Sapphirine+quartz corona around magnesian (XMg ~0.58) staurolite from the Palghat-Cauvery Suture Zone, southern India: Evidence for high-pressure and ultrahigh-temperature metamorphism within the Gondwana suture

Lithos ◽  
2010 ◽  
Vol 114 (3-4) ◽  
pp. 490-502 ◽  
Author(s):  
Yuki Nishimiya ◽  
Toshiaki Tsunogae ◽  
M. Santosh
Keyword(s):  
High Pressure ◽  
Suture Zone ◽  
Southern India ◽  
Ultrahigh Temperature

High-pressure and ultrahigh-temperature metamorphism at Komateri, northern Madurai Block, southern India

2008 ◽  
Vol 33 (5-6) ◽  
pp. 395-413 ◽  
Author(s):  
Toshiaki Tsunogae ◽  
M. Santosh ◽  
Hiroyuki Ohyama ◽  
Kei Sato
Keyword(s):  
High Pressure ◽  
Southern India ◽  
Ultrahigh Temperature

An unusual high-Mg garnet–spinel orthopyroxenite from southern India: evidence for ultrahigh-temperature metamorphism at high-pressure conditions

2006 ◽  
Vol 143 (6) ◽  
pp. 923-932 ◽  
Author(s):  
K. SAJEEV ◽  
M. SANTOSH
Keyword(s):  
High Pressure ◽  
Final Stage ◽  
Close Association ◽  
Southern India ◽  
Al Content ◽  
Multi Stage ◽  
Gondwana Supercontinent ◽  
Ultrahigh Temperature ◽  
Uht Metamorphism ◽  
High Al Content

We report here a garnet–spinel orthopyroxenite in close association with an ultrahigh-temperature (UHT) granulite from the central part of the Madurai Granulite Block in southern India. The garnet–spinel orthopyroxenite is almost entirely composed of orthopyroxene, spinel and rare garnet in a granular texture. Spinels in the rock are characterized by high Mg (XMg = 0.69–0.71) with low Cr and Fe3+, consistent with compositions reported from spinels occurring within xenoliths in kimberlites and high pressure–temperature (P–T) Alpine complexes. The orthopyroxenes have high Al content (Al2O3 up to 4.85 wt%), typical of equilibration under high P–T conditions. The P–T estimates derived for the garnet–spinel orthopyroxenite indicate temperatures of around 1000°C and pressures exceeding 17 kbar. The data indicate that UHT metamorphism in this locality traversed from above 17 kbar to 11 kbar prior to the final stage of isothermal decompression. Our study reports the highest pressures obtained by far, for extreme crustal metamorphism in southern India and elsewhere in Gondwana. The multi-stage decompression observed in the UHT rocks associated with the high P–T garnet–spinel orthopyroxenite could be correlated to extension of the crust and possibly of the lithospheric mantle and/or its delamination, with the asthenospheric mantle as the ultimate heat source, during the final stage of amalgamation of the Gondwana supercontinent.

Ultrahigh-temperature metagabbros from Wynad: Implications for Paleoproterozoic hot orogen in the Moyar Suture Zone, southern India

2016 ◽  
Vol 130 ◽  
pp. 139-154 ◽  
Author(s):  
Minami Yano ◽  
Toshiaki Tsunogae ◽  
M. Santosh ◽  
Qiong-Yan Yang ◽  
E. Shaji ◽  
...  
Keyword(s):  
Suture Zone ◽  
Southern India ◽  
Ultrahigh Temperature

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

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.

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