Brittle microtectonics: principles and practice
Brittle microtectonics: principles and practice
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DOI：
10.1016/0191-8141(85)90048-3
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发表时间：
1985
影响因子：
3.1
通讯作者：
P. Hancock
中科院分区：
文献类型：
--
作者：
P. Hancock
这里定义的脆性微构造学是细观裂缝分析在解决构造问题中的应用。为了确定区域显着应力或应变轨迹，理想的结构套件包括运动学指标，例如中断层、剪切带、阶梯状裂纹阵列、扭结带、缝合线和纤维脉。然而，在许多构造环境中，节理是唯一能够分析的广泛分布的结构。将节理分为延伸类、混合类和剪切类的主要标准是断裂系统结构和对称性、表面形态、二面角和薄片特征。正交延伸关节的结构通常为 T 形，较新的关节邻接较旧的关节。相邻的共轭混合或剪切接头通常定义 X、Y 或 V 形状，但某些 X 图案是不相关的横切断裂的假象。二面角小于 45° 的共轭接头很常见；它们被解释为在剪切-拉伸断裂转变过程中引发的混合破坏面。平台中许多节理组的方向与板块运动和盆地沉降、抬升和反转过程中产生的远场应力有关。即使在单个接头组中，通常也有现场证据表明它是在多相故障序列中形成的。有些关节比折叠更年轻，但如果系统在折叠结束之前建立，表面通常会成为滑动、膨胀或压力解决的场所，从而转变为不再归类为关节的结构。
Brittle microtectonics as defined here is the application of mesofracture analysis to the solution of tectonic problems. For the determination of regionally significant stress or strain trajectories the ideal suite of structures comprises kinematic indicators such as mesofaults, shear zones, arrays of en échelon cracks, kink bands, stylolites and fibrous veins. However, in many tectonic settings joints are the only widespread structures capable of being analysed. The principal criteria for classifying joints into extension, hybrid and shear classes are fracture-system architecture and symmetry, surface morphology, dihedral angles and thin-section characteristics. The architecture of orthogonal extension joints is commonly T-shaped, the younger joint abutting the older one. Neighbouring conjugate hybrid or shear joints generally define X, Y or V shapes but some X patterns are artefacts of unrelated cross-cutting fractures. Conjugate joints enclosing dihedral angles of less than 45° are common; they are interpreted as hybrid failure surfaces initiated in the shear-extension fracture transition.The orientations of many joint sets in platforms are related to far-field stresses generated during plate motion and the subsidence, uplift and inversion of basins. Even within a single joint set there is commonly field evidence to show that it developed during a multiphase failure sequence. Some joints are younger than folds but where a system was established before the close of folding the surfaces commonly become the sites of slip, dilation or pressure solution, and are thus transformed into structures no longer classed as joints.