CHARACTERIZING FABRIC CONNECTIVITY IN FAULT ZONES USING ANISOTROPIC WAVELET TRANSFORMS

Cataclastic zones within fault zones can exhibit poorly- to well-developed fabrics. Fabric development is largely dependent on compositional heterogeneity, which allows for mineral segregation. Connectivity, an important component of fabric, is a parameter used to describe the degree (amount) and the scale (domain size) of mineral segregation in a particular rock. Previous research suggests that the extent of fabric formation and mineral segregation may contribute to the development of anisotropic permeability, the strengthening or weakening of rock material, and the types of slip mechanisms operating in the fault zone. However, mineral connectivity has not been quantified, so its exact relationship to these characteristics is unknown. Quantification of mineral connectivity in cataclastic zones is an important step in characterizing these relationships.

Because connectivity can vary depending on the scale of observation, the most appropriate quantification method is one that can analyze and quantify the size, shape, orientation, and spatial relationship of all rock constituents at a variety of scales. Anisotropic wavelet transforms (commonly referred to as wavelets) provide a mathematical method capable of objectively analyzing complex orientation and distribution data sets at any scale. Wavelets are mathematical functions that divide data information into different frequency components and analyze these components based on an assigned resolution representing scale. Here, we introduce the wavelet approach to cataclastic rocks and present our initial results of quantification of mineral connectivity at several scales in naturally faulted rock. In future work, such quantification will help elucidate the role of connectivity with the development of other physical properties, such as permeability and strength, of the fault zone.