Post-obduction evolution of New Caledonia

Type Article
Date 2020-06
Language English
Author(s) Sevin B.1, Maurizot P.1, Cluzel D.2, Tournadour Elsa1, 3, Etienne S.1, Folcher N.2, Jeanpert J.1, Collot Julien1, Iseppi M.1, 4, Meffre S.5, Patriat MartinORCID1, 6
Affiliation(s) 1 : Service Géologique de Nouvelle-Calédonie (New Caledonia Geological Survey), BP M2, 98 849 Nouméa, New Caledonia
2 : University of New Caledonia, ISEA-EA 7484, BP R4, 98 851 Nouméa, New Caledonia
3 : ADECAL Technopole, ZoNéCo Research Program, 98845 Nouméa, New Caledonia
4 : BRGM, Antenne Nouvelle-Calédonie 1 ter rue E. Unger, Vallée du Tir – BP 56, 98 845 Nouméa Cedex, New Caledonia
5 : University of Tasmania, Private Bag 79, Hobart 7001, Australia
6 : Ifremer, UR Géosciences Marines, 29280 Plouzané, France
Source Geological Society, London, Memoirs (0435-4052) (Geological Society of London), 2020-06 , Vol. 51 , N. 1 , P. Chap.7, pp.147-188
DOI 10.1144/M51-2018-74
Abstract

The post-obduction formations of Grande Terre, New Caledonia, comprise igneous intrusions, regolith cover, and marine and terrestrial sedimentary rocks. Two restricted Late Oligocene granitoid bodies are intruded into the Peridotite Nappe and its substrate in the south of the island. Thick regolith cover developed over the Peridotite Nappe from the Late Oligocene or earlier. The Népoui Group comprises Late Oligocene–Early Miocene mixed marine carbonate and siliciclastic deposits. It mainly reworks the Peridotite Nappe and its regolith cover. Its development pattern is mainly controlled by tectonic uplift and subsidence. The Gwa N'Doro Formation on the eastern coast and the Fluvio-lacustrine Formation in the south are remnants of the Miocene–Present river network. Offshore, thick Oligocene to Neogene sedimentary successions are imaged by seismic surveys on the margins of Grande Terre, although these successions have not been drilled and remain undated. Several dredges have recovered shallow Miocene sedimentary rocks, indicating substantial Neogene subsidence. Quaternary formations are represented inland by aeolianite, vertisols and calcrete and offshore by the large barrier reef–lagoon complex, the onset of which is dated at c. 400 ka. This chapter discusses the different models proposed for the post-obduction evolution of Grand Terre.

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Sevin B., Maurizot P., Cluzel D., Tournadour Elsa, Etienne S., Folcher N., Jeanpert J., Collot Julien, Iseppi M., Meffre S., Patriat Martin (2020). Post-obduction evolution of New Caledonia. Geological Society, London, Memoirs, 51(1), Chap.7, pp.147-188. Publisher's official version : https://doi.org/10.1144/M51-2018-74 , Open Access version : https://archimer.ifremer.fr/doc/00643/75541/