Int. J. Speleol. 25 (3-4), 1996 Chapter 11.6 SOME EXAMPLES OF GYPSUM KARSTS AND THE MORE IMPORTANT GYPSUM CAVES IN SPAIN Jose Maria Calaforra & Antonio Pulido-Bosch 225 Abstract Spain possesses some of the most important examples of gypsum karst in Europe, in terms of the extent and variety of the gypsiferous outcrops. These are divided into gypsum belonging to the Triassic, Palaeogene and Neogene epochs, each of which displays different lithological and structural aspects. Some of Spain's most significant gypsum karsts, from the speleological stand- point, are described, and these share a common characteristic of all supporting the development of large caves. Reference is made to the geomorphology, hydrogeology and hydrochemistry of the gypsum karsts of Sorbas, Vallada and Gobantes-Meliones, which provide significant examples of intrastratal karst, speleogenesis by saline groundwater mixing and the influence of carbonate stra- ta, respectively. Finally, brief geomorphological and speleogenetic descriptions of the more signi- ficant gypsum caves in Spain are given, together with a list of the longest and deepest gypsum caves in Spain. 1. Introduction Spain contains some of the most extensive gypsum deposits in Europe. Some 30,000km2 of gypsum outcrop exists (Ayala et ai, 1986), all of which is, in principle, susceptible to karstification. Not only is the area of such outcrops large, but there is also a great lithological and chronostrati- graphical variety, with gypsum ranging from Triassic to Quaternary in age (Fig. 1). The most noteworthy outcrops, those most affected by karstification, are described briefly below. Triassic gypsum. These deposits occur mainly to the Betic mountain range, though there are also significant outcrops in the Pyrenees and Iberian range. They are Keuper facies gypsum, with many clayey, sandy and carbonate intercalations. The group is intensely tectonized and is even affected by diapiric phenomena. Significant examples include the gypsum karsts at Baena (C6rdoba; Calaforra and Pulido-Bosch, 1989), Fuente Camacho (Granada; Calaforra and Pulido- Bosch, 1989b), Estella-A110(Navarra; Eraso, 1959), Gobantes-Meliones (Malaga; Calaforra, 1996a), Archidona (Malaga; Duran and Burillo, 1985), Antequera (Malaga; Molina, 1982), Caravaca (Murcia), Vallada (Valencia; Pulido-Bosch, 1978) and Villena (Alicante; Cuenca, 1970), among many others. Palaeogene gypsum. These deposits are located to the north of the Ebro basin, close to the edge of the Pyrenees range. They present a great lithological variety, with massive gypsum, com- mon levels of anhydrite and marly, carbonate and clay intercalations. Some significant outcrops