西天山东段天格尔峰—艾维尔沟一带泥盆—二叠纪地层的厘定及地质意义

Redefinition of the Devonian-Permian in the Tengger Mountain-Ewirgol area,eastern segment of the West Tianshan Mountains,and its geological significance

天格尔峰—艾维尔沟一带处于东、西天山交界部位,长期以来,其地层单元划分、时代归属、分布范围和名称使用均不统一,给天山构造带的研究带来诸多的问题。通过东西6幅1∶5万区域地质调查,在北天山原奇尔古斯套组(天格尔组)分布区域发现了两条不整合面和大量化石资料。结合岩石组合特征、同位素年龄数据、变质-变形作用和沉积背景的差异,进一步将原奇尔古斯套组(天格尔组)解体为上泥盆统天格尔组(狭义)、上石炭统奇尔古斯套组(狭义)、上石炭统后峡组和下二叠统阿尔巴萨依组,并填绘出了各地层单元的分布范围,厘定了测区的构造格局。为东西天山地层单元的对比和构造区划提供了重要依据。

The Tengger Mountain-Ewirgol area is located in the boundary region of the East and West Tianshan Mountains. For a long time,no unified classification, age assignment, distribution range or nomenclature of stratigraphic units have brought many problems to the study of the Tianshan orogenic belt. Through 1：50000 regional geological surveys of six sheets of the East and West Tianshan Mountains, two unconformities and a wealth of fossils have been found in the area of the original Qiergustao （Tengger） Formation in the North Tianshan Mountains. On that basis, combined with the differences in rock association, metamorphism and deformation, depositional setting, and isotope age data, the original Qiergustao （Tengger） Formation is further disintegrated into the Upper Devonian Tengger Formation （senso stricto）, Upper Carboniferous Qiergustao Formation （senso stricto） and Houxia Formation and Lower Permian Aerbasayi Formation, and their ranges of distribution are mapped and the tectonic framework of the area is redefined. This study provides an important scientific basis for the correlation of stratigraphic units and tectonic division in the boundary region of the East and West Tianshan Mountains.