Hydrogeochemistry of volcanic lagoons in extreme environments: a case study in the region of Puna / Argentina.

Environments with extreme climatic, geological and tectonic conditions produce a chemical signature in surface and groundwaters. These hydrochemical conditions condition, in many cases, carbonate precipitation. Modern carbonate environments can serve as possible analogs to improve our understanding of the physical-chemical processes involved in the formation of ancient microbial carbonates deposited in association with various Mg-clay minerals. The Puna Argentina region is undoubtedly one of the most spectacular places on planet earth. It has exuberant scenic beauty and extreme environmental conditions such as high altitudes, low air humidity, strong winds, and high solar radiation. The region occupies the central part of the Andes, with valleys and plateaus averaging 3600 meters above sea level, and the mountains have summits of over 5500 meters. This paper aims to present a hydrochemical study of the region, focusing on two volcanic systems: Galan Volcano and Peinado Volcano. We sampled 10 points. In both places predominate chlorinated sodium waters. The temperatures of the lagoons are between 3 and 9 celcius degrees, and the temperature in the hydrothermal vents ranges from 30 degrees in the peinado volcano and 80 degrees in the Galan volcano. Extreme environmental conditions and associated volcanism imply a large number of dissolved elements in lake waters. Hydrothermal vents are less mineralized when compared to lagoons. Highlighting the values obtained in the waters of Laguna Diamante, where the concentrations of chloride, sulfate, sodium, potassium, fluoride, and sulfate presente, at least, more than 10 times the concentration of the other sampled points. In this lagoon was found the presence of the mineral gailucita. Knowledge of the physicochemical characteristics of water will help to develop a model for carbonate precipitation in extreme environments.