Dear Mark,
Some more references on clay fabrics, especially germane to clay particle
alignment in sheared clay-rich materials. All are primarily observational,
(except Cladouhos 1999b, which is more theoretical) and treat natural clay-rich
low-angle normal faults and experimentally-sheared artificial clay gouges.
Clay-rich fault gouges might well be similar enough to clastic dykes to permit
an extrapolation of behaviours. I have seen numerous examples of clastic-dyke
type flowage of clay-rich gouges into fractures in the hangingwalls of
low-angle normal faults in the field (SW USA), many with crude side-parallel
fabrics.
Cladouhos, T., et al., (1999a) J. Structural Geology 21, pp. 419-436. Shape
preferred orientations of survivor grains in fault gouge.
Cladouhos, T., et al., (1999b) J. Structural Geology 21, pp. 437-448. A
kinematic model for deformation within brittle shear zones
Hayman, N., et al., (2004) JGR B, Vol. 109, doi:10.1029/2003JB002902. Magnetic
and clast fabrics as measurements of grain-scale processes
within the Death Valley shallow crustal detachment faults.
Haines et al., (2009). JGR B, Vol. 114 (papers in press),
doi:10.1029/2008JB00586. Clay fabric intensity in natural and artificial fault
gouges: Implications for brittle fault zone processes and sedimentary basin
clay fabric evolution.
Hope this helps,
Sam
---------------------------------------------
Sam Haines
Post-Doctoral Fellow
Department of Geosciences
Pennsylvania State University
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University Park, PA, 16802
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