RESTORATION OF PALEO-SHORELINES THROUGH LITHOSPHERIC 3D MODELING AND BACKSTRIPPING ANALYSIS: THE EXAMPLE OF THE PO PLAIN-NORTHERN ADRIATIC REGION DURING LATE MESSINIAN SEA- LEVEL DROP

摘要

We present a case history of 3D modeling and backstripping analysis of the paleo-topographic surface developed in the Po Plain–Northern Adriatic region during Latest Messinian sea-level drop occurred in the Mediterranean region, with special emphasis on the reconstruction of the paleo- coastline position. The model results from the integration of 2D seismic interpretation, backstripping and numerical modeling at a lithospheric scale using TISC program (Garcia-Castellanos et al., 2002; 2003) considering both the loading of the Plio-Pleistocene sediments and the regional amount of sea- level drop reported in the literature (Ghielmi et al., 2013, Rossi et al., 2015). The best fit between facies distribution maps and the resulting modeled coastline has been reached imposing a sea level drop of only 850m. This value is quite different from the ca.1500m calculated for the Mediterranean basin, thus suggesting that the Po Plain-Adriatic basin was an isolated sub-basin from the eastern Mediterranean, protected from a complete desiccation by a sill located in the Southern Adriatic Sea. Thanks to this fruitful cooperation between industry and academia, it is now possible to describe the entire 3D basin geometry and the facies distribution during the Latest Messinian time, including the expected position of potential exploration targets provided by coarse-grained deltaic complexes presumably developed at the mouths of riverine systems during the Messinian Salinity Crisis and then sealed by Pliocene marine marls.