Distribution and nature of fault architecture in a layered sandstone and shale sequence: An example from the Moab fault, Utah

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Abstract

We examined the distribution of fault rock and damage zone structures in sandstone and shale along the Moab fault, a basin-scale normal fault with nearly 1 km (0.62 mi) of throw, in southeast Utah. We find that fault rock and damage zone structures vary along strike and dip. Variations are related to changes in fault geometry, faulted slip, lithology, and the mechanism of faulting. In sandstone, we differentiated two structural assemblages: (1) deformation bands, zones of deformation bands, and polished slip surfaces and (2) joints, sheared joints, and breccia. These structural assemblages result from the deformation band-based mechanism and the joint-based mechanism, respectively. Along the Moab fault, where both types of structures are present, joint-based deformation is always younger. Where shale is juxtaposed against the fault, a third faulting mechanism, smearing of shale by ductile deformation and associated shale fault rocks, occurs. Based on the knowledge of these three mechanisms, we projected the distribution of their structural products in three dimensions along idealized fault surfaces and evaluated the potential effect on fluid and hydrocarbon flow. We contend that these mechanisms could be used to facilitate predictions of fault and damage zone structures and their permeability from limited data sets.

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Publication type Book chapter
Publication Subtype Book Chapter
Title Distribution and nature of fault architecture in a layered sandstone and shale sequence: An example from the Moab fault, Utah
DOI 10.1306/M851033
Volume 85
Year Published 2005
Language English
Publisher American Association of Petroleum Geologists
Description 28 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Faults, Fluid Flow, and Petroleum Traps
First page 153
Last page 180
Country United States
State Utah
Other Geospatial Moab Fault
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