Along three key sections (Curone Valley, Enza Valley and Setta Valley) a quantitative study of both planktonic and benthic foraminifera has been performed on the stratigraphic interval spanning from the base of the Epiligurian Succession (Middle Eocene) to the lower portion of the Bismantova Group (Lower Miocene). The aim of this work was to collect paleobathymetric data and to unravel the uplift/subsidence history («geohistory») of the Ligurian wedge by correlating them with lithostratigraphic and biostratigraphic data. The main results are as follows: the Epiligurian deposition began in the Bartonian in a deep marine environment (2000-1000 m depth), and then, an overall shallowing trend is recorded in every section, culminating with Burdigalian shelf deposits (200-30 m depth). In the Enza Valley and Setta Valley sections, this general trend was caused by initially strong uplift of the Ligurian substratum, followed by fairly uniform subsidence which began at considerably different times in the two sections. In both, it was more than balanced by deposition (overbalanced), leading to the progressive decrease in accommodation space. In the Curone Valley section only an overall subsidence trend for the Ligurian substratum is recorded since the Priabonian also saw overbalancing of deposition. As a whole, no clear correlations resulted between the Ligurian orogenic wedge geohistory and the migration steps of the related Northern Apennines foredeep, with the possible exception of the Burdigalian unconformity, roughly fitting the foredeep shift from the Cervarola to the Marnoso Arenacea Basin.

Geohistory of the Ligurian orogenic wedge: first interferences from Epiligurian sediments

DI GIULIO, ANDREA STEFANO;MANCIN, NICOLETTA;
2002-01-01

Abstract

Along three key sections (Curone Valley, Enza Valley and Setta Valley) a quantitative study of both planktonic and benthic foraminifera has been performed on the stratigraphic interval spanning from the base of the Epiligurian Succession (Middle Eocene) to the lower portion of the Bismantova Group (Lower Miocene). The aim of this work was to collect paleobathymetric data and to unravel the uplift/subsidence history («geohistory») of the Ligurian wedge by correlating them with lithostratigraphic and biostratigraphic data. The main results are as follows: the Epiligurian deposition began in the Bartonian in a deep marine environment (2000-1000 m depth), and then, an overall shallowing trend is recorded in every section, culminating with Burdigalian shelf deposits (200-30 m depth). In the Enza Valley and Setta Valley sections, this general trend was caused by initially strong uplift of the Ligurian substratum, followed by fairly uniform subsidence which began at considerably different times in the two sections. In both, it was more than balanced by deposition (overbalanced), leading to the progressive decrease in accommodation space. In the Curone Valley section only an overall subsidence trend for the Ligurian substratum is recorded since the Priabonian also saw overbalancing of deposition. As a whole, no clear correlations resulted between the Ligurian orogenic wedge geohistory and the migration steps of the related Northern Apennines foredeep, with the possible exception of the Burdigalian unconformity, roughly fitting the foredeep shift from the Cervarola to the Marnoso Arenacea Basin.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/13286
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