NOAA/WDS Paleoclimatology - Kulishu Cave Geochemical Data from 14000 to 10400 Cal Yr BP

A high-resolution and absolute-dated stalagmite record from Kulishu Cave, Beijing characterizes Asian Monsoon (AM) history in northern China between ca 14 and 10.5 ka BP (thousand yrs before present, present = 1950), including the entire Younger Dryas (YD) event. Using 230Th dates and counting of annual-layers, the shift into the YD began at 12,850 ± 40 yr BP and took ∼340 yrs and the shift out of the YD began at 11,560 ± 40 yr BP and took <38 yrs (best estimate ∼20 yrs), broadly similar to previously reported AM records from central and southeastern China. The more gradual nature of the start of the YD event as observed in the AM records appears to contrast with the more abrupt beginning observed in the Greenland ice records. The total amplitude of the AM YD event is also smaller than the amplitude of the AM Heinrich Stadial 1 event. In addition, the general rising trend of the AM during the Bølling-Allerød period contrasts with the general cooling trend in Greenland temperature during that time. The influence of rising insolation on the AM may explain this observation.

一项采自北京葫芦洞（Kulishu Cave）的高分辨率绝对定年石笋（stalagmite）记录，刻画了距今约14至10.5 ka BP（即千年前，基准年为1950年）间中国北方的亚洲季风（Asian Monsoon, AM）演化历史，涵盖完整的新仙女木（Younger Dryas, YD）事件。研究通过230Th测年与年层计数分析，确定新仙女木事件的起始节点为12850±40 yr BP，其启动过渡过程持续约340年；而事件的终止节点为11560±40 yr BP，结束过渡时长不足38年（最优估算约20年）。该结果与此前中国中、东南部地区报道的亚洲季风记录大体一致。亚洲季风记录中观测到的新仙女木事件起始过程更为平缓，这与格陵兰冰芯记录中更为突变的事件起始特征形成显著反差。此外，亚洲季风新仙女木事件的总振幅，亦小于海因里希冷期1（Heinrich Stadial 1）的振幅。另外，波令-阿勒罗德（Bølling-Allerød）时期亚洲季风整体呈上升趋势，而同期格陵兰气温则普遍呈现降温趋势，这一现象可通过日射量增加对亚洲季风的影响得到合理解释。