银川地堑地壳挤压应力场:深地震反射剖面  

The compressive stress field of Yinchuan garben: Deep seismic reflection profile

作　　者：酆少英[1,2] 高锐[1] 龙长兴[1] 方盛明[2] 赵成彬[2] 寇昆朋[2] 谭雅丽[2] 何和英[3] 

机构地区：[1]中国地质科学院,北京100037 [2]中国地震局地球物理勘探中心,郑州450002 [3]河南油田石油物探技术研究院,河南南阳473132

出　　处：《地球物理学报》2011年第3期692-697,共6页Chinese Journal of Geophysics

基　　金：国家发展改革委员会"城市活断层试验探测"项目(20041138)资助;中国地震局地球物理勘探中心论著编号RXEG201104

摘　　要：银川地堑位于南北地震带北段,地质结构复杂,活动构造发育.为了调查银川地堑的构造特征及断裂分布情况,布设了NW向跨银川地堑的深地震反射剖面,首次获得银川地堑地壳的精细结构.结果表明,银川地堑具有典型的拉张挤压型沉积盆地特征,上地壳反射连续性好,层位丰富,能量强,断裂发育.下地壳和莫霍面记录了挤压与拉张的发展过程.莫霍面呈密集反射层,横向不连续,深度变化较大,最深处位于剖面的中部.剖面西段的地壳反射呈现弯曲状特征,剖面中部地壳包含"扁豆状"的反射形迹.这可能记录了晚三叠世以来,银川地堑受到来自西部的挤压作用.剖面东段的下地壳和莫霍面反射都被黄河断裂带错开,断裂两侧莫霍面发生错断,显示出黄河断裂带深部的走滑拉张作用.深地震反射剖面也揭露出贺兰山东麓断裂带和黄河断裂带是控制盆地的两个最主要深部断裂.贺兰山东麓断裂带切穿了上、中地壳地层.黄河断裂带是一个规模巨大的陆内走滑断裂,浅层表现为一个典型的花状构造,延伸至下地壳,切穿莫霍面.地堑逆冲推覆带与剖面中、西部地壳形态表明该地堑从盆地到基底都受到来自西南方向的区域挤压应力场作用.探讨了银川1739年8级地震的成因以及银川地堑的良好的油气远景.Yinchuan graben, located in the northern section of North-South seismic zone, has complex geological structure and active tectonics. In order to investigate the structural characteristics of Yinchuan graben and fault distribution, we laid the NW-trending deep seismic reflection profiles across the Yinchuan graben which revealed the fine crust structure of Yinchuan graben for the first time. The results show the typical characteristics of tension-compression sedimentary basin of the Yinchuan garben and the reflections of the upper crust have the characteristics of good continuity lower crust and Moho reco basin. Moho appears as an significantly in depth with t in the sections shows bent f rded , rich horizon, strong energy the development process of and abundant normal extension and compres intensive reflection layer, which is laterally di he deepest part in the middle of the section. Th eatures and contains the reflection characteristic faults. The sion of the scontinuous, changes e western lower crust s of ＂hyacinth bean＂. This may be related to the compressional effects on Yinchuan graben since the Late Triassic. The eastern lower crust and Moho reflection in the section are staggered by Yellow River fault belt, and the Moho dislocation occurs on both sides of the fault, indicating the strike-slipping and extensional effect of the Yellow River fault. The deep seismic reflection profiles also reveal that the fault belt in eastern piedmont of Helanshan and the Yellow River fault belt are two major deep faults to control the basin. The fault belt in eastern piedmont of Helanshan cut through the interface of the upper-lower crust into the lower crust. The Yellow River fault belt is a huge intra-continental strike-slip fault, and the shallow part appears as a typical flower structure, and the deep part appears as bundle-like tilt reflection. The Yellow River fault belt extends to the lower crust, cutting through the Moho. The shape of thrust-nappe belt of the graben and the crust in the middle and western profil

关 键 词：银川地堑 深地震反射剖面 贺兰山东麓断裂带 黄河断裂带 挤压应力场 

分 类 号：P315[天文地球—地震学]