Justin Gérard¹, Loïc Sablon¹, Jarno Huygh², Anne-Christine Da Silva², Alexandre Pohl³, Christian Vérard⁴ and Michel Crucifix¹, (1)Université Catholique de Louvain, Louvain-la-Neuve, Belgium, (2)University of Liege, Sedimentary Petrology, Liege, Belgium, (3)Université de Bourgogne, Biogéosciences, Dijon, France, (4)Department of Earth Sciences, University of Geneva, Geneva, Switzerland