While there are now only subtle surface geochemical indicators for geothermal activity, the existence of He in seepage gas and 3He/4He ratios are evidence for a mantle heat source in the area beneath the Nazko Cone
Hot springs or not? That was the question the Nazko First Nation posed as they looked to power their future without diesel generators. Researchers Ray Lett and Wayne Jackaman answered them by studying a wetland area 10km from the community where unusual minerals and gas seepages were identified in 2012.
The two wetlands they studied, near the Nazko volcanic area, west of Quesnel in central British Columbia, are informally named the North and South bogs. Both have deposits of travertine, a white calcium carbonate mineral known to form at hot springs, and carbon dioxide-rich gas seepages, known indicators of geothermal activity.
In a two-year study, supported by Geoscience BC as part of the major TREK (Targeting Resources for Exploration and Knowledge) program, the pair collected samples of soil, water, travertine, bedrock, vegetation and carbon dioxide-rich seepage gas from the Nazko bogs and surrounding area and tested their geochemistry, searching for geothermal indicator elements.
Although the geothermal signs at the surface are subtle, and there are no visible hot springs today, the chemistry of the soil, water and rock samples suggest that the current heat source is very deep. The temperature of the water that formed the minerals seen at the surface today were probably warmer in the past and perhaps mixed with cooler groundwater on their way up to the surface.
Geoscience BC Report 2015-16: Tracing the Source of Anomalous Geochemical Patterns in Soil, Water and Seepage Gas near the Nazko Volcanic Cone, BC (PDF)
