| 断层转折褶皱剪切裂缝发育模式探讨 |
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| 引用本文： | 祖克威,曾联波,赵向原,刘国平.断层转折褶皱剪切裂缝发育模式探讨[J].地质力学学报,2014,20(1):16-24. |
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| 作者姓名： | 祖克威 曾联波 赵向原 刘国平 |
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| 作者单位： | 1.中国石油大学（北京）地球科学学院, 北京 102249 |
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| 基金项目： | 国家自然科学基金项目（41272164）;国家科技重大专项（2011ZX05003-002） |
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| 摘 要： | 围绕库车前陆盆地内某典型断层转折褶皱剖面，实测统计该剖面不同构造部位的剪切裂缝，分析断层转折褶皱中剪切裂缝的发育规律，进而建立断层转折褶皱剪切裂缝的发育模式。统计结果表明，研究区剪切裂缝有2种类型，一类是与岩层面高角度相交的高角度缝，广泛发育在构造各个部位；另一类是与层面近于平行的顺层裂缝，主要发育在断层面附近，并随岩层的变形，产状发生改变。远离断层面，剪切裂缝发育程度整体上呈减小趋势，下盘裂缝发育强度的减小大于上盘，上盘裂缝发育强度整体大于下盘。褶皱内层剪切裂缝较外层发育，褶皱两翼裂缝发育强度大于褶皱枢纽。断层产状的改变，会引起上盘运动状态的改变，使得在上盘活动轴面附近出现应力集中，局部剪切裂缝发育强度出现增大现象。断层转折褶皱剪切裂缝的发育模式可以分为3个阶段，断层形成前主要发育与层面高角度相交的区域性剪切裂缝；断层形成初期，断层面附近两盘牵引变形不明显，上盘穿过断坡下部破折点处活动轴面的部分会产生新的剪切裂缝，即与岩层高角度相交剪切缝和与断层面低角度相交剪切缝；牵引构造明显时，断层面附近两盘弯曲部位会产生顺层剪切裂缝，两翼的裂缝发育强度大于枢纽。
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| 关 键 词： | 断层转折褶皱 剪切裂缝 分布规律 发育模式 |
| 收稿时间： | 2013/10/23 0:00:00 |
DISCUSSION ON DEVELOPMENT MODELS OF THE SHEARING FRACTURES IN FAULT BEND FOLDS |
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| ZU Ke-wei,ZENG Lian-bo,ZHAO Xiang-yuan and LIU Guo-ping.DISCUSSION ON DEVELOPMENT MODELS OF THE SHEARING FRACTURES IN FAULT BEND FOLDS[J].Journal of Geomechanics,2014,20(1):16-24. |
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| Authors: | ZU Ke-wei ZENG Lian-bo ZHAO Xiang-yuan and LIU Guo-ping |
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| Institution: | 1.College of Geosciences, China University of Petroleum, Beijing 102249, China2.State Key Laboratory of Petroleum Resource and Prospecting in China University of Petroleum, Beijing 102249, China |
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| Abstract: | This paper focuses on a typical section of fault-bend fold in Kuqa foreland basin, by useof the shear fractures data measured in different structural position of the outcrop, and the fracturesdevelopment laws are analyzed and then development models of the shearing fractures in fault-bendfold in Kuqa foreland basin are established. Statistical result shows that the shear fractures in theoutcrop can be divided into two types： shear fractures at a high angle to layers extensively developsin each position in the outcrop, and bed-parallel fractures presenting near the fault, mainly developsnear the fault with attitudes changing with the deformation of the layers. The intensity of shearfractures development decreases with the distance away from the fault as a whole. The gradient ofshear fractures development in the footwall has a greater descending rate than that in the hangingwall. The density of shear fractures in the hanging wall is greater than that in the footwall. Thedensity of shear fractures in the hinge of the fold is less than that in the forelimb and backlimb,besides higher density appears in the internal surface with respect to that in the external surface. Thechange of the dip angle in the fault bendfold causing the alteration of the movement for the hangingwall makes the stresses concentrating .on the axial faces. So the phenomenon of the increase ofintensity of shear fractures near this position can be appeared. The development model of shearfractures in the fault-bend fold shall be separated into 3 stages： regional fractures are mainlydeveloped before the generation of fault; after the formation of the fault with dragging deformationsnear not obvious, new shear fractures will be formed in the position where the axial surface pinned atthe lower ramp inflection point passes through, one at a high angle to the layer and the other at a lowangle to the fault; the bed-parallel fractures will be presented in the curved sections and the intensityof fractures development near fold hinge is higher than that |
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| Keywords: | fault-bend fold shear fractures distribution law development model |
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