Coexistence of thin- and thick-skinned tectonics: An example from the Central Apennines, Italy
Vittorio Scisciani, Raffaele Montefalcone, 2006. "Coexistence of thin- and thick-skinned tectonics: An example from the Central Apennines, Italy", Styles of Continental Contraction, Stefano Mazzoli, Robert W.H. Butler
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In this study, the outer sector of the Central Apennines of Italy and the Adriatic foreland have been analyzed in order to reconstruct the geological-structural setting and the Neogene-Quaternary evolution of the fold-and-thrust belt.
Based on fieldwork data, existing geological maps, new seismic data, and well information, a regional balanced cross section has been realized. The transect, ∼140 km in length from the inner mountain belt to the Adriatic foreland, illustrates the structural style of the Apennines thrust system, the geometry of the different thrust fronts, the physiography of the foreland ramp, and the setting of the syn-tectonic basins infill. Moreover, by sequential balancing and subsequent forward modeling of the restored cross section, the migration of the contractional deformation and the tectonic evolution of the chain-foredeep-foreland system has been unraveled, and shortening rates have been calculated.
The complex structural setting of the Central Apennines fold-and-thrust belt derived from this study mainly results from the interaction between an extremely thin-skinned thrust system and a thick-skinned tectonics. The former mainly affects the syn-orogenic siliciclastic foredeep deposits and generally predates the emplacement of the second one (i.e., the deeper thrust system) that crosscuts the whole sedimentary cover (i.e., Triassic-Miocene carbonates and the overlying Messinian-Pliocene siliciclastic sediments) and locally involves the basement. The uncoupling in space and time between thin- and thick-skinned tectonics strictly controls the evolution and the migration of syn-tectonic basins and influences the sequence of thrust-system propagation; the latter, with respect to the deeper stratigraphic levels, is mainly toward the foreland even if breaching thrusts are present. Moreover, spacing and location of thrust ramps are strictly controlled by preexisting discontinuities that affect the foreland ramp.