Origin of orthopyroxene-bearing felsic gneiss from the perspective of ultrahigh-temperature metamorphism: an example from the Chilka Lake migmatite complex, Eastern Ghats Belt, India

Bose, Sankar; Das, Kaushik; Torimoto, Junji; Dunkley, Daniel J.

doi:10.1180/mgm.2020.71

Cited by 8 publications

(2 citation statements)

References 128 publications

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“…The presence of garnet (a by‐product of the incongruent melting reaction of biotite) within the leucocratic layers (Figure 2g,h) and fine layers of crystallized plagioclase surrounding garnet (Figure 3i–k) is textural evidence for melt crystallization within the system. Similar reactions for orthopyroxene and garnet growth have been reported by Brandt et al (2003) and Baba (2003) for semipelites and Bose et al (2020), Galli et al (2011) and Grantham et al (2012) for anatectic charnockites.…”

Section: Textural Evolutionsupporting

confidence: 82%

Long‐lived high‐grade metamorphism in southern India: Constraints from charnockites and sapphirine‐bearing semipelitic granulites from the Madurai Block

Tiwari,

Sarkar,

Karmakar

et al. 2023

Journal Metamorphic Geology

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The Granulite Terrane of Southern India is a collage of Mesoarchean–Neoproterozoic crustal blocks that underwent high‐grade metamorphism associated with the final assembly of the Gondwana supercontinent during late Neoproterozoic–Cambrian. Here, we investigate the charnockites and associated sapphirine‐bearing semipelitic granulites from the eastern part of the Madurai Block (MB). We present new petrographic, mineral chemistry, and geochronological data to constrain the P–T–t evolution of the block and unravel the timescale and source of heat for the ultrahigh‐temperature metamorphism. Both the rock types contain coarse‐grained porphyroblastic garnet and orthopyroxene, yielding peak P–T conditions of 950 ± 30°C at 10.5 ± 0.8 kbar and 970 ± 40°C at 10 ± 0.5 kbar for semipelite and charnockite, respectively, using conventional thermobarometry. Peak ultrahigh temperatures are further supported by high Al content in the orthopyroxene (8.78 wt% Al2O3) coexisting with garnet (XMg: up to 0.57) and feldspar thermometry of the mesoperthites and antiperthites in the semipelite, yielding 950–980°C at 10 kbar. Subsequent decompression has led to the formation of coronal orthopyroxene3 + plagioclase3 in the charnockite and symplectic orthopyroxene3 + cordierite ± sapphirine ± plagioclase3 in the semipelite, yielding P–T range of 950–850°C and 9.5–6.8 kbar for semipelites and 950–820°C and 8–6.5 kbar for charnockite. Based on the obtained P–T estimates, preserved reaction textures, and phase equilibria modelling in the MnNCKFMASHTO system, a clockwise P–T evolution with isothermal decompression followed by cooling is inferred for both the rock types.Texturally constrained in situ monazite dating and rare earth element (REE) patterns show that the core of matrix monazite having low‐Th, Y, and extreme heavy rare earth element (HREE) depletion, yielding weighted mean ages of 582 ± 12 and 590 ± 22 Ma for semipelite and charnockite, respectively, dates the prograde evolution. The mantle of the matrix monazite in semipelite and comparable rim in charnockite, having relative Th‐enrichment compared to the core, yielding weighted mean ages of 552 ± 9 and 557 ± 13 Ma, respectively, dates extensive dissolution–reprecipitation from the melt at the peak stage. The relatively Th‐ and Y‐rich and moderately HREE‐depleted rim of matrix monazite in the semipelite, yielding weighted age of 516 ± 6 Ma, date initial garnet breakdown during post‐peak melt crystallization. By contrast, compositionally homogenous HREE + Y‐enriched monazite in the symplectite and retrograde monazites yielding weighted mean ages of 487 ± 47 Ma for semipelites and 508 ± 19 Ma for charnockites dates extensive garnet breakdown during final stages of melt crystallization and subsequent cooling. Our findings point to collision initiation at ~590 Ma, with the peak conditions attained at ~550 Ma followed by extensional collapse at ~510–490 Ma, resulting in rapid exhumation of lower crustal rocks to mid‐crustal levels under sustained ultrahigh‐temperature (UHT) conditions, followed by cooling to reach a stable geotherm. Our results suggest a long‐lived hot orogeny in the MB, where the UHT conditions were sustained for at least 40 MYr. The UHT conditions were most likely attained in the core of a long‐lived hot orogen by the combined effect of conductive heating through radioactive decay and mantle heat supply, with the former being the primary driver.

