Oxygen-isotope record of paleorainwater in authigenic carbonates of Chinese loess-paleosol sequences and its paleoclimatic significance
Oxygen-isotope record of paleorainwater in authigenic carbonates of Chinese loess-paleosol sequences and its paleoclimatic significance
复制标题
中国黄土-古土壤层序自生碳酸盐古雨水氧同位素记录及其古气候意义
DOI：
10.1016/j.palaeo.2006.10.003
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发表时间：
2007-03-16
影响因子：
3
通讯作者：
Chen, Yang
中科院分区：
文献类型：
--
作者：
Li, Gaojun;Sheng, Xuefen;Chen, Yang
通过对洛川黄土-古土壤中根结物和陆壳的氧同位素组成的测定，重建了古雨水的δ O-18（p）剖面。为了评价6180的古气候意义，研究了东亚季风区降水时空变化的控制因素。现代记录表明，现代雨水δ O-18（m）的空间变化与近地面温度（T）和降水量（P）密切相关。为了区分T和P对O-18（m）的影响，本文通过多元回归分析建立了O-18（m）、T与P的自然对数之间的线性关系：O-18（m）= 1.070 + 0.326xT-2.041xInP。计算得到的O-18值与自生碳酸盐重建的O-18值吻合较好，说明东亚季风区降水O-18值的时空变化具有相似的O-18-T-P关系，中国黄土-古土壤层序中的自生碳酸盐可以作为O-18（p）值的有效记录。评价了洛川地区近130 ka来磷的变化。重建的P与其他研究使用不同的方法是一致的。我们的研究结果表明，较高的降水在海洋同位素阶段1，3和5，反映强烈的夏季风的影响，在这些时间段。(c)2006 Elsevier B. V.保留所有权利。
Oxygen isotopic compositions of rhizoeoncretions and land snail shells were measured to reconstruct the delta O-18 profiles of paleorainwater (delta O-18(p)) for well-dated loess-paleosols in Luochuan, China. To assess the paleoclimatic significance of 6180, factors that control the spatial and temporal 6180 variations of rainwater in East Asian monsoon regions were investigated. Modem records indicate that the spatial delta O-18 variations of modem rainwater (delta O-18(m)) are closely related to near surface temperature (T) and the amount of precipitation (P). In order to separate the effects of T and P on the delta O-18(m), a linear relationship between delta O-18(m), T and the natural logarithm of P is established by multiple regressing analyses:delta O-18(m) = 1.070 + 0.326 x T-2.041 x InPThe 6180 of palcorainwater over the past 130 Ka in Luochuan area is calculated by the modem-spatial delta O-18-T-P relationship using estimated T and P from other paleoclimate records. The calculated delta O-18 match well to those reconstructed from the authigenic carbonates, which implies that the spatial and temporal delta O-18 variations of rainwater in East Asian monsoon regions have similar delta O-18-T-P relationships and the authigenic carbonates in Chinese loess-paleosol sequences can serve as valid records of delta O-18(p), As an application of the delta O-18-T-P relationship, P variation in the past 130 ka in Luochuan was evaluated. The reconstructed P is in good agreement with other studies using different approaches. Our results suggest higher precipitation in Marine Isotope Stages 1, 3 and 5, reflecting intense summer monsoon influences during these periods of time. (c) 2006 Elsevier B.V. All rights reserved.