南海北部陆缘结构及构造-岩浆演化

南海北部陆缘发育独特的远端带结构，以“裂谷宽、基底厚和地貌起伏”为主要特点，显著有别于经典贫岩浆型和富岩浆型张裂陆缘.为了解释陆缘结构的成因，综合已有研究进展和国际大洋发现计划（IODP）的钻探成果，对南海北部陆缘基底性质进行了调研，探讨了拆离断层和岩浆作用的特点以及两者间的相互作用.结果表明，在38 Ma之前南海北部大范围发育核杂岩构造，并伴随大量岩浆侵入到中下地壳；岩浆作用一方面加剧了地壳的韧性变形，导致应变无法集中而在多个地方同时发育大型拆离，另一方面对拆离面和减薄的基底进行了强烈改造.最终提出同张裂期就位的岩浆作用和中下地壳的韧性流动是形成南海北部宽裂谷陆缘的关键，深化了对陆缘结构、变形过程和岩石圈减薄机制的理解. 

Crustal Structure and Tectono-Magmatic Evolution of Northern South China Sea

The northern continental margin of the South China Sea (SCS) developed a diagnostic crustal structure in the distal domain, which is characterized by "wide rift, thick basement, and prominent topographic variations of the top basement". These characteristics are significantly different from those of the typical magma-poor and magma-rich rifted margins. In order to decipher the origin of such crustal structure in the northern SCS, in this study it defines the nature of the basement in the distal margin based on the latest research progresses and the drilling results of the International Ocean Discovery Program (IODP), and discusses the detachment faults, magmatic additions and the tectono-magmatic interaction. The results suggest that several large-scale core complex structures were developed in the northern SCS during the early rifting (before 38 Ma), which was accompanied by voluminous magma intruding into the mid-lower crust. On the one hand, the emplacement of the syn-rift magma enhanced the ductile deformation of the mid-lower crust, resulting in the delocalization of the strain and the occurrence of the detachment in many places almost at the same time. On the other hand, the magmatism strongly affected the geometries of the detachment faults, resulting in the thickened basement. Finally, the syn-rift magmatism and the ductile flow of mid-lower crust are considered as the key factors to produce the wide rift in the northern SCS. The results would help to deepen the understanding of the crustal structure, deformation process and lithospheric thinning mechanism during the development of the rifted margins.