The Achala batholith (Cordoba, Argentina): a composite intrusion made of five independent magmatic suites. Magmatic evolution and deuteric alteration

Abstract

The Achala batholith in the Sierra Grande de Cordoba (Argentina), is a major intrusion of Devonian to Early Carboniferous age. In this complex batholith, five different magmatic suites are distinguished by their geochemical characteristics and a specific metallogenic specialization; each one includes various petrographic facies ranging from tonalite to evolved leucogranites. Differences between these magmatic suites, magmatic evolution and deuteric alteration are discussed using content in major and trace elements geochemistry and mineral composition. There is a clear correlation between petrographic facies, whole rock geochemistry and mineral chemistry of biotites and of the core of the plagioclases, reflecting the magmatic differentiation. Muscovite, partial reequilibration of the plagioclase and part of the peralumineous character of the batholith, are due to an extensive deuteric alteration.