Geobarometry, Geothermometry, and Late Archean Geotherms from the Granulite Facies Terrain of South India

Harris, Nigel; Holt, R. W.; Drury, S. A.

doi:10.1086/628709

Cited by 136 publications

(29 citation statements)

References 28 publications

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“…The sequence of Previous thermobarometric studies on garnet-cordierite-sillimanite anatexites as well as garnetiferous felsic divariant FMAS reactions that occurred during this stage is illustrated in isothermal P-X Mg pseudosections to basic granulites in the Kodaikanal Massif (e.g. Harris et al, 1982;Raith et al, 1983;Mohan & Windley, 1993; (Fig. 8).…”

Section: Granulitesmentioning

confidence: 97%

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Ultra‐high‐temperature metamorphism and multistage decompressional evolution of sapphirine granulites from the Palni Hill Ranges, southern India

Raith

Karmakar²,

Brown

1997

Journal Metamorphic Geology

208

159

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Sapphirine granulites from a new locality in the Palni Hill Ranges, southern India, occur in a small enclave of migmatitic, highly magnesian metapelites (mg=85-72) within massive enderbitic orthogneiss. They show a variety of multiphase reaction textures that partially overprint a coarse-grained high-pressure assemblage of Bt+Opx+Ky+Grt+Pl+Qtz. The sequence of reactions as deduced from the corona and symplectite assemblages, together with petrogenetic grid considerations, records a clockwise P-T evolution with four distinct stages. (1) Equilibration of the initial high-P assemblage in deep overthickened crust (12 kbar/800-900°C) was followed by a stage of near-isobaric heating, presumably as a consequence of input of extra heat provided by the voluminous enderbitic intrusives. During heating, kyanite was converted to sillimanite, and biotite was involved in a series of vapour-phase-absent melting reactions, which resulted in the ultra-high-temperature assemblage Opx+Crd+Kfs+Spr±Sil, Grt, Qtz, Bt, coexisting with melt (equilibration at c. 950-1000°C/11-10 kbar). (2) Subsequently, as a result of decompression of the order of 4 kbar at ultra-high temperature, a sequence of symplectite assemblages (Opx+Sil+Spr/ Spr+Crd Opx+Spr+Crd Opx+Crd Opx+Crd+Spl/Crd+Spl) developed at the expense of garnet, orthopyroxene and sillimanite. This stage of near-isothermal decompression implies rapid ascent of the granulites into mid-crustal levels, possibly due to extensional collapse and erosion of the overthickened crust. (3) Development of late biotite through back-reaction of melt with residual garnet indicates a stage of near-isobaric cooling to c. 875°C at 7-8 kbar, i.e. relaxation of the rapidly ascended crust to the stable geotherm. (4) A second period of near-isothermal exhumation up to c. 6-5 kbar/850°C is indicated by the partial breakdown of late biotite through volatile phase-absent melting reactions. Available isotope data suggest that the early part of the evolutionary history (stages 1-3) is presumably coeval with the early Proterozoic metamorphism in the extended granulite terrane of the Nilgiri, Biligirirangan and Shevaroy Hills to the north, while the exhumation of the granulites from mid-crustal levels (stage 4) occurred only during the Pan-African thermotectonic event, which led to the accretion of the Kerala Khondalite Belt to the south.

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Section: Granulitesmentioning

confidence: 97%

“…In several melanocratic bands, sapphirine symplectites rimmed by cordierite are easily seen, and replace thermotectonic evolution (cf. Harris et al, 1982 andJayananda et al, 1995). The major portion of the millimetre-sized sillimanite aggregates through reaction with megacrystic orthopyroxene.…”

mentioning

confidence: 99%

Ultra‐high‐temperature metamorphism and multistage decompressional evolution of sapphirine granulites from the Palni Hill Ranges, southern India

Raith

Karmakar²,

Brown

1997

Journal Metamorphic Geology

208

159

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show abstract

“…Sm-Nd ages of 3.3-2.68 Ga suggest the DC as protoliths for these rocks (Devaraju et al, 2007). Geothermobarometric studies indicate that these rocks have formed at 700 ± 30°C and 5 -7 kbar (Harris et al, 1982). A gradational increase in metamorphic grade from the granite-greenstone belts (greenschist and amphibolite facies) of the DC to the granulite massif of the Salem Block, as well as a lack of a surficial structural break, call into question whether or not the Salem Block is a crustal block distinct from the DC.…”

Section: Northern Blockmentioning

confidence: 99%

Precambrian crustal evolution of Peninsular India: A 3.0 billion year odyssey

Meert

Pandit

Pradhan

et al. 2010

Journal of Asian Earth Sciences

316

115

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“…Metapelites around Kodaikanal occur as lenses and layers of variable thickness with distinct leucosome, mesosome, and restite domains. In their study of migmatites from Kodaikanal, Harris et al (1982) suggested that the peak metamorphism was at ca. 750°C and 5.3 kbar.…”

Section: Kodaikanal Granulite Beltmentioning

confidence: 99%

Linking monazite geochronology with fluid infiltration and metamorphic histories: Nature and experiment

Shazia

Harlov

Suzuki

et al. 2015

Lithos

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Geobarometry, Geothermometry, and Late Archean Geotherms from the Granulite Facies Terrain of South India

Cited by 136 publications

References 28 publications

Ultra‐high‐temperature metamorphism and multistage decompressional evolution of sapphirine granulites from the Palni Hill Ranges, southern India

Ultra‐high‐temperature metamorphism and multistage decompressional evolution of sapphirine granulites from the Palni Hill Ranges, southern India

Precambrian crustal evolution of Peninsular India: A 3.0 billion year odyssey

Linking monazite geochronology with fluid infiltration and metamorphic histories: Nature and experiment

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