Sr–Nd isotope geochemistry of the early Precambrian sub-alkaline mafic igneous rocks from the southern Bastar craton, Central India

Srivastava, Rajesh K.; Ellam, Rob M.; Gautam, Gulab C.

doi:10.1007/s00710-009-0049-2

Cited by 30 publications

(8 citation statements)

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“…Their 143 Nd/ 144 Nd i ratios vary between 0.5097 and 0.5102; εNd values correspondingly range from +1 to -10. Sr and Nd isotopic values of similar range are also reported from 1.88 Ga BD2 dykes in Bastar craton (Srivastava et al, 2009) and Bijawar igneous units (Pandey et al, 2012). In a Sr-Nd isotope plot (figure not shown), the Proterozoic mafic samples strikingly differ from the mantle components defined by Hart and Zindler (1989).…”

Section: Geochemistry and Petrological Featuressupporting

confidence: 75%

Palaeoproterozoic Mafic magmatism in the Indian Shield: Petrologic, Geochemical and Thermal constraints on Proterozoic Mantle

Kumar

2020

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Section: Geochemistry and Petrological Featuressupporting

confidence: 75%

Palaeoproterozoic Mafic magmatism in the Indian Shield: Petrologic, Geochemical and Thermal constraints on Proterozoic Mantle

Kumar

2020

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“…It is known that the early earth was hotter and therefore mafic magmatic activities were rampant and various estimates indicate that nearly 80% of the crust was formed during the Archaean [3,5]. It is observed that the mafic volcanic rocks were preserved in the greenstone belts or Precambrian continental rift basins [6,7], but in most of the cratons where the basement gneisses are exposed, we observe only the dykes and dyke swarms and no volcanic equivalents are observed because of severe erosion to the deeper levels exposing the basement rocks [8][9][10][11][12]. It is possible that during the early earth there were numerous LIPs and their equivalents were present but these got eroded with time [13][14][15][16].…”

Section: Introductionmentioning

confidence: 61%

“…Granulites from Balaghat-Bhandara and Ramakona-Katangi Ganulite belts associated with Central Indian Suture (CIS) zone [41,28] and Bhopalpatnam and Karimnagar granulite belts are exposed in Western Bastar [36,[42][43][44][45][46]. Mafic dyke swarms of Bastar Craton include NWSE trending Keshkal swarm, Bhanupratappur swarm, Dantewara swarm, and Bastanar swarm, NNW-SSE trending Sonakhan swarm, N-S trending Lakhna dykes, ENE-WSW trending Bandimal dykes are well studied [11,22,42,[47][48][49][50][51][52][53][54][55][56][57]. Dongargarh, Malanjkhand, Abhujmar and Mul granites represent the diverse Proterozoic granites from Bastar Craton [37,56,[58][59][60][61][62].…”

Section: Regional Geologymentioning

confidence: 99%

Untitled

2022

AES

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The Bastar Craton of the southern part of Central Indian shield is endowed with the presence of magmatic rocks in form of mafic magmatism (dominantly dykes, dyke swarms and sills) in the areas where they are exposed along with the basement rocks (Amgaon and Tirodi gneissic complex). The equivalent volcanic rocks occur in the supracrustal belts, where the magmatic rocks are intercalated with sedimentary rocks, as observed for example in the Sakoli and Khairagarh supracrustal belts. The studied dyke samples show large variation from low silica to high silica variants, basaltic to andesitic/ rhyolitic in composition. The low silica samples are subdivided into low silica group I and II based on their distinct evolutionary trends on various bi-elemental plots and the incompatible trace elements ratios, including those for the rare earth elements. The observed chemical variations indicate that these samples were derived from distinct and/or mixed mantle sources from different depths. These samples were derived by varying degrees of partial melting followed by dominantly clinopyroxene, amphibole, plagioclase and to some extent olivine fractionation. The multi-elements patterns and various discriminant diagrams indicate that the studied samples were generated in a subduction environment giving rise to arc magmatism. The presence of dominantly dykes, dyke swarms and sills along with the basement rocks indicate that the study area has undergone deep erosion exposing the basement rocks and these magmatic bodies (dykes, dyke swarms and sills) actually represent the plumbing system for the mantle derived melts, which contributed significantly to the Precambrian crustal evolution processes in the Central Indian shield.

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“…The juvenile nature of the samples is established in Figure 9a, where they plot close to the depleted mantle curve and are also widely separated from the Nd isotopic evolutionary trend of Archean crust. The positive ε Nd values for some of the rocks suggest their derivation from a depleted mantle source (Srivastava et al 2009). The range of initial ε Nd values from our samples strongly suggests that the rocks were produced entirely from the mantle in an oceanic setting (DePaolo, 1988), with possible minor crustal contamination.…”

Section: B Petrogenesis Of the Metavolcanic Rocks And Enclavesmentioning

confidence: 70%

Origin and tectonic significance of the metavolcanic rocks and mafic enclaves from the Palaeoproterozoic Birimian Terrane, SE West African Craton, Ghana

Sakyi

Manu

et al. 2020

Geol. Mag.

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The Palaeoproterozoic Birimian Supergroup of the West African Craton (WAC) consists of volcanic belts composed predominantly of basaltic and andesitic rocks and intervening sedimentary basins composed predominantly of wackes and argillites. Mafic metavolcanic rocks and granitoid-hosted enclaves from the Palaeoproterozoic Lawra Belt of Ghana were analysed for geochemical and Sr–Nd isotopic data to constrain the geological evolution of the southeastern part of the WAC. The metavolcanic rocks display mainly tholeiitic signatures, whereas the enclaves show calc-alkaline signatures. The high SiO2 contents (48.6–68.9 wt%) of the enclaves are suggestive of their evolved character. The high Th/Yb values of the samples relative to that of the mantle array may indicate derivation of their respective magmas from subduction-modified source(s). The rocks show positive εNd values of +0.79 to +2.86 (metavolcanic rocks) and +0.79 to +1.82 (enclaves). These signatures and their Nd model ages (TDM2) of 2.31–2.47 Ga (metavolcanic rocks) and 2.39–2.47 Ga (enclaves) suggest they were probably derived from juvenile mantle-derived protoliths, with possible input of subducted pre-Birimian (Archean?) rocks in their source(s). Their positive Ba–Th and negative Nb–Ta, Zr–Hf and Ti anomalies may indicate their formation through subduction-related magmatism consistent with an arc setting. We propose that the metavolcanic rocks and enclaves from the Lawra Belt formed in a similar island-arc setting. We infer that the granitoids developed through variable degrees of mixing/mingling between basic magma and granitic melt during subduction, when blobs of basic to intermediate parental magma became trapped in the granitic magma to form the enclaves.

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Sr–Nd isotope geochemistry of the early Precambrian sub-alkaline mafic igneous rocks from the southern Bastar craton, Central India

Cited by 30 publications

References 28 publications

Palaeoproterozoic Mafic magmatism in the Indian Shield: Petrologic, Geochemical and Thermal constraints on Proterozoic Mantle

Palaeoproterozoic Mafic magmatism in the Indian Shield: Petrologic, Geochemical and Thermal constraints on Proterozoic Mantle

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Origin and tectonic significance of the metavolcanic rocks and mafic enclaves from the Palaeoproterozoic Birimian Terrane, SE West African Craton, Ghana

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