Petrogenesis and geochemical characteristics of pyroxenite dykes in and around Salem Mafic–Ultramafic complex, southern India: an arc-related origin of Alaskan-type.
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| Title: | Petrogenesis and geochemical characteristics of pyroxenite dykes in and around Salem Mafic–Ultramafic complex, southern India: an arc-related origin of Alaskan-type. |
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| Authors: | Yellappa, Thoti1 yellappa_thoti@yahoo.co.uk |
| Source: | Current Science (00113891). 10/25/2022, Vol. 123 Issue 8, p1005-1019. 15p. |
| Subjects: | Pyroxenite, Oxide minerals, Dikes (Geology), Petrogenesis, Metasomatism, Petrology, Orthopyroxene |
| Geographic Terms: | India |
| Abstract: | Arc-related origin of pyroxenites in association with Alaskan-type tectonics has been described in many mafic–ultramafic complexes across the globe. The Salem Mafic–Ultramafic Complex (SMUC) is one such Neoproterozoic Alaskan-type complex exposed at the northern margin of the Cauvery Suture Zone (CSZ), Southern Granulite Terrane, south India. The Complex consists of mafic and ultramafic sequences along with several occurrences of pyroxenite intrusions of varied thickness in the form of dykes. Similar pyroxenite dykes were also observed in and around the Complex at several locations within the basement hornblende gneiss, trending in the NE–SW and E–W directions. Petrography of these dykes indicated websterite variety with cumulate textures and reveals the dominance of clinopyroxene along with orthopyroxene, primary amphibole, minor plagioclase and oxide minerals like magnetite, ilmenite and spinels. The whole-rock chemistry of 10 representative samples showed enrichment of LIL elements (Sr, K, Rb, Th) and depletion of HFSE (Hf, Ti, Y, Yb) with normalized primitive mantle and N-MORB. The clinopyroxene mineral chemistry represented tholeiitic signatures with high Mg# values (Mg/(Mg + Fe)) up to 0.91, and the two-pyroxene thermobarometry of these pyroxenites yielded re-equilibrium crystallization temperatures of 820–932°C with moderate pressures at 11–12 kbar. Various tectonic discrimination plots of clinopyroxene mineral chemistry together with whole-rock chemistry favoured their origin under arc settings with the interactions of fluid-related subduction zone metasomatism relevant to Neoproterozoic Alaskan-type tectonics. [ABSTRACT FROM AUTHOR] |
| Copyright of Current Science (00113891) is the property of Indian Academy of Sciences and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Items | – Name: Title Label: Title Group: Ti Data: Petrogenesis and geochemical characteristics of pyroxenite dykes in and around Salem Mafic–Ultramafic complex, southern India: an arc-related origin of Alaskan-type. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Yellappa%2C+Thoti%22">Yellappa, Thoti</searchLink><relatesTo>1</relatesTo><i> yellappa_thoti@yahoo.co.uk</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Current+Science+%2800113891%29%22">Current Science (00113891)</searchLink>. 10/25/2022, Vol. 123 Issue 8, p1005-1019. 15p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Pyroxenite%22">Pyroxenite</searchLink><br /><searchLink fieldCode="DE" term="%22Oxide+minerals%22">Oxide minerals</searchLink><br /><searchLink fieldCode="DE" term="%22Dikes+%28Geology%29%22">Dikes (Geology)</searchLink><br /><searchLink fieldCode="DE" term="%22Petrogenesis%22">Petrogenesis</searchLink><br /><searchLink fieldCode="DE" term="%22Metasomatism%22">Metasomatism</searchLink><br /><searchLink fieldCode="DE" term="%22Petrology%22">Petrology</searchLink><br /><searchLink fieldCode="DE" term="%22Orthopyroxene%22">Orthopyroxene</searchLink> – Name: SubjectGeographic Label: Geographic Terms Group: Su Data: <searchLink fieldCode="DE" term="%22India%22">India</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Arc-related origin of pyroxenites in association with Alaskan-type tectonics has been described in many mafic–ultramafic complexes across the globe. The Salem Mafic–Ultramafic Complex (SMUC) is one such Neoproterozoic Alaskan-type complex exposed at the northern margin of the Cauvery Suture Zone (CSZ), Southern Granulite Terrane, south India. The Complex consists of mafic and ultramafic sequences along with several occurrences of pyroxenite intrusions of varied thickness in the form of dykes. Similar pyroxenite dykes were also observed in and around the Complex at several locations within the basement hornblende gneiss, trending in the NE–SW and E–W directions. Petrography of these dykes indicated websterite variety with cumulate textures and reveals the dominance of clinopyroxene along with orthopyroxene, primary amphibole, minor plagioclase and oxide minerals like magnetite, ilmenite and spinels. The whole-rock chemistry of 10 representative samples showed enrichment of LIL elements (Sr, K, Rb, Th) and depletion of HFSE (Hf, Ti, Y, Yb) with normalized primitive mantle and N-MORB. The clinopyroxene mineral chemistry represented tholeiitic signatures with high Mg# values (Mg/(Mg + Fe)) up to 0.91, and the two-pyroxene thermobarometry of these pyroxenites yielded re-equilibrium crystallization temperatures of 820–932°C with moderate pressures at 11–12 kbar. Various tectonic discrimination plots of clinopyroxene mineral chemistry together with whole-rock chemistry favoured their origin under arc settings with the interactions of fluid-related subduction zone metasomatism relevant to Neoproterozoic Alaskan-type tectonics. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Current Science (00113891) is the property of Indian Academy of Sciences and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.18520/cs/v123/i8/1005-1019 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 15 StartPage: 1005 Subjects: – SubjectFull: Pyroxenite Type: general – SubjectFull: Oxide minerals Type: general – SubjectFull: Dikes (Geology) Type: general – SubjectFull: Petrogenesis Type: general – SubjectFull: Metasomatism Type: general – SubjectFull: Petrology Type: general – SubjectFull: Orthopyroxene Type: general – SubjectFull: India Type: general Titles: – TitleFull: Petrogenesis and geochemical characteristics of pyroxenite dykes in and around Salem Mafic–Ultramafic complex, southern India: an arc-related origin of Alaskan-type. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Yellappa, Thoti IsPartOfRelationships: – BibEntity: Dates: – D: 25 M: 10 Text: 10/25/2022 Type: published Y: 2022 Identifiers: – Type: issn-print Value: 00113891 Numbering: – Type: volume Value: 123 – Type: issue Value: 8 Titles: – TitleFull: Current Science (00113891) Type: main |
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