Geo-thermochronology of the Saint Antonin basin, south-eastern France
Résumé
The clastic sedimentary formations of the Saint Antonin basin in the French Maritime Alps
contain the record of the Early Oligocene erosional history of the Maures-Esterel massif, Sardinia and
Corsica. Detrital apatite fission-track dating and zircon fission-track/U-Pb double dating of samples
collected from the Saint Antonin basin confirm sediment provenance and allow obtaining first-order
estimates of drainage basin maximum and long-term average exhumation rates. Whereas average
exhumation rates were on the order of 0.1–0.2 km/Myr during the Early Oligocene, small parts of
the Saint Antonin basin source areas may have experienced maximum exhumation rates on the order of
0.4–0.7 km/Myr. Although zircons and apatites with Early Oligocene fission-track cooling ages make up
between 11–15% of the dated grains, a possible volcanic contribution is negligible, as only one single
volcanic zircon grain was identified by fission-track/U-Pb double dating. Regional geodynamic
processes with convergence in the Western Alps to the east and the end of the Pyreneo-Provençal
compression phase by the early Oligocene controlled the differences in basin fill history and sediment
provenance between the Saint Antonin basin and the largely contemporaneous Barrême basin in southeastern
France.
Domaines
Géochimie
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