Sedimentary and Compositional Evolution of Serravallian-Tortonian Buried Siliciclastic Successions of Crotone Basin

Siliciclastic Serravallian–Tortonian strata of the Crotone Basin were studied in 16 well logs (3700 m in depth), both onshore and offshore. Stratigraphical and sedimentological variations along transects of 60 km (N-S) and 27 km (W-E) were undertaken. Arenites and conglomerates of San Nicola dell’Alto Fm, of alluvional to coastal environment, 897 m to 2.976 m in depth, are about 300 m thick. The maximum thickness is 468 m in the southernmost portions of the basin, the minimum of 32 m in the centre. It passes upward to the Ponda Fm (between 780-2.570 m) with claystone, marly mudstone and sandstone strata, of slope to deep marine turbidite systems. The maximum thickness is 1.147 m in the northernmost portions and the minimum is 37 m in the southernmosts’. The allochthonous Cariati Nappe structurally cuts the uppermost Ponda Fm, and, in these wells, consists of siliciclastic turbiditic strata and minor pelagic clays. Cariati Nappe sandstones are quartzolithic (Q52 F5 L42), having abundant extrabasinal carbonate, argillite and low-grade metamorphic lithic grains. Sandstones of San Nicola dell’Alto and Ponda fms are quartzofeldspathic (Q50 F40 L10), having lower lithic content than feldspar and quartz input that increase rapidly upward. Compaction and cementation are not impressive, unless some samples show early carbonate cementation, and rarely replacement and dissolution. A next implementation in GIS points to a 3D model of compositional and diagenetic variation along the basin.