摘要
本文利用新的高分辨率海底多波束地形数据与以往研究资料对南海台西南盆地及以西和中建南盆地北部及以北陆缘区域内的麻坑与泥火山分布区进行了统计、分析与总结.本文提出根据麻坑的个体平面形态、规模量级和组合形式建立麻坑的三类分类体系并进行总结阐述.麻坑的直径与坑深总体具有线性变化关系但又有区域性分布特征,可能反映了不同海区底质性质、浅地层构造活动、海底倾斜程度和海底底流等因素的不同影响;同一区域泥火山的直径与高度具有线性关系而不同区域拟合斜率差异较大,可能说明同区域泥火山形态、流体成分和来源具有高度一致性,但其分布具有区域差异性特征.研究表明,麻坑、泥火山的产生与近5Ma新构造运动期内台湾南部和南海西缘区域性走滑断裂活动相一致,主要分布在构造活动较为活跃,沉积较为薄弱的近坡折带和大陆坡区域,在具有走滑性质的台西南、莺歌海和中建南盆地分布较广、规模较大,而在其他主要张裂性质盆地中分布较少,规模较小.其分布特征一方面能够说明某些区域流体的大量渗漏与逸散,另一方面也能够说明某些区域持续的构造活动有利于该区域深部流体的重新聚集与成藏,从而成为指导油气资源勘探的重要参考指标.
New high resolution multi-beam bathymetry data and previous research data are used tostudy the distribution characteristics of pockmarks and mud volcanoes,such as location,size and morphology,in the northern continental margin consisting of Southwest Taiwan Basin and to the west and the western continental margin consisting of Zhongjiannan Basin and to the north.Combined with the tectonic evolution and topography of the northern and western margin of the South China Sea（SCS）,this work made statistics,and classification to these characters,and linked them with the geological evolution of the South China Sea and the distribution of oil and gas resources.The SCS is surrounded by different types of continental margins.To the north is the extensional continental margin which consists of Southwest Taiwan Basin（Ⅰ）,Pearl River Mouth Basin（Ⅱ）and Qiongdongnan Basin（Ⅲ）;to the west is the strike-slip continental margin which consists of Beibuwan Basin（Ⅳ）,Yinggehai Basin（Ⅴ）and Zhongjiannan Basin（Ⅵ）;to the east is the subducted continental margin and to the south is the margin of continental collision.All the basins above have experienced almost the same stages during evolution of the SCS,which include Paleocene to mid-Miocene rifting followed by post-rift thermal subsidence and the neotectonic movement in recent ~5 Ma.In the study area,16 distribution areas（a—p）of pockmarks and mud volcanoes are recognized.The data of areas a,b,c,d,and h were collected from previous researches and the other data were collected by the Guangzhou Marine Geological Survey in 1998—1999.The acquisition system SeaBeam2112 was used to acquire data and the processing sequence includes：navigation filter,parameter calibration,correction for transducer draft,correction of sound velocity,data filtering and so on.The cell size of raster grids is ca.100 m and the vertical resolution is ca.3‰ of the water depth.The multi-beam bathymetry is utilized to study the morphology,size and shape of the pockmarks and
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第3期919-938,共20页
Chinese Journal of Geophysics
基金
国家自然科学基金重大计划重点项目(91128205)
国家重点基础研究发展计划(973)(2011CB403503)资助
关键词
麻坑
泥火山
新构造运动
流体
南海
Pockmark
Mud volcano
Neotectonics
Fluid flow
South China Sea
