Potential evidence for slab detachment from the flexural backstripping of a foredeep: Insight on the evolution of the Pescara basin (Italy)

The discrepancy between the size of the Apenninic chain and the depth of the Adriatic foredeep is investigated using 2D flexural backstripping on well-constrained depth-converted cross-sections in the Pescara basin (Central Italy). The procedure consisted of removal, uplift, unfolding and unfaulting of the Pliocene-Pleistocene foreland deposits to produce a palaeogeographic map of the basin at the end of the Messinian and to constrain sedimentary rates since the Miocene. Results are found to support the contribution of an external load to the foreland evolution together with the Apenninic chain load. The interplay of the two types of loads resulted in spatial and temporal variations of the foredeep evolution that are quantified by palaeogeographic maps and sedimentation rates obtained through backstripping. Results are interpreted as representing the effects of a southward-migrating wave linked to slab detachment beneath the Adriatic foredeep. This procedure can be useful to investigate similar problems on other chains worldwide.