Stratification of Montserrat

The Montserrat massif is made of conglomerate with calcareous cement deep strata that are separated by more clayey strips. From this lithological composition results a geomorphology of stepped pyramid like that of the temples of the Central American Mayan culture. The total height of the conglomerates is about 1000 meters, from Monistrol to the summit of Sant Jeroni. The sedimentation happened along Eocene and Oligocene periods in a deltaic environment that was progressively sinking.
The conglomerate strata in Montserrat are not arranged exactly horizontal, but somewhat tilt towards the north.
The inclination of the strata and the stepped pyramid shape can be seen from the east, in the range of Cul de Portadora, from the other side of the river Llobregat.

At smaller scale, the massif is engraved by a net of cracks following a roughly perpendicular to the stratification pattern. These cracks facilitate the formation of channels and the isolation of “serrats” first, then monoliths.

[photo Montserrat Porta and Jordi Badia]