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Pre-Late Cretaceous basement terranes of the Gondwana active margin of New Caledonia

Citation

Maurizot, P and Cluzel, D and Meffre, S and Campbell, HJ and Collot, J and Sevin, B, Pre-Late Cretaceous basement terranes of the Gondwana active margin of New Caledonia, New Caledonia: Geology, Geodynamic Evolution and Mineral Resources, Geological Society, P Maurizot and N Mortimer (ed), United Kingdom, pp. 27-52. ISBN 978-1-78620-466-0 (2020) [Research Book Chapter]

Copyright Statement

Copyright 2020 The Authors

DOI: doi:10.6084/m9.figshare.c.4984481

Abstract

The basement under the Late Cretaceous unconformity in New Caledonia consists of three amalgamated terranes. They are all oceanic, arc-related and developed offshore from the eastern Gondwana active margin during periods of marginal basin development. Téremba Terrane is composed of deep sea Permian to Mesozoic arc-derived volcanic rocks and greywackes. The Koh–Central Terrane includes at its base an ophiolite with island arc tholeiites and boninites (Koh Ophiolite) of Late Carboniferous to Early Permian age overlain by a thick sequence of greywacke (Central Range Volcaniclastic Rocks) of Permian to Late Jurassic age. The Téremba Terrane and the Koh–Central Terrane may be part of the same forearc basin, with the rocks from the Koh–Central Terrane deposited in a deeper environment. The Boghen Terrane is a metamorphic complex composed of schists, broken formations and mafic–ultramafic mélange, derived from mixed terrigenous and volcanic sources. The overall fine grain size and laminar bedding suggest deep sea and more distal deposition than the other terranes. The maximum depositional ages from detrital zircons suggest deposition during the Early Jurassic to Early Cretaceous. The terrane is interpreted as a metamorphosed subduction complex that includes blueschist and greenschist facies metamorphic rocks exhumed through the Koh–Central Terrane. At a regional scale, the nature of these three pre-Late Cretaceous terranes confirms the existing palaeogeographical reconstructions, which locate New Caledonia outboard the ocean–continent subduction that surrounded Gondwana during the Paleozoic and Early Mesozoic. A detailed analysis of these terranes and their relationship with East Australian terranes of the same age shows that a marginal basin system probably existed between mainland Gondwana and proto-New Caledonia and closed before the Late Cretaceous. A tentative detailed reconstruction of this margin during the Carboniferous–Early Cretaceous period is proposed.

Item Details

Item Type:Research Book Chapter
Keywords:SW Pacific
Research Division:Earth Sciences
Research Group:Geology
Research Field:Structural geology and tectonics
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Meffre, S (Dr Sebastien Meffre)
ID Code:139896
Year Published:2020
Funding Support:Australian Research Council (CE0561595)
Deposited By:CODES ARC
Deposited On:2020-07-13
Last Modified:2020-10-16
Downloads:0

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