δ13C Values of loess total carbonate: A sensitive proxy for Asian summer monsoon in arid northwestern margin of the Chinese loess plateau
δ13C Values of loess total carbonate: A sensitive proxy for Asian summer monsoon in arid northwestern margin of the Chinese loess plateau
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δ13C 黄土总碳酸盐值：中国黄土高原干旱西北缘亚洲夏季风的敏感代理
DOI：
10.1016/j.chemgeo.2011.03.011
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发表时间：
2011-05-24
期刊：
影响因子：
3.9
通讯作者：
Wang, Xulong
中科院分区：
文献类型：
--
作者：
Liu, Weiguo;Yang, Hong;Wang, Xulong
为了验证黄土总碳酸盐三角洲(13)CIC值作为潜在古环境指标的有效性和敏感性，测定了中国黄土高原干旱西北部靖远黄土剖面中黄土总碳酸盐(13)CIC的碳同位素比值。黄土剖面的813Cic记录显示出很大的变化，变化范围从-1%。到-7%，在过去的70ka。最负的增量(13)CIC峰与古土壤的形成相吻合；S-0、L1SS2和L1SS2，出现在全新世中期和海相三角洲O-18阶段相对湿润的气候条件下。另一方面，最小负的三角洲(13)CIC值响应了相对干燥的LGM和海相三角洲O-18阶段4的黄土堆积。干旱区黄土剖面的三角洲(13)CIC变化与散体沉积物总有机碳同位素(Delta(13)Coc)的变化具有明显的相关性，后者被广泛用作过去季风降水强度的替代指标。黄土剖面的三角洲(13)CIC值对受亚洲季风变化控制的干旱区古生境的变化更为敏感。认为黄土剖面总碳酸盐碳同位素组成可以作为中国西北干旱黄土高原亚洲夏季风的灵敏可靠的替代指标。(C)2011爱思唯尔B.V.保留所有权利。
We measured carbon isotope ratio of loess total carbonates (delta(13)Cic) from the Jingyuan loess profile in the arid northwestern portion of the Chinese Loess Plateau (CLP), in order to examine the effectiveness and sensitivity of loess total carbonate delta(13)Cic values as a potential paleoenvironmental indicator. The 813Cic record in the loess profile shows large variations ranging from -1%. to -7%., during the past 70 ka. The most negative delta(13)Cic peaks coincide with paleosol formation; S-0, L1SS2, and L1SS2, which occurred under relatively wetter climatic conditions during middle Holocene and marine delta O-18 stages 3. On the other hand, the least negative delta(13)Cic values responded to loess accumulation during relative drier phases of LGM and marine delta O-18 stages 4. While delta(13)Cic variations in the loess profile in arid area demonstrate a clear correlation with changes of total organic carbon isotope (delta(13)Coc) of bulk sediments which has been widely used as a proxy for the past monsoon precipitation intensity, the delta(13)Cic values in the loess profile are more sensitive to the changes of paleohabitat controlled by the Asian monsoon variation in the arid area. We propose that carbon isotope compositions of total carbonates in loess profile can serve as a sensitive and reliable proxy for the Asian summer monsoon in the arid northwestern Chinese Loess Plateau. (C) 2011 Elsevier B.V. All rights reserved.