Deep melting and sodic metasomatism underneath the highly oblique
Semantic Scholar extracted view of "Deep melting and sodic metasomatism underneath the highly oblique-spreading Lena Trough (Arctic Ocean)" by E. Hellebrand et al. ... plagioclase-free spinel peridotite drilled during ODP cruise 153 in the North Atlantic revealed that the peridotite represent refractory, partial residual …
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A long section of serpentinized depleted mantle …
Overall, the pyroxene content of the peridotite is unexpectedly low, which may result from both high degrees of depletion and pyroxene dissolution during melt flow. Contrary to often-invoked models, focused melt migration …
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The Beni Bousera Peridotite (Rif Belt, Morocco): an …
Detailed structural and petrological mapping in the Beni Bousera peridotite (Rif Belt, northern Morocco) shows that this orogenic peridotite massif is composed of four tectono-metamorphic...
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Oblique fabrics in porphyroclastic Alpine-type peridotites: a shear
DOI: 10.1016/0191-8141(92)90044-W Corpus ID: 129025215; Oblique fabrics in porphyroclastic Alpine-type peridotites: a shear-sense indicator for upper mantle flow @article{Wal1992ObliqueFI, title={Oblique fabrics in porphyroclastic Alpine-type peridotites: a shear-sense indicator for upper mantle flow}, author={Dirk van der Wal and Reinoud L. M. Vissers and Martyn R. Drury and …
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oblique peridotite
The similar nature of the oblique foliations within all the peridotite xenoliths indicates that their origins are related to a pervasive event in the uppermost mantle lithosphere beneath the northeast Japan arc Figure 2 Open in figure viewer PowerPoint a Photomicrograph of a peridotite xenolith with oblique foliations as defined by the.
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The Beni Bousera Peridotite (Rif Belt, Morocco): an Oblique-slip …
Detailed structural and petrological mapping in the Beni Bousera peridotite (Rif Belt, northern Morocco) shows that this orogenic peridotite massif is composed of four tectono-metamorphic domains with consistent kinematics, marked by a pervasive, shallowly dipping foliation with a NW-SE stretching lineation that progressively rotates towards a NNE-SSW orientation in the …
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(PDF) Trace elements in abyssal peridotite olivine record melting
a Global map of the sample localities. Bathymetric maps are labeled with dredge and drill site locations for the b Gakkel ridge, c Oblique and Orthogonal Segments, SWIR, d Hess Deep, EPR and e ...
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Geometry and deformation of the sole of a large obducted …
These units consist of: (1) slices of the serpentinite sole of Peridotite Nappe (upper plate), which characteristically contain fragmented supra-subduction dykes; (2) Intermediate Mélange units ...
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Deep melting and sodic metasomatism underneath the highly …
Abyssal peridotites collected along the highly oblique-spreading Lena Trough north of Greenland and Spitsbergen have mineral compositions that are similar to residual …
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Oblique fabrics in porphyroclastic Alpine-type peridotites: a shear
In this study we investigate a microstructure, similar to the oblique fabrics reported from crustal shear zone rocks, developed in a km-scale high-temperature shear zone in the …
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Oblique, southeasterly-facing view of the Burgersfort area. The …
The Apiesdooringdraai peridotite is a syn-Bushveld Complex, dominantly harzburgitic intrusion of Lower Zone parentage. Detailed mapping and three-dimensional modeling shows the intrusion to ...
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The Ronda peridotites (Los Reales nappe): An example of the
The Ronda peridotites form the lower portion of the Los Reales nappe and are overlain by a metamorphic sequence which varies from granulite- to greenschist-facies …
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Mantle flow and melting underneath oblique and …
We present an analytical solution for mantle flow beneath an oblique ridge and demonstrate that the thermal structure and crustal thickness …
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The emplacement of the Peridotite Nappe of New Caledonia …
convergence. Oblique convergence probably resulted from the initial obliquity between the subduction trench and the continental ribbon that became incorporated in it. This obliquity can solve the paradox of the Peridotite Nappe seemingly being emplaced at the same time the high-pressure rocks were exhumed.
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A long section of serpentinized depleted mantle peridotite
Dunite zones have predominantly intermediate dips, in contrast to the originally steep mantle fabrics, indicative of oblique melt transport. Extensive hydrothermal fluid-rock interaction is recorded across the full depth of the core and is overprinted by oxidation in the upper 200 meters.
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Deformation history and exhumation process of the Horoman Peridotite
Van der Wal et al. (1992) also reported a (001)[100] slip from highly deformed peridotite tectonites that have oblique shape fabrics. Thus, deformation microstructures recorded in the Porphyroclastic Zone and the Basal Shear Zone show extensional sense of shear, and indicate kinematics during uplifting in the extensional stage Fig. 11, Fig. 12.
