| TheHeilongjiang Subduction Accretionary Complex(HSAC, formerly known as Heilongjiang Group) have recorded the collisional processes between the Songnen massif and Jiamusi- Khanka block. Study of theHSAC, is the key to not only reveal the evolution and conversion from ancient Asian ocean tectonic domain to the Paleo-Pacific tectonic domain, but also to understandthe continental tectonic of the Northeast China. This thesis applies the new concept and theory of accretionary orogenic belts, carried out detailed field surveys and comprehensive analysis, based on previous studies. Some new processes have been finished in this thesis as listed below.1.The relationship of HSAC have been recognized, and have been divided into five segments(Luobei Taipinggou, Yilan- Huanan, Mudanjiang- Muling, Dongning and Hulin). The rockassemblage, tectonic deformation features and its relationship to mineralization are well analyzed. 2.After detailed study on the tectonic facies of the HSAC, the HSAC were divided into seven subfacies(e.g. the ophiolite subfacies, oceanic island- seamount subfacies,containing ophiolite fragments turbidite subfacies, excluding ophiolite fragments turbidite subfacies,basement fragments subfacies, exotic block and high pressure metamorphic rock subfacies. 3.Age and petro-geochemical results of the accretionary complex matrix and block of the Dongning region, demonstrate that the Dongningsubduction accretionary complex should be the similar products with similar age and tectonic setting with that in Luobei, Yilan, and Mudanjiang areas. 4.The HSACmatrices are mainly late Permian to Late Triassic,The collision between Jiamusi and Songnen massifs and obduction eramainly happened during late Early Jurassic to Early-middle Jurassic(185Ma to 165Ma),and have expericed later deformation in the Cretaceous. 5.Preliminary determinedophiolitein the studyarea belongs to ocean ridge type, initial subductiontype and back-arc basintype.Discussesthe tectonicevolution of the study area. |
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