内蒙古西部北山地区甜水井-青山一带双堡塘组时代讨论

通过对神螺滩双堡塘组生物地层的研究、对比,神螺滩双堡塘组中所产菊石Uraloceras是北山地区双堡塘组的特征分子,广泛分布于俄罗斯、加拿大、澳大利亚和中国的上石炭统—下、中二叠统;腕足Neospirifer ravana,Schizodus subquadratus,S.cf.elongatas,Parallelodon olseni,Pseudomonotis mongoliensis,Streblochondria?sp.,Palaeolima sp.,Myalinella cf.falcata等均见于内蒙古中部的早、中二叠世哲斯组。神螺滩双堡塘组的化石中没有发现典型的晚二叠世的特征分子。这一化石组合面貌显示神螺滩双堡塘组的时代应为早二叠世晚期—中二叠世,而不是晚二叠世。

The age of the Shuangbaotang Formation in the Tianshuijing-Qingshan area, Beishan Mountains, western Inner Mongolia, China

Biostratigraphic study and correlation of the Shuangbaotang Formation in the Shenluotan section, Tianshuijing-Qingshan area, Beishan, western Inner Mongolia, indicate that the ammonite Uraloceras is a characteristic element of the Shuangbaotang Formation of the Beishan, which is widespread in the Upper Carboniferous-Lower and Middle Permian in Russia, Canada, Australia and China and that the brachiopods Neospirifer ravana,Schizodus subquadratus, S. cf. elongates, Parallelodon olseni, Pseudomonotis mongoliensis, Streblochondria? sp., Palaeolima sp. and Myalinella cf. falcate occur in the Early-Middle Permian Zhesi Formation. No typical Late Permian characteristic element is found in the Shuangbaotang Formation of Shenluotan. The aspect of this fossil assemblage shows that the age of the Shuangbaotang Formation in the Shenluotan area should be late Early Permian to Middle Permian rather than Late Permian.