THE UPPER CRETACEOUS HELMINTHOID FLYSCH OF THENORTHERN APENNINES: PROVENANCE AND SEDIMENTATION

The Mt. Cassio, Mt. Caio, Mt. Antola and Solignano successions (Campanian to Maastrichtian) examined in the type localities are made up of three distinct types of turbidite beds: micritic-marly, arenidc-siliciclastic and mixed. The mixed beds exhibit an arenitic-siliciclastic interval sradins upward into a micritic-marly interval.The micritic-marly beds and the micritic-marly intervalsof mixed beds consist chiefly of penecontemporaneous coccolithsplus a clay component indicating resedimentarion ofcoeval pelagic mud and ponions of the underlyingsedimentary successions from structural isolated highs andmarginal shelves. The terrigenous detritus of silióiclasúcbeds and of basal intervals of mixed beds derives mainly fromgranitic and lo\4'- to medium-grade metamorphic rocks of acontinental basement and, in the case of Mt. Caio and Mt.Cassio, from a carbonate sedimentary cover.In the Mt. Cassio siliciclastic beds and intervals of mixedbeds, unlithifred squeezed grains of mudstones with Calpionellidaeand Calcisphamrlidae and argillaceous clasts arepresent, suggesting resedimentation of material from older,still unconsolidated successions. The si-liciclastic beds and intervalsof the Mt. Cassio succession also contain significantamounts of allochems characteristic of the photic àne. indicatingcontributions from Campanian to Màasuichrian-carbonate-pladorm systems