Journal Contents - 3D Model of the active extensional fault system of the high Agri River valley, Southern Apennines, Italy

Geological Setting

The high Agri River valley (Fig. 1a) is a WNW-ESE oriented intramontane basin located in the axial zone of the southern Apennines mountain belt. Here, a Quaternary fault system dissects the pre-existing fold and thrust belt. The latter is characterised by the tectonic superposition of allochthonous units, completely detached from their original substratum, onto the foreland succession of the Apulian Platform. This consists of a 6-7 km thick, Mesozoic-Tertiary shallow-water carbonate succession, stratigraphically overlain by upper Messinian and/or Pliocene terrigenous marine deposits. The buried Apulian carbonate rocks appear to be deformed by thick-skinned inversion/thrust structures (e.g. Mazzoli et al., 2000; 2001).

The allochthonous units, exposed at surface, consist of Mesozoic-Paleogene peritidal carbonate platform (Apenninic Platform) and pelagic basin (Lagonegro Basin) units unconformably overlain by Miocene siliciclastic strata (Fig. 1a). These rocks are involved in mainly NW-SE to N-S trending folds and thrusts, which formed during Late Oligocene-Neogene shortening (Mazzoli et al., 2001).

The detachment between the allochthon and the buried Apulian unit is marked by a mŽlange zone, several hundreds of metres thick. This unit (Mazzoli et al., 2001) dominantly consists of intensely deformed and overpressured deepwater mudstones and siltstones, with minor sandstones and limestones. Biostratigraphic data indicate a Miocene-Lower Pliocene age for the bulk of the sediments within this interval (Mazzoli et al., 2001, and references therein). This unit, representing the major dŽcollement at the base of the allochthon, is interpreted to include Mio-Pliocene foredeep deposits incorporated within the dŽcollement zone as the advancing fold and thrust belt over-rode its foreland basin (Mazzoli et al., 2001).

This setting is shown in the 3D model of Figs. 2-6. For the sake of simplicity, as it was not relevant to the present study, the internal structure of the allochthon is not shown in the model.

Borraccini, F., De Donatis, M., Di Bucci, D. and Mazzoli, S. 2002. 3D Model of the active extensional fault system of the high Agri River valley, Southern Apennines, Italy. In: Jessell, M. J. 2002. General Contributions: 2002. Journal of the Virtual Explorer, 6, 1-6.
3D Model of the active extensional fault system of the high Agri River valley, Southern Apennines, Italy
Geological Setting The high Agri River valley (Fig. 1a) is a WNW-ESE oriented intramontane basin located in the axial zone of the southern Apennines mountain belt. Here, a Quaternary fault system dissects the pre-existing fold and thrust belt. The latter is characterised by the tectonic superposition of allochthonous units, completely detached from their original substratum, onto the foreland succession of the Apulian Platform. This consists of a 6-7 km thick, Mesozoic-Tertiary shallow-water carbonate succession, stratigraphically overlain by upper Messinian and/or Pliocene terrigenous marine deposits. The buried Apulian carbonate rocks appear to be deformed by thick-skinned inversion/thrust structures (e.g. Mazzoli et al., 2000; 2001). The allochthonous units, exposed at surface, consist of Mesozoic-Paleogene peritidal carbonate platform (Apenninic Platform) and pelagic basin (Lagonegro Basin) units unconformably overlain by Miocene siliciclastic strata (Fig. 1a). These rocks are involved in mainly NW-SE to N-S trending folds and thrusts, which formed during Late Oligocene-Neogene shortening (Mazzoli et al., 2001). The detachment between the allochthon and the buried Apulian unit is marked by a mŽlange zone, several hundreds of metres thick. This unit (Mazzoli et al., 2001) dominantly consists of intensely deformed and overpressured deepwater mudstones and siltstones, with minor sandstones and limestones. Biostratigraphic data indicate a Miocene-Lower Pliocene age for the bulk of the sediments within this interval (Mazzoli et al., 2001, and references therein). This unit, representing the major dŽcollement at the base of the allochthon, is interpreted to include Mio-Pliocene foredeep deposits incorporated within the dŽcollement zone as the advancing fold and thrust belt over-rode its foreland basin (Mazzoli et al., 2001). This setting is shown in the 3D model of Figs. 2-6. For the sake of simplicity, as it was not relevant to the present study, the internal structure of the allochthon is not shown in the model.
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