摘要
大巴山及其前缘区位于川东北,在区域构造上位于扬子地台北缘,其北、西及东南方向分别与秦岭造山带、龙门山逆冲带及华南褶皱系毗邻,而扬子含油气地块的形成和发展均受到这些构造的影响。本文在分析大巴山及其前缘区与扬子地台、川东北盆地之间的山盆耦合关系的基础上,根据大巴山及其前缘区1:20万重力及航磁异常图,对该区的地质构造提出了新的认识。认为城口断裂并非本区深大断裂,而是切割不深、产状平缓,但推覆距离较大的逆掩大断层;城口弧形断裂前缘的局部重力低可能是推覆作用下老地层掩盖了密度相对较低且厚度较大的新地层所致。文中还采用二代小波多尺度分解对本区的重力异常进行了位场分离,并反演出前寒武褶皱基底面,ChK-ShP-WF一带是前寒武基底凹陷的中心区。
Dabashan Mountain and frontal area is situated in the northeast of Sichuan Province,and regional structure is situated in northern margin of Yangzi platform and adjacent to Qinling orogenic belt,Lungmenshan overthrust belt and south China fold system in northern,western and southeastern direction respectively,which has influence on the formation and development of Yangzi oil-bearing land mass.On the basis of analyzing the mountain-to-basin coupling relationship between Dabashan Mountain as well as frontal area and Yangzi platform,northeastern basin of Sichuan Province, the paper presented a new knowledge about geologic structure in this region based on 1-200000 gravity and aeromagnetic anomaly map.It is considered that the Chengkou fault is not deep and big fault in the region,but an overthrust with shallowcut,gentle attitude and larger nappe distance;the local gravity low in Chengkou arc fault margin may result from old strata overlying younger strata with lower density and larger thickness under nappe action.The paper also used second-generation wavelet multi scale decomposition to carry out gravity field separation for the gravity anomaly in the region and inverted Precambrian folded basement surface,considering the ChK-to-ShP-toWF region is central zone of Precambrian basement sag.
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2008年第3期349-354,370,25,共9页
Oil Geophysical Prospecting
基金
国家“十一五”资助项目“中上扬子盆山结构复合构造系统与油气成藏改造”地球物理专题
教育部高等学校博士学科点专项科研基金“第二代小波在地球物理数据处理中的应用研究”(编号：20050491504)项目
关键词
大巴山及前缘区
重磁场
城口断裂
二代小波
提升算法
褶皱基底
Dabashan Mountain and frontal area
gravity and magnetic field
Chengkou fault
second-generation wavelet
lifting scheme
folded basement
