新疆阿合奇地区晚石炭世—早二叠世■类动物群

A study of Late Carboniferous-Early Permian Fusulinids fauna from Akqi area, Xinjiang

在塔里木盆地西北缘的阿合奇地区晚石炭世—早二叠世地层中发现大量的■类化石,共计18属61种,另有较多未定种,自下而上建立了4个■带,依次为Pseudostaffella带、Profusulinella带、Fusulinella-Fusulina带和Pseudoschwagerina带。各■带与华南、帕米尔达尔瓦兹等地能很好的对比,且■类动物群面貌与华南地区相似。根据■类化石确定别根他乌组为晚石炭世早中期罗苏期—达拉期,康克林组为晚石炭世晚期小独山期—早二叠世紫松期,将该区石炭系、二叠系的界线置于71层底部。石炭纪末期区域上海退和古地形的影响导致■带Triticites带的缺失。

Abundant fusulinds were found in Upper Carboniferous-Lower Permian strata in the northwest of Tarim Basin. Four fusuline zones were recognized, namely Pseudostaffella zone, ProfusulineUa zone, Fusulinella-Fusulina zone and Pseudoschwagerina zone in upward succession, which can be well correlated with those from South China and Darwaz area of Pamir. It is indicated that Biegentawu Formation is Luosuan stage to Dalaun stage of Pennsylvanian in age, while the upper member of Kangkelin Formation belongs to the Late Carboniferous Xiaodushanian stage to Early Permian Zisongian stage. It is also inferred that the boundary between Carboniferous and Permian lies at the bottom of the 71st layer, as evidenced by the fusulind Pseudoschwagerina. The authors also hold that the late Pennsylvanian stage witnessed the sea regression with the addition of the paleotopographic factor, resulting in the stratigraphic gap of Triticites zone.