Proterozoic Events in the Eastern Ghats Granulite Belt, India: Evidence From Rb‐Sr, Sm‐Nd Systematics, and Shrimp Dating

Shaw, Rajib; Arima, Makoto; Kagami, Hiroo; Fanning, C. M.; Shiraishi, Kazuyuki; Motoyoshi, Yoichi

doi:10.1086/515968

Cited by 142 publications

(55 citation statements)

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“…1700 Ma probably record a magmatic event in the source region (see Bose et al, 2008). The granulitegrade overprint on the UHT M 1 assemblages, which is documented as M 2 in the present study is considered to be of younger age based on earlier isotopic data (1.0-0.95 Ga, Grew and Manton, 1986;Shaw et al, 1997;Mezger and Cosca, 1999;Simmat and Raith, 2008 and references therein). SHRIMP U-Pb data from the present study yield a concordant age of 953 þ 6 Ma, which tightly constrains the timing of M 2 metamorphism.…”

Section: Discussionmentioning

confidence: 57%

“…Limited radiometric dates on the Eastern Ghats rocks show overprinting by ca. 1000-950 Ma orogeny on the early UHT granulites during a second granulite facies metamorphism characterized by near isothermal decompression during retrogression (Grew and Manton, 1986;Shaw et al, 1997;Mezger and Cosca, 1999;Dasgupta et al, 1994Dasgupta et al, , 1995Dasgupta and Sengupta, 2003). However, the prograde path of the second granulite facies metamorphism in the Eastern Ghats and the nature of deformation associated with re-working of granulites remain undetermined.…”

Section: Introductionmentioning

confidence: 99%

“…The present study is concentrated in the central part of the Eastern Ghats Province (Dobmeier and Raith, 2003) or Domain 2 (Rickers et al, 2001), where metamorphic, magmatic and isotopic signatures are well constrained (reviewed in Dasgupta and Sengupta, 2003;Shaw et al, 1997;Mezger and Cosca, 1999;Simmat andRaith, 2008, Bose et al, 2008). We present structural, petrological and geochronological data on aluminous granulites to constrain multiple structural and metamorphic events.…”

Section: Introductionmentioning

confidence: 99%

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Multiple tectonometamorphic imprints in the lower crust: first evidence ofca. 950 Ma (zircon U‐Pb SHRIMP) compressional reworking of UHT aluminous granulites from the Eastern Ghats Belt, India

et al. 2011

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Integrated structural, petrological and geochronological study on a suite of granulites from the central part of the Eastern Ghats Belt (EGB), India unveils polyphase tectonothermal evolution. We document (a) M 1 ultrahigh temperature (UHT) metamorphism ($10008C at 6.5-8.5 kbar) on an anticlockwise P-T trajectory simultaneously with early deformations D 1 -D 2 involving partial melting, (b) cooling down to $ 8008C, 6 kbar that produced a variety of coronae/symplectites (M 1R ), (c) an unrelated compressional orogeny (D 3 ) that produced deep crustal shears and mylonitic foliation (S 3m ) at low angles to D 1 -D 2 structures and was associated with slight loading, and possible partial melt extraction under granulite facies condition (M 2 $7 kbar, 8508C), and (d) localized retrogression (M 3 ) in the presence of melt accompanying D 4 deformation. This is the first record of the prograde P-T path of the superimposed granulite facies metamorphism in the EGB. U-Pb SHRIMP data of zircon preserves an inherited grain domain of ca. 1700 Ma ( 207 Pb age) that traces back the history of EGB with a lineage of the Mesoproterozoic supercontinent, Columbia. The UHT metamorphosed (peak M 1 at ca. 1000 Ma) and subsequently cooled crustal segment (M 1R ) was subjected to strong tectonothermal reworking (M 2 ) along a clockwise P-T path at 953 þ 6 Ma (concordia age) that partially exhumed the rocks to mid-crustal levels. A later fluid-induced retrogressive event vis-à-vis melt crystallization occurred at ca. 900 Ma ( KEY WORDS deep crustal reworking; Eastern Ghats Belt; India; UHT aluminous granulites; zircon U-Pb SHRIMP ages Supporting information (supplementary tables S2-S6) may be found in the online version of this paper.