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Flow in the uppermost mantle during back-arc spreading revealed …
A brief petrographic study by Michibayashi et al. (2006) reported oblique foliation and the thickness of an anisotropic layer from mineral CPO. In this paper, we present a detailed microstructural analysis of peridotite xenoliths with the aim of understating the evolution of the uppermost mantle during back-arc spreading; in particular, we ...
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Lead and osmium isotopic constraints on the oceanic mantle from …
Samples in this study are from the Gakkel Ridge (spreading rates of 6–15 mm/yr; Michael et al., 2003) and Southwest Indian Ridge (SWIR) Oblique Segment (spreading rates of 8–13 mm/yr; Standish et al., 2008). Selection of Gakkel and SWIR peridotites was based on the detailed petrographic analysis of 350 thin sections from these two ridges ...
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The Beni Bousera Peridotite (Rif Belt, Morocco): an Oblique-slip …
In this framework, the Beni Bousera peridotite is a low-angle, oblique-slip, shear zone that accommodated simultaneously a belt-parallel displacement component and thinning of the mantle lithosphere. The Grt–Sp mylonites and the Se domain constituted, respectively, the …
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A revised thermal history of the Ronda peridotite, S. Spain: New
If wet peridotite is considered, temperature grain shape fabric oblique to the main foliation. These bands al- requirements are considerably lower (minimum 1000 C), but hy- ternate with finer-grained (∼100 μm) bands of mixed olivine and drous minerals such as amphiboles or micas are rare as part of the pyroxene (Fig. 3C).
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The emplacement of the Peridotite Nappe of New Caledonia …
Oblique convergence probably resulted from the initial obliquity between the subduction trench and the continental ribbon that became incorporated in it. This obliquity can solve the paradox …
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Global variations in abyssal peridotite compositions
Any peridotite with plagioclase disseminated in the matrix of the peridotite has been included in this category – even if it does not have a vein – as plagioclase in abyssal peridotites is interpreted as indicating melt infiltration (e.g., Chalot-Prat et al., 2013, Dick, 1989, Dijkstra et al., 2001, Müntener et al., 2010, Piccardo et al ...
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An assessment of upper mantle heterogeneity based on abyssal peridotite
Histograms of peridotite and basalt Nd isotopic ratios for (a) the Oblique Segment, (b) the Atlantis II Fracture Zone, and (c) global abyssal peridotite and MORB. DMM and the 2 σ variation in DMM (D-DMM and E-DMM) are shown by solid lines and global average peridotite composition by the dashed-dotted line.
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The Ronda peridotites (Los Reales nappe): An example of the
J.M. Tub / Tectonophysics 238 (1994) 381-398 385 related to eastward motions and pointing to a period of oblique tectonics within the Betic Zone. It is proposed here that such oblique tectonics produced the lithospheric thickening leading to the late extensional collapse described by the previous geodynamic models. 2. Los Reales nappe 2.1.
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(PDF) Petrology of Peridotite Xenoliths from Iraya
Oblique subduction is common in arc–trench systems, suggesting that F-type peridotite formation may be common within the mantle wedge. Location of Batan in the Luzon --- Taiwan arc and the Iraya ...
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Deep melting and sodic metasomatism underneath …
Deep melting and sodic metasomatism underneath the highly oblique-spreading Lena Trough (Arctic Ocean) Eric Hellebrand. 2003, Earth and Planetary Science Letters. See full PDF download Download PDF.
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Serpentinized peridotite versus thick mafic crust at the Romanche
This interpretation is consistent with the irregular seafloor topography, segmented and oblique ridge axis, and the presence of serpentinized peridotite (Bonatti et al., 2001), indicative of magma-poor crust, south of the TF.
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The Beni Bousera Peridotite (Rif Belt, Morocco): an Oblique-slip …
The Beni Bousera Peridotite (Rif Belt, Morocco): an Oblique-slip Low-angle Shear Zone Thinning the Subcontinental Mantle Lithosphere
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(PDF) Eocene pre- and syn-obduction tectonics in New Caledonia
Eocene pre-and synobduction tectonics in New Caledonia (Southwest Pacific), a case for oblique subduction, transcurrent tectonics and oroclinal bending; structural and paleomagnetic evidence, ... (Teyssier et al., 2016). Dykes The Peridotite Nappe is intruded by a variety of dykes, which vary in composition from ultramafic (pyroxenite) to mafic ...
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The Beni Bousera Peridotite (Rif Belt, Morocco): an Oblique-slip …
The Beni Bousera Peridotite (Rif Belt, Morocco): an Oblique-slip Low-angle Shear Zone Thinning the Subcontinental Mantle Lithosphere. Andréa Tommasi. 2013, Journal of Petrology.
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