scholarly journals High-pressure Tethyan Himalaya rocks along the India-Asia suture zone in southern Tibet

Lithosphere ◽  
2016 ◽  
Vol 8 (5) ◽  
pp. 574-582 ◽  
Author(s):  
Andrew K. Laskowski ◽  
Paul Kapp ◽  
Jeff D. Vervoort ◽  
Lin Ding
Keyword(s):  
High Pressure ◽  
Suture Zone ◽  
Southern Tibet ◽  
Tethyan Himalaya

Possibly diamond-bearing mantle peridotites and podiform chromitites in the Luobusa and Donqiao ophiolites, Tibet

1993 ◽  
Vol 30 (8) ◽  
pp. 1650-1659 ◽  
Author(s):  
Wen-Ji Bai ◽  
Mei-Fu Zhou ◽  
Paul T. Robinson
Keyword(s):  
High Pressure ◽  
Subduction Zone ◽  
Suture Zone ◽  
Ultramafic Rocks ◽  
Eurasian Plate ◽  
Southern Tibet ◽  
Suprasubduction Zone ◽  
Mantle Peridotites ◽  
Podiform Chromitites ◽  
Reducing Environment

The Luobusa ophiolite of the Yarlung–Zangbo (southern Tibet) suture zone and the Donqiao ophiolite of the Bangong–Nujiang (northern Tibet) suture zone are allochthonous bodies that contain possibly diamond-bearing mantle peridotites and podiform chromitites. The mantle sections in both massifs consist chiefly of harzburgite and diopside-bearing harzburgite with abundant lenses of dunite and chromitite. These ultramafic rocks are more strongly depleted than typical abyssal peridotites and their whole-rock and mineral chemistries suggest formation above a subduction zone. An unusual mineral association (diamond, SiC, graphite, native chromium, Ni–Fe alloy, Cr2+-bearing chromite), indicating a high-pressure, reducing environment, occurs in both the peridotites and chromitites. We suggest that these ophiolites were generated originally in a suprasubduction zone environment and were later carried deep into the mantle along a second subduction zone, at which time the diamonds and other high-pressure minerals were formed. It is not yet clear whether the diamonds formed by high-pressure metamorphism of the oceanic crust or by crystallization from mantle melts, but their occurrence in chromitites and harzburgites suggests a metamorphic origin. During the collision of India with the Eurasian plate, the mantle sections were tectonically emplaced at shallow crustal levels rapidly enough to preserve the diamonds.

High-Pressure Fault Tectonites of the Yenisei Ridge as Result of Ductile Shear Deformations in the Suture Zone

2018 ◽  
Vol 483 (4) ◽  
pp. 417-421
Author(s):  
I. Likhanov ◽  
◽  
P. Kozlov ◽  
K. Ivanov ◽  
S. Zinov'ev ◽  
...  
Keyword(s):  
High Pressure ◽  
Suture Zone ◽  
Yenisei Ridge ◽  
Shear Deformations ◽  
Ductile Shear

SLAB-DRIVEN FORMATION OF THE KAILAS BASIN WITHIN THE INDIA-ASIA SUTURE ZONE, SOUTHERN TIBET

2016 ◽  
Author(s):  
Ryan J. Leary ◽  
◽  
Devon A. Orme ◽  
Devon A. Orme ◽  
Andrew Laskowski ◽  
...  
Keyword(s):  
Suture Zone ◽  
Southern Tibet

scholarly journals Exsolution Lamellae in Orthopyroxene of Lherzolite from the Pauza Ultramafic Rocks, Ne Iraq: Evidence of Deep Mantle Signature in the Zagros Suture Zone

2013 ◽  
Vol 2 (9) ◽  
pp. 102-115
Author(s):  
Yousif Osman Mohammad ◽  
Nabaz Rashid Hama Aziz
Keyword(s):  
High Pressure ◽  
Upper Cretaceous ◽  
Suture Zone ◽  
Ultramafic Rocks ◽  
Chromian Spinel ◽  
Spinel Peridotite ◽  
Incongruent Melting ◽  
Fine Grained ◽  
Ultra High Pressure ◽  
Deep Mantle

The Pauza ultramafic body is part of Upper Cretaceous Ophiolitic massifs of the Zagros Suture Zone, NE Iraq. The present study reveals evidence of Ultra-high pressure (UHP), and deep mantle signature of these peridotites in the Zagros Suture Zone throughout the observation of backscattered images and micro analyses which have been performed on orthopyroxen crystals in lherzolite of Pauza ultramafic rocks.Theorthopyroxen shows abundant exsolution lamellae of coarse unevenly distributed clinopyroxene coupled with the submicron uniformly distributed needles of Cr-spinel. The observed clusters of Opx–Cpx–Spl represent the decompression products of pyrope-rich garnet produced as a result of the transition from ultra-high pressure garnet peridotite to low-pressure spinel peridotite (LP). Neoblastic olivine (Fo92 – 93) with abundant multi-form Cr- spinel inclusions occurs as a fine-grained aggregate around orthopyroxene, whereas coarse olivine (Fo90-91) free from chromian-spinel is found in matrix. The similarity of the Cr-spinel lamellae orientations in both olivine and orthopyroxene, moreover, the enrichments of both Cr and Fe3+ in the Cr-spinel inclusions in neoblastic olivine relative to Cr-spinel lamellae in orthopyroxene, suggest that spinel inclusions in olivine have been derived from former Cr-spinel lamellae in orthopyroxene. Neoblastic olivine is formed by reaction of silica-poor ascending melt and orthopyroxene. It is inferred that the olivines with multi-form spinel inclusions has been formed by incongruent melting of pre-existing spinel lamellae-rich orthopyroxene.

Eclogitic rocks in the St. Cyr klippe, Yukon, and their tectonic significance

1992 ◽  
Vol 29 (6) ◽  
pp. 1296-1304 ◽  
Author(s):  
Philippe Erdmer
Keyword(s):  
High Pressure ◽  
Oceanic Crust ◽  
North American ◽  
Suture Zone ◽  
Late Paleozoic ◽  
The North ◽  
Tectonic Significance ◽  
Subducted Oceanic Crust ◽  
Ophiolitic Rocks ◽  
Subducting Slab

Until recently, the Nisutlin allochthonous assemblage, a part of the Yukon–Tanana composite terrane interpreted as trench mélange from a late Paleozoic – Mesozoic arc system, was the only tectonic assemblage known to include subducted material in the northern Cordillera. The discovery of eclogitic rocks in two parts of a klippe of the Anvil allochthonous assemblage, which comprises mafic ophiolitic rocks, above the Cassiar terrane west of the Tintina fault confirms other evidence that subducted oceanic crust was also returned to the surface. The eclogitic rocks have been largely retrograded by postsubduction metamorphism. Their existence is interpreted as additional evidence of the link between nappes above the Cassiar terrane and their inferred root, the Teslin suture zone. The Nisutlin and Anvil allochthonous assemblages can now be interpreted, not simply as crustally metamorphosed assemblages with minor, structurally interleaved high-pressure components, but as deeply metamorphosed and intensely strained slices of continental and oceanic crust switched from subducting slab to overriding plate and returned to the surface during collision of the arc with the North American margin.

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