The Anna gold deposit is located at southeastern Yunnan, China, and is hosted in altered Permian diabase intrusion, with intensive milky quartz veins and vienlets. Alteration caused silicification, argillization, carbonatization and sulfidation, similar to those in the sediment-hosted Carlin-type gold deposits in the Dian-Qian-Gui "Golden Triangle" of Southwest China. Petrography, microthermometry, laser Raman spectroscopy analyses of fluid inclusions in quartz, and hydrogen and oxygen isotopic compositions of quartz are used to characterize the ore-forming fluids associated with gold mineralization in the southeastern Yunnan. The results show that the fluid inclusions in quartz are mainly two- or three-phase, aqueous-carbonic inclusions and have higher homogenization temperatures (208 similar to 312 degrees C) and low salinities of 0 similar to 2% NaCleqv, with high density of CO2 and N-2 vapor. Hydrogen and oxygen isotopic compositions of ore fluids (delta D = -79 parts per thousand similar to -47 parts per thousand, delta O-18 = 8. 9 parts per thousand similar to 12. 7 parts per thousand) indicate a metamorphic origin, possibly related to Indosinian orogeny along the southern margin of Youjiang basin during Late Permian to Early Triassic time.

Publication name	ACTA PETROLOGICA SINICA, 32 (11):3321-3330; 2016
Author(s)	Dong WenDou; Shen NengPing; Su WenChao; Cai JiaLi
Corresponding author	SHEN Nengping  shennengping@vip.gyig.ac.cn  Chinese Acad Sci, Inst Geochem, State Key Lab Ore Deposit Geochem, Guiyang 550081, Peoples R China.

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