Caracterización de las direcciones de flujo magmático en diquesAnálisis de la ASM en el dique de Ighrem (Anti-Atlas, Marruecos)

Résumé

Anisotropy of the Magnetic Susceptibility analyses has been conducted in a total of 17 sites (260 specimens) sampled along the great Ighrem dyke (Anti Atlas, Morocco). This NE-SW oriented, dolerite dyke, related with the Central Atlantic Magmatic Province (CAMP, ~200 Ma) traverses around 200 km mostly covered by older sediments. Magnetic fabric at each sampling site is related with the rock stress by means of the principal anisotropy ellipsoid parameters, the magnetic foliation and lineation, and the corrected anisotropy degree. Normal fabrics are mostly observed, foliation overcoming lineation, with nearly vertical foliation planes parallel to the dyke trend, facilitating flow directions estimation. Deviations of these directions of the magnetic ellipsoids are seldom observed in some samples and could reflect their different mineralogy and/or location in the dyke or further hydrothermal alteration. Magnetic fabric from closest country rock samples show high degree of tectonism due to dyke intrusion.