Mesoarchean gabbro-anorthosite complex from Singhbhum Craton, India

Manikyamba, C.; Pahari, Arijit; Santosh, M.; Ray, Jyotisankar; Sindhuja, C.S.; Subramanyam, K.S.V.; Singh, M. Rajanikanta

doi:10.1016/j.lithos.2020.105541

Cited by 16 publications

(3 citation statements)

References 70 publications

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“…Coarse‐grained gabbro rocks (with both melano‐ and leuco‐ varieties) show prominent igneous layering and are well exposed in the study area. Saha (1994) opined that these bodies are of Proterozoic age but recent studies by Manikyamba et al (2020) indicate their Mesoarchean age.…”

Section: Geological Settingmentioning

confidence: 99%

Mafic volcanic rocks of western Iron Ore Group, Singhbhum Craton, eastern India: Geochemical evidence for ocean–continent convergence

et al. 2020

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Precambrian mafic magmatism is an important global episode which played a significant role in the crustal evolution. In India, Singhbhum Craton being the oldest craton, witnessed significant occurrences of Precambrian geological activity, marked by several episodes of volcanism, plutonism, sedimentation spanning from Palaeoarchean to Mesoproterozoic age. Here we present petrological and geochemical characteristics of Precambrian mafic volcanic rocks (occurring in western Iron Ore Group (IOG), Singhbhum Craton, eastern India) to evaluate their petrogenetic aspects, tectonic setting, and magma generation. The mafic volcanic rocks are porphyritic in nature with the phenocrysts of plagioclase and groundmass composed of clinopyroxene, plagioclase, ilmenite, and volcanic glass. These rocks are mostly tholeiitic, sometimes with a transitional behaviour towards calc‐alkaline nature and display basalt‐basaltic andesite affinity. These mafic volcanic rocks also preserve geochemical signatures (high Nb/U, Nb/La, [Nb/Th]pm ratios) in support of Nb‐enriched basalts and are classified as Nb‐enriched basalts (NEB; Nb > 7 ppm) and high‐Nb basalts (HNB; Nb > 20 ppm) on the basis of Nb concentrations and mantle normalized Nb/La ratios (>0.5). The NEBs and HNBs are marked by lesser magnitude of negative Nb anomalies with high (Nb/Th)pm, (Nb/La)pm, and Nb/U ratios as compared to normal arc basalts. Several major element oxides, trace elements, and selected element ratios (like SiO2, CaO/Al2O3, Y, V/Cr, Zr/Nb, and ∑REE) show systematic variations with MgO which suggests role of magmatic fractionation. Chondrite‐normalized REE patterns for NEB and HNB rocks exhibit uniform LREE enrichment with distinct Eu negative anomalies while primitive mantle‐normalized incompatible trace element patterns reflect enrichment in LILE and LREE with prominent Nb‐Ta anomalies. Different HFSE ratios corroborate a subduction related setting for magma generation formed by ∼10%–20% melting in the domain of garnet lherzolite. Relative enrichment of LILE and LREE with depleted HFSE characteristics attest a garnet‐bearing mantle source and melt extraction with garnet in the residue. Geochemical signatures suggest that the genesis of NEB and HNB is attributable to slab‐melting and wedge hybridization processes during matured stages of subduction. Selected incompatible trace element ratios for the studied mafic volcanic rocks invoke an enriched (EM1‐EM2 type) mantle source and unequivocally suggest effects of continental crustal assimilation of the parent magma. Liquid immiscibility has played an important role as a differentiation mechanism leading to presence of high and low FeO types. The IOG mafic volcanic rocks preserve distinct geochemical signatures of matured stage of subduction, slab melting, crustal contamination and magma generation at an Archean ocean–continent convergent margin setting.

