Petrology of Charnockites from Madurai Block of Southern Granulite Terrain, South India

2021 ◽  
Vol 40f (1) ◽  
pp. 25-37
Author(s):  
G. Indu ◽  
E. Shaji ◽  
R.B. Binojkumar ◽  
M. Santosh ◽  
T. Tsunogae
Keyword(s):  
South India ◽  
Granulite Terrain

Tectonics of the Neoproterozoic Southern Granulite Terrain, South India

2005 ◽  
Vol 138 (1-2) ◽  
pp. 37-56 ◽  
Author(s):  
Bénédicte Cenki ◽  
Leo M. Kriegsman
Keyword(s):  
South India ◽  
Granulite Terrain

Zoned hibonites from Punalur, South India

1991 ◽  
Vol 55 (379) ◽  
pp. 159-162 ◽  
Author(s):  
M. Santosh ◽  
M. Sandiford ◽  
S. J. B. Reed
Keyword(s):  
South India ◽  
Microprobe Analysis ◽  
Site Occupancy ◽  
Ion Microprobe ◽  
Analytical Uncertainty ◽  
Granulite Terrain

AbstractZoned hibonites from a kalsilite, leucite, spinel, corundum, perovskite gneiss from the southern Indian granulite terrain near Punalur, Kerala, have rims that are the most Ti-rich yet recorded (0.83–0.87 Ti atoms per 19 O) and are essentially free of REE elements (ΣREE < 0.01 atoms per 19 O) while the cores are the most REE-rich compositions yet recorded (ΣREE = 0.55–0.65 atoms per 19 O). Within the limits of analytical uncertainty, the compositions of the hibonite can be related to the theoretical end-member CaAl12O19 by the substitutions REE R2+ ⇌ CaAl and R2+R4+ ⇌ Al2 with the REE-rich cores containing in excess of 50% of the REE R2+ Al11O19 end member. Minor substitution of Na for Ca occurs in the rims, while non-stoichiometry in both the cores and rims is indicated by partial 12-fold site occupancy. Ion-microprobe analysis of the REE-rich hibonites reveals strong enrichment in LREE with La/Lu c. 250 000.

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