SEDIMENTARY EVENTS AND RUDIST ASSEMBLAGES OF MAIELLA MOUNTAIN CENTRAL ITALY PALEOBIOGEOGRAPHIC IMPLICATIONS

The set up of an extensional margin in the Maiella Mt. during the early Cenomanian causes the growth of a flourishing Rudist assemblage. A community with Apricardia, Distefanella, Caprina, Schiosia and Caprinula evidence a rimmed shelf, with flat top and a marked break of slope in correspondence of the high energy shallow shelf edge. Abundant skeletal remains are resedimented along a steep and gullied slope. The facies sequence is to be connected with a relative sea level rise together with development of lowstand depositional systems. The occurring of a prograding biodetrital wedge is shown by upward shoaling cycles in the platform areas. During the Senonian, the relative sea level rise generates the building of an Hippuritid shallow-water complex with clear aggradational and retrogradational trend, characterized by Milovanovicia, Hippurites, Sabinia, Vaccinites, Sauvagesia, Hippuritella, Apricardia, Joufia, Pironaea, Rajka and Radiolitella, showing different ecological conditions at the water/sediment interface. During the Campanian p.p-Maastrichtian a stillstand and a slow fall of relative sea level are followed by new progradation phenomena and a decreasing of the water energy in the inner zone, evidenced by Apricardia and Radiolitella muddy facies. This evolutive sequence may be connected with a gradual decreasing of the slope angle and consequent enlargement of the transitional shallow-water belt. The Rudist fauna of Maiella Mt. shows clear affinities both with the external Dinarid-Hellenid belt and with the apulian-iblean foreland. Such evidence of faunistic and ecological correspondence could suggest the hypothesis that the previous mentioned areas were part of a single paleobiogeographic province.