Mesozoic and Cenozoic Granitoid Complexes in the Stucture of the Continental Margin of Northeast Asia

摘要

The integral data on structural position, age, and paleo-geodynamic setting of Mesozoic and Cenozoic granitoid complexes in northeast Asia make it possible to divide them into preaccretionary, accretion-ary, and postaccretionary groups participating in the structure of the accretionary-type continental margin. The preaccretionary granitoids are members of volcanic-plutonic associations of ensimatic island arcs or suprasubduction ophiolitic complexes, which mark the onset of growth of the granitic-metamorphic layer in the future continental crust. The accretionary granitoids emplaced during the accretion of diverse rock complexes to the continental margin and are localized in its frontal zone, where granitic-metamorphic layer grows further. The postaccretionary granitoid plutons of the marginal continental volcanic-plutonic belts seal up fold-nappe structures, determining the upper age limit of accretion and deformation. The origin of postaccretionary granitoids is related to remelting of older heterogeneous accretionary-island arc crust.