The Basic Characteristics And Evolution Of Tectonomagmatic Complex Belt Of The Gudong River In Eastern Jilin

The study area is located in the southeastern of the Jilin Province,nearbyLongjing and Helong, which belongs to the eastern margin of the Central AsianOrogenic Belt between the North China Craton and the Siberian Craton,are theintersections of the Paleo-Asian Ocean tectonic domain and the Pacific tectonicdomain.The pre-Mesozoic era was mainly controled by the Paleo-Asian Oceantectonic system,but since the Mesozoic,it had a strong transformation by the Pacificplate activity. This region is the key to solute the tetonic evolution of the northeast ofChina and even the East Asia continent.The study area bounded to the Gudong River fault has two distinctly differentregions,the northwestern region and the southeastern region.The northwestern regionis regarded as the northern of the North China Craton-Helong plot,and theNortheastern region is the Xing-meng orogenic belt,tectonomagmatic complex belt ofthe Gudong River.The Helong plot is the Archean geological unit which is the mosteastern section of the north China Craton,and tectonomagmatic complex belt of theGudong River is mainly consist of blocks and matrixs from different times andDifferent lithologies.The block is made up of metamorphic rocks of the Jinanyangroup,marble of the Changren group, shallow metamorphic clastic of the Xindongcungroup and diorite.The zircon age of the Jinanyan group is2524±25Ma,belongs tonew Archean; Marble of the Changren group belongs to Late Carboniferous.Theisotopic dating of zircon between shallow metamorphic clastic of the Xindongcun group and diorite rock are253.2±1.2Ma and252.55±0.95Ma.Matrix mainly consistby syn-tectonic granite which distributed the Northeastern of the Gudong River,andits isotopic age is252.8±0.7Ma.The deformation temperature of ductile shear zone in tectonomagmatic complexbelt of the Gudong River is approximately400-550°C.Flynn index K is between0.029-0.746.The strain types is flattening strain.Ancient difference stress is between25.77-46.78MPa.The strain rate applicated the formula of Parrish and Gleason andTullis is almost exactly the same,mainly in the range of10-13—10-16S-1, slower thanthe average regional strain rate,the results of vorticity analysis turns out that the sheartype of study area belongs to general shear mode mainly based on pure shear,and isbound up with the flattening type of flynn graphic, it is generally acknowledged thatductile shear zone was formed under strong compression.In the late Permian,the Asian Ocean make final closure in the eastern part of theJilin Province,formed a deep EW-trending fault of the Gudong river,from then on tothe early Mesozoic,due to the continuation of the collision,the study area suffered thesrong compression from north to south,and make the occurrence of a very strongtectonic movement,making the Carboniferous-Permian strata suffer intensedeformation and metamorphism,on that time, magma intrusion was extremelyactive.To the Mesozoic, the Pacific tectonic domain began to have influence on thisarea,and the Tanlu fault occurs sinistral strike-slip and extended northward to productDun-Mi fault, And the sinistral translation of Dunmi fault increased the occurrence ofsinistral strike-slip from south to north and make the original,nearly EW-trendingtectonic zone of the Gudong River was cutted,thereafter,most of east-west structure ofthe northern region was transformed, displacement occurred was WNW orNW-trending.