| 西藏拉萨地块设兴组孢粉化石新发现及其地层学意义 |
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| 关键词:Lasa Terrance Shexing Formation Dianzhong-Nama Section Sporopollen |
| 基金项目:地质调查局地质大调查项目(DKD9901001)，国家自然科学基金项目(49972014) |
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| New Palynological Materials from the Shexing Formation in the Lhasa Block, Tibet, and Their Stratigraphic Significance |
| New materials of sporopollen were discovered in the upper part of the Shexing Formation along the Dianzhong Nama section of the Lhasa block. The sporopollen assemblage has the following characteristics:Most of the sporopollens found are common elements of Tertiary, so the related strata cannot be Cretaceous sediments; Deciduous and latifoliate vegetation, including Alnipollenites, Betulaepollenites, Carpiniptes, Quercoidites, Juglanspollenites, Ulmipollenites, and Tiliaepollenites, constitute dominant species in this assemblage; Tropic sporopollen and semi tropical vegetation occur in a relatively small amount. Herbage sporopollens, such as Chenopodiaceae, Compositae, Gramineae, and Polygonaceae, are rarely seen. All this indicates that the climate was not drought when they deposited. Triporopollenites and Tricolporopllenites which are very widely spread in Palaeogene also occur in small amounts; The whole conditions of sporopollen imply warm cool and moist climate of temperate zone at that time, suggesting wide distribution of deciduous and latifoliate forests. The Sporollen assemblage is close to that of the middle and late Palaeogene, probably belonging to Eocene Oligocene. The condition of the sporollen assemblage in the upper part of the Shexing Formation is similar to that of the middle Member of Niubao Formation in Lunpola Basin, indicating that the age of the sporopollen assemblage was nearly contemporaneous with the middle Member of Niubao Formation or a little later. The Shexing Formation includes not only the upper part of the Upper Cretaceous but also the lower part of the Lower Tertiary. |
| JI Zhan-sheng,YANG Xin-de,ZANG Wen-shuan,YAO Jian-xin,WU Zhong-hai,WU Gui-chun.2002.New Palynological Materials from the Shexing Formation in the Lhasa Block, Tibet, and Their Stratigraphic Significance[J].Acta Geoscientica Sinica,23(4):323-328. |
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