Fluid inclusions at different depths in the<scp>S</scp>anshandao gold deposit,<scp>J</scp>iaodong<scp>P</scp>eninsula,<scp>C</scp>hina

Abstract

Abstract The S anshandao gold deposit, located at northwestern edge of the J iaodong P eninsula, eastern N orth C hina C raton, is one of the largest gold deposits in the J iaodong gold province. In the deposit, disseminated‐ and stockwork‐style ores are hosted in M esozoic granitoids. Mineralization and alteration are largely controlled by the regional S anshandao– C angshang fault. Sericite separated from alteration rocks in the mineralized zone yields an Rb–Sr isochron age of 117.6 ± 3.0 Ma. The ore‐forming fluids in the S anshandao gold deposit contain CO 2 ‐H 2 O‐NaCl±CH 4 with low to intermediate temperatures and low salinities. Microthermometric analysis shows that homogenization temperatures gradually decrease from the early mineralizing stage (258–416°C) to main mineralizing stage (180–321°C) and to late mineralizing stage (112–231°C). Homogenization temperatures from the same mineralizing stage are nearly same and do not show an increase with depth. The nature of the ore‐forming fluids remains nearly the same over a 2000 m vertical depth interval.