Characterization and Formation Process of Phayaung Taung Mesothermal Gold Deposit, Central Myanmar: Constraints From Raman Analysis of CO2 Bearing Fluid Inclusions

초록

Myanmar hosts a rich diversity of ore deposits, ranging from numerous artisanal operations to several world-class mines. One of the important gold deposits is the Phayaung Taung mine, located in the northeastern part of the Mandalay region, central Myanmar. This gold deposit is hosted in the interbedded layers of quartzite and phyllite units of the Late Proterozoic Chaung Magyi Group in the Mergui Belt. Although the occurrence, geological setting, and ore mineralogy of the deposit have been previously studied, detailed Raman spectroscopy-based fluid inclusion investigations have not yet been conducted. Here, we present the results of the Raman analysis of CO2 bearing fluid inclusions and the pressure-depth relationships using the density and temperature range of the CO2 fluid inclusions. Raman analysis indicates a very minimum water content inside the bubbles in CO2 bearing fluid inclusions with density ranging from 288.82 to 969.68 kg/m3. Nitrogen (N2) is present only in trace amounts in the analyzed inclusions. The latest recrystallization entrapment pressures of CO2 bearing fluid inclusions were estimated at 7 MPa (approximate to 0.26 km) for low-density inclusions and 34 MPa (approximate to 1.28 km) for high-density inclusions. The low-pressure inclusions are interpreted to record uplift and deformation events associated with the Mergui Belt. This research classifies the Phayaung Taung deposit in the Mergui Belt as a mesozonal, structurally emplaced orogenic gold deposit, providing insights into its geological characteristics and formation processes.

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