Characteristics And Evolution Of Fluids Associated With Lode Gold Deposits Of The Zhaoyuan District, Eastern Shandong, China

The characteristics of the mineralizing fluids and their evolution in the Zhaoyuan district are studied based on microthermometric analysis of fluid inclusions from the Huangbuling, Jinchiling, Ynantuan and Aizizhaojia gold deposits, hosted in the Mesozoic Linglong gneissoid biotite granite suite. Three types of fluid inclusions (aqueous-carbonic, aqueous, and aqueous with daughter minerals) were recognized as secondary inclusions in quartz and were divided into 5 stages (A to E). The homogenization temperatures decrease from 307-341 degrees C (stage A), through 240-280 degrees C (stage B), 146-194 degrees C (stage C), to 112-159 degrees C (stage D), and salinities are 6.5-8.4, 5.0-10.6, 5.95-9.1, and 3.6-5.6 wt.% NaCl equivalent for stages A, B, C and D, respectively. The final stage E is represented by halite-saturated aqueous fluids with salinities of 30.8-34.8 wt.% NaCl equivalent. The fluid inclusion data and P-T-X analysis suggest that the mineralization fluids in the Zhaoyuan district were of aqueous-carbonic type and that gold precipitation was related to phase separation.