The？Annage gold deposit is located at the
east part of the eastern Kunlun orogenic belt. The characteristics of ore-forming
fluids and metallogenesis were discussed by using fluid petrography,
micro-thermometry and hydrogen-oxygen isotope analysis. Three stages, namely
quartz-pyrite stage (A), quartz-polymetallic-sulfide stage (B) and
quartz-ankerite stage (C) were included in the hydrothermal process as
indicated by the results of this study. Inclusions developed in ore-bearing
quartz veins from stages A and B are of three types: aqueous inclusions (type
I), CO2-bearing inclusions (type II) and pure CO2？inclusions
(type III). All three types of inclusions, mainly type I, are presented in
stage A, having homogenization temperatures at 180°C - 360°C, and salinities
ranging from 0.53% to 21.44%. In addition to development of type I inclusions,
type II and III inclusions increase significantly in stage B, with
homogenization temperatures ranging from 160°C to 330°C, and salinities are
from 1.32% to 22.01%. Based on micro-thermometry, fluids in Annage deposit are
of H2O-NaCl-CO2？type
with medium-high temperature (140°C - 395°C) and medium-low salinity (0.53% -
22.01%). Results of hydrogen-oxygen isotope analysis show that ore-forming
fluid is mainly CO2-rich magmatic fluid, mixed with shallow
groundwater or metamorphic hydrothermal in the late mineralization stages.
Calculated metallogenic pressures are in the range of
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