Grotte e abissi in terreno Dolomia

Dolomite is a magnesium-rich carbonate rock, related to limestone but more resistant. It dissolves more slowly and usually forms karsts with rough morphology and robust galleries.

The catalogue gathers 371 cavities of this lithology: 224 pits and 147 caves, with a total length of 20991 metres and a maximum depth of 283 metres. Among the longest cavities are the Avenc de la Miloquera, 769 metres long in Marçà, with five entrances and a drop reaching -78 metres; the Avenc del Cim de l'obaga del Pollo, 754 metres; the Avenc dels Mamelons, 700 metres; the Avenc Cp.1, 675 metres; and the Avenc Cp.3, 665 metres.

The deepest cavities are the Avenc Cp.6, 283 metres deep on the S slope of Mont Caro (el Port), explored by the Espeleo Club Tortosa since 1985; the Avenc Cp.1, 195 metres of drop in the Cova Pintada sector (el Port); the Avenc del Camí de Xàquera, 180 metres deep in Tivenys (Baix Ebre); the Avenc dels Mamelons, 167 metres deep in the Mola de Catí (el Port, Tortosa); and the Avenc del Cim de l'obaga del Pollo, almost 141 metres deep in the Serra del Boix (Tivenys – el Perelló).