摘要
本文选取廊固凹陷为例,利用平面恢复方法,研究伸展盆地断块平面运动特征。根据大兴断层的分段性,将研究区分为3个区块:西南区,中区以及东北区,又根据研究区的断块旋转特征,将中区分为中北区以及中南区。每个区块的断块运动差异性很大。通过对廊固凹陷古近系的断块进行构造平面恢复,发现其平面运动具有以下特征:西南区,断块主要以顺时针旋转,位移方向为东南—西北;中区,中南区断块主要以顺时针旋转,中北区主要以逆时针旋转,位移方向为西北—东南,中间位移量最大,向东北及西南端位移量逐渐减小;东北区,除沙二段外,断块主要受桐柏镇断裂影响以逆时针旋转,位移方向为近似南—北。其中东北区和西南区的位移方向相似,且与中区的位移方向相反,猜测与主控断层大兴断层的分段性有关。中区的中南部断块主要以顺时针旋转,而中北部断块主要以逆时针旋转,由于中区主应力集中在凹陷中间,向两端应力逐渐减小,导致应力作用不平衡。
This paper uses map-view restoration of Langgu fault-sag to study the characteristic of the fault blocks in fauh-blocks in extensional basin. According to the segments of Daxing fault, the study area is divided into three zones： southwest zone, middle zone and northeast zone. According to the characteristic of fault-blocks＇ rotation, middle zone is divided into middle-south zone and middle-east zone. The movement of each zone is different. After the map-view restoration of the fault-blocks of Paleogene in Langgu sag,we have found that,the fault-blocks in southwest zone mainly rotate by clockwise, and the direction of displacement is southeast to northwest; in middle zone, the fault-blocks in middle-south zone mainly rotate by clockwise while in middle-east zone by anticlockwise, and the direction of displacement is northwest to southeast, and the displacement decreases from middle to the tips; in northeast zone, the faultblocks mainly rotate by anticlockwise except that in second member of Shahejie group,and the direction displacement is nearly south to north. The direction of displacement in southwest zone and northeast zone is nearly similar but different from that in middle-east zone, which we think has relation with the segments of Daxing fault. The different rotation between middle-south zone and middle-east zone results from the unbalanced stress which decreases from middle to the tips.
出处
《地质科学》
CAS
CSCD
北大核心
2011年第2期426-444,共19页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
国家重点基础研究发展计划项目(编号:2006CB202300)
国家自然科学基金重点项目(编号:40739906)资助
关键词
廊固凹陷
伸展盆地
大兴断层
古近系
平面恢复
复杂断块
平面运动
Langgu sag, Extensional basin, I）axing fault, Paleogene, Map-view restoration, Complex fult-blocks, Movement in plane
