Platform-to-basin anatomy of a Barremian–Aptian Tethyan carbonate system: New insights into the regional to global factors controlling the stratigraphic architecture of the Urgonian Provence platform (southeast France)

Abstract

The recognition of regional ammonite bio-events spanning the late Barremian–early Aptian interval in Provence invalidates previous chronostratigraphic models of the Urgonian carbonate platform. Based on high-resolution correlations across the Provence platform and the Vocontian Basin, this study provides a comprehensive revision of the temporal and spatial evolution of this sedimentary system through the definition of seven depositional sequences. Close to the early–late Barremian transition, the South Provence domain was marked by the inception of rudistid, Agriopleura-dominated, carbonates, while further to the North, the expansion of the latter biota was delayed, presumably due to greater subsidence rates driven by extensive E–W-trending basement faults. Northward installation of a rudist-rich succession in the North Provence region – including, from oldest to youngest, the Agriopleura, requieniid–monopleurid and caprinid episodes – strictly spans the late Barremian. Intermittent shedding of platform-derived material influenced the basinal series in the pre-Vocontian margin at that time. Structural inheritance and active contribution of syn-sedimentary tectonics into the stratigraphic architecture are suggested through similar orientation of depositional environment belts along with important thickness and facies variations within the North Provence area. Large-scale deformation due to the progressive rotation of the Iberian plate is likely to have direct implications into the Provence domain. Concomitant rudistid production crises, replaced by mass occurrence of Palorbitolina deposits, are documented across the peri-Vocontian Urgonian platforms. The final demise of the Urgonian-type rudistid regime, previously linked to the onset of the Oceanic Anoxic Event 1a, rather correlates to the intermittently anoxic Taxy episode. These results call for a reconsideration of the chronology of events controlling the development of Urgonian shallow-water carbonate systems through the Barremian.