Thermobarometry of the Rajmahal Continental Flood Basalts and Their Primary Magmas: Implications for the Magmatic Plumbing System
The Late Aptian Rajmahal Traps originated through Kerguelen-Plume-related volcanism at the eastern margin of the Indian Shield. Clinopyroxene and whole-rock thermobarometry reveals that the Rajmahal magmas crystallized at P-T conditions of ≤~5 kbar/~1100–1200 °C. These pressures correspond to upper...
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MDPI AG
2023-03-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/13/3/426 |
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| author | Nilanjan Chatterjee Naresh C. Ghose |
| author_facet | Nilanjan Chatterjee Naresh C. Ghose |
| author_sort | Nilanjan Chatterjee |
| collection | DOAJ |
| description | The Late Aptian Rajmahal Traps originated through Kerguelen-Plume-related volcanism at the eastern margin of the Indian Shield. Clinopyroxene and whole-rock thermobarometry reveals that the Rajmahal magmas crystallized at P-T conditions of ≤~5 kbar/~1100–1200 °C. These pressures correspond to upper crustal depths (≤~19 km). Modeling shows that the Rajmahal primary magmas were last in equilibrium with mantle at P-T conditions of ~9 kbar/~1280 °C. The corresponding depths (~33 km) are consistent with gravity data that indicate a high-density layer at lower crustal depths below an upwarped Moho. Thus, the high-density layer probably represents anomalous mantle. It is likely that the mantle-derived magmas accumulated below the upwarped Moho and were subsequently transported via trans-crustal faults/fractures to the upper crust where they evolved by fractional crystallization in small staging chambers before eruption. In the lower part of the Rajmahal plumbing system, buoyant melts from the Kerguelen Plume may have moved laterally and upward along the base of the lithosphere to accumulate and erode the eastern Indian lithospheric root. The Rajmahal plumbing system was probably shaped by tectonic forces related to the breakup of Gondwana. |
| first_indexed | 2024-03-11T06:08:52Z |
| format | Article |
| id | doaj.art-fab0921a780f4f75a7ff86de3580d61d |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-11T06:08:52Z |
| publishDate | 2023-03-01 |
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| record_format | Article |
| series | Minerals |
| spelling | doaj.art-fab0921a780f4f75a7ff86de3580d61d2023-11-17T12:48:25ZengMDPI AGMinerals2075-163X2023-03-0113342610.3390/min13030426Thermobarometry of the Rajmahal Continental Flood Basalts and Their Primary Magmas: Implications for the Magmatic Plumbing SystemNilanjan Chatterjee0Naresh C. Ghose1Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USADepartment of Geology, Patna University, Patna 800005, IndiaThe Late Aptian Rajmahal Traps originated through Kerguelen-Plume-related volcanism at the eastern margin of the Indian Shield. Clinopyroxene and whole-rock thermobarometry reveals that the Rajmahal magmas crystallized at P-T conditions of ≤~5 kbar/~1100–1200 °C. These pressures correspond to upper crustal depths (≤~19 km). Modeling shows that the Rajmahal primary magmas were last in equilibrium with mantle at P-T conditions of ~9 kbar/~1280 °C. The corresponding depths (~33 km) are consistent with gravity data that indicate a high-density layer at lower crustal depths below an upwarped Moho. Thus, the high-density layer probably represents anomalous mantle. It is likely that the mantle-derived magmas accumulated below the upwarped Moho and were subsequently transported via trans-crustal faults/fractures to the upper crust where they evolved by fractional crystallization in small staging chambers before eruption. In the lower part of the Rajmahal plumbing system, buoyant melts from the Kerguelen Plume may have moved laterally and upward along the base of the lithosphere to accumulate and erode the eastern Indian lithospheric root. The Rajmahal plumbing system was probably shaped by tectonic forces related to the breakup of Gondwana.https://www.mdpi.com/2075-163X/13/3/426flood basaltRajmahal Trapsthermobarometryprimary magmamagma plumbing system |
| spellingShingle | Nilanjan Chatterjee Naresh C. Ghose Thermobarometry of the Rajmahal Continental Flood Basalts and Their Primary Magmas: Implications for the Magmatic Plumbing System Minerals flood basalt Rajmahal Traps thermobarometry primary magma magma plumbing system |
| title | Thermobarometry of the Rajmahal Continental Flood Basalts and Their Primary Magmas: Implications for the Magmatic Plumbing System |
| title_full | Thermobarometry of the Rajmahal Continental Flood Basalts and Their Primary Magmas: Implications for the Magmatic Plumbing System |
| title_fullStr | Thermobarometry of the Rajmahal Continental Flood Basalts and Their Primary Magmas: Implications for the Magmatic Plumbing System |
| title_full_unstemmed | Thermobarometry of the Rajmahal Continental Flood Basalts and Their Primary Magmas: Implications for the Magmatic Plumbing System |
| title_short | Thermobarometry of the Rajmahal Continental Flood Basalts and Their Primary Magmas: Implications for the Magmatic Plumbing System |
| title_sort | thermobarometry of the rajmahal continental flood basalts and their primary magmas implications for the magmatic plumbing system |
| topic | flood basalt Rajmahal Traps thermobarometry primary magma magma plumbing system |
| url | https://www.mdpi.com/2075-163X/13/3/426 |
| work_keys_str_mv | AT nilanjanchatterjee thermobarometryoftherajmahalcontinentalfloodbasaltsandtheirprimarymagmasimplicationsforthemagmaticplumbingsystem AT nareshcghose thermobarometryoftherajmahalcontinentalfloodbasaltsandtheirprimarymagmasimplicationsforthemagmaticplumbingsystem |