Plant-wax hydrogen isotopic evidence for postglacial variations in delivery of precipitation in the monsoon domain of China
Plant-wax hydrogen isotopic evidence for postglacial variations in delivery of precipitation in the monsoon domain of China
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DOI：
10.1130/g32117.1
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发表时间：
2011-09
期刊：
影响因子：
5.8
通讯作者：
O. Seki;P. Meyers;Shinya Yamamoto;K. Kawamura;T. Nakatsuka;Weijian Zhou;Yanhong Zheng
中科院分区：
文献类型：
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作者：
O. Seki;P. Meyers;Shinya Yamamoto;K. Kawamura;T. Nakatsuka;Weijian Zhou;Yanhong Zheng
亚洲季风是地球气候系统的重要组成部分，直接影响到世界60%人口的生计。全新世季风降水变化的可靠重建是更好地了解当前气候条件和预测未来亚洲季风区气候过程的必要条件。利用各种古气候指标重建了该区不同地区全新世季风降水的变化。然而，不同的代用物产生了不同的古气候记录的长期季风降雨变率。正构烷烃的D/H比值解决了不同古气候指标之间的明显差异。结果表明，湖位波动是夏季季风降水变化的可靠记录，而长期同位素记录主要反映了水汽来源的大尺度变化，而不是局地降水信号。综合湖泊水位、生物标志物和碳酸盐同位素记录，我们认为中国西南地区早全新世季风降水受到印度季风的极大影响。
The Asian monsoon is a key component of the Earth's climate system that directly affects the livelihood of 60% of the world population. Reliable reconstruction of changes in monsoon precipitation during the Holocene is required to better understand the present climate conditions and to predict future climate processes in the Asian monsoon domain. Reconstruction of changes in Holocene monsoon precipitation has been done in various regions of this domain using a variety of paleoclimate proxies. However, different proxies have yielded different paleoclimate records of long-term monsoon rainfall variability. We apply compound-specific stable hydrogen isotope compositions of the plant wax n -alkanes isolated from the Hongyuan peat sequence in eastern Tibet to reevaluate the regional carbonate oxygen isotopic and lake-level records. The D/H ratios of the n -alkanes resolve the apparent discrepancy among the different paleoclimate proxies. Our result indicates that lake-level fluctuation is a reliable recorder of changes in the amount of summer monsoonal precipitation while long-term isotope records largely reflect large-scale changes in the source of water vapor rather than a local precipitation signal. Combining lake-level, biomarker, and carbonate isotopic records, we conclude that the early Holocene monsoon precipitation in southwest China has been greatly influenced by the Indian monsoon.