冲绳海槽西部陆坡泥底辟和泥火山特征及其形成动力机制

Characteristics and genetic dynamics of mud diapirs and mud volcanoes on the western slope of Okinawa Trough schematic geographic map of studied area mud diapirs with different morphology in multi-channel seismic section

  • 摘要: 海底泥底辟和泥火山对研究海底深部地球化学过程与全球碳循环、油气与天然气水合物资源勘查和新构造运动等具有重要的意义。利用高分辨率多道地震、浅地层剖面以及多波束等地球物理数据,对冲绳海槽西部陆坡泥底辟和泥火山的特征进行了分析和总结。冲绳海槽西部陆坡发育大量的泥底辟和泥火山,多发育于断裂活动强烈的区域,随着泥底辟的活动和甲烷流体的运移,在海底形成泥火山和气烟囱,因此,泥火山和气烟囱多发育于泥底辟上部,两翼存在强振幅异常,内部表现为低频特征,证明泥底辟和泥火山与甲烷流体活动存在密切联系。冲绳海槽西部陆坡泥火山和泥底辟的形成演化的动力学过程与成因主要包括3个方面,即区域拉张作用形成的构造薄弱带、快速沉积造成的超压和浮力作用以及流体的驱动作用。

     

    Abstract: Submarine mud diapirs and mud volcanoes are of great significance to the study of deep sea geochemical processes and global carbon cycle, the exploration of oil and gas hydrate resources and neotectonic activities. In this paper, the characteristics of mud diapir and mud volcanoes on the western slope of the Okinawa Trough are described and summarized with the geophysical data of high-resolution multi-channel seismic, sub-bottom profiling and multi-beam bathymetry survey. A large number of mud diapirs and mud volcanoes have been observed on the western slope of Okinawa Trough, mostly in the areas with strong fault activities. With the movement of mud diapirs and the migration of methane fluid, mud volcanoes and gas chimneys are commonly formed on the seafloor, mostly on the upper part of mud diapirs, with strong amplitude anomalies on the two wings and low frequency inside, which proves that the formation of mud diapirs and mud volcanoes are closely related to methane fluid activities. The dynamic evolution of mud volcanoes and mud diapirs on the western slope of the Okinawa Trough mainly includes three types: the weak structural zone formed by regional tension, the overpressure and buoyancy zone caused by rapid deposition, and the type formed by fluid driving.

     

/

返回文章
返回