Alicia Pollett1, Betina Bendall2, Tom Raimondo1, Martin Hand3
1School of Natural and Built Environments, University Of South Australia, Adelaide, Australia, 2Energy and Resources Division, Department of Premier and Cabinet, Adelaide, Australia, 3Geology and Geophysics, School of Physical Sciences, University of Adelaide, Adelaide, Australia
A critical parameter in accurately modelling Antarctic ice sheet behaviour is basal heat flux, which has a significant impact on ice viscosity and melt generation. Currently, this input is poorly constrained due to the logistical and financial challenges of obtaining boreholes that intersect basement rocks blanketed by thick ice cover. Consequently, we have pursued an alternative approach that employs heat flow measurements from analogous rock units in the Coompana Province of southern Australia, representing the geological counterparts of those beneath the Totten Glacier in eastern Antarctica. The Coompana Province is underlain largely by Mesoproterozoic granitic and gneissic rocks characteristic of the Musgrave orogenic system, observed to project into Wilkes and Queen Mary Land. Facilitated by mineral exploration drilling as part of the PACE Program undertaken by the Geological Survey of South Australia and Geoscience Australia, we have compiled 10 new continuous temperature logs from this previously uncharacterised region. Drill core samples have also enabled an accompanying dataset of thermal conductivity values to be obtained. Preliminary calculations indicate heat flow estimates in the range 52–62 mWm-², equivalent to global continental averages. All values are slightly lower than the single heat flow measurement of 72 mWm-² obtained from Law Dome located on the conjugate margin of eastern Antarctica, and appreciably lower than the average of ~80 mWm-² for Proterozoic terranes of the central Australian heat flow province. Combined with existing data from adjacent parts of southern Australia, this provides the first regional heat flow characterisation of geological provinces previously contiguous with eastern Antarctica, allowing a more robust evaluation of the contribution of anomalous basal heat flux to ice sheet instability.