西藏札达盆地上新世托林组剖面环境变化记录

Records of Environmental Change in Pliocene along Tuolin Formation in Zanda Basin,Tibet

对西藏札达盆地上新世托林组的孢粉、沉积物粒度、磁化率、碳酸盐、易溶盐和ESR年代等测试数据的综合分析,得到5·40～4·40Ma时期环境变化的丰富信息。5·24～4·72Ma时期,气候温凉干旱,属于针阔叶疏林草原环境特征;4·72～4·67Ma时期,河流水量增多,气候湿润,孢粉组合表现出温带森林草原环境特征;4·67～4·40Ma时期,气候进一步向温暖湿润方向发展,属于暖温带针阔叶混交林环境特征。

Based on an analysis of such measured data of environmental proxies as sporopollen, grain size, magnetic sus- ceptibility, carbonate content, soluble salts and ESR dating, It is held that Tuolin section contains abundant information of environmental changes from 5.40 Ma to 4.40 Ma. During 5.24 - 4.72 Ma, the climate was warm and dry, and the forest vegetation consisted of needle leaf and broadleaf veld; during 4.72 - 4.67 Ma, the river flow increased, the climate was warm and wet, and the vegetation comprised temperate forest and veld; during 4-. 67-4.40 Ma, the climate became more and more warm and wet, and the vegetation was composed of warm temperate deciduous and broadleaf veld.