Stable isotope geochemistry and microfossil assemblages of carbonate rocks in the ophiolite mélange zone of the Indo– Myanmar orogenic Belt, NE India: Implications on age and depositional environment
A comprehensive data of whole‐rock and stable isotopic geochemistry along with microfossil assemblages of the carbonate rocks of the ophiolite mélange zone of the Indo–Myanmar orogenic Belt (IMOB), north‐east India are discussed, to determine the influence of terrigenous contamination during the for...
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crwiley:10.1002/gj.4550 2024-10-13T14:10:21+00:00 Stable isotope geochemistry and microfossil assemblages of carbonate rocks in the ophiolite mélange zone of the Indo– Myanmar orogenic Belt, NE India: Implications on age and depositional environment Singh, Athokpam Krishnakanta Guruaribam, Venus Singh, Yengkhom Raghumani Singh, Nongmaithem Ibotombi Singh, Leimapokpam Romendro Chaubey, Monika Tewari, Vinod Chandra Singh, Wangkheimayum Inaocha Lakhan, Nongmaithem Devi, Loitongbam Debala Chanu, Rajkumari Sanalembi Ministry of Earth Sciences 2022 http://dx.doi.org/10.1002/gj.4550 https://onlinelibrary.wiley.com/doi/pdf/10.1002/gj.4550 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/gj.4550 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Geological Journal volume 57, issue 12, page 5308-5325 ISSN 0072-1050 1099-1034 journal-article 2022 crwiley https://doi.org/10.1002/gj.4550 2024-09-17T04:48:26Z A comprehensive data of whole‐rock and stable isotopic geochemistry along with microfossil assemblages of the carbonate rocks of the ophiolite mélange zone of the Indo–Myanmar orogenic Belt (IMOB), north‐east India are discussed, to determine the influence of terrigenous contamination during the formation of these carbonate rocks and also to understand their depositional environment and ages. These carbonate rocks contain a diverse fauna with the dominance of foraminiferal assemblages of planktonic foraminifera ( Globotruncana sp. and Heterohelix sp., etc.) which indicates they were formed during the Santonian to Maastrichtian age. Based on chemical compositions, these carbonate rocks have been identified as limestone (CaO/MgO > 50.1) to slightly dolomitic limestone (9.1 < CaO/MgO < 50.1). Total rare earth element (REE) contents in these carbonates are variable (22.39–146.05 ppm). The Post‐Archean Australian Shale (PAAS)‐normalized REE + Y patterns of these carbonates exhibit seawater‐like REE patterns with LREE depletion and relative HREE enrichment with negative Ce anomalies (Ce/Ce* = 0.32–0.79) and positive Y (4.42–27.81 ppm) and Eu anomalies (Eu/Eu* = 1.11–1.86), suggesting that they were deposited under an oxygenated environment with contamination by hydrothermal activity. They are also depleted in δ 13 C 0 / 00 (PDB) (1.02–1.57 0 / 00 ) and δ 18 O 0 / 00 (PDB) (−6.37 to −9.00%) values which characterize marine precipitates. Eu anomalies and spread in negative δ 18 O 0 / 00 (PDB) values to a lesser extent of δ 13 C 0 / 00 (PDB) values of these carbonates suggest their formation was altered by diagenesis in the shallow marine environment. Our new whole‐rock and stable isotope geochemical characteristics, in conjunction with microfacies, suggest that the investigated carbonate rocks might have been formed in low‐energy environments, and deposited in neritic to bathyal palaeoenvironments during the Santonian to Maastrichtian interval. Article in Journal/Newspaper Planktonic foraminifera Wiley Online Library Geological Journal 57 12 5308 5325 |
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Wiley Online Library |
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English |
description |
A comprehensive data of whole‐rock and stable isotopic geochemistry along with microfossil assemblages of the carbonate rocks of the ophiolite mélange zone of the Indo–Myanmar orogenic Belt (IMOB), north‐east India are discussed, to determine the influence of terrigenous contamination during the formation of these carbonate rocks and also to understand their depositional environment and ages. These carbonate rocks contain a diverse fauna with the dominance of foraminiferal assemblages of planktonic foraminifera ( Globotruncana sp. and Heterohelix sp., etc.) which indicates they were formed during the Santonian to Maastrichtian age. Based on chemical compositions, these carbonate rocks have been identified as limestone (CaO/MgO > 50.1) to slightly