Geochemistry and geochronology of the Precambrian Basement Domains in the Vicinity of Fort McMurray, Alberta: A Geothermal Perspective

The geochemistry and geochronology of the Precambrian basement in the vicinity of Fort McMurray was investigated to evaluate the feasibility of geothermal heat production. The basement is composed of older (1.95-1.98 Ga) and younger (1.92-1.94 Ga) granitoids suites of the Taltson Magmatic Zone that have intruded the 2.25 to 2.40 Ga gneisses and amphibolites of Taltson Basement Complex. Thermal conductivities (TC) calculated for 35 samples yielded an average of 3.1+/-0.43 W/m K. Average radiogenic heat production (RHP) of the same samples is 2.9+/-2.8 muW/m3. Geothermal modeling using these values indicates that at 5 km depth, a one standard deviation shift in TC changes temperature by only ∼25 °C. However, a one standard deviation shift in RHP at the same depth changes temperature by ∼70 °C. The feasibility of using geothermal heat in oil sands processing will depend on RHP values in the crustal column near oil sands processing sites.