Hydrogeochemistry of Groundwaters Associated with Epithermal Hot-Spring-Type Hg Deposits

摘要

This study characterizes the hydrogeochemistry of roundwaters near opalite-hosted epithermal hot-spring type mercury deposits in the Ivanhoe mining district, Elko County, Nevada. Local groundwaters generally range from Ca-HCO_3 to Ca-Mg-Na-SO_4 type waters with background mercury concentrations ranging from 0.014 to 0.32 mu g/l. Leaching expeirments conducted on mineralized rocks, using typical water chemistries to represent local groundwaters, yield total mercury concentrations ranging from 6.3 mu g/l to 27.4 mu g/l after one year of reaction. Geochemical modeling indicates dissolved merocury is dominated by Hg_((a1))~0 and that precipitation of quicksilver controls mercury concentrations to an upper limit of 63 mu g/l.