| 江汉盆地始新世中、晚期古气候定量重建初探 |
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| 引用本文： | 童国榜,刘志明,郑绵平,袁鹤然,刘俊英,王伟铭,李月丛.江汉盆地始新世中、晚期古气候定量重建初探[J].地球科学,2002,27(4):446-452. |
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| 作者姓名： | 童国榜 刘志明 郑绵平 袁鹤然 刘俊英 王伟铭 李月丛 |
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| 作者单位： | 1.中国地质科学院水文地质环境地质研究所, 河北正定 050803 |
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| 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”(No .4983 0 10 ) |
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| 摘 要： | 依据江汉盆地明钾1孔中、晚始新统系统的孢粉资料, 应用化石孢子花粉亲缘植物的生态位估算孢粉组合所反映的古气候特征.气候参数曲线的变化趋势显示江汉盆地始新世中期气候参数与现今北纬2 2°~ 2 6°的数值相接近, 为中-南亚热带湿润半湿润气候.晚期气温较前期低1~ 4℃, 相当于现今北纬2 3°~ 2 8°处的数值, 为北-中亚热带气候.但是, 气候构型与现今截然不同, 具有气温高、年较差小、降水波动大的特点.始新世中期1月均温比今高5~ 9℃, 表明冬季风作用尚不明显, 晚期略显冬季风的影响.气候的降温发生在孔深2 10 0m处, 主要表现为1月均温的下降和年较差增长, 因而孢粉组合中落叶阔叶树种增多.年降水量波动强烈, 一般于30 0~ 170 0mm之间, 这有利于盐类矿物的迁移和堆积.降水量低于10 0 0mm时, 麻黄灌木花粉增多, 且与膏盐堆积深度相一致.高山深盆的干热环境是本区盐类矿物沉积的主要原因, 年降水量波动强烈且偏低, 有利于盐类的持续堆积, 从而有别于现今西北地区的盐类堆积.
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| 关 键 词： | 古气候定量重建 年较差 生态位函数 模糊数学 始新世 江汉盆地 |
| 文章编号： | 1000-2383(2002)04-0446-07 |
| 收稿时间： | 2002-03-27 |
Primary Study on Quantitative Reconstruction of Middle-Late Eocene Climate in Jianghan Basin |
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| TONG Guo-bang ,LIU Zhi-ming ,ZHENG Mian ping ,YUAN He ran ,LIU Jun ying ,WANG Wei ming ,LI Yue cong.Primary Study on Quantitative Reconstruction of Middle-Late Eocene Climate in Jianghan Basin[J].Earth Science-Journal of China University of Geosciences,2002,27(4):446-452. |
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| Authors: | TONG Guo-bang LIU Zhi-ming ZHENG Mian ping YUAN He ran LIU Jun ying WANG Wei ming LI Yue cong |
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| Institution: | TONG Guo-bang 1,2,LIU Zhi-ming 1,ZHENG Mian ping 3,4,YUAN He ran 3,LIU Jun ying 3,WANG Wei ming 5,LI Yue cong 6 |
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| Abstract: | This paper reports our primary effort in quantitatively reconstructing paleoclimate based on the niche of the affinity parent plants in the stratigraphic pollen record. Eocene pollen data come from our former study on the core Mingjia 1 in the Jianghan basin. The changing trend in the parameter curve of climate shows that the middle Eocene climate in the Jianghan basin is more or less comparable with that of the present 22°-26°N, reflecting a humid, semi humid central southern subtropical climate. The annual temperature then declined 1-4 ℃ lower at the late Eocene, approximately equal to the present 23°-28°N of northern central subtropical climate. However, the climate composite at that time was different from the present one, and was characterized by higher temperature, small annual range, and big fluctuation in precipitation. The January average temperature in the middle Eocene was 5-9 ℃ higher than that of today, indicating that there was no winter monsoon influence in the middle Eocene, though it may have partly happened in late Eocene. Major temperature decline is recognized at depth 2 100 m of the core, as was indicated by the decline in January average temperature and an increase in annual range. It is also indicated by the increase of the deciduous broad leaved types in the pollen assemblage. The sharp fluctuation in the annual precipitation, raging from 300 to 1 700 mm, was favorable for the migration and accumulation of salty deposits. When the precipitation was lower than 1 000 mm, ephedra shrub increased, which happened in the same depth with the salty deposit. It is deduced that the dry and hot environment in the high mountain and deep basin could have been the main reason for the formation of the salty deposit in the core. The annual precipitation was not very lower at that time, and this is different from the present salty deposit in Northwest China. |
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| Keywords: | Quantitative reconstruction of paleoclimate annual range niche function fuzzy mathematics Eocene Jianghan basin |
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