西藏塔惹增地区中—上侏罗统仁多组的厘定及其地质意义

在西藏塔惹增地区前人划分的中二叠统下拉组中发现了具有典型意义的、代表中—晚侏罗世的Classopollis,Annulispora,Chasmatosporites等孢粉化石,以及较为丰富的Systematophora cf,Ctenidodinium等沟鞭藻类。表明在该区下拉组中至少有一部分以前没有被识别出的中—上侏罗统。通过岩石组合特征、基本层序、生物化石时代对比,将该套地层归属于仁多组。该地层的厘定,为区域地层对比、地层格架建立及探讨中生代盆地演化提供了基础资料。

The determination of Middle-Upper Jurassic Ringtor Formation in the Tarezeng area, Tibet, and its geological significance

Pollen fossils such as Classopollis, Annulispora, and Chasmatosporites as well as abundant dinoflagellates like Systematophora cf., and Ctenidodinium, which indicate Middle-Upper Jurassic strata with a typical significance, were found in the formerly-regarded Middle Permian Xiala Formation within the Tarezeng area, Tibet. The findings show that at least part of Middle-Upper Jurassic strata has not been identified previously in the Xiala Formation. The assemblage characteristics of the rock, basic sequence, and fossil comparison show that this set of strata belongs to the Ringtor Formation. The determination of this formation provides basic information for the correlation of regional strata, the establishment of the stratigraphic framework and the investigation of the evolution of the Mesozoic basin.