Multiple mantle melting events for two overlapping ca. 2.21-2.18 Ga mafic dyke swarms in the Dharwar craton, India

Samal, Amiya K.; Apratim, K.; Srivastava, Rajesh K.

doi:10.1080/00206814.2020.1827460

Cited by 12 publications

(5 citation statements)

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“…The NW-to WNW-trending ca. 2.21 Ga Anantapur-Kunigal dyke swarm displays a radiating geometry (one sub-swarm is NWtrending and another is WNW-trending) as confirmed by its available geochronological (French & Heaman, 2010) and geochemical data (French & Heaman, 2010;Srivastava et al 2015;Samal et al 2021b) (see Fig. 1a, b).…”

Section: A Sampling and Field Observationsmentioning

confidence: 64%

“…However, research on the emplacement systematics and magma flow dynamics of these swarms are limited and restricted (e.g., Kumar et al 2015;Nagaraju & Parashuramulu, 2019;Ramesh et al 2020;Datta et al 2023). Moreover, earlier geochemical studies (Srivastava et al 2014a(Srivastava et al , 2014b2015;Samal et al 2021bSamal et al , 2021cParashuramulu et al 2022) have unanimously characterized these dykes as unmetamorphosed and undeformed. This makes the dykes of the Dharwar Craton even better candidates for studying the primary magma flow dynamics.…”

Section: Introductionmentioning

confidence: 94%

“…These dyke swarms have been studied in detail throughout the past two decades and are considered as part of different LIP events (Samal et al 2019b). Various geochemical and paleomagnetic studies (Halls et al 2007;French & Heaman, 2010;Srivastava, 2011;Kumar et al 2012;Pivarunas et al 2018;Söderlund et al 2019) on these dyke swarms have established their plume related origin and have even demarcated their potential plume centres (Ernst & Srivastava, 2008;French & Heaman, 2010;Kumar et al 2012Kumar et al , 2015Nagaraju et al 2019;Ramesh et al 2020;Samal et al 2021bSamal et al , 2021cYadav et al 2020, 2021and Parashuramulu et al 2022 among several others). Their exposures are denser in the EDC relative to WDC, likely due to differences in their crustal lithologies or a weaker lithosphere beneath the EDC or proximity of the plume centre to the EDC (cf.…”

Section: Regional Geologymentioning

confidence: 99%

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Contextual relationship between mechanical heterogeneity and dyking: constraints from magma emplacement dynamics of the ca. 2.21 Ga Anantapur–Kunigal mafic dyke swarm, Dharwar Craton, India

Datta,

Samal,

Banerjee

et al. 2023

Geol. Mag.

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Mafic dykes are typically emplaced through primary hydraulic fracturing of undeformed crust or may make use of pre-existing crustal inhomogeneities, representing the plumbing systems of a large igneous province. The Eastern Dharwar Craton has dense exposures of several generations of Paleoproterozoic mafic dyke swarms ranging from ca. 2.37 Ga to ca. 1.79 Ga. Herein, using anisotropy of magnetic susceptibility fabric data of mafic dykes and associated host granites, the emplacement systematics of the NW- to W-trending ca. 2.21 Ga Anantapur–Kunigal dyke swarm, displaying a radiating geometry, have been studied to understand magma flow dynamics. A low-angle relationship between the silicate and opaque fabrics and good correlation with magnetic lineation, identified via petrographic studies and shape preferred orientation analyses of multiple oriented thin sections, suggest a primary flow-related magnetic anisotropy for the studied dyke samples. The classic subparallel relationship between the trend of the dyke planes and magnetic fabric of the associated host granites suggests that the radiating geometry of the ca. 2.21 Ga dyke swarm was supported by a favourable pre-existing structural grain of the country rock. We interpret the magma for the studied dyke swarm was fed laterally from a distant plume. It was emplaced as laterally propagating primary dyke fractures as well as injected into the pre-existing subparallel crustal inhomogeneities. Corroborating all these inferences, a detailed emplacement model for ca. 2.21 Ga Anantapur–Kunigal dyke swarm is also proposed.