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Section: Textural Evolutionsupporting

confidence: 82%

Long‐lived high‐grade metamorphism in southern India: Constraints from charnockites and sapphirine‐bearing semipelitic granulites from the Madurai Block

Tiwari,

Sarkar,

Karmakar

et al. 2023

Journal Metamorphic Geology

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“…780 Ma, and ca. 500-550 Ma [111]. The Phulbani domain witnessed the earliest granulite facies orogenic imprint (D 2 -D 3 ) at ca.…”

Section: Mesoarchean Deformation In Sc and Development Of Siog Fold-thrusts (D 1cmentioning

confidence: 99%

Development of Crustal-Scale Shear Zones at the Singhbhum Craton–Eastern Ghats Belt Boundary Region: A Critical Review of the Mesoarchean–Neoproterozoic Odyssey

et al. 2021

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A number of crustal-scale shear zones have developed along the southern margin of the Singhbhum Craton, in the boundary with the Neoarchean Rengali Province and the Meso-Neoproterozoic Eastern Ghats Belt. The cratonic part, evolved in a suprasubduction zone setting, bears imprints of late Mesoarchean orogenic episode (D1C) at ca. 3.1 Ga with folding and thrust imbrication of the cratonic rocks. The succeeding orogenic imprint is etched in the Neoarchean (~2.8 Ga) with development of the Sukinda thrust along the craton margin and thrust-related deformation of the rocks of the Rengali Province (D2C-D1R). The latter event remobilized cratonic fringe with development of a spectacular E-W trending transpressional belt in the Southern Iron Ore Group rocks cored by the Sukinda ultramafics. In the Eastern Ghats Belt, the major ultrahigh-temperature orogeny took place during the Grenvillian-age (~1.0-0.9 Ga) assembly of the supercontinent Rodinia. This belt eventually got juxtaposed against the expanded Singhbhum Craton in the end-Neoproterozoic time (~0.5 Ga) along the Kerajang Fault Zone. This latter event remobilized a large part of the Rengali Province (D2R) with development of an intraterrane transpressional belt bounded by the Barkot Shear Zone in the north. The northern fringe of the intruding Eastern Ghats Belt developed a complex network of strike-slip fault system under this impact, probably an outcome of tectonic activity along the Kuunga suture, which signifies the joining of greater India with East Antarctica. The present synthesis visualizes early development in the craton through formation of a typical orogenic sequence, imbricated in thrust piles, resulting from a ca. 3.1 Ga orogeny. Further cratonic expansion was achieved via repetitive accretion and remobilization, development of crustal-scale faults and transpressional belts at ca. 2.8 Ga and ca. 0.5 Ga, much in a similar fashion as documented along oblique convergent margins of all ages.

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Polyphase deformation and ultrahigh temperature metamorphism of the deep continental crust: Implications for tectonic evolution of the northern Eastern Ghats Belt, India

Ganguly¹,

Ghosh

Bose

et al. 2021

Journal of Structural Geology

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Origin of orthopyroxene-bearing felsic gneiss from the perspective of ultrahigh-temperature metamorphism: an example from the Chilka Lake migmatite complex, Eastern Ghats Belt, India

Cited by 8 publications

References 128 publications

Long‐lived high‐grade metamorphism in southern India: Constraints from charnockites and sapphirine‐bearing semipelitic granulites from the Madurai Block

Long‐lived high‐grade metamorphism in southern India: Constraints from charnockites and sapphirine‐bearing semipelitic granulites from the Madurai Block

Development of Crustal-Scale Shear Zones at the Singhbhum Craton–Eastern Ghats Belt Boundary Region: A Critical Review of the Mesoarchean–Neoproterozoic Odyssey

Polyphase deformation and ultrahigh temperature metamorphism of the deep continental crust: Implications for tectonic evolution of the northern Eastern Ghats Belt, India

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