The Capillitas Batholith, NW-Argentina: geophysical and petrological evidences of crustal genesis.

TOSELLI, A; MARTINEZ, M PATRICIA; ROSSI DE TOSELLI, J.; GIMENEZ, MARIO E; INTROCASO, ANTONIO

Neus Jahrbuch für Geologie und Paläontologie

E. Schweizerbart´sche Verlagsbchhandlung

Lugar: Stuttgart; Año: 2005 vol. 236 p. 129 - 147

0077-7749

The Capillitas batholith consists of porphyritic to equigranular granites, biotite-cordierite rich, and felsic granites, with andalusite and sillimanite. The host rocks are schists, which have developed hornfels bearing cordierite-andalusite-biotite. A gravity-altimetric profile constrains the regional tendency of the Moho as a S-N-descent of 0.13°. Applying a model of densities of 3300 kg m-3 for the upper-mantle, and 2900 kg m-3 for the lower-crust, we ascertained depths between 45 and 50 km for the Moho. By the gravity inversion method (2 ½ D) applied to the residual Bouguer anomaly, depthdown to 9 km from today´s topographical level of the Cerro Negro can be assumed for the maximum granite root. Field, petrological and geochemical data suggest that the mafic and felsic granites have a common quartz-feldspar-biotite-rich crustal source. The anatexis took place at temperatures between 630 and 720ºC, and pressures between 2 and 4 kbar, in the stability field of cordierite-biotite-andalusite-sillimanite.