<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>The Ghansura Rhyolite Dome (GRD) is an integral part of the Bathani volcano-sedimentary sequence (BVSs), which in turn is a vital component of the Chotanagpur Granite Gneiss Complex (CGGC), eastern India. The rhyolite dome represents a shallow-level felsic magma chamber that underwent intrusion by basaltic magma during its evolution. The rocks present in the felsic dome such as basalts, rhyolites, and intermediate hybrid rocks preserve evidence of magma mixing and mingling. The objective of this contribution is to take into account, for the first time, that magma mixing processes can play an important role in the generation of calcite in magmatic rocks. The present study focuses on the mingled rocks exposed within the rhyolite dome. Previous reports have documented the existence of two distinct zones (mafic and felsic) interfacing each other in the mingled rocks of the rhyolite dome. The mafic zones dominantly consist of mineral phases such as actinolite, hornblende, biotite, plagioclase, ilmenite, calcite, and titanite. The felsic zones comprise quartz, K-feldspar, plagioclase, and biotite. When mafic magma intruded into the felsic magma chamber, interaction between the mafic and felsic magmas caused diffusion of H, Al, and K ions from the felsic to the mafic endmember. Such diffusive activities resulted in the breakdown of augite, already crystallized in the mafic magma, to form newer minerals like actinolite, hornblende, biotite, calcite, and ilmenite. The presence of ilmenite in the mingled rocks indicates the prevalence of reducing conditions during magma interaction and evolution. Breakdown of hornblende to biotite in such a reduced environmental condition led to the formation of calcite in the mingled rocks. From the results presented in this work, we are proposing that magma mixing can be a viable mechanism to form calcite in igneous rocks by magmatic processes.</p>
</abstract>

The Ghansura Rhyolite Dome (GRD) is an integral part of the Bathani volcano-sedimentary sequence (BVSs), which in turn is a vital component of the Chotanagpur Granite Gneiss Complex (CGGC), eastern India. The rhyolite dome represents a shallow-level felsic magma chamber that underwent intrusion by basaltic magma during its evolution. The rocks present in the felsic dome such as basalts, rhyolites, and intermediate hybrid rocks preserve evidence of magma mixing and mingling. The objective of this contribution is to take into account, for the first time, that magma mixing processes can play an important role in the generation of calcite in magmatic rocks. The present study focuses on the mingled rocks exposed within the rhyolite dome. Previous reports have documented the existence of two distinct zones (mafic and felsic) interfacing each other in the mingled rocks of the rhyolite dome. The mafic zones dominantly consist of mineral phases such as actinolite, hornblende, biotite, plagioclase, ilmenite, calcite, and titanite. The felsic zones comprise quartz, K-feldspar, plagioclase, and biotite. When mafic magma intruded into the felsic magma chamber, interaction between the mafic and felsic magmas caused diffusion of H, Al, and K ions from the felsic to the mafic endmember. Such diffusive activities resulted in the breakdown of augite, already crystallized in the mafic magma, to form newer minerals like actinolite, hornblende, biotite, calcite, and ilmenite. The presence of ilmenite in the mingled rocks indicates the prevalence of reducing conditions during magma interaction and evolution. Breakdown of hornblende to biotite in such a reduced environmental condition led to the formation of calcite in the mingled rocks. From the results presented in this work, we are proposing that magma mixing can be a viable mechanism to form calcite in igneous rocks by magmatic processes.

Origin of calcite by magma mixing in mingled rocks of the Ghansura Rhyolite Dome, Bathani volcano-sedimentary sequence, eastern India

Mineralogia

This work is licensed under the Creative Commons Attribution 4.0 International License.

The Ghansura Rhyolite Dome (GRD) is an integral part of the Bathani volcano-sedimentary sequence (BVSs), which in turn is a vital component of the Chotanagpur...

Origin of calcite by magma mixing in mingled rocks of the Ghansura Rhyolite Dome, Bathani volcano-sedimentary sequence, eastern India

Article Category: Original Paper

Publié en ligne: 22 juil. 2024

Pages: 15 - 29

Reçu: 28 févr. 2024

Accepté: 19 juin 2024

DOI: https://doi.org/10.2478/mipo-2024-0002

Mots clés
Calcite, Ilmenite, Magma mixing, Diffusion, Bathani volcano-sedimentary sequence, Chotanagpur Granite Gneiss Complex

© 2024 Bibhuti Gogoi et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Origin of calcite by magma mixing in mingled rocks of the Ghansura Rhyolite Dome, Bathani volcano-sedimentary sequence, eastern India

Article Category: Original Paper

Publié en ligne: 22 juil. 2024

Pages: 15 - 29

Reçu: 28 févr. 2024

Accepté: 19 juin 2024

DOI: https://doi.org/10.2478/mipo-2024-0002

Mots clésCalcite, Ilmenite, Magma mixing, Diffusion, Bathani volcano-sedimentary sequence, Chotanagpur Granite Gneiss Complex

© 2024 Bibhuti Gogoi et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Mots clés
Calcite, Ilmenite, Magma mixing, Diffusion, Bathani volcano-sedimentary sequence, Chotanagpur Granite Gneiss Complex