Tectonic control on the deposition of the Lower Miocene sediments of the Monti della Maddalena Ridge (Southern Apennines): synsedimentary extensional deformation in a foreland setting
The Lower-Middle (?) Miocene deposits stratigraphically overly- ing the Meso-Cenozoic carbonate substratum in the Monti della Maddalena ridge (Southern Apennines) represent a pre-orogenic sedimentary cycle deposited in a foreland area that occupied the for- mer external margin of the Campano-Lucana Platform (CLP), before the tectonic emplacement of the Liguride accretionary wedge. A detailed stratigraphic and sedimentologic analysis has revealed that these deposits are characterized by strong vertical and lateral thick- ness and facies changes. These features are interpreted as the result of a complex basin geometry, consisting of asymmetric horst and graben structures bordered by steep fault planes. Thick calciclastic successions, made of breccia and turbidites, deposited in the down- thrown blocks, close to fault scarps, while the more distal areas are characterized by thinner and fine-grained successions. Condensed deposits are found on submerged structural highs. All the succes- sions show an overall thinning and fining upward trend and an evo- lution from calciclastic to siliciclastic deposits. Facies and stratigra- phy of the Lower-Middle (?) Miocene succession are best explained by a depositional setting strongly controlled by extensional tectonics related to flexural subsidence. The occurrence of lower Miocene deposits in neptunian dykes crosscutting the underlying carbonate succession strongly supports this hypothesis