Enriched Subcontinental Upper Mantle beneath Southern India: Evidence from Pb, Nd, Sr, and C-O Isotopic Studies on Tamil Nadu Carbonatites

Schleicher, Helmut; Kramm, U.; Pernicka, Ernst; Schidlowski, Manfred; Schmidt, Fatemeh; Subramanian, Vaidyanathan; Todt, W.; Viladkar, Shrinivas G.

doi:10.1093/petroj/39.10.1765

Cited by 67 publications

(37 citation statements)

References 31 publications

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“…The differences in mantle heat flow between the greenstonegranite-gneiss and gneiss-granulite terrains can be attributed to contrasting subcrustal composition between the terrains. Isotopic geochemical studies on carbonatite complexes and dykes in the gneiss-granulite terrain point to a radioelement-enriched mantle relative to the greenstonegranite-gneiss terrain (Schleicher et al 1998;Anil Kumar et al 1998;Radhakrishna et al 1991Radhakrishna et al , 1995. The enhanced mantle heat flow is also consistent with lower than normal mantle seismic velocity beneath the gneiss-granulite terrain (Srinagesh and Rai 1996).…”

Section: Discussionmentioning

confidence: 78%

Heat flow and crustal thermal structure in the Late Archaean Closepet Granite batholith, south India

Roy

Ray

Bhattacharya

et al. 2007

Int J Earth Sci (Geol Rundsch)

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The Late Archaean Closepet Granite batholith in south India is exposed at different crustal levels grading from greenschist facies in the north through amphibolite and granulite facies in the south along a *400 km long segment in the Dharwar craton. Two areas, Pavagada and Magadi, located in the Main Mass of the batholith, best represent the granitoid of the greenschist and amphibolite facies crustal levels respectively. Heat flow estimates of 38 mW m -2 from Pavagada and 25 mW m -2 from Magadi have been obtained through measurements in deep (430 and 445 m) and carefully sited boreholes. Measurements made in four boreholes of opportunity in Pavagada area yield a mean heat flow of 39 ± 4 (s.d.) mW m -2 , which is in good agreement with the estimate from deep borehole. The study, therefore, demonstrates a clear-cut heat flow variation concomitant with the crustal levels exposed in the two areas. The mean heat production estimates for the greenschist facies and amphibolite facies layers constituting the Main Mass of the batholith are 2.9 and 1.8 lW m -3 , respectively. The enhanced heat flow in the Pavagada area is consistent with the occurrence of a radioelement-enriched 2-km-thick greenschist facies layer granitoid overlying the granitoid of the amphibolite facies layer which is twice as thick as represented in the Magadi area. The crustal heat production models indicate similar mantle heat flow estimates in the range 12-14 mW m -2 , consistent with the other parts of the greenstone-granite-gneiss terrain of the Dharwar craton.

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Section: Discussionmentioning

confidence: 78%

Heat flow and crustal thermal structure in the Late Archaean Closepet Granite batholith, south India

Roy

Ray

Bhattacharya

et al. 2007

Int J Earth Sci (Geol Rundsch)

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“…The emplacement of alkali granitic and carbonatitic magmas probably represents the only important episode of Neoproterozoic crustal growth in the SGT and geochronological investigations point to intrusion and cooling between 800 and 516Ma (Odom 1982;Santosh & Drury 1988;Soman et al 1995;compilation in Rajesh & Santosh 1996b;Miller et al 1997;Kovach et al 1998;Schleicher et al 1998;Ghosh 1999). However, the only published Nd model age for an alkali granite from the Madurai Block yields a value of c. 2Ga, indicating crustal reworking ).…”

Section: Crust-forming Processes and Productsmentioning

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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“…4a) (Schleicher et al 1998); Pakkanadu (South India), cross sign (Schleicher et al 1998) and Amba Donger complex (Western India), open triangle (Viladkar and Schidlowski 2000). Probable field of primary igneous carbonatites that have been unaffected by weathering or by deuteric and hydrothermal alterations (Taylor et al 1967) is shown by solid lines, while the enlarged field of primary igneous carbonatites (Keller and Hoefs 1995) is shown by dashed line generally characterizes metasomatic conditions acting in conjunction with tectonic deformation, wherein a chemical alteration of rocks takes place due to interaction with hydrothermal and other fluids.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…This figure also includes data from other carbonatite complexes for comparison. Jacupiranga (Brazil), plus sign (Santos and Clayton 1995); South Greenland, open circle(Halama et al 2005); Decker Willem complex (South Namibia), solid triangle(Reid and Cooper 1992); Sevattur (South India), solid rectangle(Schleicher et al 1998); Jogipatti (South India), open rectangle…”

mentioning

confidence: 99%

Mantle-derived fluids in the basement of the Deccan Trap: evidence from stable carbon and oxygen isotopes of carbonates from the Killari borehole basement, Maharashtra, India

Tripathi

Parthasarathy

Ahmad

et al. 2011

Int J Earth Sci (Geol Rundsch)

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We report here for the first time geochemical, mineralogical and stable carbon and oxygen isotopic data on the crystalline basement rocks of the 1993 Killari earthquake region of Maharashtra (India), which is covered by a thick suite of Deccan volcanics. Our results revealed the hitherto unknown amphibolite-granulite nature of the 2.5 Ga basement, which contains 2.00-2.28 wt% of CO 2 . The stable carbon (d 13 C) and oxygen (d 18 O) isotopic measurements on carbonates separated from two basement samples KIL-13 (440.5 m depth) and KIL-20 (499.6 m depth) collected from the KLR-1 borehole drilled in the epicentral region showed the respective values of -6.23 and -6.22% versus PDB for d 13 C and 7.94 and 8.11% versus SMOW for d 18 O. The samples plot in the primary igneous carbonatite field, indicating the mantle origin of the carbonates, derived through the process of mantle metasomatism from the deep mantle carbon reservoir. This would suggest large-scale crust-mantle thermal fluid interaction beneath the Killari seismogenic region, which is characterized by massive upwarping of the high-velocity mafic crust and retrograde metamorphism.

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Enriched Subcontinental Upper Mantle beneath Southern India: Evidence from Pb, Nd, Sr, and C-O Isotopic Studies on Tamil Nadu Carbonatites

Cited by 67 publications

References 31 publications

Heat flow and crustal thermal structure in the Late Archaean Closepet Granite batholith, south India

Heat flow and crustal thermal structure in the Late Archaean Closepet Granite batholith, south India

Proterozoic crustal evolution of southernmost India and Sri Lanka

Mantle-derived fluids in the basement of the Deccan Trap: evidence from stable carbon and oxygen isotopes of carbonates from the Killari borehole basement, Maharashtra, India

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