The Campo de Calatrava volcanic field is a volcanic field in Spain. The field has an area of more than 5000km² and more than 300 individual structures next to Ciudad Real and contains pyroclastic cones, lava domes and maars. The field erupted basaltic to foiditic lavas from the Pliocene to the Holocene in Columba volcano with phreatomagmatic activity, and fumaroles were observed in the 16-18 centuries in the Sierra de Valenzuela territory. Earlier activity has been subdivided in several phases. The first affecting mostly the centre of the field is K-Ar dated between 8.7 and 6.4 Ma. A second phase occurred in the Pleistocene 1.3 Ma and 0.7 Ma. The maars involve both hard-substrate maars formed in metasediments of the basement and soft-substrate maars in Pliocene unconsolidated sediments. Both types of maars are distributed in NE-SW and NW-SE directions following faults established during the Miocene. During the lower Pliocene, the system underwent uplift and erosion. Some maars contain sediments including travertine possibly related to carbon dioxide emissions. Gas emissions, sometimes increased following earthquake activity, are common in the field and include hydrogen sulfide, CO₂ and water.