Deformation microfabrics of clay gouge, Lewis Thrust, Canada: a case for fault weakening from clay transformation
Published:January 01, 2001
Yonghong Yan, Ben A. Van Der Pluijm, Donald R. Peacor, 2001. "Deformation microfabrics of clay gouge, Lewis Thrust, Canada: a case for fault weakening from clay transformation", The Nature and Tectonic Significance of Fault Zone Weakening, R. E. Holdsworth, R. A. Strachan, J. F. Magloughlin, R. J. Knipe
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A sequence of bentonite and shale samples in a gouge zone of the Lewis Thrust (Alberta, Canada) that display increasing degree of transformation of clay minerals toward the hanging wall of the thrust has been studied by X-ray diffraction (XRD), X-ray texture goniometry (XTG), scanning electron microscopy (SEM), and transmission and analytical electron microscopy (ΤΈΜ–ΑΕΜ), to examine the relations among mineral transformations, microfabrics and fault zone properties. TEM images of authigenic clays show abundant smectite in shale away from the hanging wall, characterized by anasto-mosing layers with an average orientation that parallels bedding, coexisting with uncom-mon RI illite–smectite (I–S)....
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The Nature and Tectonic Significance of Fault Zone Weakening
Many faults appears to form persistent zones of weakness that fundamentally influence the distribution, arichitecture and movement patterns of crustal-scale deformation and associated processes in both continental and oceanic regions. They act as conduits for the focused migration of economically important fluids and, as most seismicity is associated with active faults, they also constitute one of the most important global geological hazards.
This book brings together papers by an international group of Earth Scientists to discuss a broad range of topics centred upon the controls of fault weakening and the role of such faults during lithosphere deformation.
The book will be of interests to both academic and industrial Earth Scientists with an interest in geodynamics, structure at all scales, tectonics and the migration of petroleum and water.