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The Hamadi gold deposit, hosted in the metamorphic strata of the Arabian-Nubian Shield (ANS), is a shear zone-controlling orogenic gold deposit. Ore bodies occur in foliated alteration zone striking south to north within hornblende schist, which were mainly altered by beresitization, as well as chloritization and carbonatization. Fluid inclusion studies by microthermometry and laser Raman microspectroscopy revealed that the quartz veinlets in ores is dominated by primary population of extremely CO2-rich (carbonic) fluid inclusions with no visible water and small amount of CH4(X-CH4 = 0 similar to 0. 10). Primary carbonic inclusions in vein quartz either occur as isolated or as random distribution, whereas secondary carbonic inclusions orientate in tiny fissures. Secondary aqueous inclusions can be found in the latest fissures. The solid CO, melting temperatures (T-m,T- Co2) of carbonic inclusions have a narrow range of -58.4 similar to -57.0 degrees C, whereas the homogenization temperatures (T-h,T- co2) vary widely (-19 degrees C similar to +29 degrees C). According to the densities or the T-h,T- Co2 of carbonic fluid inclusions and the final homogenization temperatures (T-h,T- TOT) of associated CO2-H2O inclusions, the trapping P-T conditions of carbonic inclusions can be estimated to be 280 similar to 360 degrees C and 80 similar to 320MPa. Gold deposition may occur in late, retrogress metamorphism after the peak regional metamorphism. Carbonic inclusions might not be a single CO2 source because of widely distributed alteration, while post-trapping leakage of water from original H2O-CO2-salt fluids and consequently forming carbonic inclusions is also not accepted due to weakly deformed host quartz. The reasonable interpretation for the origin of carbonic inclusions in the Hamadi gold deposit is that unmixing might happen in an immiscible aqueous-carbonic mixture during retrogress metamorphism because of decreasing of P-T conditions; H2O was depleted in hydrothermal alteration, and CO2 was trapped as carbonic inclusions in vein quartz.