Constraints on kinematics and strain from feldspar porphyroclast populations
Published:January 01, 2004
Scott Giorgis, Basil Tikoff, 2004. "Constraints on kinematics and strain from feldspar porphyroclast populations", Flow Processes in Faults and Shear Zones, G. I. Alsop, R. E. Holdsworth, K. J. W. McCaffrey, M. Hand
Download citation file:
We develop a method for constraining the kinematics and finite strain of deformation in shear zones based on a three-dimensional numerical model of the rotation populations of rigid clasts. The results of the model are characterized in terms of a fabric ellipsoid, which is directly measurable from field data. Fabric ellipsoids measured from populations of prolate clasts have anisotropies that increase steadily and plateau; the shape of the fabric ellipsoid becomes increasingly more prolate with progressive deformation. The behaviour of populations of oblate clasts is much more complex because the stability of individual oblate clasts depends on their aspect...
Figures & Tables
Flow Processes in Faults and Shear Zones
Faults and their deeper level equivalents, shear zones, are localized regions of intense deformation within the Earth. They are recognized at all scales from micro to plate boundary, and are important examples of the nature of heterogeneous deformation in natural rocks. Faults and shear zones are significant as they profoundly influence the location, architecture and evolution of a broad range of geological phenomenao The topography and bathymetry of the Earth’s surface is marked by mountain belts and sedimentary basins that are controlled by faults and shear zoneso In addition, faults and shear zones control fluid migration and transport including hydrothermal and hydrocarbon systems. Once faults and shear zones are established, they are often long-lived features prone to multiple reactivation over very large time-scales. This collection of papers addresses lithospheric deformation and the rheology of shear zones, together with processes of partitioning and the unravelling of fault and shear zone histories.