| 江汉盆地始新世中、晚期气候变化周期性的孢粉学证据 |
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| 关键词:time sequence of the sporo-pollen record cycling climatic oscillation Jianghan Basin Eocene |
| 基金项目:国家重点基金项目“中国晚新生代盐湖带变化及对全球变化的响应”项目(批准号:4983010) |
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| 摘要: |
| Palynological Evidence of Middle-Late Eocene Climatic Cycles in Jianghan Basin |
| The time sequence of sporo-pollen record from Core Mingjia 1, Jianghan Basin, was analysed to exhibit its climatic significance. Evidence shows that some cycling elements occurred in the Middle-Late Eocene palynoflora, with 1.2 Ma,2.0 Ma and 5.0 Ma as the long-term cycles, and 0.2 Ma, 0.4 Ma, 0.6 Ma and 0.8 Ma as the intermediate-term cycles. Among them, the cycling elements with terms of 1.2 Ma and 0.2 Ma, 0.4 Ma, 0.6 Ma are also recognized in the evolution of the Quaternary pollen floras. They coincide with the 0.4 Ma and 1.2 Ma tectonic-climatic sub-cycle since 8.0 Ma B.P., implying that the astronomical influence on climate could date back to Eocene. The index pollen elements in the time sequences of the core indicate at least four development levels, reflecting four evolutional stages in the palynoflora. A distinct change in the palynoflora is recognized around 36 Ma BP, exhibiting a major environmental transition. It is mostly consistent with the first stage of the Himalayan Movement as well as a major oceanographic and climatic cooling event in the Southern Hemisphere. |
| TONG Guo-bang,JIA Xiu-mei,ZHENG Mian-ping,YUAN He-ran,LIU Jun-ying,WANG Wei-ming.2002.Palynological Evidence of Middle-Late Eocene Climatic Cycles in Jianghan Basin[J].Acta Geoscientica Sinica,23(2):159-164. |
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