In this paper we present a study of a segment of the southern Apennine mountain belt which extends from the Pollino mountain range to the south and the Sele valley to the north. Combining regional data and structural information with the results based on the interpretation of several seismic reflection lines and many deep well logs, three regional cross sections have been constructed. The cross sections highlight the overall architecture of the orogenic belt which is constituted by a thin tectonic layer of allochthonous nappes represented by remnants of the Neotethyan accretionary wedge (e.g., Liguride and Sicilide units) resting above a thick imbricated thrust belt. This latter comprises distinct units represented by platform carbonates (western platform, Monte Alpi, Costamolina and Tempa Rossa units) and pelagic basin domains (Lagonegro, Campomaggiore and Faeto units) deriving from the Late Tortonian- Quaternary deformation of the Adria paleomargin. The restoration of the three cross sections furnished information on the primary geometry of the Adria paleomargin which was characterized by the occurrence of a large platform domain dissected by distinct pelagic basins with complex and irregular margins represented by pelagic embayments and platform promontories developed during the Mesozoic and the Late Cretaceous-Tertiary times. The reconstructed geometry of the paleomargin provided, moreover, useful insights to evaluate the mode of deformation and the rates of shortening of the thrust belt and to explain the Neogene stratigraphy of the distinct platform domains. The mode of deformation of this portion of the southern Apennines was dominated by the occurrence of crustal thrusts located along previous weakness zones represented by the boundaries between platform and pelagic domains. These crustal thrusts caused the complete closure of the basin areas and the direct overthrusting of the different buoyant platform domains, with contractional rates characterized by values ranging from 3.1 to 4.3 cm/yr. Finally, a geodynamic model in which the southern Apennine mountain belt is considered the result of lateral extrusion produced by the indentation of the Pelagian block and by the consequent opening of the Tyrrhenian Sea is also proposed.
|Titolo:||Neogene-Quaternary tectonic evolution of the southern Apennines|
|Data di pubblicazione:||2004|
|Appare nelle tipologie:||1.1 Articolo in rivista|