40Ar/39Ar geochronolgy and Neoproterozoic tectonics along the northern margin of the Eastern Ghats Belt in north Orissa, India

Crowe, Warwick A.

doi:10.1016/s0301-9268(01)00132-2

Cited by 78 publications

(22 citation statements)

References 54 publications

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“…Also this later resetting event may be represented by significant recrystallization noted in one sample. Further, both the group of ages has been reported from the northern margin of the Eastern Ghats belt (Crowe et al 2001). Most importantly, Pan-African reactivation of major shear zones was also documented from the northern margin by these authors.…”

Section: Discussionsupporting

confidence: 59%

Mafic dykes at the southwestern margin of Eastern Ghats belt: Evidence of rifting and collision

Bhattacharya

Chaudhary

Teixeira³

2010

J Earth Syst Sci

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The southwestern margin of the Eastern Ghats Belt characteristically exposes mafic dykes intruding massif-type charnockites. Dykes of olivine basalt of alkaline composition have characteristic trace element signatures comparable with Ocean Island Basalt (OIB). Most importantly strong positive Nb anomaly and low values of Zr/Nb ratio are consistent with OIB source of the mafic dykes. K-Ar isotopic data indicate two cooling ages at 740 and 530 Ma. The Pan-African thermal event could be related to reactivation of major shear zones and represented by leuco-granite vein along minor shear bands. And 740 Ma cooling age may indicate the low grade metamorphic imprints, noted in some of the dykes. Although no intrusion age could be determined from the present dataset, it could be constrained by some age data of the host charnockite gneiss and Alkaline rocks of the adjacent Prakasam Province. Assuming an intrusion age of ∼ 1.3 Ga, Sr-Nd isotopic composition of the dykes indicate that they preserved time-integrated LREE enrichment. In view of the chemical signatures of OIB source, the mafic dykes could as well be related to continental rifting, around 1.3 Ga, which may have been initiated by intra-plate volcanism.

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Section: Discussionsupporting

confidence: 59%

Mafic dykes at the southwestern margin of Eastern Ghats belt: Evidence of rifting and collision

Bhattacharya

Chaudhary

Teixeira³

2010

J Earth Syst Sci

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“…1), preserve evidence for a granulite-facies metamorphic event at w2.8 Ga (Kovach et al, 2001). Although no subsequent metamorphic imprints are identified from the Jeypore and Rengali provinces, the shear zones and fault zones forming respective boundaries with the Eastern Ghats province were reactivated during w1.1e1.0 Ga and w0.6e0.5 Ga orognesis (Crowe et al, 2001;. The Ongole domain of the Krishna province, which is closer to the eastern Dharwar Craton, preserves evidence for a pervasive metamorphic event at w1.7e1.6 Ga (Mezger and Cosca, 1999;Kovach et al, 2001;Simmat and Raith, 2008;Upadhyay et al, 2009).…”

Section: Eastern Ghats Beltmentioning

confidence: 88%

A geochemical perspective on charnockite magmatism in Peninsular India

Rajesh

2012

Geoscience Frontiers

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Large charnockite massifs occur in the high-grade Southern Granulite Terrain (SGT) and Eastern Ghats Belt (EGB) crustal provinces of Peninsular India. Available geochronological data indicate that the magmatism is episodic, associated with distinct orogenic cycles in the different crustal domains. The geochemical data also indicate a change in composition from trondhjemitic at w3.0e2.9 Ga to dominantly tonalitic at w2.6e2.5 Ga to tonalitic-granodiorite-granitic at w2.0e1.9 Ga to dominantly tonalitic at 1.7e1.6 Ga to quartz monzonitic or tonalitic at w1.0e0.9 Ga to granodiorite-granitic at w0.8e0.7 Ga. The trondhjemitic and tonalitic end members are metaluminous, magnesian and calcic to calc-alkalic, characteristic of magnesian group charnockites. The granodioritic to granitic end members are metaluminous to slightly peraluminous, ferroan and calc-alkalic to alkali-calcic, characteristic of ferroan group charnockites. The quartz monzonitic end members are metaluminous to peraluminous, magnesian to ferroan and calcic to calc-alkalic, neither characteristic of the magnesian group nor of the ferroan group of charnockites. Based on the occurrence and difference in composition of the charnockite massifs, it is suggested that the charnockite magmatism registers the crustal growth of the Indian plate on its southern (SGT) and eastern (EGB) sides, along active continental margins by accretion of arcs. ª 2012, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved.

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“…The present authors speculate that it continues eastwards, then swings around and joins up with the Prydz Bay area, where it again transects the coastline at an oblique angle. Retrograde Pan-African reworking in the Eastern Ghats Belt (Crowe et al 2001) may be a related phenomenon.…”

Section: Southern Granulite Terrain (Sgt) and Srimentioning

confidence: 99%

Proterozoic crustal evolution of southernmost India and Sri Lanka

Braun

Kriegsman

2003

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The Southern Granulite Terrain of India comprises four Proterozoic domains (from north to south): the Madurai Block, and the Achankovil, Ponmudi and Nagercoil Units. All but the Achankovil Unit share similarities with the Highland Complex of Sri Lanka: (1) evidence for Palaeoproterozoic crust formation (from U-Pb ages and 2.0–3.0 Ga Nd model ages); and (2) Pan-African ultrahigh-temperature metamorphism between 610 and 550 Ma. More specifically, the Ponmudi Unit and the Madurai Block share lithological and petrological characteristics with the low-P and high-P domains of the Highland Complex, respectively. The Achankovil Unit is correlated with the Wanni Complex of Sri Lanka on the basis of lithologies and Nd model ages (1.0–2.0Ga). These domains and the Vijayan and Kadugannawa Complexes of Sri Lanka represent Late Mesoproterozoic-Early Neoproterozoic crustal domains.Similarities in tectonic style, degree of metamorphism and Neoproterozoic U-Pb ages, suggest a common Pan-African tectonothermal evolution for the lower crustal domains of southern India, Sri Lanka and the Lützow-Holm Bay of Eastern Antarctica. Sri Lanka may have been located at the junction between the Mozambique Belt and a second belt partly involving areas that underwent a Grenvillian high-grade event during the formation of Rodinia. Madagascar shows a similar Pan-African metamorphic overprint, but is located in a different position and lacks the influence of the second belt. Alternative views are discussed.

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40Ar/39Ar geochronolgy and Neoproterozoic tectonics along the northern margin of the Eastern Ghats Belt in north Orissa, India

Cited by 78 publications

References 54 publications

Mafic dykes at the southwestern margin of Eastern Ghats belt: Evidence of rifting and collision

Mafic dykes at the southwestern margin of Eastern Ghats belt: Evidence of rifting and collision

A geochemical perspective on charnockite magmatism in Peninsular India

Proterozoic crustal evolution of southernmost India and Sri Lanka

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