Petrology and Sr-Nd isotope systematics of the Ahobil kimberlite (Pipe-16) from the Wajrakarur field, Eastern Dharwar craton, southern India
Detailed mineralogical, bulk-rock geochemical and Sr-Nd isotopic data for the recently discovered Ahobil kimberlite (Pipe-16) from the Wajrakarur kimberlite field (WKF), Eastern Dharwar craton (EDC), southern India, are presented. Two generations of compositionally distinct olivine, Ti-poor phlogopi...
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| Format: | Article |
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Elsevier
2019-05-01
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| Series: | Geoscience Frontiers |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674987118301798 |
| _version_ | 1797723530419240960 |
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| author | Abhinay Sharma Alok Kumar Praveer Pankaj Dinesh Pandit Ramananda Chakrabarti N.V. Chalapathi Rao |
| author_facet | Abhinay Sharma Alok Kumar Praveer Pankaj Dinesh Pandit Ramananda Chakrabarti N.V. Chalapathi Rao |
| author_sort | Abhinay Sharma |
| collection | DOAJ |
| description | Detailed mineralogical, bulk-rock geochemical and Sr-Nd isotopic data for the recently discovered Ahobil kimberlite (Pipe-16) from the Wajrakarur kimberlite field (WKF), Eastern Dharwar craton (EDC), southern India, are presented. Two generations of compositionally distinct olivine, Ti-poor phlogopite showing orangeitic evolutionary trends, spinel displaying magmatic trend-1, abundant perovskite, Ti-rich hydrogarnet, calcite and serpentine are the various mineral constituents. On the basis of (i) liquidus mineral composition, (ii) bulk-rock chemistry, and (iii) Sr-Nd isotopic composition, we show that Ahobil kimberlite shares several characteristic features of archetypal kimberlites than orangeites and lamproites. Geochemical modelling indicate Ahobil kimberlite magma derivation from small-degree melting of a carbonated peridotite source having higher Gd/Yb and lower La/Sm in contrast to those of orangeites from the Eastern Dharwar and Bastar cratons of Indian shield. The TDM Nd model age (∼2.0 Ga) of the Ahobil kimberlite is (i) significantly older than those (1.5–1.3 Ga) reported for Wajrakarur and Narayanpet kimberlites of EDC, (ii) indistinguishable from those of the Mesoproterozoic EDC lamproites, and (iii) strikingly coincides with the timing of the amalgamation of the Columbia supercontinent. High bulk-rock Fe-Ti contents and wide variation in oxygen fugacity fO2, as inferred from perovskite oxybarometry, suggest non-prospective nature of the Ahobil kimberlite for diamond. Keywords: Petrology, Isotopes, Kimberlite, Wajrakarur, Dharwar craton, India |
| first_indexed | 2024-03-12T10:03:05Z |
| format | Article |
| id | doaj.art-21bf5e7f47c4436186e4627777761610 |
| institution | Directory Open Access Journal |
| issn | 1674-9871 |
| language | English |
| last_indexed | 2024-03-12T10:03:05Z |
| publishDate | 2019-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Geoscience Frontiers |
| spelling | doaj.art-21bf5e7f47c4436186e46277777616102023-09-02T11:25:24ZengElsevierGeoscience Frontiers1674-98712019-05-0110311671186Petrology and Sr-Nd isotope systematics of the Ahobil kimberlite (Pipe-16) from the Wajrakarur field, Eastern Dharwar craton, southern IndiaAbhinay Sharma0Alok Kumar1Praveer Pankaj2Dinesh Pandit3Ramananda Chakrabarti4N.V. Chalapathi Rao5EPMA and SEM Laboratories, Department of Geology, Banaras Hindu University, Varanasi 221005, IndiaEPMA and SEM Laboratories, Department of Geology, Banaras Hindu University, Varanasi 221005, IndiaEPMA and SEM Laboratories, Department of Geology, Banaras Hindu University, Varanasi 221005, IndiaEPMA and SEM Laboratories, Department of Geology, Banaras Hindu University, Varanasi 221005, IndiaCentre for Earth Sciences, Indian Institute of Science, Bangalore 560012, IndiaEPMA and SEM Laboratories, Department of Geology, Banaras Hindu University, Varanasi 221005, India; Corresponding author.Detailed mineralogical, bulk-rock geochemical and Sr-Nd isotopic data for the recently discovered Ahobil kimberlite (Pipe-16) from the Wajrakarur kimberlite field (WKF), Eastern Dharwar craton (EDC), southern India, are presented. Two generations of compositionally distinct olivine, Ti-poor phlogopite showing orangeitic evolutionary trends, spinel displaying magmatic trend-1, abundant perovskite, Ti-rich hydrogarnet, calcite and serpentine are the various mineral constituents. On the basis of (i) liquidus mineral composition, (ii) bulk-rock chemistry, and (iii) Sr-Nd isotopic composition, we show that Ahobil kimberlite shares several characteristic features of archetypal kimberlites than orangeites and lamproites. Geochemical modelling indicate Ahobil kimberlite magma derivation from small-degree melting of a carbonated peridotite source having higher Gd/Yb and lower La/Sm in contrast to those of orangeites from the Eastern Dharwar and Bastar cratons of Indian shield. The TDM Nd model age (∼2.0 Ga) of the Ahobil kimberlite is (i) significantly older than those (1.5–1.3 Ga) reported for Wajrakarur and Narayanpet kimberlites of EDC, (ii) indistinguishable from those of the Mesoproterozoic EDC lamproites, and (iii) strikingly coincides with the timing of the amalgamation of the Columbia supercontinent. High bulk-rock Fe-Ti contents and wide variation in oxygen fugacity fO2, as inferred from perovskite oxybarometry, suggest non-prospective nature of the Ahobil kimberlite for diamond. Keywords: Petrology, Isotopes, Kimberlite, Wajrakarur, Dharwar craton, Indiahttp://www.sciencedirect.com/science/article/pii/S1674987118301798 |
| spellingShingle | Abhinay Sharma Alok Kumar Praveer Pankaj Dinesh Pandit Ramananda Chakrabarti N.V. Chalapathi Rao Petrology and Sr-Nd isotope systematics of the Ahobil kimberlite (Pipe-16) from the Wajrakarur field, Eastern Dharwar craton, southern India Geoscience Frontiers |
| title | Petrology and Sr-Nd isotope systematics of the Ahobil kimberlite (Pipe-16) from the Wajrakarur field, Eastern Dharwar craton, southern India |
| title_full | Petrology and Sr-Nd isotope systematics of the Ahobil kimberlite (Pipe-16) from the Wajrakarur field, Eastern Dharwar craton, southern India |
| title_fullStr | Petrology and Sr-Nd isotope systematics of the Ahobil kimberlite (Pipe-16) from the Wajrakarur field, Eastern Dharwar craton, southern India |
| title_full_unstemmed | Petrology and Sr-Nd isotope systematics of the Ahobil kimberlite (Pipe-16) from the Wajrakarur field, Eastern Dharwar craton, southern India |
| title_short | Petrology and Sr-Nd isotope systematics of the Ahobil kimberlite (Pipe-16) from the Wajrakarur field, Eastern Dharwar craton, southern India |
| title_sort | petrology and sr nd isotope systematics of the ahobil kimberlite pipe 16 from the wajrakarur field eastern dharwar craton southern india |
| url | http://www.sciencedirect.com/science/article/pii/S1674987118301798 |
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