Neoproterozoic Mafic Magmatism in Nagercoil Block, Southern India and Its Implications on the Gondwana Collisional Orogeny
The Nagercoil block situated at the southernmost tip of India occupies a key position in the East Gondwana collisional tectonic models. The Nagercoil block is dominated by Orosirian I-type charnockite massifs that host numerous gabbroic emplacements. Our present understanding about the crustal archi...
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MDPI AG
2022-11-01
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| Series: | Minerals |
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| author | S. Sajna J. K. Tomson J. Amal Dev Nilanjana Sorcar T. Vijaya Kumar |
| author_facet | S. Sajna J. K. Tomson J. Amal Dev Nilanjana Sorcar T. Vijaya Kumar |
| author_sort | S. Sajna |
| collection | DOAJ |
| description | The Nagercoil block situated at the southernmost tip of India occupies a key position in the East Gondwana collisional tectonic models. The Nagercoil block is dominated by Orosirian I-type charnockite massifs that host numerous gabbroic emplacements. Our present understanding about the crustal architecture of the Nagercoil block is derived mostly from these charnockites, while detailed studies on gabbros are lacking. We present new petrology, geochemistry, and zircon U-Pb/Hf isotopic data of gabbros from the Nagercoil block to understand their petrogenesis and tectonic significance. The results reveal that these are formed by the partial melting of a subduction-modified lithospheric mantle source in a continental arc setting. Zircon U-Pb geochronology results reveal that the gabbros were emplaced between 561 and 531 Ma. Hafnium isotopic studies on zircons argue for a mid-Mesoproterozoic melting source with near-juvenile magmatic signatures. The Hf-T<sub>DM</sub> ages together with the available data from the terrane point to the involvement of the adjacent Achankovil unit as a possible melting source contributor. The genetic link between the Achankovil unit and Sri Lanka together with the remarkable similarity in ages and isotopic characteristics of mafic rocks from both these terranes point to their coeval formation during the East African Orogeny associated with the final stages of the Gondwana supercontinent assembly. |
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| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T16:04:15Z |
| publishDate | 2022-11-01 |
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| series | Minerals |
| spelling | doaj.art-71b98ebad09242dc812b6f45b1180b2c2023-11-24T16:50:59ZengMDPI AGMinerals2075-163X2022-11-011212150910.3390/min12121509Neoproterozoic Mafic Magmatism in Nagercoil Block, Southern India and Its Implications on the Gondwana Collisional OrogenyS. Sajna0J. K. Tomson1J. Amal Dev2Nilanjana Sorcar3T. Vijaya Kumar4Solid Earth Research Group, National Centre for Earth Science Studies, Thiruvananthapuram 695011, IndiaSolid Earth Research Group, National Centre for Earth Science Studies, Thiruvananthapuram 695011, IndiaSolid Earth Research Group, National Centre for Earth Science Studies, Thiruvananthapuram 695011, IndiaSolid Earth Research Group, National Centre for Earth Science Studies, Thiruvananthapuram 695011, IndiaCouncil of Scientific and Industrial Research-National Geophysical Research Institute, Hyderabad 500007, IndiaThe Nagercoil block situated at the southernmost tip of India occupies a key position in the East Gondwana collisional tectonic models. The Nagercoil block is dominated by Orosirian I-type charnockite massifs that host numerous gabbroic emplacements. Our present understanding about the crustal architecture of the Nagercoil block is derived mostly from these charnockites, while detailed studies on gabbros are lacking. We present new petrology, geochemistry, and zircon U-Pb/Hf isotopic data of gabbros from the Nagercoil block to understand their petrogenesis and tectonic significance. The results reveal that these are formed by the partial melting of a subduction-modified lithospheric mantle source in a continental arc setting. Zircon U-Pb geochronology results reveal that the gabbros were emplaced between 561 and 531 Ma. Hafnium isotopic studies on zircons argue for a mid-Mesoproterozoic melting source with near-juvenile magmatic signatures. The Hf-T<sub>DM</sub> ages together with the available data from the terrane point to the involvement of the adjacent Achankovil unit as a possible melting source contributor. The genetic link between the Achankovil unit and Sri Lanka together with the remarkable similarity in ages and isotopic characteristics of mafic rocks from both these terranes point to their coeval formation during the East African Orogeny associated with the final stages of the Gondwana supercontinent assembly.https://www.mdpi.com/2075-163X/12/12/1509gabbrozircon U-Pb/Hf geochronologySouthern Granulite TerraneNagercoil block |
| spellingShingle | S. Sajna J. K. Tomson J. Amal Dev Nilanjana Sorcar T. Vijaya Kumar Neoproterozoic Mafic Magmatism in Nagercoil Block, Southern India and Its Implications on the Gondwana Collisional Orogeny Minerals gabbro zircon U-Pb/Hf geochronology Southern Granulite Terrane Nagercoil block |
| title | Neoproterozoic Mafic Magmatism in Nagercoil Block, Southern India and Its Implications on the Gondwana Collisional Orogeny |
| title_full | Neoproterozoic Mafic Magmatism in Nagercoil Block, Southern India and Its Implications on the Gondwana Collisional Orogeny |
| title_fullStr | Neoproterozoic Mafic Magmatism in Nagercoil Block, Southern India and Its Implications on the Gondwana Collisional Orogeny |
| title_full_unstemmed | Neoproterozoic Mafic Magmatism in Nagercoil Block, Southern India and Its Implications on the Gondwana Collisional Orogeny |
| title_short | Neoproterozoic Mafic Magmatism in Nagercoil Block, Southern India and Its Implications on the Gondwana Collisional Orogeny |
| title_sort | neoproterozoic mafic magmatism in nagercoil block southern india and its implications on the gondwana collisional orogeny |
| topic | gabbro zircon U-Pb/Hf geochronology Southern Granulite Terrane Nagercoil block |
| url | https://www.mdpi.com/2075-163X/12/12/1509 |
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