Insights into the Ore Genesis of the Harla Gold Deposit in Eastern Tianshan, NW China: Evidence from Geology, Fluid Inclusions, and H-O-C-S-Pb Isotopes

The Harla gold deposit is located on the eastern segment of Kanggur-Huangshan ductile shear belt in Eastern Tianshan, southern margin Central Asian Orogenic Belt. orebodies show close spatial association with NEE-trending faults and are hosted volcanic rocks Lower Carboniferous Xiaorequanzi Formation. Three mineralization stages were recognized: an early stage characterized by specularite–pyrite–quartz mineralization, intermediate pyrite–chalcopyrite–gold–quartz genesis, a late defined sulfide-poor calcite quartz veins. types fluid inclusions (FIs) daughter mineral-bearing triphase FIs (S-type), liquid-dominated biphase (LV-type), liquid-only monophase (L-type). S- LV-type entrapped similar homogenization temperatures (Th) at 216–229 °C 199–222 °C. However, they display contrasting salinities 32.2–33.4 6.7–8.9 wt.% NaCl eqv., respectively. Th 163–191 °C, 5.6–7.4 eqv. occur 135–258 3.7–5.6 Insights from hydrogen, oxygen, carbon isotope analyses (δ18OH2O = −10.7 to 3.3‰, δDH2O −88.1 −61.4‰, δ13CH2O −8.9 −6.2‰), combined FI characteristics, indicate that ore-forming fluids derived hybrid source magmatic meteoric water, latter becoming dominant later stage. Sulfide lead isotopic compositions (δ34Spyrite 0.2 2.5‰, 206Pb/204Pb 17.709–18.273, 207Pb/204Pb 15.483–15.569, 208Pb/204Pb 37.533–37.754) suggest materials mainly wall (Xiaorequanzi Formation plagiogranite). By integrating geological background work inclusion analyses, as well data, we conclude epithermal-type deposit.