Heat flow and inferred ground surface temperature history at Tynong North, southeastern Australia

Abstract

Borehole temperature data have the potential to record historical variations in ground and air surface temperature, yet very few reliable, purpose-drilled, boreholes are available to explore such impacts, particularly in the southern hemisphere. The 400-m deep Tynong-1 borehole, approximately 65 km ESE of Melbourne, Australia, was drilled specifically to determine conductive heat flow and provides a unique dataset for evaluating ground surface temperature history in southeastern Australia. Steady-state conductive heat flow of 87 ± 1 mW m−2 was determined in the deeper borehole sections, with measured temperature profiles clearly demonstrating a progressive divergence of the observed temperat..