高分辨率、精确定年、来自同一洞穴的MIS11阶段和全新世石笋记录对比研究

Based on the theory of astronomical climatology and paleoclimatic records, Marine isotope stage 11 (MIS11: ~360-425ka) has been considered to be a good candidate for the present and future climate change, and climate change trend and amplitude increasingly drawn the attention of scholars.Because of the similar orbitally driven insolation and comparable atmospheric greenhose gas concentrations during the MIS11 and Holocene, the process and characteristic of climae variations during MIS11 could help us understand current climate change and further predict the future climate change trend. Comparing to marine and ice core records, the terrestrial record has higher resolution, but they also deposit discontinuous, chronology constraint difficult and easily disturbed by regional environment. It is difficult for MIS11 and neighboring stages research because of these characteristics. Fortunately, the Chinese cave stalagmites continually, and it completely record the East Asian monsoon variation during the past 600ka.So,this study has the following objectives:The oxygen isotope records of stalagmites from Jinfo Cave of Nanchuan dated with MC-ICP-MS dating methods provides variations of the Asian monsoon with a high resolution of 1~20 years during 340-440ka BP in Yangtze Gorges Reservoir, which fills the blank of stalagmite records of this time in the upper and middle reaches of the Yangtze River region during MIS11. We try to predict the future trend of climate change by comparing stalagmite records from the Jinfo cave between MIS11 and the Holocene. We will accurately determine the timing and termination V and MIS11 duration to discuss climate change during the beginning stages, the peak period and ending of MIS11.In this study, we will anatomize the internal details of the structure and the oscillation mode of a typical monsoon abrupt events, and explore Millennium-century-scale oscillation laws and driving mechanism of monsoon climate during MIS11. Meanwhile, we will discuss also variation characteristics of the glacial-interglacial transitions period in the Asian monsoon region and accurately measure the duration of transition of periods glacial-interglacial.Thus, based on the research of modern carbonate-water oxygen isotope system and the instrumental observation data, this study probes into the stalagmite oxygen isotopic composition and its implications and discusses the relationship between monsoon precipitation, Historical documents and meteorological data, which would help us improve understanding the variations of the Asian monsoon and the future climate. By the comparing simultaneous high resolution time series which were published worldwide and systematic analyzing the global and regional climate signals contained in the series, we will construct the monsoon climate’s variation in eastern China during MIS11 and predict the future trend of climate change.

利用来自重庆市金佛洞的石笋，在亚洲季风气候影响显著的三峡库区建立340-440ka BP时段精确定年、高分辨率的石笋记录，对比来自同一洞穴内的MIS11时段和全新世石笋记录，预测未来气候变化趋势，为建立中国石笋记录解析的亚洲季风演变全球对比基准提供基础数据：利用MC-ICP-MS测年方法测试较老石笋年龄技术建立340-440ka BP时段独立的年代标尺，精确测定终止点V时间和MIS11持续时间，探讨MIS11阶段的开始阶段、高峰期和结束时期的气候变化特征；深入剖析MIS11阶段内部细节结构、振荡模式、千年尺度气候事件；与其他地质记录进行对比，并借助小波分析方法，深入探讨长江中上游地区MIS11阶段气候演化规律和驱动机制；对比分析MIS11阶段和全新世石笋记录，探讨MIS11阶段与全新世气候变化关系，为预测全新世气候发展趋势提供参考数据。

海洋同位素阶段（MIS）11作为全新世的一个类似物的效用及其自然演化仍有争议，称之为“mis11悖论”。在这里我们发现，在过去的冰期时期，千年尺度的振荡高度依赖于背景气候和日晒状态。因此，我们探讨了千年气候变化在回答“MIS 11悖论”中的作用，并推断了在没有人为干扰的情况下，未来冰期形成的时间。我们的结论补充了冰期-间冰期旋回的天文强迫理论。MIS11长期以来被用来确定现今全新世间冰期的自然长度，因为它们在天文学驱动的日射变化方面具有相似性。然而，根据不同的对齐策略，MIS11的哪一部分应该与全新世对齐，这一点还存在争议。在这里，我们使用覆盖整个MIS11的年代久远、高分辨率的亚洲夏季风（ASM）记录来试图解决这个问题。我们发现，日晒的倾角周期对千年尺度ASM变化的频率和幅度起主导控制作用。在此基础上，终端I和V可以对齐。我们认为，假设的下一次冰期的时间可以通过MIS11期间第一次两极跷跷板事件的发生来预测。如果没有人为的影响，当前的间冰期应该在现在之后结束一个进动周期的一半。