The problem addressed in this article is a te n ta tiv e explanation o f the coexistence of partially miscible "ncompatible" fluids in different primary inclusions of the same crystal (or group of crystals). It is based on a study of sphalerite crystals from Cerro del Toro, containing two groups of primary inclusions with fillings displaying contrasting compositions, respectively suggestive on one hand of a "Mississippi Valley type“(MVT) brine, and on the other hand of a metamorphic fluid. The interpretation is based on a comparison of the composition of both " primary " fluids and a tentative explanation involving partial metamorphic recrystallization, whose possible markers are solid inclusions of briartite (a Ge-rich mineral)