Improving thermal properties estimates of the Antarctic crust and their
uncertainties
Abstract
Geothermal heat flux (GHF) is an important basal boundary condition for
models of ice sheet dynamics, but is poorly constrained by conventional
borehole-based estimates. The accuracy and uncertainties associated with
geophysical proxy-based GHF models are contingent upon reliable models
of heat production and thermal conductivity that are difficult to
constrain. In this study, we examine (1) the statistical distribution of
these thermal properties to gain insight into the Antarctic crust, (2)
revaluate GHF estimates using these new constraints, and (3) identify
areas where a lack of knowledge still hampers our ability to produce
accurate models of GHF. Our approach centers on developing statistical
models for the thermal properties based on global and regional
distributions from global geochemical datasets. We then calibrate our
heat production models of Antarctica using a combination of exposed
Antarctic terranes, conjugate terranes and crustal tomography models of
Antarctica. Regions where exposures and conjugate terranes are not
accessible, we use a terrane model of Antarctica to reduce uncertainty.
We then estimate GHF for different proxy-based temperature models using
our thermal property calibrations. We find more diversity in GHF models
derived from geophysical-based proxies when using a standardized crustal
property model than predicted by the original. We suggest that there is
still much to learn about the thermal state of Antarctica, which
requires further improvements in predictors of thermal properties,
especially their variation with depth.