温基本一致。MIS 2结束时的海温为13℃，比核心位置偏北4.5度。类似的海温迁移也可以从肿皮新种的盘绕率中推断出来。C/N比值δ^<13>C_<TOC>和δ^<15>N_<TOC>表明TOC主要为海相来源，尽管在MIS 6期间陆相来源略有增加。暖花粉指数曲线与黄粉菊δ^<18>O曲线基本一致，但在MIS 6和MIS 5e中，由花粉曲线推断的地表温度变化先于δ^<18>O曲线。

The northwest Pacific, where the cold Oyashio and the warm Kuroshio Currents meet each other today, is the most sensitive region in the North Pacific for monitoring the migration of the western boundary corrects in response to the past climatic change. A long core (45.82 m length) was recovered from 2,224 m water depths off the central Japan during the IMAGES cruise in 2001. A multi-disciplinary study was carried out on the core by analyzing the following research items : color, grain size, mineral composition, paleomagnetism, δ^<18>O, δ^<13>C Opal, CaCO_3, species of diatoms, coccolithophorids, radiolaria, planktonic foraminifera and benthic foraminifera, CaCO_3 preservation, Uk37', TOC, C/N, δ^<13>C_<TOC>, δ^<15>N_<TOC>, biomakers and pollen. The following main results ware obtained. The δ^<18>O curve of G.bulloides is similar to the standard oxygen isotope curve, suggesting continuous deposition over the last 145 ka. All warm water indices yielded by the four microfossil assemblages (diatoms, coccolith, radiolaria, planktonic foraminifera) show temperature decreases during the MIS 2 and 6, and increases during the MIS 5, although their correlation coefficients with each other are not always high (between 0.5 and 0,6). The Alkenon-derived temperature (19℃) at the core top agrees with the mean annual SST at present time in this region. The SST at the end of the MIS 2 was 13℃, which is seen today about 4.5 degree latitude north than the core site. Similar migrations in SST are inferred from the coiling ratio of N.pachyderma. The C/N ratio, δ^<13>C_<TOC> and δ^<15>N_<TOC> indicate that the TOC is mainly of marine origin, although terrestrial origin slightly increases during the MIS 6. The curve of the warm pollen index is similar to the δ^<18>O curve of G.bulloides, except for the MIS 6 and 5e when the land temperature changes inferred from the pollen curve precede the δ^<18>O curve.