DEEP TECTONOTHERMAL MECHANISM FOR THE TECTONIC EXTENSION OF THE EASTERN ASIAN CONTINENTAL MARGIN

作者：ZHANGJian SHIYaolin

摘要：The continental marginal extension concept developed by Chinese geologists recently may be applied to the explanation about the Cenozoic extension and divergent movement of the Eastern Asian continental margin. From the viewpoint of continental marginal extension, this paper discusses the deep tectonothermal mechanism of the tectonic extension of the Eastern Asian continental margin.The Eastern Asian continental margin is an extensional belt with intensive magmatism and structural deformation, geophysically characterized by continual earthquakes and obvious geothermal anomaly.Seismic tomographical results about the Eastern Asian continental margin imply that the Pacific Plate is subducted toward the Eurasian Plate at a low angle and the diving Pacific Plate lies on the surface of the 670-km phase transitional zone. We interpret this feature to be resulted from retrogressive subduction followed by continental marginal extension. Our thermal modeling and geodynamical computation results suggest that the retrogressive subduction occurred at about 76Ma and the withdrawal of the trench served to supply the volume for the continental growth, which led to the formation of the growing front of the Eastern Asian continental margin. The growth width of the Eastern Asian continental margin is about 700 km.

发文机构：LaboratoryofComputationalGeodynamics

关键词：地壳热力学亚洲东部堆积区域地壳延伸热力学模型the Eastern Asian continental margintectonothermal modelingretrogressive subductioncontinental marginal growth

分类号： P541[天文地球—构造地质学][天文地球—地质学]