GeoActa Special Publication 1
2008
Acquisto online |
GeoActa
an international Journal of Earth Sciences
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Andrea Artoni, Giovanni Papani, Francesca Rizzini, Massimo Bernini, Marco Roveri, Rocco Gennari
Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di Parma, Parco Area delle Scienze 157/A, 43100, Parma, Italy, e-mail: andrea.artoni@unipr.it, giovanni.papani@unipr.it, francesca.rizzini@unipr.it, massimo.bernini@unipr.it, marco.roveri@unirp.it, rocco.gennari@unipr.it
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The Salsomaggiore structure (Northwestern Apennine foothills, Italy): a Messinian mountain front shaped by mass-wasting products
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PDF (2.0 MB)
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Abstract
The Salsomaggiore structure is a tectonic window that exposes the Langhian-Serravallian foredeep units in a thrust-related and overturned anticline surrounded by the allochthonous Mesozoic-Paleogene Ligurian units and by remnants of Eocene-Messinian epiligurian deposits. The late Messinian succession, deposited after the Messinian evaporative event, shows a characteristic onlap against the Salsomaggiore structure and rests above an erosional unconformity that truncates both foredeep and allochthonous units. The tectonic and depositional setting of the Salsomaggiore structure, representative of the Northwestern Apennine foothill, was reached during the intra-Messinian phase, a tectonic phase of major reorganisation of the Northern Apenninic chain.
New surface and subsurface data suggest that the allochthonous units moved north of the present day Salsomaggiore anticline immediately after the early Messinian evaporative event, and formed the Messinian mountain front of Northwestern Apennines. The allochthonous units, preserving a clear tectonic imprint, show also evidence of large-scale slided masses, suggesting that they were emplaced by mass-wasting processes. These processes, shaping the topographic surface of the allochthonous units, were triggered by the contemporaneous uplift of the underlying foredeep units and by mutate climate conditions that enhanced an overall base-level rise. In fact, after the evaporative event, the widespread occurrence of fluvio-deltaic deposits testifies a wetter and rainy climate. Similar intra-Messinian mass-wasting products are widespread along the whole Northwestern Apennine foothills, suggesting that the Northern Apennines Messinian mountain front was dominated by mass-wasting processes.
Keywords: Foreland, Mountain front, Messinian, Stratigraphy, Mass-wasting.
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