Geochemistry of the waters realted to the Planchón-Peteroa Volcanic Complex, Mendoza-Argentina

Abstract

The present work was developed in the Planchón-Peteroa Volcanic Complex in the Mendoza province, Argentina. Its goal is to analyze and describe for the first time the main geochemical processes that are developed and control the waters composition in the studied volcanic complex hydric system. Those waters were classified from its compositions and fisicochemical characteristics in four groups: sulfate-chlorided, acidic and hot waters from the crater lakes; thermal neutral sulfated waters; thermal neutral bicarbonated waters; and cold and acidic to slightly acidic stream waters. The main processes recognized in the described waters are its interaction with the hot and acidic gases emanated from the magmatic chamber, the precipitation of secondary minerals as calcium sulfate, the water-rock interaction, particularly with the Auquilco formation evaporites, and its interaction with the ashes emitted from the Peteroa volcano during eruptive activity periods. The presence or the combination of some of these processes defines the geochemical composition of each water group.