Gold and antimony metallogenic relationship of the Awanda Au (Sb) deposit, South Tianshan, NW China: Constraints from textures, in-situ trace elements and s-pb isotope systematics

Abstract

The Tianshan is one of the most important gold ± antimony metallogenic province in the world. However, the relationship between Au and Sb mineralization remains poorly understood, largely due to lacking of systematic investigation on typical Au-Sb deposits. Here, we reported in-situ trace elements and S-Pb isotopic dataset on the Awanda Au (Sb) deposit, which is currently the second largest gold deposit in Chinese South Tianshan, and contain highly antimony (Sb) by our new petrographic observations. Sulfide from two minelization stages, i.e., Stage Ⅰ (arsenopyrite, pyrite, pyrrhotite, and minor chalcopyrite) and Stage II (gudmundite, aurostibite and stibnite), were analyzed using laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). Trace element compositions reveal that ore minerals display positive correlations between As and Au-Sb-Cu-Zn-Pb, implying a common source for these elements. In situ δ34S values of sulfides that cluster in the range of − 2.94 to + 0.8 ‰, suggesting that sulfur contained in Au-As-Sb-bearing fluids were most likely derived from Upper Paleozoic sediments (δ34S = − 1.6 to + 0.3 ‰) during regional metamorphism. In-situ 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios (17.882 to 18.002, 15.467to 15.620 and 37.831 to 38.344) from sulfides are also support that the Upper Paleozoic strata may have supplied substantial metals. Combined with published electron microprobe and fluid inclusions data, our textural and chemical data suggest that fluid-rock interaction and decrease in pressure, temperature, and oxygen-sulfur fugacity were the main cause for Au-As and Au-Sb minelization, respectively. In summary, we propose that the Awanda Au (Sb) deposit fits the crust metamorphic model with Au-As and Au-Sb mineralization occur at mesozonal and epizonal depths, respectively.