Geochemistry and isotope hydrogeology of the Mount Edziza-Mess Creek geothermal area

This Recent volcanic complex in the Intermontane belt of British Columbia has been studied to evaluate the origin, geothermal history and age of associated thermal waters. Samples of thermal and cold ground-waters, runoff and glacier ice were collected for chemical and environmental isotope analysis. Mt Edziza thermal waters discharging at 36 and 46 degrees C at the base of the pile originate as glacial meltwater on the summit of the complex. They are a product of reactions with alkali basalts at high CO (sub 2) partial P at a probable subsurface T of <100 degrees C. The high CO (sub 2) contents demonstrate a deep geothermal component in an essentially high-level geothermal flow system. Mess Creek thermal waters discharge at 43 degrees C from a separate flow system showing evidence of equilibrium with local basement rocks at T <100 degrees C. Deep circulation in a region with above normal geothermal gradients is the suggested heating mechanism. The low (super 3) H contents suggest that the thermal waters are tritium free (>30 yr old) and are mixing with 10-40% ground-water in the discharge areas.