The Oxfordian–Kimmeridgian transition in the Boulonnais (France) and the onset of organic-rich marine deposits in NW Europe: a climatic control?

We characterised the organic matter content of marine deposits at Oxfordian–Kimmeridgian transition in Boulonnais (France). Organic rich platform environments are evidenced uppermost Cymodoce and lowermost Mutabilis Zone (early late Kimmeridgian), associated with enhanced planktonic palaeoproductivity and/or developing dysoxia/anoxia. Similar intervals early Kimmeridgian also Normandy Charentes France, basinal from Yorkshire Dorset UK. This refined onset bands (ORB), as described NW Europe during Jurassic, is coeval seawater warming. propose that this warming was an important trigger Jurassic ORB deposition system Europe, which began Cymodoce–Mutabilis boundary lasted until middle part Tithonian, over a time span 6.8 Myr.