ON THE FRAMEWORK OF MESOZOIC STRATA ON THE NORTHERN MARGIN OF DABIE OROGENIC BELT
LI Shuang ying 1) , YUE Shu cang 1) , WANG Dao xuan 1) , LIU Yin 1) , LI Ren wei 2) , MEN Qing ren 2) , and JIN Fu quan 1) ( 1) College of Resources and Environmental Engineering, Hefei University of Technology, H
The continental Mesozoic strata on the northern margin of Dabei Orogenic Belt are well deve loped, but owing to the lack for convincing fossil evidence, the division and correlation of these strata have been a controversial subject for a long time. Thus, an intensive study of the orogenic belt has been limited. Studies of the debris of the discovered volcanic rocks and their characteristics as well as the K Ar isotopic geochronology show that the Fenghuangtai, Zhougongshan, and Maotanchang Formations all belong to the Early Cretaceous and are probably the heteropic contemporaneous products. The Heishidu Formation overlying the Maotanchang Formation is also Early Cretaceous in age. Based on the stratigraphic contact, isotopic dating, and lithofacies correlation, the Sanjianpu Formation is mostly of Middle Jurassic age and probadly straddles the Early Middle Jurassic and Middle Late Jurassic boundaries. The Sanjianpu Formation and the Yuantongshan Formation are contemporaneous and heteropic. The analyses of the garnets and the sporopollen support the conclusion mentioned above. The stratigraphic contact shows that the Baidafan Formation is volcanic rocks of Early Cretaceous age.