Evidences of Past and Present Hypogenesis in the Serrezuela De Carratraca Massif (Málaga, Southern Spain)

[EN] The Serrezuela de Carratraca Massif is a small carbonate massif located in the South of Spain. It corresponds to an outcrop of a geological unit formed by Triassic dolomitic marbles and limestones, belonging to the Alpujárride Complex of the Betic Cordillera. The surface of this karstic massif lacks well-developed exokarstic features, however, there are several known caves, with significant dimensions, as well as a spring with relatively high flow rates. Ardales Cave (1522 m of horizontal development) is a maze-type cave, with a great amount of cupolas inside, in the walls and ceilings. It is situated above the water table, without current hydrological activity. Sima Gorda (121 m of vertical development) is a rising shaft type cave, that reaches the actual water table and that contains different gases in its underground atmosphere (H2S, CO2, and methane). The main spring, located near Sima Gorda, is the Baños de Carratraca spring (Carratraca Baths), a well-known sulphurous spring used for centuries as a spa. These characteristics, as well as the presence of large amounts of pyrite transformed into iron oxy-hydroxides (limonite) in the Triassic marbles, suggest the possible common origin of all of these phenomena, linked to a deep regional groundwater flow. The Serrezuela Massif is a region of deep vertical water discharge that conditioned the hypogenic speleogenesis of the caves in the massif, induced by the mix of deep water and local recharge water. The presence of recent travertines near the spring suggest that the processes of dissolution–precipitation are still active.