地学前缘 ›› 2012, Vol. 19 ›› Issue (5): 19-26.

• 论文 • 上一篇    下一篇

陆内裂陷盆地构造动力学分析

漆家福,杨桥   

  1. 1. 中国石油大学（北京） 油气资源与探测国家重点实验室， 北京 102249
    2. 中国石油大学（北京） 地球科学系， 北京 102249
  • 收稿日期:2012-03-05 修回日期:2012-06-25 出版日期:2012-09-10 发布日期:2012-09-10
  • 作者简介:漆家福（1957—），男，博士，教授，长期从事盆地构造分析教学和科研工作。E-mail：qjiafu@cup.edu.cn
  • 基金资助:

    国家自然科学基金项目（90914006,40772085）

Dynamic analysis of continental rifting basin

  1. 1. State Key Lab of Petroleum Resources and Prospecting, China Petroleum University (Beijing), Beijing 102249, China
    2. Department of Geosciences, China Petroleum University (Beijing),  Beijing 102249, China
  • Received:2012-03-05 Revised:2012-06-25 Online:2012-09-10 Published:2012-09-10

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摘要：

陆内裂陷盆地区形成和演化过程中的构造力包括4方面：（1）地幔对流由岩石圈板块底面边界施加到岩石圈板块内部的构造力F1；（2）板块相对运动通过岩石圈板块侧面边界施加到岩石圈板块内部的构造力F2；（3）岩石圈受热膨胀和冷却收缩在地壳内部产生的构造力F3；（4）地壳质量在地壳内部产生的围压F4。地壳中的应力是这4方面的构造力的函数S(Fi)，其中，F1和 F2的大小和方向对三轴应力状态的主应力大小和方向起决定作用。地壳发育正断层的条件是应力状态方程S（Fi）中σ2σ3主应力平面大致处于水平面状态、σ1近直立。当F1和F2的方向一致且F1＞F2或F1和F2的作用方向相互垂直的情况下，F1和F2合成的应力场中的最小主应力方向与X轴方向一致，地壳发生正向裂陷作用。在F1和F2的方向既不平行也不垂直的情况下， F1和F2叠加产生最小主应力（σ3）的方向与X轴方向不一致，地壳发生斜向裂陷作用。当地幔对流从岩石圈底部对岩石圈产生的引张作用力减小、板块之间相对运动从岩石圈侧面边界对岩石圈产生的挤压作用力增强的情形下，地壳应力状态S（Fi）在X轴和Y轴构成的水平面上的最大主应力可能超过Z轴方向的主应力，使σZ相当于三轴应力状态的σ2，裂陷盆地发生走滑构造变形。如果地壳应力状态S（Fi）在X轴和Y轴构成的水平面上的最小主应力也超过Z轴方向的主应力，则σZ相当于三轴应力状态的σ3，裂陷盆地发生收缩构造变形,可能发育逆冲断层或使早期的正断层发生反转位移。随着裂陷作用的渐进发展，不同时期F1和F2的大小和方向的变化导致地壳应力场的主应力轴方向也相应发生变化，使裂陷盆地在不同演化阶段表现出不同的构造变形特征。

关键词: 裂陷盆地, 伸展构造, 走滑构造, 盆地反转, 构造动力学

Abstract:

There are four tectonic forces controlling the dynamics of continental rifting basin: F1an adhesive traction force generated by the mantle convection from the bottom of lithosphere, F2a lateral push force generated by the relative movement of plates from the plate boundary, F3an isotropic force generated by expanding and shrinking of the lithosphere due to temperature changes, and F4a lithostatic force generated by the mass of the lithosphere. The stress within the crust is a function S(Fi) of these four variables，but the magnitude and direction of F1 and F2 effects the magnitude and direction of the principal stress in the triaxial stress unit. The condition of lithospheric stretching, i.e., the formation of normal fault in the crust, is to have the principal stress σ2σ3 plan in the stress function S(Fi) close to horizontal level, and direction of maximal principal stress σ1 close to vertical. That means the composition of forces between F1 and F2 should be tensile force. In the case of F1 and F2 are in same direction and F1>F2, or directions of F1 and F2 are perpendicular to each other and the minimal principal stress of the stressunit is in the xaxis, the crust could have arisen  normal rifting. If the direction of F1 and F2 is neither perpendicular nor parallel to each other and the minimal principal stress σ3 of the stressunit is not directional on the xaxis, the crust could have arisen oblique rifting. As the force generated by the mantle convection from the bottom of lithosphere to lithospheric interior decreases, and the extrusion force generated by movements of the plates from lateral boundary of lithosphere plate to lithospheric  interior increases, the principal stress of crusts stress state S(Fi) on the X and Y axis can exceed the principal stress on the Z axis, making σZ equivalent to σ2 in the triaxial stress state, the strikeslip fault could be arisen  in rifting basin. If the magnitude of principal stress of crust stress state S(Fi) on the XY plane exceeds the principal stress on the Z axis, then σZ is the equivalent of σ3, the thrust faults or inverted normal faults could be arisen  in rifting basin. Along with the gradually advancing process of the rifting, the  variation of tectonic forces F1 and F2, both in magnitude and direction, must have induced the changes of the stress state S(Fi), causing different structural characteristics of the rifting basin  appeared in  various stages of tectonic evolution.

Key words:  rifting basin, extensional structure, strikeslip structure, inverted structure, tectonic dynamics