Structural features of Mass-Transport deposits within carbonates from Southern Italy

A detailed characterization of submarine mass-transport deposits (MTDs), in terms of both emplacement processes and internal architecture of depositional products, is crucial to define the hydraulic properties of slope-to-basinal deposits. When compared to underlying and overlying undeformed strata, MTDs form distinct mechanichal units and may represent significant heterogeneities within sedimentary successions and may act as barriers or conduits for fluid flow in the subsurface. The Late Jurassic-early Cretaceous basinal maiolica Formation exposed in the Gargano Promontory (southern Italy) represents an ideal natural laboratory to study the complex stratigraphic architecture of ancient MTDs. This formation consists of undisturbed intervals of flat-lying, thin-bedded, cherty micritic limestone interbedded with chaotic intervals of lithologically similar strata characterised by significant internal distortion. The stratigraphic thickness of these deformed beds, which are interpreted to represent several types of mass movements (e.G., slumps and, to a lesser extent, slides and debris flows), varies from several decimetres to tens of metres. The internal deformation features comprise down-slope verging folds, and both normal and reverse faults. The structural analysis of the folds and thrusts reveals the transport directionof observed MTD's, so it is possible to reconstruct the palaeo-morphology of the continental margin. The study shows that the transport direction was prevalent to E and NE in the eastern part of the promontory and to the N direction in the NE part. In several places, the studied MTDs exhibit signs of reworking, as demonstrated by reactivation of the slump-related faults resulting in deformation of beds overlying the MTDs. Moreover, in internal architecture of studied MTDs is discussed in the context of triggering mechanisms related to the characteristics of the Cretaceous Paleoslope of Apulian Platform.