MUTINAÍTE IN ZEOLITIC ASSEMBLAGE IN JURASSIC/CRETACIC METABASALTS OF VILLEGAS, NORTHERN PATAGONIAN ANDES, RIO NEGRO, ARGENTINA

MARIA ELENA VATTUONE; LEAL, PABLO; ANDREA MARTÍNEZ

Paris - Francia

Congreso; 4° International FEZA Conference, “Zeolites and related Materials: Trends, Targets and Challenges”; 2008

French zeolite Group-Federation of European Zeolite Association (FEZA)

In Northern Patagonian Andes, mutinaite in assemblage with clinoptilolite in amygdales of altered Cretacic/Jurassic metabasalts was found. The outcrops are located at 39°54´57" south and 71°03´10" west. The zeolites were studied by optical, SEM, EDS and XRD methods. The rocks have fresh pyroxene and andesine altered to pumpellyite, in a matrix with albite, interstratified chlorite/smectite, pumpellyite and epidote. There are veins with laumontite and amygdales infilled with clinoptilolite and mutinaite. This last mineral is white and pinky with perfect cleavage parallel to {100} and imperfect cleavage parallel to {001}. It is orthorhombic, the elongation is negative, 2Vα = 70°/80° and a0 = 19.166Å, b0 = 21.025Å, c0 = 14.558Å. Amygdales filled by mutinaite–clinoptilolite-quartz and veinlets with wairakite-laumontite suggest that their crystallization was related to low grade hydrothermal/geothermal metamorphism. The temperature of formation should be near 200°C/250°C range