[S25-P] Poster

[S25-P-01] Temperature and heat flux changes at the base of Laurentide Ice Sheet inferred from geothermal data (evidence from province of Alberta, Canada)

^○Dmitry Demezhko¹, Anastasia Gornostaeva¹, Jacek Majorowicz², Jan Safanda³ (1.Institute of Geophysics UB RAS, Yekaterinburg, Russia, 2.Department of Physics, University of Alberta, Edmonton, Canada, 3.Geophysical Institute, AS CR, Prague, Czech Republic)

Using a previously published temperature log of the 2363 meter-deep borehole Hunt well (Alberta, Canada) and the results of its previous interpretation, the new reconstructions of ground surface temperature (GST) and surface heat flux (SHF) histories for the last 30 ka have been obtained. Two ways to adjust the timescale of geothermal reconstructions are discussed, namely the traditional method based on the a priori data on thermal diffusivity value, and the alternative one including the orbital tuning of the surface heat flux and the Earth's insolation changes. It is shown that the thermal regime of the Earth's surface in the area during the last glacial cycle was formed under the influence of a number of factors. These include the orbital related insolation changes, thermomechanical properties of the Ice Sheet, deglaciation, formation of glacial lakes and their subsequent draining. Still, the insolation remains the main factor which determines the behavior of the other factors through a complex system of climate feedbacks.