自然资源部岩岩溶动力学重点实验室

贵州荔波 1200 年来石笋高分辨率的古气候环境记录

2009-12-10KDL 2517

A High Resolution Paleoclimate Record of the Last 1,200 Years in Stalagmite L2 from the Longquan Cave, Guizhou Province

Abstract: The time sequence of high resolution paleoclimatic change since 1200 a BP was reconstructed by age dating of the high precision ICP-MS-230Th-U series and an analysis of stable isotopes for a stalagmite of Longquan Cave in Libo, Guizhou. The results show that the monsoon climate from stalagmite L2 record since 1200 a BP has experienced eight stages, i.e., the warm stage of 1200~1100 a BP, the cold stage of 1100~940 a BP, the warm stage of 940~840 a BP, the cold stage of 840~700 a BP, the warm stage of 700~450 a BP, the cold stage of 450~300 a BP, the warm stage of 300~200 a BP and the cold stage of 200~70 a BP on the century time scale of dry-humid and cold-warm changes. In addition, a series of decade time scales of climate changes were superimposed on the century time scale of monsoon climate undulation. The records from stalagmite L2 reveal the instability of the climate of the East Asian monsoon and the periodical change since 1200 a BP. Being very similar to ice core records, the climate changes suggest that the century time scale of the monsoon climate changes from stalagmite records in the low latitude region has a wonderful correlation with the climate change in the high latitude region and the Arctic pole, and that the monsoon rainfall of the century time scale stalagmite record is mainly driven and controlled by the solar action and radiation. Moreover, the rainfall or drought events of the East Asian monsoon are closely related to the solar radiation intensity. The understanding of the changes of modern climate systems is of important scientific significance in forecasting the driving mechanism of climatic evolution in future.

Key words: stalagmite; age dating of ICP-MS; high resolution; paleoclimate environment; Longquan Cave in Libo; Guizhou Province
[ ] 通过笔者对荔波龙泉洞L2 石笋进行高精度的ICP-MS-230Th 测年和碳、氧同位素分析,建立了荔波地区1200 a BP来高分辨率的古气候变化的时间序列。研究结果表明,荔波地区1200 a BP 以来石笋记录的季风气候经历了1200~1100 a BP()1100~940 a BP ()940~840 a BP()840~700 a BP()700~450 aBP()450~300 a BP()300~200 a BP()以及200~70 a BP()8个阶段百年尺度的干湿、冷暖波动,并在这些百年尺度的波动上又叠加了一系列数十年尺度的气候变化。石笋记录揭示了1200 a 以来东亚季风气候的不稳定性,呈百年尺度(Gleissberg)的周期性变化。这些气候变化事件,与冰芯记录极为相似,反映低纬度地区百年尺度石笋记录的季风气候变化与高纬度及北极地区的气候变化具有极好的相关性,反映百年尺度石笋记录的季风降水主要受太阳辐射驱动、控制,而东亚季风的降水事件(或干旱事件)与太阳的辐射强度密切相关。石笋记录的百年尺度季风降水事件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和演化的驱动机制,具有重要的科学意义。

[关键词] 石笋;ICP-MS-230Th 年龄;高分辨率;古气候环境;荔波龙泉洞;贵州
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