Control of differential compaction on the geometry of sediments onlapping paleoescarpments: Insights from field geology (Central Apennines, Italy) and numerical modeling

Basin strata onlapping pelagic carbonate platform margins in the Central Apennines commonly dip considerably (as much as 20 degrees-30 degrees) toward the basin when platform strata (Calcare Massiccio) are retrodeformed to horizontal in order to undo the tilting related to Apenninic compressional tectonics. These angular relationships are commonly ascribed to normal drag associated with synsedimentary faulting. We show that such angular relationships are fully consistent with results of numerical simulations that aim at modeling first-order geometric features associated with sedimentation and compaction of de posits onlapping the escarpment at the margin of basins. Therefore, growth of an underlying normal fault is not generally required to generate them. This conclusion is also supported by field investigations of the contacts at pelagic carbonate platform margins and by paleoescarpment analysis, which strongly suggest post-early Liassic tectonic quiescence.