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辽吉地区是我国典型的早前寒武纪大陆壳出露区之一 ,由花岗岩 绿岩带和高级变质区构成。绿岩带可划分为Ⅰ型 (岛弧型 )和R型 (裂谷或盆地型 )两类 ,其形成的古构造环境分别为类似于现代岛弧的大陆边缘活动带和类似于大陆边缘裂谷环境或弧后盆地。与绿岩带共同产出的花岗质岩石可划分为三类 :即片麻状花岗质杂岩体 ,花岗岩底辟岩基 /岩株和钾质花岗岩。高级区是本区早前寒武纪大陆壳的主要组成部分 ,主要以卵型隆起形式产出 ,遭受了高角闪岩相—麻粒岩相区域变质作用 ,是花岗岩—绿岩带的基底。单颗粒锆石U Pb、4 0 Ar / 39Ar、Sm Nd和Rb Sr等时线年龄表明绿岩带形成时代为 2 60 5～ 2 84 4Ma ,三期花岗质岩石的形成时代分别为 ( 2 555± 35)Ma ,( 2 515± 4 )Ma和 2 50 5Ma。高级区表壳岩和花岗岩的形成时代分别为 30 18Ma和 2 971Ma。本区早前寒武纪大陆壳的克拉通化时期为新太古代末期
The Liaogi area is one of typical early Precambrian continental outcrops in China. It consists of granite greenstone belt and high-grade metamorphic zone. The greenstone belts can be divided into two types: type I (island arc) and type R (rift or basin type). The paleo-tectonic setting is similar to the continental margin active belt of modern island arc and similar to the continental margin Valley environment or backarc basin. The granitic rocks co-produced with the greenstone belts can be divided into three types: gneissic granitic complex, granite diabase basement / granite and potash granite. The high-level zone is the main component of the Early Precambrian continental crust in this area. The high-level zone is mainly produced in the form of ovoid uplift and is subjected to the metamorphism of the amphibolite facies-granulite facies and is the base of the granite-greenstone belt. The dating of monolithic zircon U Pb, 40Ar / 39Ar, Sm Nd and Rb Sr shows that the age of greenstone belts was 2 60 5 ~ 2 84 4Ma, and the age of the third granitic rocks was (2 555 ± 35) Ma, (2 515 ± 4) Ma and 2 50 5 Ma. The age of formation of the upper crust and granite are 30 18 Ma and 2 971 Ma, respectively. The cratonization period of the Early Precambrian continental crust in this area was Neoarlyian