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

Kumar, T. Radhakrishnaand K. Vijaya

doi:10.18814/epiiugs/2020/020012

Cited by 4 publications

(1 citation statement)

References 84 publications

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“…Only limited data are available for the mafic dyke swarms in the Western Dharwar Craton. Previous researchers recognized three main dyke swarms in the WDC, concentrated towards the southern part of the craton (Murthy et al, 1987;Radhakrishna and Joseph, 1993;Meert and Pandit, 2015). However, recent studies on the mafic dyke swarms of WDC reported dykes that are exclusive to the Western Dharwar Craton along with younger generations of dykes that are geochemically coherent to the ~2.37 Ga dykes of the EDC (Silpa and Satish-Kumar, 2018;Rai et al, 2019;Yadav et al, 2020;Silpa et al, 2021;Silpa et al, 2021;Pandey and Paul., 2022).…”

Section: Geological Backgroundmentioning

confidence: 97%

Sm-Nd isotopic constraints on the metadolerite dykes from Western Dharwar Craton, Southern India: implications on the evolution of Archean subcontinental lithospheric mantle

et al. 2023

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Introduction: Metadolerite dykes in the Western Dharwar Craton represent the oldest generation of mafic dyke swarms in the craton. The emplacement of these dykes after a period of crust building activity and komatiite volcanism, helps to understand the evolution of Subcontinental Lithospheric Mantle (SCLM) and Archean dynamics.Methods: We report whole rock major, trace element geochemistry and Sr-Nd isotope characteristics for this weakly metamorphosed suite of dykes. Remnant igneous textures and mineralogy are well preserved.Results: The trace and rare earth element concentrations and an overall flat pattern suggests depleted mantle source for these dykes. Three groups are primarily identified: Group one with initial 87Sr/86Sr ratios varying between 0.70041 and 0.70102, Group two dykes and Group three dykes with initial ratios 0.70045–0.70154, and 0.70041–0.70153 respectively. Group one dykes show a good Rb-Sr isochron relationship and an errorchron age of ca. 3,003 ± 102 Ma is obtained. The initial 143Nd/144Nd ratios varies from 0.508,245 to 0.509,172. The epsilon Nd values are mostly negative, ranging between −12 and +5. Group one and two show an epsilon Nd value ranging between −1 and +5 and 0.1 to +5 respectively and group three varies between −0.5 and −12.Discussion: The geochemical characteristics suggest that the group one dykes are derived from a homogenous depleted SCLM source, group two formed by a lower degree of partial melting of a source mantle with enriched components. Group three may have formed from a progressively enriched group one source. All these dykes can be considered as exposed remnants of feeders for the greenstone volcanism in the Western Dharwar Craton.

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Section: Geological Backgroundmentioning

confidence: 97%

Sm-Nd isotopic constraints on the metadolerite dykes from Western Dharwar Craton, Southern India: implications on the evolution of Archean subcontinental lithospheric mantle

et al. 2023

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Geochemistry of Mafic Rocks From the Nagrota–Kathindi Section, Himachal Pradesh, Northwestern Himalaya: A Probable Example of Plume–Lithosphere Interaction

Singh,

Sethy

et al. 2024

Geological Journal

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The Northwest Himalayan region has a record of several phases of mafic magmatic activity spanning from Precambrian to Cenozoic in a dynamic tectonic setting. Here, we studied detailed petrography and new whole‐rock geochemistry of mafic volcanic and dykes from the Nagrota–Kathindi Section (NKS), Himachal region of the NW Himalaya, to understand the petrogenesis and possible tectonic setting. Both rock types have comparable mineralogical compositions (clinopyroxene + plagioclase + actinolite‐tremolite + chlorite + iron oxides ± hornblende ± epidote ± quartz ± carbonates) overprinted by greenschist to lower amphibolite facies metamorphism. The mafic volcanic and dykes of NKS exhibit subalkaline basalts to basaltic andesites and a typical tholeiite compositional character. The chondrite‐normalized rare earth element pattern exhibits similar LREE‐enrichment and strong HREE‐fractionation, whereas primitive mantle‐normalized multi‐element patterns show pronounced LILE‐enrichment of Rb, Ba, Th, LREE, and HFSE depletion of Nb, K, P, and Ti. The Zr–Y–Nb–Th relationships indicate that both rock types were derived from the plume source, whereas low Nb/La (< 1), similar high large‐ion lithophile element concentrations, and pronounced negative Nb, Zr, P, and Ti anomalies suggest that components other than mantle plume must have been involved in the generation and evolution of both rock types, that is, most likely plume and subcontinental lithosphere mantle (SCLM) interaction. The genesis of parent magma for the NKS volcanic and dykes was derived by 4%–6% and 10%–20% partial melting from the spinel + garnet lherzolite stability field. The majority of the studied samples correspond to spinel + garnet peridotite melting on (Gd/Yb)N versus CaO/Al2O3 diagram, thereby corroborating residual garnet in the mantle restite. All the basalts and dykes from the NK section did erupt/intrude in an intracontinental rift setting based on geochemical discrimination. The key petro‐tectonic processes attributed to the formation of these rocks are as follows: (i) the melting of the ascending plume by adiabatic decompression; (ii) the partial melting of this plume–SCLM source in the melting regime, which produces basaltic magma with a tholeiitic composition; and (iii) the release of heat that provides the thermal condition for melting of SCLM and interaction between upwelling mantle plume and subduction metasomatized SCLM.

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Secular evolution of the subcontinental lithospheric mantle beneath Indian cratons: Insights from geochemistry and geochronology of the Precambrian mafic dykes

Pandey

Paul

2022

Lithos

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

Abstract: https: //doi.org/10.18814/epiiugs/2020/020012 melts of deep mantle origin. We suggest that the major segments of the Indian SCLM were generated at around 3 Ga coinciding with a major crustal building activity in the Indian shield.

Cited by 4 publications

References 84 publications

Sm-Nd isotopic constraints on the metadolerite dykes from Western Dharwar Craton, Southern India: implications on the evolution of Archean subcontinental lithospheric mantle

Sm-Nd isotopic constraints on the metadolerite dykes from Western Dharwar Craton, Southern India: implications on the evolution of Archean subcontinental lithospheric mantle

Geochemistry of Mafic Rocks From the Nagrota–Kathindi Section, Himachal Pradesh, Northwestern Himalaya: A Probable Example of Plume–Lithosphere Interaction

Secular evolution of the subcontinental lithospheric mantle beneath Indian cratons: Insights from geochemistry and geochronology of the Precambrian mafic dykes

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