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[摘要]
西藏纳木错西岸班戈县新吉乡的早白垩世地层发育, 珊瑚化石丰富, 经过鉴定、描述、研究, 计有白垩纪石珊瑚10属10种(其中有3新种), 它们是Axosmilia sp., Cyathophora? sp., Eohydnophora baingoinensis sp. nov., Epistrepto-phyllum cf. diatritum Wu, Hydnophora styriaca (Michelin), Ironella giseldonensis Starostina and Krasnov in Krasnov and Starostina, Placophyllia baingoinensis sp. nov., Protethmos cf. discus Liao and Xia, Protochocyathus ? sp., Stylina namcoensis sp. nov.。上述石珊瑚属在欧亚大陆的侏罗、白垩纪地层中都有广泛分布。其中, Cyathophora ? sp. 与申扎县果芒错下白垩统所产出的Cyathophora gomangcoensis Liao and Xia比较相似, 只是个体直径要稍微小一些; Hydnophora styriaca与欧洲上白垩统的模式种也有某些相似之处, 只是我们的标本每个脊塍上有较多的隔片; 新种Eohydnophora baingoinensis与日本早白垩世的Eohydnophora tosaensis Yabe and Eguchi的主要区别只是其脊塍和隔片都比较细薄; Protochocyathus? sp.的外壁比匈牙利下白垩统的Protochocyathus valanginicus Kolosvary的外壁薄。总之, 西藏班戈县新吉乡的早白垩世石珊瑚群与西藏申扎、日本、俄罗斯、匈牙利和斯洛文尼亚等地同期的石珊瑚有许多相似之处, 完全可以进行对比。本文的研究成果将对我国西藏地区地层层序的建立和详细对比以及对早白垩世石珊瑚群的动物地理亲缘关系的了解提供重要依据。
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[Abstract]
The Early Cretaceous scleractinian corals described in the present paper were collected by the Geological Survey of Jilin Province from the Duomi and Langshan formations of Xenkyer, Baingoin, Xizang (Tibet). These fossil corals occur in asso-ciation with some typical Early Cretaceous Orbitolina. The scleractinian corals described and illustrated comprise 10 species within 10 genera including 3 new species. They include: Cyathophora ? sp., Stylina namcoensis sp. nov., Epistreptophyllum cf. diatritum Wu, 1975, Protethmos cf. discus Liao and Xia, 1985, Axosmilia sp., Placophyllia baingoingensis sp. nov., Hydnophora styriaca (Michelin), 1847, Eohydnophora baingoinensis sp. nov. Prototrochocyathus ? sp., Ironella giseldonensis Starostina and Krasnov, 1970. Although the material described herein are not much, a few genera and species afford evidence for constraining the age of the fossil–bearing deposits. Even the geological range of the greater part of the genera is from the Jurassic to Cretaceous, however, the genera Eohydnophora and Prototrochocyathus are the characteristic Cretaceous corals. The genus Eohyd-nophora has hitherto been known from the Cretaceous of Japan and China. The range of Hydnophora lasted from Creta-ceous up to now but the holotype of Hydnophora styriaca (Michelin) was from the Upper Cretaceous of Austria. Taken to-gether, the fossil asemblage indicates an Early Cretaceous age, obviously bearing a much closer relationship with those of Japan, the Himalayas, the Caucasus, the Carpathians, the Alps, Austria, Germany and France. Since very few scleractinian corals have been reported from the Early Cretaceous of Tibet, these fossils are important for the stratigraphical correlation of the Cretaceous in Tibet.
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