Publication Date:
2022-02-25
Description:
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 beltforeland 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 foldthrust 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.
Description:
Published
Description:
2817-2836
Description:
6A. Geochimica per l'ambiente e geologia medica
Description:
JCR Journal
Keywords:
central-southern Apennines (Italy)
;
fold-thrust belt
;
forebulge
;
foredeep
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
