La fábrica magnética del batolito de Renca (San Luis, Argentina). En: Cortés, J.M., Rossello, E. Y Dalla Salda, L. (Eds.): Avances en Microtectónica

RAPALINI, A.E.; LÓPEZ DE LUCHI, M.; GEUNA, S. E.; ROSSELLO, E.

Serie D Publicaciones especiales - Asociación Geológica Argentina

Asociación Geológica Argentina

Año: 2001 vol. 5 p. 131 - 137

0328-2767

The Renca Batholith is an ellipsoidal composite and zonal pluton exposed in the northeastern part of the Sierra de San Luis, Argentina. A porphyroid granodiorite and monzogranite external zone (Unit 1) and an equigranular biotite-muscovite monzo to leuco-monzogranite inner zone (Unit 2) constitute its principal units.  As part of its geophysical characterization and in order to help determining the processes involved in its emplacement, a systematic magnetic fabric study was carried out.  Bulk susceptibility (k) and anisotropy of magnetic susceptibility (AMS) measurements were done on all specimens from sixty sampling sites.  k values indicate a bimodal distribution that correspond to Unit 1 (ferromagnetic) and Unit 2 (paramagnetic).  Same distribution is observed in the anisotropy degree, with higher values in Unit 1.  The AMS has a predominantly foliated fabric, with a distribution of magnetic foliation planes generally sub-vertical and parallel to the boundaries of the ring-like Unit 1.  Unit 2 usually shows low and outward inclination of these planes.  The magnetic fabrics of this body agree with other fabric parameters and are consistent with a model of high temperature solid state deformation of Unit 1 due to radial stress associated with the emplacement of the central Unit 2, which shows a dominantly magmatic fabric.