The halitas of cabo frio salinas: an identification of the crystal morphologies as a contribution to the understanding of the ancient halites

Abstract

Halite crystals with varied morphologies observed on salinas of the Araruama Lagoon (Cabo Frio region - Rio de Janeiro State) are presented herein. The distribution of such crystals within the individual tanks is also discussed, aiming at the understanding of the processes that lead to their formations. Our observations confirm a model proposed by Handford (1990). According to such model, the distribution of different crystal morphologies is controlled by the wind energy. Thus, hopper crystals concentrate on lower energy areas, while chevrons are preferentially found in agitated waters. With this study, we hope to help to improve the knowledge on the formation of the different crystal morphologies of ancient evaporite deposits and their environmental implications as well.