3D modelling of Supergene Alteration of the Koniambo Massif, New Caledonian Peridotite Nappe

Abstract : Resulting from the weathering of the Peridotite Nappe, laterites are abundant in New Caledonia and host one of the largest nickel ore deposit worldwide. Based on an exceptional drilling dataset provided by the Koniambo Nickel SAS company, this work presents a preliminary 3D modelling. It shows that the laterites are located along the ridges of the massif and are organized as a set of sinkhole-like patches. Between these patches, areas with thin or no limonite cover are characterized by higher averaged Ni-contents. Therefore, lateritization and Ni mineralisation should not be considered as resulting from a strictly vertical progression of the alteration front, but must involve more complex processes, such as lateral transfers or tectonic control.