dolomitic limestone (9.1 < CaO/MgO < 50.1). Total rare earth element (REE) contents in these carbonates are variable (22.39–146.05 ppm). The Post‐Archean Australian Shale (PAAS)‐normalized REE + Y patterns of these carbonates exhibit seawater‐like REE patterns with LREE depletion and relative HREE enrichment with negative Ce anomalies (Ce/Ce* = 0.32–0.79) and positive Y (4.42–27.81 ppm) and Eu anomalies (Eu/Eu* = 1.11–1.86), suggesting that they were deposited under an oxygenated environment with contamination by hydrothermal activity. They are also depleted in δ 13 C 0 / 00 (PDB) (1.02–1.57 0 / 00 ) and δ 18 O 0 / 00 (PDB) (−6.37 to −9.00%) values which characterize marine precipitates. Eu anomalies and spread in negative δ 18 O 0 / 00 (PDB) values to a lesser extent of δ 13 C 0 / 00 (PDB) values of these carbonates suggest their formation was altered by diagenesis in the shallow marine environment. Our new whole‐rock and stable isotope geochemical characteristics, in conjunction with microfacies, suggest that the investigated carbonate rocks might have been formed in low‐energy environments, and deposited in neritic to bathyal palaeoenvironments during the Santonian to Maastrichtian interval. |
author2 |
Ministry of Earth Sciences |
format |
Article in Journal/Newspaper |
author |
Singh, Athokpam Krishnakanta Guruaribam, Venus Singh, Yengkhom Raghumani Singh, Nongmaithem Ibotombi Singh, Leimapokpam Romendro Chaubey, Monika Tewari, Vinod Chandra Singh, Wangkheimayum Inaocha Lakhan, Nongmaithem Devi, Loitongbam Debala Chanu, Rajkumari Sanalembi |
spellingShingle |
Singh, Athokpam Krishnakanta Guruaribam, Venus Singh, Yengkhom Raghumani Singh, Nongmaithem Ibotombi Singh, Leimapokpam Romendro Chaubey, Monika Tewari, Vinod Chandra Singh, Wangkheimayum Inaocha Lakhan, Nongmaithem Devi, Loitongbam Debala Chanu, Rajkumari Sanalembi Stable isotope geochemistry and microfossil assemblages of carbonate rocks in the ophiolite mélange zone of the Indo– Myanmar orogenic Belt, NE India: Implications on age and depositional environment |
author_facet |
Singh, Athokpam Krishnakanta Guruaribam, Venus Singh, Yengkhom Raghumani Singh, Nongmaithem Ibotombi Singh, Leimapokpam Romendro Chaubey, Monika Tewari, Vinod Chandra Singh, Wangkheimayum Inaocha Lakhan, Nongmaithem Devi, Loitongbam Debala Chanu, Rajkumari Sanalembi |
author_sort |
Singh, Athokpam Krishnakanta |
title |
Stable isotope geochemistry and microfossil assemblages of carbonate rocks in the ophiolite mélange zone of the Indo– Myanmar orogenic Belt, NE India: Implications on age and depositional environment |
title_short |
Stable isotope geochemistry and microfossil assemblages of carbonate rocks in the ophiolite mélange zone of the Indo– Myanmar orogenic Belt, NE India: Implications on age and depositional environment |
title_full |
Stable isotope geochemistry and microfossil assemblages of carbonate rocks in the ophiolite mélange zone of the Indo– Myanmar orogenic Belt, NE India: Implications on age and depositional environment |
title_fullStr |
Stable isotope geochemistry and microfossil assemblages of carbonate rocks in the ophiolite mélange zone of the Indo– Myanmar orogenic Belt, NE India: Implications on age and depositional environment |
title_full_unstemmed |
Stable isotope geochemistry and microfossil assemblages of carbonate rocks in the ophiolite mélange zone of the Indo– Myanmar orogenic Belt, NE India: Implications on age and depositional environment |
title_sort |
stable isotope geochemistry and microfossil assemblages of carbonate rocks in the ophiolite mélange zone of the indo– myanmar orogenic belt, ne india: implications on age and depositional environment |
publisher |
Wiley |
publishDate |
2022 |
url |
http://dx.doi.org/10.1002/gj.4550 https://onlinelibrary.wiley.com/doi/pdf/10.1002/gj.4550 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/gj.4550 |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
Geological Journal volume 57, issue 12, page 5308-5325 ISSN 0072-1050 1099-1034 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/gj.4550 |
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Geological Journal |
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57 |
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12 |
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5308 |
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5325 |
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1812817595368210432 |