Forebulge migration in the foreland basin system of the central‐southern Apennine fold‐thrust belt (Italy): New high‐resolution Sr‐isotope dating constraints. (4th August 2021)

• Record Type: Journal Article
• Authors: Sabbatino, Monia; Tavani, Stefano; Vitale, Stefano; Ogata, Kei; Corradetti, Amerigo; Consorti, Lorenzo; Arienzo, Ilenia; Cipriani, Anna; Parente, Mariano
• Is Part Of: Basin research. Volume 33:Number 5(2021)
• Page Start: 2817
• Page End: 2836
• Publication Date: 2021-08-04
• Subjects: central‐southern Apennines (Italy) -- fold‐thrust belt -- forebulge -- foredeep -- foreland basin system -- strontium isotope stratigraphy; Sedimentation and deposition -- Periodicals; Sedimentary basins -- Periodicals; 551
• DOI: 10.1111/bre.12587
• Languages: English
• ISSNs: 0950-091X

Abstract

Abstract: The Apennines are a retreating collisional belt where the foreland basin system, across large domains, is floored by a subaerial forebulge unconformity developed due to forebulge uplift and erosion. This unconformity is overlain by a diachronous sequence of three lithostratigraphic units made of (a) shallow‐water carbonates, (b) hemipelagic marls and shales and (c) siliciclastic turbidites. Typically, the latter two have been interpreted regionally as the onset of syn‐orogenic deposition in the foredeep depozone, whereas little attention has been given to the underlying unit. Accordingly, the rate of migration of the central‐southern Apennine fold‐thrust belt‐foreland basin system has been constrained, so far, exclusively considering the age of the hemipelagites and turbidites, which largely post‐date the onset of foredeep depozone. In this work, we provide new high‐resolution ages obtained by strontium isotope stratigraphy applied to calcitic bivalve shells sampled at the base of the first syn‐orogenic deposits overlying the Eocene‐Cretaceous pre‐orogenic substratum. Integration of our results with published data indicates progressive rejuvenation of the strata sealing the forebulge unconformity towards the outer portions of the fold‐thrust belt. In particular, the age of the forebulge unconformity linearly scales with the pre‐orogenic position of the analysed sites, pointing to an overall constant migration velocity of the forebulge wave in the last 25 Myr. Abstract : Tectono‐stratigraphic evolution of the central‐southern Apennine foreland basin system. The shape and migration rate of the foreland basin is constrained by a new high‐resolution regional dataset of Sr‐isotope dating for the base of the time‐transgressive shallow‐water carbonate unit at the bottom of the foreland basinal megasequence sealing the forebulge unconformity.