Magnetic fabrics of Late to Post-Tectonic Paleoproterozoic intrusive bodies of the Piedra Alta Terrane, Río de la Plata Craton, Uruguay

Nine Paleoproterozoic intrusive bodies of the Piedra Alta terrane, in western Uruguay, with ages between 2.2 and 2.0 Ga, were sampled in order to obtain information on emplacement kinematics and regional stress regime during intrusion by means of studies of anisotropy of magnetic susceptibility (AMS). Petrographic thin sections were analyzed in order to obtain information about the degree of deformation and its potential influence in the AMS results. Most plutons show K1 subvertical axes and E-W subvertical foliations planes suggesting an extensional N-S regional stress field controlling the magma ascent. This is consistent with the E-W structural grain of the Piedra Alta terrane and the geographic distribution of the plutons in the San José metamorphic belt. Keywords: Piedra Alta terrane, Paleoproterozoic, anisotropy of magnetic susceptibility (AMS)