Abstract:

The Tabei Pb-Zn deposit，located in the Tulasu basin，Western Tianshan，is a newly explored hydrothermal deposit. The Pb-Zn orebodies are controlled by fault and hosted in acid tuff of the fifth member of the Upper Devonian to Lower Carboniferous Dahalajunshan Formation. The δ³⁴S values of the sulfides in the main stage range from 0.5‰ to 7.3‰，and the estimated δ³⁴S_∑S of the ore-forming hydrothermal system is around 2.7‰，which reflects a characteristic of sulfur from magmatic source. The δ³⁴S values of the gypsum in the late stage vary from 4.7‰ to 5.3‰，indicating that the aqueous sulfate may be derived from the disproportionation of SO₂ or the oxidation of H₂S. The compositions of Pb isotopes of sulfides are stable and similar to those of host volcanic rocks，suggesting that the ore-forming materials were derived from the ore-bearing volcanic rocks. Carbon and oxygen isotopic compositions of calcite show that carbon in ore-forming fluid was mainly derived from the magma. The Tabei Pb-Zn deposit may belong to the epithermal deposit with deeper mineralization.

Key words: S, Pb, C and O isotopes, source of ore-forming material, epithermal deposit, Tabei Pb-Zn deposit, Xinjiang