Emplacement age and tectonic setting of the Paleoproterozoic Liaoji granites in Tonghua area, southern Jilin province
吉林南部通化地区古元古代辽吉花岗岩的侵位年代与形成构造背景

Paleoproterozoic granites are widely distributed in southern Liaoning and Jilin Provinces. The most well-known is the streak-like syenogranites which was called "Jiaoji Granites", in the Chinese literatures. It was thought before that this kind of granites either came from the Archean or Paleoproterozoic strata by metamorphism and deformation, or was migmatite by metasomatism. As a typical example of above granites, the Qianzhuogou pluton, located in Tonghua, southern Jilin Province, is chosen for a detailed field mapping and geochemical study in this paper. It is shown petrologically and geochemically that this pluton is A-type granite with emplacement age of about 2160 Ma. Combined with the ages of the detrial zircons in the Paleoproterozoic strata, it was suggested that the Liaoji Granites were the basement rock on which the Paleoproterozoic strata were deposited. It was formed by extension resulted in the deposition of Paleoproterozoic strata, therefore, the Liaoji Granites were anorogenic tectonically.