Comparison of paleoenvironmental changes between both hemispheres

在这笔赠款的第一年，我们获得了北太平洋西北部沉积物岩心记录的400ka以来的烷酮类海表面温度和浮游有孔虫的氧同位素剖面的数据集。第二年，在R/V Mirai MR03-K04巡航期间，在智利边缘地区、麦哲伦海峡、东南印度洋海脊和凯尔盖伦高原共采集了6个大尺寸沉积物岩芯。第三、四年间，对本区沉积岩心的化学古代理、烯酮、浮游有孔虫、蛋白石、~(210)Pb、放射性碳、有孔虫组合等进行了分析。另一方面，对北太平洋和鄂霍次克海高纬度沉积岩心，以百年时间分辨率重建了100ka以来的海温。此外，水团从中水到深水…的通风变化。更像是在北太平洋西北部重建的百年-千年时间尺度结果。结果，在年轻仙女木冷期(11ka)之前的Bolling-Allorod间歇期(12ka)，通风速度迅速下降。在12ka时，中间水团的通风减慢，这与在Tokachi地区附近的沉积物岩心记录的巨大甲烷水合物释放的时间相对应。中间水团通气量的变化可能会影响北太平洋西北部的区域碳循环，为了重建麦哲伦海峡太平洋侧出海口的海表面温度，分析了一种可靠的古温度计--烷烃。Alkenon温度在8.7~12℃之间变化，从底部到600 cm深度呈逐渐增加的趋势。我们可以在520 cm处发现烯烃温度急剧下降(&lt；10℃)。在520 cm深度的低烯酮温度事件后，烯酮温度再次上升到12℃。根据14&gt；C数据或岩心顶部，4-5kyrBP开始了烯酮温度的急剧降温。为了与北半球高时间分辨率的古环境变化进行对比，需要更多来自南半球的优质沉积岩芯。较少

During the first year of the term of this grant, we couls obtained the data set of alkenone sea surface temperature and oxygen isotopic profile of planktonic foraminifera over the past 400 ka recorded in the sedimnet cores collected in the northwestern North Pacific. In the second year, total six long-size sediment cores were collected in the Chilean marginal area, Magellan strait, south eastern Indian Ridge, and Kelgueren Plateau during r/V MIRAI MR03-K04 cruise. During the third and forth years, chemical paleo proxides, alkenone, oxygen isotopic ratio of planktonic foraminifera, opal, 210Pb, radiocarbon, foraminiferal assemblanges of sediment cores collected in the above area has been analyzed onshore.On the other hand, for the sediment cores in high latitude of the North Pacific and the Okhotsk Sea, sea surface temperature was reconstructed with decadal-centennial time resolution over the past 100ka. In addition, variation of ventilation of water mass from the intermediate to deep w … More as reconstructed in the northwestern North Pacific with centennial - millennial time scale resulution. As a result, ventilation speed was rapidly down at the Bolling-Allorod interstatial (12 ka) when is just before the Younger Dryas cooling period (11ka). This slow down of ventilation of the intermediate water mass at 12 ka corresponded to the timing of enormous methane dydrate release recorded in the sediment cores Off Tokachi area. The change in the ventilation of intermediate water mass might affect the regional carbon cycle in the northwestern North Pacific.In order to reconstruct of sea surface temperature at the Pacific side mouth of Magellan strait, alkenon, which is a robust paleothermometer was analyzed. Alkenon temperature varied from 8.7℃ to 12℃ and garadually increased from the bottom to 600cm depth. We could find a sharp decrease in alkenon temperature (<10℃) at 520cm depth. After the low alkenone temperature event at 520cm depth, alkenone teperature again up to 12℃. According to the ^<14>C data or core top, the dramatic cooling of alkenone temperature had started at 4-5 kyrBP.More high quality sediments cores from the southern hemisphiere are necessary to compare with teh paleoenvironmental changes in the northern hemisphere with high time resolution. Less