Typical Geochemical Elements in Loess Deposit in the Northeastern Tibetan Plateau and Its Paleoclimatic Implication |
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作者姓名: | TAN Hongbing MA Haizhou ZHANG Xiying LU Huayu WANG Jianguo |
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作者单位: | [1]Institute of Salt Lakes, Chinese Academy of Sciences, Xining, Qinghai 810008 [2]Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, Shaanxi 710075 |
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摘 要: | Widespread and thick loess deposit in the northeastern Tibetan Plateau records paleoclimatic changes over the Quaternary period. In this study, we investigate a loess section located in a high terrace of the Huangshui River in the Xining Basin, and collect samples at 20-cm intervals by digging a well of 16-m depth (including paleosol S1 and SO and several loess interlayers over the last glacial-interglacial cycle and the Holocene). Concentration of some active elements (Sr and Ca) and inert elements (Rb, Zr, Ti) in these loess samples are measured. The results show that ratios of those elements (oxide), such as Rb/Sr, Ti/Sr, and Zr/CaO ratios, would indicate sensitively paleoclimatic changes, especially the history of precipitation over the last glacial-interglacial and the Holocene. Moreover, the curves of Rb/Sr, Ti/Sr, and Zr/CaO ratios had almost the same variable trends from the bottom to the top and also closely correlated with values of magnetic susceptibility and the global marine δ^18O record. But compared with the curves of magnetic susceptibility, the changes of ratios of these elements (oxide) are clearer and easy to understand. Therefore, the ratios of these typical chemical elements in the loess deposit may be used as an excellent index to investigate the history of paleoclimate, particularly precipitation changes in the northeastern Tibetan Plateau.
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关 键 词: | 古气候 地球化学 黄土 青藏高原 |
收稿时间: | 2004-06-11 |
修稿时间: | 9/7/2005 12:00:00 AM |
Typical Geochemical Elements in Loess Deposit in the Northeastern Tibetan Plateau and Its Paleoclimatic Implication |
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Authors: | TAN;Hongbing;MA;Haizhou;ZHANG;Xiying;LU;Huayu;WANG;Jianguo |
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Abstract: | Abstract Widespread and thick loess deposit in the northeastern Tibetan Plateau records paleoclimatic changes over the Quaternary period. In this study, we investigate a loess section located in a high terrace of the Huangshui River in the Xining Basin, and collect samples at 20‐cm intervals by digging a well of 16‐m depth (including paleosol S1 and S0 and several loess interlayers over the last glacial‐interglacial cycle and the Holocene). Concentration of some active elements (Sr and Ca) and inert elements (Rb, Zr, Ti) in these loess samples are measured. The results show that ratios of those elements (oxide), such as Rb/Sr, Ti/Sr, and Zr/CaO ratios, would indicate sensitively paleoclimatic changes, especially the history of precipitation over the last glacial‐interglacial and the Holocene. Moreover, the curves of Rb/Sr, Ti/Sr, and Zr/CaO ratios had almost the same variable trends from the bottom to the top and also closely correlated with values of magnetic susceptibility and the global marine δ18O record. But compared with the curves of magnetic susceptibility, the changes of ratios of these elements (oxide) are clearer and easy to understand. Therefore, the ratios of these typical chemical elements in the loess deposit may be used as an excellent index to investigate the history of paleoclimate, particularly precipitation changes in the northeastern Tibetan Plateau. |
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Keywords: | northeastern Tibetan Plateau loess aleosol geochemical elements paleoclimate |
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