MAGNETIC FABRICS OF LATE TO POST-TECTONIC PALEOPROTEROZOIC INTRUSIVE BODIES OF THE PIEDRA ALTA TERRANE, RÍO DE LA PLATA CRATON, URUGUAY

MILANESE, FLORENCIA N.; MARTÍNEZ DOPICO, CARMEN; SÁNCHEZ BETTUCHI, LEDA; RAPALINI, AUGUSTO E.; FRANCESCHINIS, PABLO R

LatinMag Letters

Universidad Nacional Autónoma de México

Lugar: -; Año: 2017 vol. 7 p. 1 - 4

2007-9656

Nine Paleoproterozoic intrusive bodies of the Piedra Alta terrane, in western Uruguay, with ages between2.2 and 2.0 Ga, were sampled in order to obtain information on emplacement kinematics and regional stressregime during intrusion by means of studies of anisotropy of magnetic susceptibility (AMS). Petrographicthin sections were analyzed in order to obtain information about the degree of deformation and its potentialinfluence in the AMS results. Most plutons show K1 subvertical axes and E-W subvertical foliations planessuggesting an extensional N-S regional stress field controlling the magma ascent. This is consistent with theE-W structural grain of the Piedra Alta terrane and the geographic distribution of the plutons in the San Josémetamorphic belt.