Journal of Tropical Oceanography ›› 2016, Vol. 35 ›› Issue (1): 1-16.doi: 10.11978/2015030CSTR: 32234.14.2015030

• Marine Geology •     Next Articles

Recent research progress on the rifting-breakup process in passive continental margins

SUN Zhen1, LIU Siqing1, PANG Xiong2, JIANG Jianqun3, MAO Shuang3   

  1. 1. Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;
    2. Department of Science and Technology, Shenzhen Branch of China National Offshore Oil Corporation, Guangzhou 510420, China;
    3. Hainan Oil and Gas Exploration Branch Company, Liaohe Oil field, PetroChina Company Limited, Panjin 124010, China
  • Received:2015-02-27 Online:2016-01-10 Published:2016-02-02
  • Contact: LIU Siqing, E-mail: lsq13140307@foxmail.com
  • Supported by:
    Major National Oil and Gas Projects (2011ZX05025-003-005); The Joint Program of NSFC and Guangdong Province(U1301233)

Abstract: With the comprehensive utilization of deep reflection and refraction seismic data, ocean drilling program and field outcrops, great progress was made in understanding continental margin. Especially on the structure, evolution and formation mechanisms of passive continental margins, which are undergoing a paradigm shift. Starting from basic concept and classification, this paper reviewed the deep crustal to lithospheric structure, the layer velocity, the subsidence feature, and the breakup pattern of several types of passive continental margins based on recent seismic explorations. Then, mechanisms of passive continental margin formation were discussed. Based on existing research progress, we found that magma-poor and magma-rich margins may have lots of similarities in pre-rift and syn-rift stages, either in lithological components or rifting structures. They just differentiated during breakup depending on whether there was the involvement of hot mantle. During rifting stage, passive continental margin may evolve into four or more types, such as the whole lithospheric breakup type, the upper crust remnant type, the lower crust exhumation type, the upper mantle exhumation type, among others. The different rheological structures, stretching rate and mantle temperature are among the most important factors affecting the marginal structure evolution. Mechanism for high velocity lower crust is summarized. Usually, serpentinization of exhumed mantle is responsible for magma-poor margin, whereas underplating caused by high temperature mantle is responsible for magma-rich margin. Inherited high-grade metamorphic rocks were suggested to be one of the other causes. The above research progresses on passive continental margins provide us references to the research of the South China Sea.

Key words: passive continental margin, magma-rich margin, magma-poor margin, high velocity lower crust, differential evolution