SmNd ages of Archaean metavolcanics of the Dharwar craton, South India

Kumar, Anil; Rao, Y. J. Bhaskar; Sivaraman, T.V.; Gopalan, K.

doi:10.1016/s0301-9268(96)00015-0

Cited by 160 publications

(61 citation statements)

References 31 publications

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“…The steep mylonitic zone along the eastern boundary of the Chitradurga greenstone belt is considered dividing line between two crustal blocks (Jayananda et al, 2006;Chardon et al, 2008). In the WDC, greenstone belts of the Dharwar supergroup (3.0 -2.6 Ga) are subdivided into the Bababudan Group and the overlying Chitradurga Group (Nutman et al, 1996;Anil Kumar et al, 1996;Swaminath and Ramakrishnan, 1981). Both Bababudan and Chitradurga Group volcano-sedimentary greenstone sequences are affected by varying degree of metamorphism, from greenschist to amphibolite facies (Fig.…”

Section: Geological Settingmentioning

confidence: 99%

“…1A; about 2km east of Kibbanahalli cross on the way to temple in the hill top) is located in the Kibbanahalli arm in WDC and belongs to the 2.9 -2.7 Ga Bababudan Group (Swaminath and Ramakrishnan, 1981;Anil Kumar et al, 1996;Trendall et al, 1997) in the Kibbanahalli arm of Chitradurga Greenstone Belt (Seshadri et al, 1981;Chardon et al, 1996). At the sample location, the lithological succession is typical of the shallow water platform lithologies of the Bababudan Group (Swaminath and Ramakrishnan, 1981;Kumar and Das Sharma, 1998;Srinivasan and Ojakangas, 1986), Fig.…”

Section: Geological Settingmentioning

confidence: 99%

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Origin of iron oxide spherules in the banded iron formation of the Bababudan Group, Dharwar Craton, Southern India

Orberger

Wagner

Wirth

et al. 2012

Journal of Asian Earth Sciences

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The banded iron formation of the Bababudan Group (Western Dhawar Craton, India) is composed of millimetric to centimetric alternating quartz and grey to red Fe-oxide bands.Major phases are quartz and martite (hematized magnetite) with minor Fe-sulfides and CaMg-Fe-carbonates. Micrometric Fe-oxide spherules fill cavities in discontinuous micrometric layers of Fe-oxides that occur in the massive quartz layers and at the interface of massive Feoxide and quartz layers. The spherules are composed of micrometric radial plates of hematite intergrown with nanometric magnetite. These spherules contain carbonaceous matter (CM) with nanometric Fe-particles and have low N contents (~ 900 ppm; CM1). The spherule formation is attributed to a low temperature hydrothermal process (150-200°C) at around 2.52 Ga, possibly favored by the presence of CM. These hydrothermal fluids dissolved diagenetic interstitial sulfides or carbonates creating cavities which, provided space for the spherule precipitation. Carbonaceous matter of semi-anthracite maturity is encapsulated in quartz grains adjacent to the Fe-oxide spherules (CM2) and it is thus concluded that CM1 and CM2 are most likely contemporaneous and of the same origin, either incorporated at the time of BIF formation or during the hydrothermal event at 2.52 Ga from the underlying phyllitised black shales. Carbonaceous matter (CM3) was also found around the Fe-oxide spherules and the martite grains. CM3 has much higher N contents (> 5000 ppm) and is of a lower maturity than CM1 and CM2 and is related to weathering, also indicated by the presence of goethite and kaolinite. The  13 C of all CMs varies from -19.4 to -24.7 ‰, similar to values measured in the underlying phyllitised black shales and likely reflect denitrifying microbial activity.

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Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Origin of iron oxide spherules in the banded iron formation of the Bababudan Group, Dharwar Craton, Southern India

Orberger

Wagner

Wirth

et al. 2012

Journal of Asian Earth Sciences

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“…The Bababudan Group consists of quartz pebble conglomerate-metabasaltquartz arenite-rhyodacite-BIF sequence. Sm-Nd dating of mafic volcanic rocks shows that the Bababudan volcanism occurred between 2.91 and 2.85 Ga (Anil Kumar et al 1996). Zircons separated from volcanic tuffs interbedded with BIFs have yielded SHRIMP U-Pb age of 2.72 Ga (Trendall et al 1997).…”

Section: Geological and Geochronological Settingmentioning

confidence: 99%

“…The Sm-Nd isochron age for the volcanic rocks of the Chitradurga Group is 2.75 Ga (Anil Kumar et al 1996). The acid volcanics of Chitradurga Group have yielded SHRIMP U-Pb ages of 2.61 Ga (Nutman et al 1996;Trendall et al 1997).…”

Section: Geological and Geochronological Settingmentioning

confidence: 99%

Pb–Pb zircon ages of Archaean metasediments and gneisses from the Dharwar craton, southern India: Implications for the antiquity of the eastern Dharwar craton

