A Synthesis: Heat Sources and Flux Distributions in the Western Ross Sea Seafloor, Antarctica - Links between Rifting, Volcanism and Ice Sheets

There has been little in situ investigation made in the Ross Sea on how lithospheric heat flux contributes to cryospheric dynamics over time despite advancement in reconstructing cryosphere timeseries in Antarctica. We discuss available geological samples, geophysical remote sensing data and observations to date from the western Ross Sea seafloor in demonstrating the distribution and impacts from heat source and flux. Local, short-term heat flux from volcanism and associated hydrothermal circulation along fault systems contribute to instantaneous melting of ice whereas longer-term heat flux, such as geothermal gradient radiating from magmatism, contribute to background heat that likely facilitated ice flow dynamics. Particularly in the western Ross Sea is the Terror Rift, which represents the youngest phase of extension within the West Antarctic Rift System, one of the world's largest rifts and the only one covered by continental ice sheets. The thinned western Ross Sea lithosphere and Terror Rift encompasses active volcanism that range from 5 Ma to present-day, suggesting that Pliocene-Quaternary fault movement and dynamic changes in ice sheet extent and thickness over this period are concurrent with magmatic activities. Refining our understanding of the space/time linkages between heat sources and flux relative to faulting and glacial cyclicity is a novel science effort in the western Ross Sea seafloor. We consider that magma intrusion and volcanism is the primary lithospheric heat source, which in turn, is a consequence of lithospheric thinning and craton-directed edge-driven mantle flow beneath the Terror Rift. Importantly, the distribution of the subsequent heat flux from magmatism has controlled the evolution of geothermal gradient and seafloor hydrothermal activities and, because of that, has significantly influenced the dynamics of the hydrosphere-cryosphere system in this region.