Els col·lapses paleocàrstics del miocè superior de Mallorca: estructura, origen i reconeixement als perfils sísmics.

Abstract

[eng] Based on the geometry and the stratigraphic relationships between the two Upper Miocene units of the SE of Mallorca (from base to top, the Reefal Unit and the Santanyí Limestone Unit) a series of sinsedimentary karst paleocollapse formation models are presented. The karstic paleocollapses of the study area are formed when a void is created due to the dissolution of the limestone levels of the Reefal Unit, when some layers of the Santanyí Limestone Unit had already been deposited. The void causes synclinal bending of the upper limestones, which may or may not be accompanied by breccia formation in the central part of the fold and also filling the solution void. Karst collapses have been studied both in the cliffs of the coast of Santanyí and in seismic reflection profiles carried out in 1998 during an oceanographic campaign in the coastal area of Santanyí. The results show that the karst collapses are also below the seabed and have the same dimensions and morphologies as those observed in the coastal cliffs of SE Mallorca. Finally, the sedimentological and geomorphological evolution of this area of SE Mallorca, from the Upper Miocene to the present day, is shown.