ABSTRACT This study presents, for the first time, the metamorphic history of garnet–scapolite‐bearing calc‐silicate rocks from the Pur‐Banera Belt (PBB), Aravalli orogen (NW India). These rocks record three deformation stages (S 1 –S 3 ) and typically contain scapolite‐rich (Grt + Kfs + Scp + Pl + Qz + Cpx + Bt + Cal + Ttn ± Amp) and K‐feldspar‐rich (Grt + Kfs + Pl + Qz + Cpx + Bt + Cal + Ttn ± Amp) assemblages. The T‐X CO2 phase modelling indicates that the stability of these mineral assemblages was strongly influenced by variations in fluid composition. Both observed and modelled mineral modes suggest that the growth of minerals in the PBB calc‐silicates was controlled by the infiltration of externally derived hydrous fluids. Integration of conventional thermobarometry with pseudosection modelling constrains the P–T conditions of metamorphism. The prograde stage is estimated at ~6.2–8.1 kbar and ~486°C–539°C, whereas peak metamorphism occurred at ~7.5–9.2 kbar and ~640°C–730°C. Retrograde conditions were estimated at ~6.0–8.0 kbar and ~451°C–498°C. U–Pb dating of Type‐I (inclusion type) titanite constrains prograde metamorphism at ~1284 ± 3 Ma, corresponding to D 1 deformation. In contrast, the Type‐II titanites from matrix grain boundaries record peak metamorphism at ~1024 ± 5 Ma, synchronous with D 2 deformation. Additionally, discordant Type‐II titanites yield an age of ~903 ± 28 Ma, which most likely corresponds to D 3 deformation in the region. These results emphasize the significance of externally sourced fluids in driving recrystallization and element redistribution during metamorphism of the PBB, associated with basin closure, crustal thickening and subsequent exhumation during the assembly and breakup of Rodinia.
Praharaj et al. (Tue,) studied this question.