Paleozoic Igneous Rock Assemblages And Tectonic Evolution In Southern Xiaoxing'anling-northern Zhangguangcailing, Northeastern China

Southern Xiaoxing'anling - northern zhangguangcailing was located in the east part of huge Xing Meng orogenic belt between the Siberia plate and north China plate. Paleozoic - Early Mesozoic igneous rocks, especially granitoid were widely developed in the area. These rocks will be extremely good samples for the study of tectonic evolution and geodynamic processes in the region. Based on 1 / 50000, 1 / 250000 regional survey of Jiayin, Yichun, Hegang, Mudanjiang in the last several years, guided by the concepts and methods of igneous tectonic assemblage combination, we have established tectonomagma evolution sequence based on the intrusive rocks zircon SHRIMP ages, elaborated in detail the igneous rock petrography, Petrography, petrochemistry and geochemistry has discussed tectonic evolution of the region based on igneous tectonic assemblage combination and its temporal and spatial dwastribution.Five periods of igneous rock assemblages associated with subduction of oceanic crust have beenestablished. They were Caledonian, Early Cambrian, early and Middle Ordovician and Variscan , LateCarboniferous-Late Permian. However, there were two igneous tectonic assemblage combination related tocontinent-continent collision, Caledonian Early Cambrian and Variscan Middle Permian. Accordingly, thephases of tectonomagma spontaneously can ploted out as Caledonian and middle Variscan-Indosinian. Theformer includes intrusive rocks of Early Cambrian which was igneous rocks concern to oceanic crustsubduction (Songnen-Zhangguangcailing Blocks) or continent-continent collision, grew in the activecontinental margin. Convergences and hyperplasias of continental crusts within blocks of the Paleo-AsianOcean were integrality recorded after split of Rodinia. The appearance of peraluminous garnet granite inEarly Cambrian in Jiamusi block suggests that Jiamusi block was in the course of collision collage andbonding with Xingkai block. Shangzhi group early-middle ordovician volcanic rocks, mainly developed inthe Southern Xiaoxing'anling - northern zhangguangcailing, was arc - continental margin arc igneoustectonic assemblage related with the oceanic crust subduction. Middle - Late Silurian, rock was high-Kcalc-alkaline rock association, and appearance and typical subduction-related high-Mg diorite category.A-type granite in the end of the Silurian represents the end of Caledonian movement and Songnen -zhangguangcailing and Jiamusi-Xingkai blocks assembled together. Variscan late Carboniferousmetaluminous high-K calc-alkaline igneous rocks were island arc - continental margin arc igneouspetrotectonic assemblage related with Oceanic crust subduction. Early Permian Daheishan parlkalinegranite possibly symbolizes that the completion of the collision of the joint plot formed by Songnen -Zhangguangcailing block, Jiamusi - Xingkai block and Eerguna - Xingan block, thus formatted northeastreunification mainland. Middle Permian S-type strong peraluminous two-mica granitiod of themiddle-south Xiaoxing'anling Hegang and the continental margin arc I-type granite of Shichang - Chaihe- Chushan in Jiamusi - Xingkai block Pair distribution, suggested that when the south side oceanlithosphere (Changchun - Yanji) Subduction to Jiamusi - Xingkai block, the north side Songnen—Zhangguangcailing developed collision within the block. Late Permian active continental margin intrusiverocks and island arc - continental margin arc volcanic were widely developed in the Songnen -Zhangguangcailing block and Jiamusi - Xingkai block, suggested that Songnen - Zhangguangcailingblock and Jiamusi - Xingkai block already welded together as a whole, has the unification Earth dynamicsbackground. At this time, orogeny did not end until the Triassic in regional, Late Triassic post-orogenicassemblage, indicated that the North China - Northeast China together assembly had finished.