Origin of granites in an Archean high-grade terrane, southern India

1986 ◽  
Vol 92 (1) ◽  
pp. 93-103 ◽  
Author(s):  
K. C. Condie ◽  
G. P. Bowling ◽  
P. Allen
Keyword(s):  
Southern India ◽  
High Grade

Sr, Nd, and Pb Isotopic Systematics in the Archean Low- to High-Grade Transition Zone of Southern India: Syn-Accretion vs. Post-Accretion Granulites

1989 ◽  
Vol 97 (5) ◽  
pp. 537-549 ◽  
Author(s):  
J. J. Peucat ◽  
P. Vidal ◽  
J. Bernard-Griffiths ◽  
K. C. Condie
Keyword(s):  
Transition Zone ◽  
Southern India ◽  
High Grade ◽  
Grade Transition

scholarly journals Constraints on the timing and conditions of high-grade metamorphism, charnockite formation and fluid-rock interaction in the Trivandrum Block, southern India

2016 ◽  
Vol 34 (6) ◽  
pp. 527-549 ◽  
Author(s):  
E. Blereau ◽  
C. Clark ◽  
R. J. M. Taylor ◽  
T. E. Johnson ◽  
I. C. W. Fitzsimons ◽  
...  
Keyword(s):  
Southern India ◽  
High Grade ◽  
Rock Interaction ◽  
Grade Metamorphism ◽  
High Grade Metamorphism

Pressure-temperature-time evolution of ultrahigh-temperature granulites from the Trivandrum Block, southern India: Implications for long-lived high-grade metamorphism

2019 ◽  
Vol 54 (5) ◽  
pp. 3041-3059 ◽  
Author(s):  
Hikaru Kadowaki ◽  
Toshiaki Tsunogae ◽  
Xiao-Fang He ◽  
M. Santosh ◽  
Yusuke Takamura ◽  
...  
Keyword(s):  
Time Evolution ◽  
Southern India ◽  
High Grade ◽  
Grade Metamorphism ◽  
High Grade Metamorphism ◽  
Ultrahigh Temperature ◽  
Temperature Time

Silicate, Oxide and Sulphide Trends in Neo-Archean Rocks from the Nilgiri Block, Southern India: the Role of Fluids During High-grade Metamorphism

2019 ◽  
Vol 60 (5) ◽  
pp. 1027-1062 ◽  
Author(s):  
Vinod O Samuel ◽  
Daniel E Harlov ◽  
Sanghoon Kwon ◽  
K Sajeev
Keyword(s):  
Granulite Facies ◽  
Southern India ◽  
Sulphide Mineral ◽  
High Grade ◽  
Regional Trend ◽  
Granulite Facies Metamorphism ◽  
Facies Metamorphism ◽  
High Grade Metamorphism ◽  
Specific Oxidation

Abstract The Nilgiri Block, southern India represents an exhumed section of lower, late Archean (2500 Ma) crust. The northern highlands of the Nilgiri Block are characterized by metagabbros with pyroxenite inlayers. A two-pyroxene granulite zone acts as a transition between the metagabbros and charnockites, which are exposed in the central and southern part of the Nilgiri highlands. Thermobarometry results indicate a SW–NE regional trend both in temperature (∼650–800°C) and in pressure (700–1100 MPa) over the Nilgiri highlands. In the charnockites, composite rutile–ilmenite grains are the dominant oxide assemblage. In the two-pyroxene granulites, hemo-ilmenite–magnetite is dominant with coexisting rutile–ilmenite composite grains in a few samples in the vicinity of the boundary with the charnockites. In the metagabbros, hemo-ilmenite–magnetite is the dominant oxide assemblage. The principal sulphide mineral in the charnockite is pyrrhotite with minor pyrite–chalcopyrite exsolution lamellae or blebs. In the two-pyroxene granulites and the metagabbros, the principal sulphide assemblage consists of discrete pyrite grains with magnetite rims and pyrite–pyrrhotite–chalcocopyrite associations. From these observations, a specific oxidation trend is seen. The northern granulite-facies metagabbros and two-pyroxene granulites of the Nilgiri highlands are highly oxidized compared with the charnockites from the central and southern regions. This higher oxidation state is proposed to be the result of highly oxidizing agents (probably as SO3) in low H2O activity grain boundary NaCl saline fluids with a dissolved CaSO4 component present during granulite-facies metamorphism of the metagabbros and two-pyroxene granulites. Eventually these agents became more reducing, owing to the inherent buffering of the original tonalite–granodiorite granitoids at the graphite–CO2 buffer, such that S took the form of H2S during the granulite-facies metamorphism of the charnockites. At the same time, these saline fluids were also responsible the solid-state conversion of biotite and amphibole to orthopyroxene and clinopyroxene in the metagabbro, two-pyroxene granulite, and charnockite.

Geochemistry of the Archean low- to high-grade transition zone, Southern India

1982 ◽  
Vol 81 (3) ◽  
pp. 157-167 ◽  
Author(s):  
Kent C. Condie ◽  
Philip Allen ◽  
B. L. Narayana
Keyword(s):  
Transition Zone ◽  
Southern India ◽  
High Grade ◽  
Grade Transition

The Sargur Schist Complex - An Archaean High-Grade Terrain in Southern India

1978 ◽  
pp. 127-149 ◽  
Author(s):  
A.S. Janardhan ◽  
C. Srikantappa ◽  
H.M. Ramaohandra
Keyword(s):  
Southern India ◽  
High Grade
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