豫西末次盛冰期以来季风事件的高分辨率石笋记录与气候意义

古气候 石笋 氧同位素 气候意义 河南西部
杨琰 2014-01 项目
We will compare multi-proxies of cave stalagmite records in different space-time scales between Southern China and Western Henan Province, which is located in the south-eastern edge of the Loess Plateau in typical Central China. Based on the previous work in cave monitoring from Chongqing and Guizhou Province, we focus on monitoring Jiguan Cave areas, those areas are sensitively influenced by monsoonal climate and near to the China geographical North and South boundaries. The proxies include the modern atmospheric precipitation, cave drip water and modern cave sediments etc, and then make sure the relationship with temperature, humidity and the monsoon index etc, in study areas, Luanchuan, Henan Province. Based on the absolute high-precision MC-ICP-MS U-series dating and high-resolution oxygen and carbon isotope data of environmental record etc,we will analyse several stalagmites from study areas, the millennium-to-annual timescales records of the Asian Monsoon will be established from the Last Glacial Maximum (LGM)on precessional cycle. We focus on the time of beginning and end, and the characteristics of typical abrupt climate events (H1 and LIA, etc.) and those internal structural changes. According to the cave monitoring, the long-to-short timescales of stalagmites and other geological records,we will make a clear to the transmittable mechanism of climatic signal and climate significance for those oxygen isotopes proxies, etc. Moreover, we will analyse changes of the Asian Monsoon climate system and possible driving mechanism from the LGM, and further validate the circulation effect of stalagmite oxygen isotopes by the Chinese monsoon, and further validate the origin and transition of Chinese civilization by the climate factors.
对黄土高原东南缘河南西部地区和中国南方已有洞穴石笋记录进行多环境指标的时空演变对比研究,在对重庆和贵州洞穴监测的基础上,重点监测受季风影响敏感的中国地理南北分界附近我国典型中部地区河南栾川鸡冠洞区域现代大气降水、洞穴滴水、洞穴现代沉积物等和温度/湿度、季风指数等的关系。对研究区生长于末次盛冰期(LGM)以来的多根石笋样品进行绝对高精度的MC-ICP-MS铀系定年和高分辨率的氧碳同位素等环境记录指标的分析,建立岁差周期内豫西LGM阶段以来千年-年际时间尺度上季风气候变化序列,重点研究典型季风突变事件(H1、LIA等)开始和结束的年代学以及内部结构变化的特征。综合现代过程洞穴监测和亚洲季风区长、短尺度石笋等地质记录的结果,明确氧同位素等信号传输的机理及气候意义,分析LGM以来亚洲季风气候系统变化的驱动机制,进一步验证中国季风区石笋氧同位素环流效应和中华文明起源、转型中的气候因素驱动的有效性。