Juan Manuel Garcia-Ruiz, from the University of Granada, is a Visiting Professor in the NYU Department of Chemistry's Molecular Design Institute. He will deliver a seminar entitled, "The Mineral Beauty of the Most Extreme Terrestrial Hydrothermal System: Dallol, Ethiopia." Hosted by Bart Kahr and Mike Ward.
Abstract: The Dallol hydrothermal system emerges from the salty plain of the Danakil depression near the border between Ethiopia and Eritrea. It is geologically located in the Afar Triangle, a region where the Rift Valley meets the Gulf of Aden and the Red Sea drawing a Y letter that is breaking apart Africa while moving Arabia away. We have explored this fascinating location during two scientific expeditions in 2016 and 2017. We performed in situ measurements, sampling brines from hydrothermal springs and pools, mineral precipitates, and gases. The highly dynamic hydrothermal activity of the site is manifested in numerous fumarolic fields and springs, both subaerial and subaqueous, that discharge O2-free, hyper-acidic brines (pH near and below 0), of 105-108 °C temperature, supersaturated in NaCl, containing more than 30 g/L of Fe. Besides the uniqueness of its chemistry and its economical interest, the site is of special beauty due to the different shades of reds, yellows, and greens of their pools and precipitates. I will present in this lecture the results of these missions. In summary, our work demonstrated that, unlike other terrestrial and submarine hydrothermal systems, the mineral garden of Dallol can be explained by pure inorganic reactions, thus challenging the shibboleth of “liquid water equals life”.