Segundo rerporte de corieritas ricas en Na-Be en Argentina, sierra de Velasco

DAHLQUIST, J. Y ALASINO, P.

Río Cuarto, Córdoba

Congreso; 7º Congreso de Mineralogía y Metalogenia; 2004

UBA-UNRC

Na-Be cordierites (Na2O = 1,50 ? 1,58 and estimated BeO = 0,92 ? 0,94 %) occur in peraluminous granitoide outcrops in NE sierra de Velasco. His is the second report from Argentina of this type of cordierite founded in granitoids. Based of bulk analysis of the cordierite, we provisionally argue that Na and Be were introduced trough the substitution 2Na(ch)+2Be(VI-IV) ? Mn(VI)+Si(IV) and proposed a way to estimated the Be content in Na-cordierite. The crystallization of Na-Be cordierites would have been supported by the composition of the parental magma, which was derived by melting of metapelites with a distinctive alkali and Be content and lack of cordierite.