La sismicité du Sud de la Nouvelle-Calédonie: implications structurales

Régnier, Marc; Beuque, Sabrina Van de; Baldassari, Catherine

doi:10.1016/s1251-8050(00)88508-0

Cited by 2 publications

(2 citation statements)

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“…The development of the barrier reef has been shown to be controlled by a longitudinal flexure-fault that accommodates slow subsidence of the New-Caledonia shelf [Dugas and Debenay, 1978;Cabioch et al, 1996]. Some of these faults are seismically active, with earthquake magnitudes ranging between 2 and 5 [Régnier et al, 1999]. Seismic lines shot across the New-Caledonia and Norfolk ridges show that the overall topography of the northern and southern tips of the island is controlled by major normal faults having offsets of the order of 1 km ( fig.…”

Section: Introductionmentioning

confidence: 99%

The role of extensional tectonics in shaping Cenozoic New-Caledonia

Lagabrielle

Chauvet

2008

Bulletin De La Société Géologique De France

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New-Caledonia island consists of an ultramafic nappe thrusted over a continental and arc-derived basement as the result of the closure of a back-arc basin during the upper Eocene. The morphology of New-Caledonia is mostly characterized by its elongated shape and rectilinear coastline. Indeed, the western and eastern edges of the island are delineated by N140 trending normal faults that are well imaged on seismic lines. Major tectonic lineaments onland, including the scarps corresponding to the main boundary of the ultramafic nappe, also trend N140 suggesting a morphotectonic control by faults having similar kinematics (longitudinal flexure-fault of previous authors). We provide detailed observations from some of these scarps demonstrating indeed that these are not erosional features in origin. We explore the possibility that such surfaces do represent major tectonic limits that accommodated extension and significant tectonic thinning of both the peridotite nappe and its basement. Remnants of a complex extensional fault zone, 200 m wide, are still preserved along the western scarp of the Mont Dore mountain, close to Noumea city. The deformed zone is composed of an early shallow dipping detachment fault, some decimeters thick, offset by a group of late high angle normal faults and is bounded by cataclastic breccias that progressively pass into the fractured host peridotite. The late high angle fault zones have been the site of important syn-tectonic fluid circulation and are underlined by cm-thick silica infills bearing vertical striae. Typical morphology of the main scarps with break of slope is related to the combination of high angle normal faults and low angle detachment. Similar shallow dipping detachment surfaces have been observed along the east coast of southern New-Caledonia as well as within the ultramafic nappe itself and its basement. This study confirms that N140 oriented, large fault zones, with pure-normal to transtensional component of displacement, controlled the morphotectonic evolution of New-Caledonia at the regional scale, after the obduction of ophiolite nappe at the end of the Eocene. Such a fact has to be taken into account when attempting to reconstruct the post-obduction evolution of the island and more particularly when considering the development and distribution of the Ni-rich lateritic surfaces

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Section: Introductionmentioning

confidence: 99%

The role of extensional tectonics in shaping Cenozoic New-Caledonia

Lagabrielle

Chauvet

2008

Bulletin De La Société Géologique De France

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“…et al, 2001) « suivi par l'arrivée du cortège uîtramafïque surmontant ainsi les membres de l'Unité de Poya. (Routhier, 1953;Régnier et al, 1999;Lagabrielle et al, 2005) transformations est encore à préciser, mais peut être reliée à la remontée des péridotites serpentinisées le long du plan de Bénioff selon des modalités proches de celles définies par les travaux de Koons (1994), Beaumont et al (1996Beaumont et al ( , 1999, Walcott (1998), Waschbusch et al (1998), Pysklywec et al (2002), Chemenda et al (2001) et Boutelier et al (2003 Dans ce qui suit, nous cherchons à améliorer nos connaissances sur l'aspect économique des profils résiduels dérivés de la îatéritisation des massifs ultramafîques, en soulignant pour la première fois en Nouvelle-Calédonie, la présence de scandium (Se) en proportion potentiellement économique.…”

Section: Evolution Anté-et Sym-obductionunclassified

massif du Koniambo, Nouvelle-Calédonie :

Audet¹

2009

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La sismicité du Sud de la Nouvelle-Calédonie: implications structurales

Cited by 2 publications

References 1 publication

The role of extensional tectonics in shaping Cenozoic New-Caledonia

The role of extensional tectonics in shaping Cenozoic New-Caledonia

massif du Koniambo, Nouvelle-Calédonie :

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