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Section: Discussionmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multiple tectonometamorphic imprints in the lower crust: first evidence ofca. 950 Ma (zircon U‐Pb SHRIMP) compressional reworking of UHT aluminous granulites from the Eastern Ghats Belt, India

et al. 2011

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“…[7] A predominant Grenvillian-age granulite facies metamorphism and charnockite emplacement characterize the EGMB ( Figure 2); that forms the basis for correlation with the Rayner Complex of Antarctica [Vishakhapatnam and Angul area, circa 1.0 Ga, Grew and Manton, 1986;Aftalion et al, 1988;Paul et al, 1990;Shaw et al, 1997;Mezger and Cosca, 1999]. However, imprints of late Archean and Mesoproterozoic events have been documented from Puri and WCZ from south of Godavari rift respectively, suggesting temporal and spatial variation of such events in the belt [circa 2.6 Ga, Vinogradov et al, 1964; circa 1.6 Ga, Mezger and Cosca, 1999;Mahanadi rift, Lisker and Fachmann, 2001;Vinukonda area, Dobmeier et al, 2006].…”

Section: Geochronologymentioning

confidence: 99%

Timing and dynamics of the juxtaposition of the Eastern Ghats Mobile Belt against the Bhandara Craton, India: A structural and zircon U‐Pb SHRIMP study of the fold‐thrust belt and associated nepheline syenite plutons

2007

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Sensitive High Resolution Ion MicroProbe (SHRIMP) U‐Pb dating of zircon from basement granite gneisses and nepheline syenites of the Sinapalli Nappe, occurring along the northwestern margin of the Eastern Ghats Mobile Belt, indicate high grade regional metamorphism and associated folding accompanying juxtaposition of the nappe with the Bhandara Craton, to have taken place between 617 ± 85 Ma (lower intercept age of a reworked basement unit) and 517 Ma (age of the youngest syenite). This shows, for the first time, that the final juxtaposition of the northwestern parts of the Eastern Ghats Mobile Belt against the Bhandara Craton came about in the late Neoproterozoic and not, as previously thought, during the Mesoproterozoic. The northwestern part of the Eastern Ghats Mobile Belt comprises a fold‐ thrust belt consisting of a stack of northwesterly verging nappes that have been thrust over the Bhandara Craton. The Sinapalli Nappe is the lowermost nappe and rests over a tectonic contact on the Archean granites and gneisses of the craton. The basal décollement is exposed as a two‐km‐wide ductile‐brittle thrust, hosting nepheline syenite plutons that show fabrics consistent with a synkinematic emplacement during thrusting. The Sinapalli Nappe is comprised of a sequence of alternating mafic granulites and quartzofeldspathic gneisses with slivers of basement granites, which are folded in three phases of folding (F1, F2 and F3) and were subjected to granulite facies metamorphism during F1 folding. Thrusting is synkinematic to F2 folding and is responsible for the juxtaposition of the northwestern part of the Eastern Ghats Terrane over the Bhandara Craton during the assembly of parts of eastern Gondwana.

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“…Isotopic record on the granulite facies rocks of the NEGMB denotes Greenville thermal event (Mezger and Cosca, 1999), but Archaean, Mid-Proterozoic and PanAfrican dates are also reported (Vinogradov et al, 1964;Paul et al, 1990;Shaw et al, 1997;Dobmeier and Simmat, 2002;Krause et al, 2001). Jarick (2000) dated the UHT metamorphism at Anakapalle to be 1100 Ma for the rocks that occur as xenoliths in basic granulites.…”

Section: Northern Segmentmentioning

confidence: 99%

Eastern Ghats Mobile Belt

Sharma

2009

Cratons and Fold Belts of India

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Proterozoic Events in the Eastern Ghats Granulite Belt, India: Evidence From Rb‐Sr, Sm‐Nd Systematics, and Shrimp Dating

Cited by 142 publications

References 0 publications

Multiple tectonometamorphic imprints in the lower crust: first evidence ofca. 950 Ma (zircon U‐Pb SHRIMP) compressional reworking of UHT aluminous granulites from the Eastern Ghats Belt, India

Multiple tectonometamorphic imprints in the lower crust: first evidence ofca. 950 Ma (zircon U‐Pb SHRIMP) compressional reworking of UHT aluminous granulites from the Eastern Ghats Belt, India

Timing and dynamics of the juxtaposition of the Eastern Ghats Mobile Belt against the Bhandara Craton, India: A structural and zircon U‐Pb SHRIMP study of the fold‐thrust belt and associated nepheline syenite plutons

Eastern Ghats Mobile Belt

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