Upper Messinian siliciclastic rocks in southeastern Calabria (southern Italy): palaeotectonic and eustatic implications for the evolution of the central Mediterranean region

The Messinian stratigraphy of eastern Calabria (southern Italy) is characte rised by a threefold subdivision: (1) a pelite section with local limestone and gypsum, deposited in a restricted-marine environment, is unconformably , or disconformably, overlain by (2) coarse-grained alluvial conglomerate, which is in turn locally overlain by (3) a thin and discontinuous ribbon-sh aped sedimentary body of sandstone and pelite, commonly displaying a shallo w-marine to continental progradational trend. The basal unconformity/discon formity, coarse grain-size, and abrupt compositional-sedimentological chang e of unit 2 with respect to unit 1 can be explained as a response to tecton ic instability and out-of-sequence thrusting in the Calabrian orogenic wedg e, possibly induced by isostatic back-tilting of the wedge following the de siccation of the Mediterranean Sea. This mechanism could explain widespread late Messinian thrusting and syntectonic sedimentation along the Apenninic -Maghrebian orogenic belt. The uppermost Messinian continental to shallow-m arine siliciclastic deposits of unit 3 crop out today at elevations of up t o 300 m. Similar, age-equivalent sedimentary deposits can be traced along t he Apennines and the Sicilian Maghrebides, thus, indicating that the Medite rranean area was flooded before deposition of the Trubi Formation, the base of which is traditionally regarded as marking the reestablishment of marin e conditions in the Mediterranean region. (C) 1998 Elsevier Science B.V. Al l rights reserved.