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

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.

Synneusis: does its preservation imply magma mixing?

Mineralogia

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"Synneusis: does its preservation imply magma mixing?"}

The Ghansura Felsic Dome (GFD) occurring in the Bathani volcano-sedimentary sequence was intruded by mafic magma during its evolution leading to magma mixing....

Synneusis: does its preservation imply magma mixing?

Publié en ligne: 02 mars 2019

Pages: 99 - 117

Reçu: 26 avr. 2018

Accepté: 18 déc. 2018

DOI: https://doi.org/10.2478/mipo-2018-0009

Mots clés
hybrid rock, glomerocrysts, porphyritic, plagioclase, Bathani volcano-sedimentary sequence

© 2018 Bibhuti Gogoi et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Synneusis: does its preservation imply magma mixing?

Publié en ligne: 02 mars 2019

Pages: 99 - 117

Reçu: 26 avr. 2018

Accepté: 18 déc. 2018

DOI: https://doi.org/10.2478/mipo-2018-0009

Mots cléshybrid rock, glomerocrysts, porphyritic, plagioclase, Bathani volcano-sedimentary sequence

© 2018 Bibhuti Gogoi et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Mots clés
hybrid rock, glomerocrysts, porphyritic, plagioclase, Bathani volcano-sedimentary sequence