Heat flow, heat generation and crustal temperature in the kapuskasing area of the Canadian Shield

Abstract

Combined heat flow and heat production measurements in three boreholes in the Superior Province of the Canadian Shield were made to test the geothermal consequences of the Kapuskasing fault zone. The evidence of gravity and geomagnetic investigation suggests that this zone is a deeply eroded remnant of a crustal rift. A linear relation between heat flow ( q) and surface heat production ( P), q = qo + bP, where q o and b are empirical constants, has been found by F. Birch, R. Roy and A. Lachenbruch for different heat-flow provinces over the North American continent. The results from the Kapuskasing zone clearly confirmed this relation, giving q o = 0.63 μcal. · cm −2 · sec −1 and b = 13.5 km. The significance of these parameters for the crustal structure study and the probable temperature-depth distribution are discussed in the paper. The influence of different surface temperature during the past on the underground temperature is mentioned. The consistent elimination of the climatic effect on measured heat flow is necessary when a geothermal model is to be constructed.