Effects of mantle rheologies on viscous heating induced by Glacial Isostatic Adjustment

Characterization of Viscous Dissipative Heating in the Earth's Mantle Caused by Surface Forces

“…The dissipation occurs mostly at the edges of the box or near the viscosity interface for all the cases except for short wavelength and short period for which horizontal variation in dissipation is minimal (Figures 7i and 8i). That the dissipation concentrates in the weak upper mantle at intermediate and short wavelengths and long periods (i.e., ∼300τ M ) is consistent with Hanyk et al (2005) and Huang et al (2018).…”

“…(2005) and Huang et al. (2018) considered realistic ice loading models and found that the time‐averaged surface heat flux from the loading‐induced dissipation for the last glaciation‐deglaciation cycle is ∼0.03 TW. Considering that North American and Fennoscandian ice sheets may only cover ∼2% of the Earth's surface, their surface heat flux results are broadly consistent with ours.…”

“…The Cartesian model may present different spatial patterns of dissipation than a spherical model due to the flat geometry, and because of the small size of the domain compared to the load. Future research into this topic using full spherical geometries would provide better understanding of behaviors under tidal forcing, as these are not necessarily well approximated by a surface loading force, and the use of more sophisticated rheology models (e.g., Huang et al., 2018) is likely necessary to understand more about how these bodies react to all types of exogenic forces. Even with these shortcomings, we believe that this study represents an important step in understanding the dynamics of dissipative heating in planetary bodies.…”

“…Dissipative heating in planetary mantles generated by exogenic forcing has been computed in the contexts of tidal heating for planetary bodies including Io, Europa and Enceladus (e.g., Beuthe, 2013; Ojakangas & Stevenson, 1989; Roberts & Nimmo, 2008; Ross & Schubert, 1986; Sotin et al., 2002; Steinke et al., 2020; Tobie et al., 2005, 2008) and glaciation/deglaciation induced heating in the Earth's mantle (e.g., Hanyk et al., 2005; Huang et al., 2018). In this type of calculation, stress, deformation, and dissipative heat are determined for a viscoelastic mantle in response to an exogenic loading force.…”

“…It should be pointed out that tidal heating generated in the ocean below Enceladus' icy mantle and Io's magma ocean may be significant (Tyler, 2009(Tyler, , 2011Tyler et al, 2015). Using realistic mantle viscosity and glaciation/deglaciation history of the last glacial cycle (i.e., the last 100,000 years) on Earth, the dissipative heating from the glaciation-deglaciation process has been estimated to be approximately 0.03 TW over the cycle, which is significantly smaller than the present-day heat flux of 44 TW (Hanyk et al, 2005;Huang et al, 2018).…”