Structures in the new caledonia peridotites-gabbros: Implications for oceanic mantle and crust

Prinzhofer, Alain; Nicolas, Adolphe; Cassard, Daniel; Moutte, Jacques; Leblanc, Marc; Paris, J.; Rabinovitch, M.

doi:10.1016/0040-1951(80)90128-6

Cited by 69 publications

(23 citation statements)

References 28 publications

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“…alpine-type peridotite, similar olivine fabrics have been reported from various localities (Prinzhofer et al 1980;Wedel et al 1992). These LPOs also resemble the AG-type (Mainprice 2007) or [010]-fiber pattern (Tommasi et al 1999).…”

Section: Lpo Of Olivinesupporting

confidence: 76%

Characterization of olivine fabrics and mylonite in the presence of fluid and implications for seismic anisotropy and shear localization

Jung

Austrheim

2014

Earth Planet Sp

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The Lindås Nappe, Bergen Arc, is located in western Norway and displays two high-grade metamorphic structures. A Precambrian granulite facies foliation is transected by Caledonian fluid-induced eclogite-facies shear zones and pseudotachylytes. To understand how a superimposed tectonic event may influence olivine fabric and change seismic anisotropy, two lenses of spinel lherzolite were studied by scanning electron microscope (SEM) and electron back-scattered diffraction (EBSD) techniques. The granulite foliation of the surrounding anorthosite complex is displayed in ultramafic lenses as a modal variation in olivine, pyroxenes, and spinel, and the Caledonian eclogite-facies structure in the surrounding anorthosite gabbro is represented by thin (<1 cm) garnet-bearing ultramylonite zones. The olivine fabrics in the spinel bearing assemblage were E-type and B-type and a combination of A-and B-type lattice preferred orientations (LPOs). There was a change in olivine fabric from a combination of A-and B-type LPOs in the spinel bearing assemblage to B-and E-type LPOs in the garnet lherzolite mylonite zones. Fourier transform infrared (FTIR) spectroscopy analyses reveal that the water content of olivine in mylonite is much higher (approximately 600 ppm H/Si) than that in spinel lherzolite (approximately 350 ppm H/Si), indicating that water caused the difference in olivine fabric. Fabric strength of olivine gets weaker as the grain size reduced, and as a result, calculated seismic properties for the two deformation stages reveal that P-and S-velocity anisotropies are significantly weaker in the mylonite. Microtextures and LPO data indicate that the deformation mechanism changed from dominant dislocation creep in spinel lherzolite to dislocation creep accompanied by grain-boundary sliding in mylonite. Shear localization in the mylonite appears to be originated from the grain size reduction through (1) enhanced dynamic recrystallization of olivine in the presence of water and (2) Zener pinning of clinopyroxene or (3) by ultracomminution during the pseudotachylyte stage.

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Section: Lpo Of Olivinesupporting

confidence: 76%

Characterization of olivine fabrics and mylonite in the presence of fluid and implications for seismic anisotropy and shear localization

Jung

Austrheim

2014

Earth Planet Sp

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“…This new result has several implications regarding the New Caledonia Basin in terms of age, tectonic and sedimentary evolution and links with its neighboring structural elements. Taking a close look at the New Caledonia onshore geology [ Avias , 1967; Brothers and Blake , 1973; Prinzhofer et al , 1980; Paris , 1981; Collot et al , 1987; Aitchison and Meffre , 1992; Aitchison , 1995; Cluzel et al , 1997; Aitchison et al , 1998; Cluzel , 1998; Cluzel et al , 1998; Ali and Aitchison , 2000; Cluzel et al , 2001; Ali and Aitchison , 2002; Spandler et al , 2004; Fitzherbert et al , 2005; Spandler et al , 2005; Cluzel et al , 2006], we here propose to establish links between the marine tectonic event observed in the seismic data and the tectonic events observed onshore.…”

Section: Discussionmentioning

confidence: 77%

Tectonic history of northern New Caledonia Basin from deep offshore seismic reflection: Relation to late Eocene obduction in New Caledonia, southwest Pacific

et al. 2008

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International audienceNew, high-quality multichannel seismic reflection data from the western New Caledonia offshore domain allow for the first time the direct, continuous connection of seismic reflectors between the Deep Sea Drilling Project 208 drill hole on the Lord Howe Rise and the New Caledonia Basin. A novel seismic interpretation is hence proposed for the northern New Caledonia Basin stratigraphy, which places the Eocene/Oligocene unconformity deeper than previously thought and revisits the actual thickness of the pre-Oligocene sequences. A causal link is proposed between the obduction of the South Loyalty Basin over New Caledonia (NC) and the tectonic history of the northern New Caledonia Basin. Here it is suggested that as the South Loyalty Basin was being obducted during early Oligocene times, the NC Basin subsided under the effect of the overloading and underthrusted to accommodate the compressional deformation, which resulted in (1) the uplift of the northern Fairway Ridge and (2) the sinking of the western flank of New Caledonia. This event also had repercussions farther west with the incipient subsidence of the Lord Howe Rise

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“…This inversion has been discovered in a few ophiolite massifs at depths ranging from a few hundred metres to 2kin (Table Mountain and Blow-Me-Down in Newfoundland (Girardeau & Nicolas 1981); Coto in the Philippines (Violette 1980); Massif du Sud in New Caledonia (Prinzhofer et al 1980). These massifs display a flat foliation and a homogeneous structure in the upper peridotites.…”

Section: (Ii) Asthenosphere Flow In Ridge Vicinitymentioning

confidence: 87%

Mantle flow pattern at oceanic spreading centres: relation with ophiolitic and oceanic structures

Nicolas¹,

Rabinowicz²

1984

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The rolling-mill effect concerning asthenosphere circulation beneath a fast-spreading centre (Rabinowicz et al. in press) is recalled and discussed in terms of its geological assessment. The model predicts a fast and narrow jet of asthenosphere which carries 70% of the total melt produced beneath the ridge. This explains both the structural data in most ophiolites and the formation of the crust within a few kilometres at fast-spreading ridges. It is proposed that the more diffuse activity at slow-spreading ridges from mid-oceans or marginal basins, along with the more diffuse magmatism recorded in a few ophiotites is related to the disappearance of this narrow stream as a consequence of an increase of viscosity due to lower temperatures beneath the ridge.at Simon Fraser University on June 2, 2015 http://sp.lyellcollection.org/ Downloaded from

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Structures in the new caledonia peridotites-gabbros: Implications for oceanic mantle and crust

Cited by 69 publications

References 28 publications

Characterization of olivine fabrics and mylonite in the presence of fluid and implications for seismic anisotropy and shear localization

Characterization of olivine fabrics and mylonite in the presence of fluid and implications for seismic anisotropy and shear localization

Tectonic history of northern New Caledonia Basin from deep offshore seismic reflection: Relation to late Eocene obduction in New Caledonia, southwest Pacific

Mantle flow pattern at oceanic spreading centres: relation with ophiolitic and oceanic structures

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