Geothermal heat flux from measured temperature profiles in deep ice boreholes in Antarctica Journal Article uri icon

Overview

abstract

  • Abstract. The temperature at the Antarctic Ice Sheet bed and the; temperature gradient in subglacial rocks have been directly measured only a; few times, although extensive thermodynamic modeling has been used to; estimate the geothermal heat flux (GHF) under the ice sheet. During the last; 5 decades, deep ice-core drilling projects at six sites – Byrd, WAIS; Divide, Dome C, Kohnen, Dome F, and Vostok – have succeeded in reaching or nearly reaching the bed at inland locations in Antarctica. When temperature; profiles in these boreholes and steady-state heat flow modeling are combined; with estimates of vertical velocity, the heat flow at the ice-sheet base is; translated to a geothermal heat flux of 57.9 ± 6.4 mW m−2 at Dome; C, 78.9 ± 5.0 mW m−2 at Dome F, and 86.9 ± 16.6 mW m−2; at Kohnen, all higher than the predicted values at these sites. This warm; base under the East Antarctic Ice Sheet (EAIS) could be caused by radiogenic; heat effects or hydrothermal circulation not accounted for by the models.; The GHF at the base of the ice sheet at Vostok has a negative value of; −3.6 ± 5.3 mW m−2, indicating that water from Lake Vostok is; freezing onto the ice-sheet base. Correlation analyses between modeled and; measured depth–age scales at the EAIS sites indicate that all of them can be; adequately approximated by a steady-state model. Horizontal velocities and; their variation over ice-age cycles are much greater for the West Antarctic; Ice Sheet than for the interior EAIS sites; a steady-state model cannot; precisely describe the temperature distribution here. Even if the; correlation factors for the best fitting age–depth curve are only moderate; for the West Antarctic sites, the GHF values estimated here of 88.4 ± 7.6 mW m−2 at Byrd and 113.3 ± 16.9 mW m−2 at WAIS Divide can be; used as references before more precise estimates are made on the subject.;

publication date

  • November 14, 2020

Full Author List

  • Talalay P; Li Y; Augustin L; Clow GD; Hong J; Lefebvre E; Markov A; Motoyama H; Ritz C

Other Profiles

Additional Document Info

start page

  • 4021

end page

  • 4037

volume

  • 14

issue

  • 11