| 中国南方新元古代可能后生动物成因的硅化和磷酸盐化球状微化石Tianzhushania |
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| 关键词:Tianzhushania Megasphaera spherical microfossil metazoan Doushantuo Formation Weng'an |
| 基金项目:国家自然科学基金项目(编号:49872002,40272015)
;科技部项目(编号:G2000077701)
;地质调查局项目(编号:200213000042) |
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| 摘要: |
| Silicified and Phosphatized Tianzhushania, Spheroidal Microfossils of Possible Animal Origin from the Neoproterozoic Doushantuo Phosphorites of Guizhou, South China |
| Comparative study of microfossils from two kindsof sediments: chert intercalations (studied in thin section) and phospho-rite/phosphatic carbonate (in thin section and maceration), from the upper Neoproterozoic Doushantuo phosphorites in the Weng'an area, Guizhou Province, South China, shows that the phosphatized Megasphaera ornata Xiao and Knoll, 2000, and the chert-preserved Tianzhushania tuberifera Yin, Gao and Xing, 2001, should be regarded as representing the same taxon preserved by different mineralization processes. In phosphatized specimens the outer wall is often peeled off, exposing the ornamented middle wall. Some phosphatized specimens isolated from the rock matrix and specimens seen in thin sections of phosphorites show a partly preserved outer wall with spines, which can be compared to the thin-sectioned specimens from the chert beds. The small pits usually seen on the surface of the ornamented middle wall of phosphatized specimens correspond to the attachment spots of the spines in the outer wall. The presence of a spiny outer wall is a characteristic of Tianzhushania Yin and Li, 1978. Tianzhushania ornata (Xiao and Knoll, 2000) comb. nov. is here proposed as the valid name for the species. The proposed resting-egg nature of T. ornata, mainly based on the ornament type of the middle wall, cannot be excluded. The presence of a spiny outer wall, however, suggests that it is a pelagic rather than a benthic form. |
| YIN Chong-yu,STEFAN Bengtson,YUE Zhao.2005.Silicified and Phosphatized Tianzhushania, Spheroidal Microfossils of Possible Animal Origin from the Neoproterozoic Doushantuo Phosphorites of Guizhou, South China[J].Acta Geoscientica Sinica,26(1):31-43. |
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