Numerical modelling of geothermal heat flux and ice velocity influencing the thermal conditions of the Priestley Glacier trough (northern Victoria Land, Antarctica)

Deep geothermal contributions can affect the thermal equilibrium of glacial systems, which can induce changes in their thermal state. These changes can be influenced by glacier dynamics and by the different ice flow velocities experienced over time, which dictate the static and dynamic interactions with glacial trough bedrock. To assess such interactions and to weight the effects of ice mass thermalisations on bedrock, 2D multistage numerical modelling was performed for Priestley Glacier (an outlet glacier) in the East Antarctic glacial system (northern Victoria Land), which has experienced extreme heat flux variations related to rifting and late Cenozoic volcanism. The thermal evolution of Priestley Glacier over the last similar to 500 ka was modelled considering the mutual contributions of local and deep thermal sources through a parametric variation in the geothermal heat flux. The icemass velocity was indirectly taken into account by assuming an ice persistence time over the bedrock under timelled considering the mutual contributions of local and deep thermal sources through a parametric variation in the geothermal heat flux. The ice mass velocity was indirectly taken into account by assuming an ice persistence time over the bedrock under time-dependentmodelling conditions. Ice thickness and geothermal heat fluxes, varying from 50 to 120mW/ m2, were conditions are strongly linked in determining the thermal state of the glacier base and consequently its impact on basal erosion. According to the adopted ice stationing levels, heat flux conditions not exceeding 70 mW/m2 are needed for preserving a dry-based glacier only assuming velocity conditions equal to or lower than those observed to date along Priestley Glacier. Assuming increased velocity conditions, the glacier sensitivity to heat fluxes decreases, and high to very high heat fluxes are not sufficient to cause glacier base transitions to wet states. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study demonstrates that deep geothermal contributions significantly impact the thermal equilibrium and state of glacial systems. Simulation results show that the effects of different geothermal heat fluxes on the glacier base depend on the ice mass velocity.