Magnetic fabrics of experimentally deformed artificial clay-water dispersions

Abstract

The magnetic fabrics of experimentally deformed clay-water dispersions. Tectonophysics, 2001 143-155. The development of magnetic fabrics in artificial clay-water dispersions and natural, hematite-bearing mudstones is investigated in plane-strain pure shear Iaborato~ experiments under strain rates of 1.6 X lo-' and 2 X 10m4 s-'. The mixtures contain 0,15,30 and 45% chlorite in an illite matrix, and 0, 1,3,6 and 8% magnetite in a kaolin matrix. Shortening up to 40% is imposed. The resulting fabrics show the following characteristics: (1) In the clay mixtures, the principal susceptibility axes (k,,, 2 kin, ;z k,,,) rotate away from the well defined initial fabric orientations into the principal strain directions (e, > e2 2 es) at strains > 30%. (2) Both mineralogical composition and initial magnetic fabric, but not the applied strain, influence the magnitudes of the principal susceptibility axes. (3) The illite-chlorite mixture series show an aimost linear correlation between mineral ~ncent~tion and susceptibility magnitudes. (4) Magnetite dominates the fabric of the magnetite-~olin mixtures; the fabric is'independent of the magnetite ~ncentration. MAGNETlC FABRICS IN ARTIFICIAL CLAY-WATER DISPERSIONS