西藏改则多不杂地区中侏罗世介形类化石的发现及其地层归属探讨

Discovery of Middle Jurassic Ostracoda Fossils and Discussion on Stratigraphic Assignment in the Duobuza aera of Gaze County,Tibet

通过1∶5万区域地质矿产调查,在西藏改则多不杂地区前人划分的下侏罗统曲色组变质碎屑岩层位中,采集到中侏罗世(可能延续至晚侏罗世)的Amphicythere?sp.2,Darwinula lufengensis Ye,Metacypris menglaensis Ye介形类化石。结合该套地层的岩性组合特征与区域资料对比,把该套地层暂归属为拉贡塘组,这一地层的归属不仅对南羌塘侏罗系地层的划分对比、地层格架建立提供了重要的依据,而且还丰富了侏罗纪地层古生物数据,为今后进一步的地质研究工作提供了线索,具有重要的研究意义。

Based on a 1∶50000 regional geological and mineral survey,the metamorphic clastic rocks of the Quse Formation of the Lower Jurassic,which were divided by predecessors in Duobuza areas of Gaize,Tibet,were collected from the Amphithoere sp.2,Darwinula lufengensis Ye,Metacypris menglaensis Ye Ostracods of the Middle Jurassic(possibly extending to the Late Jurassic).Combining the lithologic assemblage characteristics of the stratum with the regional data,the stratum is temporarily assigned to Lagongtang Formation,which not only provides an important basis for the division and correlation of Jurassic strata and the establishment of stratigraphic framework in South Qiangtang,but also enriches the data of Jurassic strata and paleontology,and provides clues for further geological research in the future.It has important studying significance.