| Mongolia orogenic belt(MOB) ,which has many ophiolite belts,is a production of the Paleo-Asian Ocean closed. Many studies have attempted to delineate the architecture of this belt and to reconstruct its evolutionary history. The Chaobuleng area,north of the Dong Ujimqin, belong to the southeast margin of the Siberian Plate Paleozoic accretion zone, has experienced many structural transformations and superpositions, is a important area to study the separation and closure between Siberian Plate and the North China plate.Base on the theory of modern structural geology, structural analysis theory and method, the article has studied stratum,paleontology, igneous rocks, structural of Chaobuleng area, analysed the geometry characteristics and kinematic characteristics of structural characteristics in different sizes, different levels and different structural systems. The article establishes structural deformation sequence for Chaobuleng area and divides into six generations: Rheomorphic fold, stiucturalsu perposition (D1); NWW Angular fold (D2); NEE - NE Middling fold and thrust faults form (D3); NE fold, regional metamorphism (D4) ;NNW Broad fold (D5); Extensional faulting (D6).According to fossils in different formations and the isotopic age of magmatic rocks, the article has discussed the time limit of structural events. Based on structural deformation sequence in Chaobuleng area, the article has determined the time of events.Combined with regional tectonic setting, the tectonic evolution of Chaobuleng region divided into five stages:①∈3-O:Subduction of the Paleo-Asian Ocean, island arc development;②D2-C1:Back-arc basin;③C2-P1:Continental collision, Paleo-Asian Ocean closed;④J-K:Continental margin volcanic eruptions, plate deformation;⑤N-Q:Intracontinental rift basin.
|
PDF Full Text Request