Peak-metamorphic conditions derived from conventional geothermobarometry and pseudosection modelling of enderbites from the southeastern Madurai Block, southern India

The mineral chemistry using Electron Probe Micro Analysis (EPMA) is a powerful tool for establishing the pressure-temperature (P-T) conditions of a metamorphic terrain. The study area, The Madurai Block, a pivotal component of the Southern Granulite Terrain (India), preserves a complex record of high-grade metamorphism linked to the assembly of the Gondwana supercontinent. However, the precise pressure-temperature (P-T) evolution of its northern, central, and southern sub-blocks remains ambiguous. This study presents a detailed petrological and mineral-chemical investigation of enderbites from the Southeastern Madurai Block to quantify their metamorphic history. Mineral chemistry data, acquired by EPMA, were utilised for conventional geothermobarometry, constraining peak P-T conditions of 6–8.4 kbar and 840–900 °C. Phase-equilibrium modelling in the NCKFMASHT system for a representative sample confirms the stability of the peak assemblage within this medium-pressure, high-temperature granulite-facies field. The modelling further reveals that the mineral paragenesis is robust and insensitive to variations in water activity, indicating fluid-absent conditions during peak metamorphism. Our results demonstrate that the Southeastern Madurai Block experienced regional high-temperature metamorphism under an elevated thermal gradient, distinctly higher than those recorded in other domains of the Southern Granulite Terrain. These quantitative P-T constraints provide critical new data for unravelling the differential tectonic evolution and final assembly of the Gondwana supercontinent.