新疆北部二叠系特征及其与三叠系界线划分

目的对新疆准噶尔盆地南缘、吐哈盆地和三塘湖盆地的二叠系及其与三叠系界线的划分提供新的依据。方法在该区长期工作的基础上,参考前人地层划分成果及当地使用习惯,利用岩石地层、生物地层、火山岩同位素年龄、古地磁等方法进行综合分析,对三地区的二叠系进行了综合划分与对比。结果将新疆北部二叠系分别称下、中、上统,与中国南方及国际标准的3个统对应;中二叠统对应于瓜德鲁普统,地质时代为早二叠世(290~265 Ma),中、上二叠统界线在中二叠统塔尔郎组上部,上二叠统与三叠系界线在上二叠统锅底坑组内;中二叠统分布于准噶尔盆地中南部、吐哈盆地北部和三塘湖盆地南部。结论建议将大龙口、锅底坑、塔尔郎沟、照壁山剖面和跃进沟剖面分别作为北疆地区二叠系—三叠系标准剖面。

Characterristics of Permian and the boundary between Permian and Triassic system in the northern Xinjiang

Aim To provide new evidence for the stragraphie division and contrast of Permain-Triassie systems and rectify the boundary between the Permain and Trassic in southern margin of Juggur Basin,Turpan-Hami Basin and Santanghu Basin. Methods On the basis of the long-term work, synthetic analysis has been made by using methods of lithostratigraphy, biostratigraphy as well as of dating of volcanic isotope, and reference to the stratigraphic division of forefathers in these area. There is new stratigraphic division of Permain-Trassic in the area. Results The Permian of northern Xinjiang can be defined as the lower, Middle and Upper Permian, they correspond separately to the three series of the sourthern China and the international subdivision of Permain. Especially, the Middle Permian corresponds to the Guadalupian serie, that coincides with the age of Early Permian in the range of 290 - 265 Ma. The boundary between Middle and Upper Permian series should be at the top of the Taerlang Group. The boundary of Upper Permian and Triassic should be within Guodikeng Group. The Middle Permian was distributed in middlesourthem Juggur Basin, northern Turpan-Hami Basin and sourthem Santanghu Basin. Conclusion The sections including Dalongkou, Guodikeng, Taerlanggou, Zhaobishan and Yuejingou were suggested as the typical sections of Permain-Trassic in these basins respectively.