THE GEOTHERMAL POTENTIAL OF NAZKO CONE, BRITISH COLUMBIA

Nazko Cone, located in the Nechako basin near Quesnel, British Columbia, is the youngest volcanic member of the Anahim volcanic belt, an eastward-younging field of small volcanic centers related to a hot spot. While the last eruptive activity in the area dates to 7200 BP, an earthquake swarm in 2007 was in all likelihood the result of magma injection into the lower crust. Initial exploration into a possible deeply-circulating/volcanic geothermal system associated with the volcano has revealed geothermal manifestations such as travertine mounds, both fossil and actively forming, and vigorous CO₂ degassing (up to 14% concentration in the diluted, diffuse gas) from various vents in two bogs near Nazko Cone. Chemical analyses of the gases collected in pre-evacuated Giggenbach-style bottles indicate that CO₂ is the dominant species with minor amounts of CH₄ and He (< 1 wt %). Isotopic analyses of the ¹³C_CO2 suggest the gas is mainly of magmatic origin, although additional analyses need to be carried out to fully characterize the emissions. In this regard, a shallow ground temperature and CO₂/H₂S gas flux survey was performed in the bogs. A Bouguer gravity survey was carried out to map the subsurface structures in the area to determine the relationship, if present, between subsurface structures/geology and the surface manifestations. The high resolution geophysical and geochemical data collected will be modelled in 3D (inverse/forward) in conjunction with pre-existing regional data sets of surficial geology and regional gravity to determine the extent and potential of any geothermal system in the Nazko Cone area.