Bidyananda

Goswami

Srinivasan³

2011

J Earth Syst Sci

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207 Pb-206 Pb ages of zircons in samples of metasediments as well as ortho-and para-gneisses from both the western and the eastern parts of the Dharwar craton have been determined using an ion microprobe. Detrital zircons in metasedimentary rocks from both yielded ages ranging from 3.2 to 3.5 Ga. Zircons from orthogneisses from the two parts also yielded similar ages. Imprints of younger events have been discerned in the ages of overgrowths on older zircon cores in samples collected throughout the craton. Our data show that the evolution of the southwestern part of eastern Dharwar craton involved a significant amount of older crust (>3.0 Ga). This would suggest that crust formation in both the western and eastern parts of the Dharwar craton took place over similar time interval starting in the Mesoarchaean at ca. 3.5 Ga and continuing until 2.5 Ga. Our data coupled with geological features and geodynamic setting of the Dharwar craton tend to suggest that the eastern Dharwar craton and the western Dharwar craton formed part of a single terrane.

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“…3.38-3.15 Ga volcanic sequences and interlayered sediments (quartzite-pelite-carbonate), indicating detrital zircon ages as old as 3.6 Ga for their provenance (Meen et al 1992;Nutman et al 1992;Peucat et al 1993;Bhaskar Rao et al 2008;Jayananda et al 2008). The TTG and associated Sargur Group greenstone sequences form a basement for the younger 2.91-2.67 Ga Dharwar Supergroup greenstone sequences forming the Bababudan-Chitradurga and ShimogaDharwar basins (Kumar et al 1996;Nutman et al 1996;Trendall et al 1997;Jayananda et al 2013b;Manikyamba et al 2014aManikyamba et al , 2014b. Several late 2.62-2.60 Ga potassic plutons intrude the basement, as well as greenstone sequences forming the terminal magmatic event and reworking corresponding to cratonization of Archaean crust in the western Dharwar craton (Bhaskar Rao et al 1992;Jayananda et al 2006Jayananda et al , 2015Chadwick et al 2007;Sarma et al 2012;Ram Mohan et al 2014).…”

Section: Regional Geological Frameworkmentioning

confidence: 97%

Physical volcanology and geochemistry of Palaeoarchaean komatiite lava flows from the western Dharwar craton, southern India: implications for Archaean mantle evolution and crustal growth

Jayananda

Duraiswami

Aadhiseshan

et al. 2016

International Geology Review

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Palaeoarchaean (3.38-3.35 Ga) komatiites from the Jayachamaraja Pura (J.C. Pura) and Banasandra greenstone belts of the western Dharwar craton, southern India were erupted as submarine lava flows. These high-temperature (1450-1550°C), low-viscosity lavas produced thick, massive, polygonal jointed sheet flows with sporadic flow top breccias. Thick olivine cumulate zones within differentiated komatiites suggest channel/conduit facies. Compound, undifferentiated flow fields developed marginal-lobate thin flows with several spinifex-textured lobes. Individual lobes experienced two distinct vesiculation episodes and grew by inflation. Occasionally komatiite flows form pillows and quench fragmented hyaloclastites. J.C. Pura komatiite lavas represent massive coherent facies with minor channel facies, whilst the Bansandra komatiites correspond to compound flow fields interspersed with pillow facies. The komatiites are metamorphosed to greenschist facies and consist of serpentine-talc ± carbonate, actinolite-tremolite with remnants of primary olivine, chromite, and pyroxene. The majority of the studied samples are komatiites (22.46-42.41 wt.% MgO) whilst a few are komatiitic basalts (12.94-16.18 wt.% MgO) extending into basaltic (7.71 -10.80 wt.% MgO) composition. The studied komatiites are Al-depleted Barberton type whilst komatiite basalts belong to the Al-undepleted Munro type. Trace element data suggest variable fractionation of garnet, olivine, pyroxene, and chromite. Incompatible element ratios (Nb/Th, Nb/U, Zr/Y Nb/Y) show that the komatiites were derived from heterogeneous sources ranging from depleted to primitive mantle. CaO/Al 2 O 3 and (Gd/Yb) N ratios show that the Al-depleted komatiite magmas were generated at great depth (350-400 km) by 40-50% partial melting of deep mantle with or without garnet (majorite?) in residue whilst komatiite basalts and basalts were generated at shallow depth in an ascending plume. The widespread Palaeoarchaean deep depleted mantle-derived komatiite volcanism and sub-contemporaneous TTG accretion implies a major earlier episode of mantle differentiation and crustal growth during ca. 3.6-3.8 Ga.ARTICLE HISTORY

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SmNd ages of Archaean metavolcanics of the Dharwar craton, South India

Cited by 160 publications

References 31 publications

Origin of iron oxide spherules in the banded iron formation of the Bababudan Group, Dharwar Craton, Southern India

Origin of iron oxide spherules in the banded iron formation of the Bababudan Group, Dharwar Craton, Southern India

Pb–Pb zircon ages of Archaean metasediments and gneisses from the Dharwar craton, southern India: Implications for the antiquity of the eastern Dharwar craton

Physical volcanology and geochemistry of Palaeoarchaean komatiite lava flows from the western Dharwar craton, southern India: implications for Archaean mantle evolution and crustal growth

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