| ORGANIC GEOCHEMISTRY MARKERSOF CLIMATIC EVOLUTION IN LOESSREGION OF CHINA |
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| 摘 要： |
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| 收稿时间： | 16 December 1996 |
Organic geochemistry markers of climatic evolution in loess region of China |
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| Authors: | Rongfen Jia Zhao Lin Youmei Liu Qizhong Wen |
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| Institution: | (1) Guangzhou Institute of Geochemistry, the Chinese Academy of Sciences, 510640 Guangzhou, P. R. China |
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| Abstract: | Two hundred and thirty-five samples collected from Weinan loess section (L2 – S0) have been analyzed by TOC (total organic carbon) and pyrolysis hydrocarbons. The curve of TOC with depth has been set up
and compared well with other climatic markers. The main periods of TOC variation of the last 0.14 Ma are 67.08 ka and 18.29
ka, which is near with the periods of the variation of sunshine, showing that the TOC variation may be controlled by the variation
of 65°N sun-shine. The distribution of pyrolysis hydrocarbon and its parameters shows that there are two kinds of hydrocarbon
associated with climatic change. One is called hydrocarbon pyrolysted directly from organism (pHC2–1) which is in the range of T
max350°C – 500°C, and associated with atmospheric water. The other is called carbonate inclusion hydrocarbon (pHC2–2) which is in the range of T
max 500°C – 600°C and formed by evaporation and associated with dry climate. The formula calculating humidity has been deduced
Og=pHC2–1/(pHC2–1 + pHC2–2). The range of humidity of the section is 47% – 77% and the reducing order is S1–3, S1–2, S0, S1–1, S1–4, S1–1, L1–1, L1–3, and L1–5. And the trend of the humidity is still increasing today. |
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| Keywords: | Weinan loess section organic matter climatic evolution humidity |
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