Evolution of the Banded Gneissic Complex of central Rajasthan, India

1967 ◽  
Vol 15 (3) ◽  
pp. 191-201 ◽  
Author(s):  
K. Naha ◽  
A. K. Chaudhuri ◽  
P. Mukherji
Keyword(s):  
Banded Gneissic Complex

Mineral parageneses and metamorphic reactions in metasedimentary enclaves from the Archaean Gneiss Complex of north-west India

1984 ◽  
Vol 48 (347) ◽  
pp. 195-209
Author(s):  
Ram. S. Sharma ◽  
Brian F. Windley
Keyword(s):  
Regional Metamorphism ◽  
Recrystallization Temperature ◽  
Prograde Metamorphism ◽  
Basement Complex ◽  
North West ◽  
Gneiss Complex ◽  
Two Generations ◽  
Orogenic Cycle ◽  
Banded Gneissic Complex ◽  
Partial Resorption

AbstractThree metasedimentary enclaves up to a kilometre in length of contrasting compositions within the polymetamorphic Banded Gneissic Complex (> 2580Ma) have been studied for their mineral parageneses and metamorphic conditions. The largest enclave, consisting of kyanite-chloritoid-muscovite schist with quartz or corundum, and kyanite-fuchsite-corundum ± diaspore, was metamorphosed at most under lower amphibolite conditions, and is thus not isofacial with the surrounding schists and gneisses (of the ‘basement’ complex) which reached sillimanite-grade metamorphism in the last orogenic cycle (Aravalli: 1650–950Ma Orogeny) in Rajasthan.The second enclave is a calc-silicate rock which occurs as a small lens. The presence of two generations of wollastonite which formed during different metamorphic events in the calcite-quartz-grossularite-anorthite-clinopyroxene assemblage indicates polymetamorphism.The third enclave is a metabasic rock which records a complete polymetamorphic history in discontinuous zones in garnet coexisting with hornblende-chlorite-plagioclase-quartz±epidote. To explain the garnet zoning a model involving partial resorption of early garnet during the initial recrystallization stage of superimposed regional metamorphism is preferred to the alternative based on a single prograde metamorphism and retrogression.The mineralogy of the calc-silicate and metabasic enclaves gives a recrystallization temperature of c. 700°C and a pressure in the range of 8–3 kbar during the second metamorphism.

Reinterpretation of the Aravalli basal conglomerate at Morchana, Udaipur district, Rajasthan, western India

1971 ◽  
Vol 108 (2) ◽  
pp. 111-114 ◽  
Author(s):  
K. Naha ◽  
A. Majumdar
Keyword(s):  
Western India ◽  
Mica Schist ◽  
Vein Quartz ◽  
Basal Conglomerate ◽  
Tectonic Mélange ◽  
Banded Gneissic Complex

SummaryThe supposed Aravalli basal conglomerate near Morchana, considered to mark an erosional unconformity above the older Precambrian Banded Gneissic Complex in central Rajasthan, is a tectonic mélange in a terrain involved in superposed deformations. The supposed pebbles represent tectonic inclusions of various shapes, formed by isoclinal folding, stretching and disruption of concordant, pre- or early-kinematic vein quartz and rare pegmatite sheets in the Aravalli mica schist during the first folding.

Sm-Nd systemics of The Banded Gneissic Complex, Northwestern India

1988 ◽  
Vol 70 (1-2) ◽  
pp. 144
Author(s):  
K. Gopalan ◽  
J.D. Macdougall ◽  
A.B. Roy
Keyword(s):  
Northwestern India ◽  
Banded Gneissic Complex
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