The most extensive karst landscape in the Algarvensis territory is developed in the Upper Jurassic limestone and dolomite rocks. These big and diverse features include sinkholes, lapiás, megalapiás, dolines, caves, sinkholes and karst pavements. The megalapiás stand out in the blue sky, like great statues of rock, sometimes in the shape of an arch, sometimes in the shape of a needle or tower. These structures, several metres high, result from the action of the water, which dissolves the limestone rocks, opening fractures and depressions, excavating the rock and sculpting the relief, thus giving rise to an important karst geomorphology.

This intense karstification is also responsible for the formation of the red sediment, which covers the ground and fills the rock crevices and fissures: the "red land", which gives the Barrocal its characteristic colour.

All these elements highlight the important role of the underground karstic system as a recharge area for the Querença-Silves aquifer system.