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Section: A Sampling and Field Observationsmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 94%

Section: Regional Geologymentioning

confidence: 99%

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Contextual relationship between mechanical heterogeneity and dyking: constraints from magma emplacement dynamics of the ca. 2.21 Ga Anantapur–Kunigal mafic dyke swarm, Dharwar Craton, India

Datta,

Samal,

Banerjee

et al. 2023

Geol. Mag.

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“…Rai et al (2020Rai et al ( , 2019 have reported geochemistry of the ENE-WSW to NE-SW and N to NNW set of mafic dykes. Samal et al (2020) have recently published geochemistry for NW to WNW trending mafic dykes from DC. However, the 2.21 Ga NNW-SSE to NW-SE dated mafic dykes widely present in the WDC have not been studied for geochemistry.…”

Section: Introductionmentioning

confidence: 99%

Geochemistry of 2.21 Ga giant radiating dyke swarm from the Western Dharwar Craton, India: Implications for petrogenesis and tectonic evolution

Yadav

Sarma

2021

Geological Journal

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The Western Dharwar Craton (WDC) exhibits numerous exposures of NNW-SSE to NW-SE trending mafic dykes. Geochemistry of four 2.21 Ga NNW-NW trending dykes and 21 other similar trending dykes provides new insights into the geochemical behaviour, mantle source characteristics, and tectonic history of mafic magmatic event, which have also affected the Eastern Dharwar Craton (EDC). Based on modal mineralogy and texture, these dykes can be classified into dolerite, olivine dolerite, gabbro, and olivine gabbro. They show basaltic to basaltic-andesitic composition and have sub-alkaline tholeiitic nature. La N /Lu N ratio classifies the dykes into two groups: Group I, with values close to 2, shows relatively flat REE patterns while, Group II, with values 4-6, has inclined REE patterns. In general, both groups show LREE enrichment and most of the samples exhibit negative Nb-Ta and Ti anomalies, indicating crustal contamination. However, negative Zr-Hf anomaly and low Th/Nb values (0.14-0.73) noticed within the samples preclude significant crustal inputs. Petrogenetic modelling using batch melting equation suggests that the dykes fractionated from two distinct mantle melts and had slightly different sources, both within the spinel-garnet transition zone. The overall composition of these 2.21 Ga dykes is consistent with a mantle plume-induced heterogeneous source that was previously modified by some ancient subduction event. Coeval dykes from EDC exhibit similar geochemical behaviour, mantle source characteristics, and tectonic history. These and other synchronous dykes from distant cratons, viz. Superior, Slave, Greenland, represent a 2.21 Ga large igneous province event, which is linked with the Sclavia/ Superia supercraton.

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“…Mafic and ultramafic magmatism poured mafic magma on the oceanic floor via the divergent plate boundaries, but rocks on the ocean floor are not older than 200 My [5,20,21]. Thus, we have to focus our studies on the continental crust, which preserves the oldest rocks to younger rocks produced at the continental arc, rift basins and LIPs [2,5].The Bastar Craton has preserved enormous dykes, dyke swarms and even major sills emplaced at deeper levels and now exposed along with the basement rocks as the supra crustal rocks have disappeared because of long term erosion [12,[22][23][24][25][26], although some of the supracrustal rocks including volcanic flows are preserved in the rift basins such as the Sakoli belt volcanics and Khairagarh supracrustal volcanics [22,27,28]. We present here new geochemical data (major, trace including rare earth elements (REE) on the mafic dykes from the Amgaon and Khairagarh regions of the Bastar Craton (Figure 1).…”

Section: Introductionmentioning

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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Multiple mantle melting events for two overlapping ca. 2.21-2.18 Ga mafic dyke swarms in the Dharwar craton, India

Cited by 12 publications

References 146 publications

Contextual relationship between mechanical heterogeneity and dyking: constraints from magma emplacement dynamics of the ca. 2.21 Ga Anantapur–Kunigal mafic dyke swarm, Dharwar Craton, India

Contextual relationship between mechanical heterogeneity and dyking: constraints from magma emplacement dynamics of the ca. 2.21 Ga Anantapur–Kunigal mafic dyke swarm, Dharwar Craton, India

Geochemistry of 2.21 Ga giant radiating dyke swarm from the Western Dharwar Craton, India: Implications for petrogenesis and tectonic evolution

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