Field evidence, mineral chemical and geochemical constraints on mafic-felsic magma interactions in a vertically zoned magma chamber from the Chotanagpur Granite Gneiss Complex of Eastern India

Gogoi, Bibhuti; Saikia, Ashima; Ahmad, Mansoor

doi:10.1016/j.chemer.2017.11.003

Cited by 13 publications

(10 citation statements)

References 51 publications

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“…Field and petrographical observations have revealed that the leucocratic veins occurring in the neosome are transporting mineral phases from the granitic intrusions to the melanosome. Such veins transporting mineral phases have been reported from other magma mixing scenarios (Gogoi & Saikia 2018Gogoi et al 2018A, B). According to Ubide et al (2014), crystal transfer mechanism can play an efficient role to enable two rheologically different magmas overcome some of the physical constraints of interaction and facilitate mixing between them.…”

Section: Chaotic Mixingmentioning

confidence: 66%

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Significance of viscous folding in the migmatites of Chotanagpur Granite Gneiss Complex, eastern India

Gogoi

Chauhan

Hazarika

et al. 2020

Earth and Environmental Science Transactions of the Royal Socie

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To understand the physico-chemical processes associated with migmatisation is an interesting petrological problem. New developments in microfluidics and chaotic mixing experiments have helped us to better perceive these processes from the migmatic rocks of the Proterozoic Chotanagpur Granite Gneiss Complex (CGGC), eastern India. The migmatic rocks of CGGC have preserved folded leucocratic veins in amphibolites representing viscous folding. The viscous folding phenomenon occurred due to the interaction between leucosome and melanosome. Based on textural features and mineral chemical data interpretations, we infer that when granitic and pegmatitic magmas intruded the gneissic rocks and amphibolites of our study area, diffusion of heat and volatiles from the hotter felsic magmas to the colder country rocks initiated partial melting in the amphibolites, forming melanosomes. After their formation, the highly viscous felsic magmas veined into the melanosomes, by progressively melting them and then interacting, leading to chaotic mixing dynamics. The development of chaotic mixing allowed the leucosome to venture into the melanosome as veins by stretching and folding dynamics. As the leucocratic veins or leucosome traversed through the partially molten rock or melanosome due to advection, the veins underwent viscous folding owing to the exertion of compressional stress brought about by the viscosity difference between the two mediums. The occurrence of viscous folding exponentially increased the contact area between the leucosome and the melanosome, eventually leading to enhanced diffusion and augmented mixing between the two mediums. Evidence of mixing through elemental diffusion is well documented by the compositions of amphibole and biotite occurring in the leucosome and melanosome. These minerals show substitution of magnesium and ferrous ion that show linear variation between the endmember compositions.

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Section: Chaotic Mixingmentioning

confidence: 66%

“…Such veins transporting mineral phases have been reported from other magma mixing scenarios (Gogoi & Saikia 2018, 2019; Gogoi et al . 2018A, B). According to Ubide et al .…”

Section: Discussionmentioning

confidence: 99%

Significance of viscous folding in the migmatites of Chotanagpur Granite Gneiss Complex, eastern India

Gogoi

Chauhan

Hazarika

et al. 2020

Earth and Environmental Science Transactions of the Royal Socie

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“…As such, the late-stage mafic dykes were not or least contaminated by the felsic host and represent the closest kin to the parental mafic magmas. A detailed overview on the field relationships in the NGP can be found in Gogoi et al (2018a).…”

Section: Field Relationships Of the Volcanic-plutonic Complexmentioning

confidence: 99%

“…The Bathani volcano-sedimentary sequence (BVSs) is a volcanicplutonic complex located in the northern fringe of Chotanagpur Granite Gneiss Complex (CGGC) of the Central India Tectonic Zone (CITZ), eastern India (Saikia et al, 2014). The BVSs houses two magma mixing domains-one unit is a granitic pluton that was intruded by eight small to large mafic dykes during the whole crystallization history of the pluton (Gogoi et al, 2018a), the other unit is a rhyolite dome invaded by mafic magma with a distinct mixing zone of hybrid rocks (Gogoi et al, 2018b). These two units display well preserved signatures of magma mixing at both outcrop structures and textural scale.…”

