Home – Home – Jornals – Russian Geology and Geophysics 2013 number 12

The thermal conductivity of rocks (λ) used previously to estimate heat flow in high-latitude Siberia was assumed to be λ = 1.8–2.0 W/(m·K), according to published evidence, but was almost never measured specially. We measured the thermal conductivity of core samples from boreholes drilled in the northeastern West Siberian Plate and in the Yenisei–Khatanga basin in the 1990s, using two advanced instruments: a comparator and a scanner of thermal conductivity. Altogether there were 305 samples of air-dry sediments (λ _d) from the 1100–4200 m interval of 23 holes, 77 samples of which were then moistened (λ _w). The average thermal conductivities of rocks in dry and wet conditions were found to be λ _d = 1.9 ± 0.2 and λ _w = 2.6 ± 0.1 W/(m·K), respectively. Thus, the true thermal conductivity of sediments, which are saturated with water in this northern area, must be about 20–30 % higher than that assumed in the previous heat flow determinations, and the latter are thus underestimated correspondingly. The updates to the thermal conductivity values imply major revision of the existing ideas of the thermal regime in the Siberian high latitudes. Such a serious revision of geothermal data will obviously require a large amount of additional experimental work.