【摘要】 辽吉南部古元古代花岗岩极为发育,其中最著名的是具有条痕状构造的正长花岗岩,俗称辽吉花岗岩。因该花岗岩具有条带状、条痕状和似层状构造特征,而被前人认为是由太古宙或元古宙沉积地层经变质变形作用形成,或是交代成因的混合岩。本文通过对分布于吉林南部通化地区辽吉花岗岩的典型代表-钱桌沟岩体的详实野外地质填图及地球化学研究,确定该岩体属岩浆成因的“A”型花岗岩,其岩浆侵位年龄为2160Ma左右。结合目前获得的该区古元古代地层的碎屑锆石年龄,本文认为辽吉花岗岩是辽吉地区古元古代地层沉积的基底岩石,是地层沉积之前地壳拉张作用的结果,属于一种非造山型花岗岩。更多还原

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