Field trip to Malaga

This field trip of Prometheus project in search of alkaline systems was near its base; at the alkaline springs related to serpentinized peridotites in Malaga province. We visited several methane-rich and hyper-alkaline spring sites within Ronda peridotite massif (La Hedionda, Fuente Amarga Spa Tolox, Fuente Alfaguara, Fuente Amargosa, Baños del Puerto and Baños del Duque). Getting access to the spring sites included “negotiations” with spa owners and local farmers as some of the sites were within private properties. Aim of our trip is the investigation of mineral assemblages and their textural characteristics coupled to the spring system hydrogeochemistry. Discharges of hyper-alkaline waters (pH 11.4 – 12.2) are associated with carbonate mineral precipitation and travertine terracing structures. Water and precipitated mineral samples were collected in addition to on site pH, conductivity, temperature and oxygen fugacity measurements.  Slightly alkaline (pH 7.9 – 8.6), methane-rich springs were also visited. Main characteristics of these springs were the intensive gas bubbling, high contents in biological material and the total absence of carbonate precipitation.

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