ANATOMY OF SOME MESSINIAN PROGRADATIONAL CARBONATE PLATFORMS IN THE WESTERN MEDITERRANEAN

The prograding Messinian carbonate platforms of Melilla-Nador (Morocco ), Djebel Murdjadjo (Algeria) and Cariatiz (Spain) have been studied b y reconstructing their original anatomy. Original anatomies were deter mined by removing late deformations, and include palaeostructural, sed imentological and palaeoenvironmental data. The organization and succe ssion of the sedimentary units, especially the bioclastic then reefal units, in the three platforms. The reconstructed cross-sections show a variable number of superimposed prograding units, with probably high frequency relative sea-level changes in some of them. In the three pla tforms, aggrading reefs develop after the prograding reefs. Then is a general infilling of the sedimentation areas, with diverse sediments a mongst them are some evaporites. The maximum carbonate accumulation oc curs during the progradation. The biological content of the platforms does not display major break throughout times, but progressive changes .