Petrographic considerations on the effusive basic rocks of the Los Rastrojitos Formation and their K-Ar age

Abstract

Petrographic considerations on the effusive basic rocks of the Los Rastrojitos Formation and their K-Ar age?. In the central eastern part of Catamarca Province (Argentine) effusive basic rocks outcropp, conforming two small bodies, which belong to Los Rastrojitos Formation (quaternary age according Turner). Radiometric dating (K-Ar method), gives 17 + 2 m.y.and 21 +2 m.y. for each one of them (Miocene), modifying the original conception.