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Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences, vol.36, no.6, pp.2498-2512, 2025 (Scopus)
Um Solimate emerald deposit is a unique example for the well-known beryl-related schist type. Where, the Be-mineralization is restricted to NNE-trending quartz veins/lenses and as disseminated emerald grains within the altered-metasomatic zones of phlogopite- and graphiteschists. The study of fluid inclusions for the mineralized quartz vein revealed three major groups: (i) aqueous (H2O-NaCl), (ii) aqueous-carbonic (H2O-CO2-[CH4]-NaCl), and (iii) aqueous-hydrocarbonic (H2O-CH4) FIs. They have been further classified into five types (namely: types 1, 2, 3, 4 and 5) according to number of phases at the room temperature (20 °C) as well as microthermometric measurements. Based upon the study of fluid inclusions, the initial-ore forming fluid was supposed to be of magmatic nature, characterized by a relatively high temperature of homogenization (Th, tot: 269- 485 °C) and higher salinity (8.4 wt.%-9.6 wt.% NaCl equiv.), followed by development of aqueouscarbonic inclusions at lower temperature (Th, tot: 241-355 °C) and lower salinity (3.3 wt.%-4.9 wt.% NaCl equiv.) through metamorphic dehydration/decarbonation. Methane-rich FIs were suggested to be formed as a result of local re-equilibration of graphite in reduced environment at the contact aureole of the felsic intrusion. The P-T conditions of ore formation were estimated as modal temperature between (330-370 °C) and fluid pressures of about 200 MPa, corresponding to an estimated depth ranges from 7 to10 km. The formation of emerald is closely associated with multiple events through the ore evolution, the deposition is ascribed to destabilization process of continuous metasomatic interactions and elemental substitutions between felsic-derived Be-bearing fluids with the adjacent mafic-ultramafic rocks at the zone of mineralization.