Grotte e abissi nella grande unità geologica Prepirineu

The Prepirineu is a strip of folded limestone ranges between the Pirineu axial and the Ebre depression. Its powerful karst —Cadí-Moixeró, Montsec, Boumort— contains some of the deepest pits and systems in Catalonia. The catalogue records 1306 cavities: 814 caves and 492 pits, with a total passage of 84385 m and a maximum depth of 328 m.

Among the longest cavities are the Cova Cuberes, at Serradell (Conca de Dalt), with 13513.15 m of passage and 328 m of vertical extent, excavated in conglomerates; the Forat de l'Or, a spring of 2213 m in the Terradets gorge (Camarasa), with 1400 m submerged in sump and 93.5 m of vertical extent; the Grallera Gran del Corralot, of 1977 m in the Montsec d'Ares (Sant Esteve de la Sarga); les Correjades, of 1835 m in the Vall d'en Bas; and the Botet de Casa Rei, of 1579 m at Tremp (Serra de Lleràs), with 41 m of vertical extent.

The recorded lithologies are Limestone (857), Conglomerate (320), Sandstone (64), Marl (25), Travertine (18), Gypsum (16), Dolomite (5) and Clay (1).