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通过对寻甸仙人洞X1石笋进行高精度的TIMS-U系测年和碳、氧同位素分析,建立了寻甸地区8000aB.P.以来高分辨率的古气候变化时间序列。研究结果表明,寻甸地区8000aB.P.以来石笋记录的古气候环境变化,大致可分为3个气候期:中全新世8000—5560aB.P.为气候适宜期,显示印度季风由强盛逐渐减弱的趋势,气候温暖湿润期,与太阳辐射增强引起的北半球季风环流加强有关;中全新世中晚期5560—4400aB.P.为季风转变期,显示印度季风减弱并快速退出、萎缩,东亚冬季风加强并快速推进,太阳辐射强度减弱,气候为干冷期;中全新世晚期4400—2000aB.P.,显示东亚冬季风逐渐减弱,东亚夏季风有所增加,气温有所回升,但气候变化的波动大。研究还表明,全新世以来石笋记录的气候变化非常不稳定,在千年尺度上表现为台阶状,在短尺度———百年尺度上呈锯齿状波动。石笋记录的突发性气候波动事件,与冰芯记录极为相似,反映低纬度地区石笋记录的季风气候与高纬度及北极地区的气候具有极好的相关性,这对于认识现代气候系统变化以及对未来十年、百年尺度的气候预测具有重要的科学意义。
By means of high-precision TIMS-U dating and carbon and oxygen isotopic analysis of X1 stalagmite in Xindian Cave of Xundian, a high-resolution palaeoclimate change time series since 8000aB.P. was established in Xundian area. The results show that the paleoclimate changes recorded by Stalagmite since 8000aB.P. In Xundian can be divided into three periods: Mid-Holocene (8000-5560aB.P.), which shows that the Indian monsoon weakens gradually from strong The trend of warm and humid climate is related to the enhanced monsoon circulation in the northern hemisphere caused by enhanced solar radiation. The mid-late Mid-Holocene 5560-4400aB.P. is the monsoon transition period, which shows that the Indian monsoon weakens and exits rapidly, shrinks and the winter monsoon in East Asia strengthens And accelerated rapidly. The intensity of solar radiation weakened and the climate was dry-cold. In the late Mid-Holocene 4400-2000 aB.P., the easterly monsoon in East Asia was gradually weakened, the easterly monsoon in East Asia slightly increased, and the temperature rose somewhat, but the climate change fluctuated greatly . The study also shows that the climatic changes recorded by stalagmites since the Holocene have been very unstable and appear to be stepped on the millennium scale, with jagged fluctuations on the short scale --- a hundred-year scale. Sudden climatic fluctuations recorded by stalagmites are very similar to ice core records, reflecting the excellent correlation between the monsoon climate recorded in stalagmite and the climate in high latitudes and the Arctic. This is very important for understanding the changes of the modern climate system and the future Ten years and one hundred years of climate prediction have important scientific significance.