Reconstructions of long-term ground surface heat flux changes from deep-borehole temperature data

Based on analysis of geothermal data from the Ural superdeep borehole (SG-4) and Onega parametric borehole, the first reconstructions of ground surface heat flux changes for the last 40 kyr have been made. The increase in heat flux during the Pleistocene-Holocene warming (20-10 ka) proceeded ~ 2 kyr earlier than the growth in surface temperature; reaching the maximum value of 0.08-0.13 W/m2 at ~ 13 ka, the heat flux was reduced. The coordinated changes in heat flux and average annual insolation at 60° N at 5-24 ka indicate that the orbital factors were the main cause of climatic changes in this period. The correlations between the changes in heat flux and CO2 content in the Antarctic ice cores and the temperature changes are analyzed.© 2014, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.