72 by Dominique Cluzel1, Pierre Maurizot1,2, Julien Collot1,3 and Brice Sevin1,3 An outline of the Geology of New Caledonia; from Permian–Mesozoic Southeast Gondwanaland active margin to Cenozoic obduction and supergene evolution 1 Pôle Pluri-disciplinaire de la Matière et de l’Environnement-EA 3325, University of New Caledonia, BP R4, 98851 Noumea cedex, New Caledonia. E-mail:
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[email protected] 2 B.R.G.M. Nouvelle-Calédonie, BP 56, 98845 Nouméa cedex, New Caledonia 3 Service de la Géologie de Nouvelle-Calédonie, Direction de l’industrie, des mines et de l’énergie de Nouvelle-Calédonie, B.P. 465 - 98845 Nouméa cedex, New Caledonia. The geological evolution of New Caledonia may be New Caledonia has provided new impetus and opportunity to gather divided into three phases. The Gondwanan phase new field data, harmonise and synthesise already mapped areas, and create geological databases; therefore, knowledge of the geology of (Permian–Early Cretaceous), is marked by subduction New Caledonia has made significant progress. along the SE Gondwaland margin. At that time, proto- Since earliest Permian time, the age of New Caledonia’s oldest New Caledonia was located in a fore-arc region in which rocks (Aitchison et al., 1998), three phases of development have been volcanic-arc detritus accumulated; whilst accretion and recognised: Permian–Early Cretaceous, Late Cretaceous–Eocene, and subduction of oceanic and terrigenous material formed Oligocene–Holocene. The oldest is related to the evolution of the SE Gondwanaland active margin, Mesozoic marginal basin opening and an accretionary complex metamorphosed into the subsequent closure; the second corresponds to the rifting that isolated blueschist facies.