Volume 14, Issue 12

Metamorphic Evolution of Mafic Granulite Enclave, Clinopyroxene-Plagioclase-Ilmenite Symplectite Formed by Garnet Breakdown, of Chotanagpur Gneissic Complex (CGC), Jharkhand, India

Author

Debapriya Adhikary and Chinchu S.V

Abstract

Abstract:
Porphyroblastic garnet grains are found in the mafic granulite enclave in the eastern region of the Chotanagpur Gneissic Complex (CGC). Grain composition varies from the core to the rim of this porphyroblastic garnet. According to the petrography and geothermobarometry investigation, there is a breakdown symplectite texture and temperature change from the garnet grain's centre to its rim. These occurrences demonstrated that this rock would undergo decompression once it reaches its peak metamorphic state. Garnet porphyroblasts in a retrogressed mafic granulite enclave create Cpx-Plag-Ilm intergrowth as a result of decompression and cooling. The chemical composition of the core, rim, and symplectite section clearly differs, according to Electron Micro Probe Analysis (EPMA). Garnet from symplectite (Cpx-Plag-Ilm) and high-grade granulite facies rock breakup is an obvious sign of isothermal decompression or rock upliftment.

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DOI

https://doi.org/10.62226/ijarst20252591

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