The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes – reassessment of the boundary criterion for the base-Lutetian GSSP

Re-excavation of the famous Mont-des-Récollets quarry in northern France and re-interpretation adjacent Cassel borehole have led to reconstruction one most complete Upper Ypresian Lutetian stratigraphic successions southern North Sea Basin. It includes entire suite formations members, from top Hyon Sand Formation (top NP12) base Maldegem (mid-NP15), originally defined central Belgium, extending lateral distribution these units up France. The similarity lithofacies calcareous nannofossil assemblages identification situ specimens Nummulites laevigatus (Bruguière, 1792) Campanile giganteum (Lamarck, 1804) at bear witness direct north-south connections between Belgian Basin Paris during Biochron NP14 early NP15. However, only been intermittent. During late NP12 NP13, both basins became disconnected because lowering global sea level combination with uplift massively reworked large-sized N. presence laevigatus-bearing sandstone blocks lignitic pebbles Lede indicate a major erosion phase NP14-NP15 transition This was probably due Brabant Massif. new data, including introduction genus (Luminocanthus n. gen.) ten species (Blackites minusculus sp., Blackites praeinflatus Luminocanthus eolutetiensis gen., plenilutetiensis Martiniaster cecellanoriae Nannoturba joceliniae Sphenolithus quadricornutus recolletensis Trochoaster nodosus sp. Trochastrites pyramidalis sp.) allowed substantially refine stratigraphy. subdivision Zone NP13 into 3 subzones (NP13-a NP13-c) as well turnover nine nannofossil-events within recognised throughout Several recorded Basin, Hampshire Aquitaine highlighting their interbasinal correlation potential. data provide for first time evidence that ‘Chaumont-en-Vexin sands' (term informally introduced herein designate historical stratotype) Unit A4 upper Aalter Fomation are coeval or nearly coeval. is also case overlying units, ‘Glauconie Grossière s.s.' (as redefined by Blondeau 1980) Brussel (‘Bruxellian' Belgium Dumont 1839). investigation its continuation, detailed forthcoming study Formation, revealed internationally accepted base-Lutetian boundary criterion (lowest occurrence LO inflatus) difficult apply extreme rarity this marker (e.g. not Mont-des-Récollets). Worst all, strict application would imply part sands’ lower s.s.’, stratotype, should be age, which contradictio terminis. To resolve contradiction, it suggested amend original (LO B. inflatus), proved inadequate middle high latitudes diachronous low latitudes, replace lowest (LO) Discoaster sublodoensis. latter (= BALCAT-event), has identified stratotype. proposal mean lowered down Gorrondatxe GSSP, about 130 m (c. 1.3 Myr), Chron C22n, around 800 kyr earlier than Turborotalia frontosa. If case, then range age 49.11 Ma 49.20 Ma, depending on model used.