Section: Introductionmentioning

confidence: 99%

Mafic-felsic magma interactions in the Bathani volcanic-plutonic complex of Chotanagpur Granite Gneiss Complex, eastern India: implications for assembly of the Greater Indian Landmass during the Proterozoic

2020

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The Bathani volcano-sedimentary sequence (BVSs) is a typical example of volcanic-plutonic complex from the Proterozoic Chotanagpur Granite Gneiss Complex. We conducted petrological and geochemical studies on two domains of the BVSs; one is a granite pluton, while the other is a subvolcanic rhyolite dome. These two domains were intruded by mafic magmas during their evolution leading to magma mixing. The mafic rocks show tholeiitic trend, while calcalkaline affinities are displayed by the felsic rocks. The rocks display enriched LILE and fractionated REE patterns with enrichments in LREE relative to HREE. The felsic rocks have comparable whole-rock Sr-Nd isotopic compositions (( 87 Sr/ 86 Sr) = 0.7960-0.8596; ε Nd = -26.06 to -13.57), which are different from the Sr-Nd compositions of the mafic rocks (( 87 Sr/ 86 Sr) = 0.7036-0.7169; ε Nd = -7.07 to -1.99). The hybrid rocks show intermediate Sr-Nd compositions between mafic and felsic rocks (( 87 Sr/ 86 Sr) = 0.7116-0.8064; ε Nd = -23.76 to -4.56), which conform their mixed nature. Our results suggest that the BVSs evolved in an island arc subduction-related setting. Subduction of the South Indian Block beneath the North Indian Block during the Proterozoic led to the generation of mafic magmas in the mantle, which interacted with shallow crustal felsic magma chambers leading to magma mixing.

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“…However, the exact mechanisms by which mixing occurs between two disparate magmas remains uncertain. There is a consensus that textural analysis can play a vital role in deciphering the behavior of two disparate magmas during their mixing (Perugini et al 2003;Martin et al 2006, Charreteur, Tegner 2013Gogoi et al 2017;Gogoi et al 2018a). Furthermore, textural features preserved in volcanic-and hypovolcanic rocks can significantly contribute to understanding magma-chamber dynamics (Martin et al 2006, Charreteur, Tegner, 2013Gogoi et al 2018b;Gogoi, Saikia 2018).…”

Section: Introductionmentioning

confidence: 99%

Synneusis: does its preservation imply magma mixing?

Gogoi

Saikia

2018

Mineralogia

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The Ghansura Felsic Dome (GFD) occurring in the Bathani volcano-sedimentary sequence was intruded by mafic magma during its evolution leading to magma mixing. In addition to the mafic and felsic rocks, a porphyritic intermediate rock occurs in the GFD. The study of this rock may significantly contribute toward understanding the magmatic evolution of the Ghansura dome. The porphyritic rock preserves several textures indicating its hybrid nature, i.e. that it is a product of mafic-felsic magma mixing. Here, we aim to explain the origin of the intermediate rock with the help of textural features and mineral compositions. Monomineralic aggregates or glomerocrysts of plagioclase give the rock its characteristic porphyritic appearance. The fact that the plagioclase crystals constituting the glomerocrysts are joined along prominent euhedral crystal faces suggests the role of synneusis in the formation of the glomerocrysts. The compositions of the glomerocryst plagioclases are similar to those of plagioclases in the mafic rocks. The results from this study indicate that the porphyritic intermediate rock formed by the mixing of a crystal-rich mafic magma and a crystal-poor felsic melt.

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Field evidence, mineral chemical and geochemical constraints on mafic-felsic magma interactions in a vertically zoned magma chamber from the Chotanagpur Granite Gneiss Complex of Eastern India

Cited by 13 publications

References 51 publications

Significance of viscous folding in the migmatites of Chotanagpur Granite Gneiss Complex, eastern India

Significance of viscous folding in the migmatites of Chotanagpur Granite Gneiss Complex, eastern India

Mafic-felsic magma interactions in the Bathani volcanic-plutonic complex of Chotanagpur Granite Gneiss Complex, eastern India: implications for assembly of the Greater Indian Landmass during the Proterozoic

Synneusis: does its preservation imply magma mixing?

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