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Section: Geological Settingmentioning

confidence: 99%

Mafic volcanic rocks of western Iron Ore Group, Singhbhum Craton, eastern India: Geochemical evidence for ocean–continent convergence

et al. 2020

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“…In the anorthosite rocks (Ghose et al, 2008; this study), both Fe 2 O 3 (t) and MgO contents decline steeply, whereas Al 2 O 3 increases sharply with an increase in SiO 2 from 45.69 to 51.16 wt%. In the gabbro (Manikyamba et al, 2020;Rasheed et al, 2021) and granite (Singh and Krishna, 2009;Saikia et al, 2014;Yadav et al, 2016;Saikia et al, 2017;Saikia et al, 2019) rocks, both Fe 2 O 3T and MgO decrease gradually with increase in SiO 2 from ~48 to ~78 wt%.…”

Section: Whole-rock Geochemistrymentioning

confidence: 98%

“…Our input parameters were p = 3 kbar, f o 2 = QFM, and H 2 O = 1 wt% with all phases included in the check box. Our first approach was to use the starting compositions such as 1) hornblendite, pyroxenite, and dolerite samples of this study; 2) basalt sample RJ 8 of Ahmad et al (2021); and 3) gabbro sample B7 of Manikyamba et al (2020). However, it was seen that plagioclase was not the first liquidus phase in any of these samples.…”

Section: Figure 11mentioning

confidence: 99%

Nature and origin of anorthosite enclaves within Proterozoic granite of Chotanagpur Granite Gneiss Complex of Eastern India

et al. 2022

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The Central Indian Tectonic Zone (CITZ) is a Proterozoic suture along which the Northern and Southern Indian Blocks are inferred to have amalgamated, forming the Greater Indian Landmass. The Chotanagpur Granite Gneiss Complex (CGGC) represents the eastern extension of the CITZ and exposes several granite plutons. Enclaves of diverse origin are present as minor constituents within these granitic bodies. This study reports new major and trace element data for anorthosite enclaves hosted within granites in the Pattharkatti and Rajgir area from the northern margin of CGGC to get modern insights into the petrogenesis of anorthosites. Anorthosite enclaves show sharp contact with the host granite. They contain cumulus plagioclase (An87–94), intercumulus amphibole (magnesiohornblende and ferrotschermakite), and biotite (Mg-biotite and phlogopite) along with minor iron oxides. Amphibole crystallization pressure and temperature are constrained between 0.5 and 6.4 kbar and 653–780°C for the anorthosites. The studied anorthosites display a very gradual and steady increase in whole-rock rare earth element (REE) contents from Lu to La [(La/Yb)N = 1.22–13.08]. They also show a sharp decline in Fe2O3(t) and MgO, whereas Al2O3 increases with increasing silica contents from 45.69 to 51.16 wt%. In the chondrite normalized REE diagram, plagioclase exhibits LREE enriched patterns with strong positive Eu anomaly. The composition of parental liquid for anorthosite from the study area was estimated by adopting the equilibrium distribution method. Parental melt curves from Sm to La are near parallel and constrained broadly between trapped melt fractions (TMF) = ∼5%–15%. Anorthosites of the study area may have formed from the plagioclase-saturated basaltic melt.

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Arc–Back Arc Cohabitation and Associated Bimodal Volcanism: Evidence from Neoarchean Raichur Greenstone Belt, Eastern Dharwar Craton, India

Pahari¹,

Manikyamba²

2022

Geochemical Treasures and Petrogenetic Processes

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Mesoarchean gabbro-anorthosite complex from Singhbhum Craton, India

Cited by 16 publications

References 70 publications

Mafic volcanic rocks of western Iron Ore Group, Singhbhum Craton, eastern India: Geochemical evidence for ocean–continent convergence

Mafic volcanic rocks of western Iron Ore Group, Singhbhum Craton, eastern India: Geochemical evidence for ocean–continent convergence

Nature and origin of anorthosite enclaves within Proterozoic granite of Chotanagpur Granite Gneiss Complex of Eastern India

Arc–Back Arc Cohabitation and Associated Bimodal Volcanism: Evidence from Neoarchean Raichur Greenstone Belt, Eastern Dharwar Craton, India

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