江汉盆地始新世中、晚期孢粉组合特征及其环境意义 |
修订日期:2000-10-18 |
关键词:palynological assembla palynoflora climate event Jianghan Basin Eocenege |
基金项目:国家自然科学基金重点项目“中国晚新生代盐湖带演化对全球变化的响应”(批准号4983010) |
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摘要: |
A Study of Middle and Late Eocene Palynological Assemblages in Jianghan Basin and Their Environmental Significance |
On the basis of pollen analyses of samples from the Mingjia No. 1 borehole, the Middle and Late Eocene pollen assemblage sequences in Jianghan basin were studied. Six zones and fourteen subzones were distinguished. It is thought that the evolution of vegetation can be divided into four periods, during which conifer and broad-leaf mixed forest changed gradually into broad-leaf forest. Six climate periods can be recognized. At the beginning, there was a kind of arid or semiarid climate of mid-subtropics, which then gradually converted into most or sub-moist climate of North subtropics. In the course of transformation, totally five times of climate abrupt change, i.e., palynoflora climate events, appeared. The first three events belonged to quick and intense oscillation events from drought to most and from warm to hot, whereas the last two belonged to the climate transformation evnets, in which the warm and wet or hot and dry climate became hot and wet or warm and dry. In the saltstone? glauberite mudstone? purple mudstone? marl mudstone? siltstone rock sequence, the palynological assemblages changed in accordance with some regularities. These changes indicate that the fluctuation of clamate could govern the changes of vegetation and sediment environment. |
TONG Guo-bang,ZHENG Mian-ping,YUAN He-ran,LIU Jun-ying,LI Yue-cong,WANG Wei-ming.2001.A Study of Middle and Late Eocene Palynological Assemblages in Jianghan Basin and Their Environmental Significance[J].Acta Geoscientica Sinica,22(1):73-78. |
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