Geothermometry and physiochemical condition of Qaleh- Zari Cu-Au ore bearing solution based on chlorite composition and fluid inclusion study

Qaleh-Zari mine is the largest Cu-Au vein type deposit in Iran
and is located about 182 km south of Birjand (Khorasan province). The
ore grade ranges from Cu= 0.5-8%, Au= 0.5-15 ppm, and Ag= 20-150
ppm. Mineralization concentrated in three major veins. Host rock. .. are
mainly andesite to basaltic andesite (paleocene-Eocene). The main
paragenesis is: quartz. hematite (specularite), chlorite, chalcopyrite,
± pyrite, ± Ag-sulfosaJts, and ± gold.
Samples were collected from three veins at depth of -70, -100, -135,
and -1 70 meters. At each level, sample. .. are taken every 10m. Chlorite. ..
arc mainly Fe-rich ripidolite, however a few sam pels are brunsvigite and
pycnochlorite. Temperature or chloritcs formation were calculated
based on the Cathelineau and Nieva (1985) equation. The chlorites
were formed between 260-300"C. The temperature of chlorite fonnation
is to-3erC less than temperature measured from fluid inclusion. Using
chlorite composition and fluid inclusion data from Qaleh- Zari, new
equation i'l presented for calculation of temperature for chlorite
formation . The ore tluid contained
log mH,S= -3 to -3.5 , log mH, < -5.5 , log f02= -30 to -29.