IL LANGHIANO-SERRAVALLIANO TRA LE VALLI DEL TANARO E DEL BELBO. CONFRONTI CON I DINTORNI DI GAVI E DI FINALE LIGURE

The Langhian-Serravallian sequences cropping out in the southwestern part of the Tertiary Piedmont Basin (NW Italy) are firstly examined. Secondly, comparisons are stated with coeval sequences cropping out in the Gavi region (easternmost Tertiary Piedmont Basin) and in the Finale Ligure area (Liguria).During Langhian two sedimentary basins have been recognized. The northern one extended at least from Cuneo region up to Novi Ligure area: in the northeastern part of this basin mainly hemipelagic mudstones are present; the southwestern part, on the contrary, is characterized by thick siliciclastic turbidites. The southern basin is testified only by small outcrops of shallow-water grainstones and hybrid arenites. During Serravallian turbidites occupied most of the northern basin; south-east of the turbidites area a slope-to-platform transition has been identified. The southern basin, only represented by marginal shallow-water sediments, is characterized by grainstones and hybrid arenites, as during Langhian time