Genesis of coronae and implications of an early Neoproterozoic thermal event: a case study from SE Chotanagpur Granite Gneissic Complex, India
Abstract Partial equilibrium textures such as corona provide information on changing pressure–temperature ( P - T ) conditions experienced by a rock during its geological evolution. Coronae layers may form in single or multiple stages; understanding the genesis of each layer is necessary to correctl...
Published in: | Geological Magazine |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Cambridge University Press (CUP)
2020
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1017/s0016756820000357 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756820000357 |
id |
crcambridgeupr:10.1017/s0016756820000357 |
---|---|
record_format |
openpolar |
spelling |
crcambridgeupr:10.1017/s0016756820000357 2024-09-15T17:44:22+00:00 Genesis of coronae and implications of an early Neoproterozoic thermal event: a case study from SE Chotanagpur Granite Gneissic Complex, India Adak, Vedanta Dutta, Upama 2020 http://dx.doi.org/10.1017/s0016756820000357 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756820000357 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Geological Magazine volume 158, issue 2, page 199-218 ISSN 0016-7568 1469-5081 journal-article 2020 crcambridgeupr https://doi.org/10.1017/s0016756820000357 2024-08-14T04:01:06Z Abstract Partial equilibrium textures such as corona provide information on changing pressure–temperature ( P - T ) conditions experienced by a rock during its geological evolution. Coronae layers may form in single or multiple stages; understanding the genesis of each layer is necessary to correctly extract information regarding the physicochemical conditions experienced by the rock. Mafic rocks from SE Chotanagpur Granite Gneissic Complex, India, show the presence of multi-layered coronae at olivine–plagioclase contact with the mineral sequence: olivine | orthopyroxene | amphibole + spinel | plagioclase. Textural studies indicate that the coronae formed during metamorphism in a single stage due to a reaction between olivine and plagioclase. Reaction modelling shows that the corona formation occurred in an open system and experienced a minor volume loss. Pseudosection modelling and thermobarometry suggest that the P - T conditions related to corona formation are 860 ± 50°C and 7 ± 0.5 kbar. A μ MgO -μ CaO diagram shows that the layers in coronae formed in response to chemical potential gradients between the reactant minerals. A combination of field observations and the P - T conditions of coronae formation suggest a fluid-driven metamorphism. Correlation with extant geological information indicates that the corona-forming event is possibly related to the accretion of India and Antarctica during the assembly of Rodinia. Article in Journal/Newspaper Antarc* Antarctica Cambridge University Press Geological Magazine 158 2 199 218 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract Partial equilibrium textures such as corona provide information on changing pressure–temperature ( P - T ) conditions experienced by a rock during its geological evolution. Coronae layers may form in single or multiple stages; understanding the genesis of each layer is necessary to correctly extract information regarding the physicochemical conditions experienced by the rock. Mafic rocks from SE Chotanagpur Granite Gneissic Complex, India, show the presence of multi-layered coronae at olivine–plagioclase contact with the mineral sequence: olivine | orthopyroxene | amphibole + spinel | plagioclase. Textural studies indicate that the coronae formed during metamorphism in a single stage due to a reaction between olivine and plagioclase. Reaction modelling shows that the corona formation occurred in an open system and experienced a minor volume loss. Pseudosection modelling and thermobarometry suggest that the P - T conditions related to corona formation are 860 ± 50°C and 7 ± 0.5 kbar. A μ MgO -μ CaO diagram shows that the layers in coronae formed in response to chemical potential gradients between the reactant minerals. A combination of field observations and the P - T conditions of coronae formation suggest a fluid-driven metamorphism. Correlation with extant geological information indicates that the corona-forming event is possibly related to the accretion of India and Antarctica during the assembly of Rodinia. |
format |
Article in Journal/Newspaper |
author |
Adak, Vedanta Dutta, Upama |
spellingShingle |
Adak, Vedanta Dutta, Upama Genesis of coronae and implications of an early Neoproterozoic thermal event: a case study from SE Chotanagpur Granite Gneissic Complex, India |
author_facet |
Adak, Vedanta Dutta, Upama |
author_sort |
Adak, Vedanta |
title |
Genesis of coronae and implications of an early Neoproterozoic thermal event: a case study from SE Chotanagpur Granite Gneissic Complex, India |
title_short |
Genesis of coronae and implications of an early Neoproterozoic thermal event: a case study from SE Chotanagpur Granite Gneissic Complex, India |
title_full |
Genesis of coronae and implications of an early Neoproterozoic thermal event: a case study from SE Chotanagpur Granite Gneissic Complex, India |
title_fullStr |
Genesis of coronae and implications of an early Neoproterozoic thermal event: a case study from SE Chotanagpur Granite Gneissic Complex, India |
title_full_unstemmed |
Genesis of coronae and implications of an early Neoproterozoic thermal event: a case study from SE Chotanagpur Granite Gneissic Complex, India |
title_sort |
genesis of coronae and implications of an early neoproterozoic thermal event: a case study from se chotanagpur granite gneissic complex, india |
publisher |
Cambridge University Press (CUP) |
publishDate |
2020 |
url |
http://dx.doi.org/10.1017/s0016756820000357 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756820000357 |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_source |
Geological Magazine volume 158, issue 2, page 199-218 ISSN 0016-7568 1469-5081 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0016756820000357 |
container_title |
Geological Magazine |
container_volume |
158 |
container_issue |
2 |
container_start_page |
199 |
op_container_end_page |
218 |
_version_ |
1810491845834178560 |