Fracture formation and evolution in crystalline rocks: Insights from attribute analysis
Fracture formation and evolution in crystalline rocks: Insights from attribute analysis
复制标题
结晶岩石的裂缝形成和演化：属性分析的见解
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
R. Holdsworth
中科院分区：
文献类型：
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作者：
K. McCaffrey;J. M. Sleight;S. Pugliese;R. Holdsworth
摘要裂隙普遍存在于结晶岩中，它控制着地球上地壳的强度、地球物理和流体输运特征。裂缝属性的定量描述可以约束裂缝形成和演化的模型。在这项研究中，从典型结晶岩暴露的一维样品中收集的裂缝属性显示出与沉积岩相当的裂缝尺寸和间距的变化。脉厚度和裂缝开度数据显示出占主导地位的幂律分布。脉和裂缝间距数据最好用负斜率的指数分布来描述，并且似乎随侵入岩的成分而变化。断裂系统表现出一系列的反集群到集群模式，和密度是一个数量级更高的关节相比，静脉。裂缝聚类数据可以与空间分布相结合，提供裂缝间距控制过程的信息。我们建议，指数间距分布产生的采样效果为两个间距和集群裂缝集。在这里给出的例子中，热应力相关的联合模式是可区分的构造相关的断裂在深成岩和断裂密度和集群增加对一个主要的复活基底断层。
Abstract Fractures are ubiquitous in crystalline rocks and control the strength and geophysical and fluid transport characteristics of the Earth’s upper crust. A quantitative description of fracture attributes may constrain models of fracture formation and evolution. In this study, fracture attributes collected from one-dimensional samples across exposures of typical crystalline rocks show comparable variability in fracture size and spacing to sedimentary rocks. Vein thickness and fracture aperture data show predominately power-law distributions. Vein and fracture spacing data are best described by exponential distributions with negative slopes and appear to vary with composition in intrusive rocks. The fracture systems exhibit a range of anti-clustered to clustered patterns, and densities are an order of magnitude higher for joints compared to veins. Fracture clustering data can be used in conjunction with the spatial distributions to provide information on the controlling processes of fracture spacing. We suggest that exponential spacing distribution is produced as a sampling effect for both periodic-spaced and clustered fracture sets. In the examples given here, thermal stress-related joint patterns are distinguishable from tectonic-related fractures in plutonic rocks and fracture density and clustering is increased towards a major reactivated basement fault.