Errores cronoestratigráficos en la Faja Pirítica Ibérica: el caso de la Secuencia Carbonatada de Aznalcóllar (nota previa)

The Aznalcollar Carbonate Sequence is constituted by black shales surrounding carbonate lenses. The black shales contain lowermost upper Visean palynomorphs and the carbonate lenses have lower Visean conodont faunas. Sedimentological, petrographical and biostratigraphical analysis of the sequence confirms a turbiditic character of the carbonate lenses and an autochthonous character of black shales. Until now, conodont age has been considered synchronous with carbonate sedimentation. This study evidences that fossils included in the carbonate lenses are reworked clasts. Miospore assemblage of black shales points to a 10 m.y. span between conodonts age and deposition time. This is a case of study that casts doubt on the chronostratigraphical data of the IPB obtained from fossils of carbonate lenses with similar facies to the Aznalcollar Carbonate Sequence.