EEPS Colloquium: Shijie Zhong

The glacial isostatic adjustment (GIA) process represents the dynamic response of the Earth’s mantle and crust to ice melting and sea-level changes on timescales of years to 100,000 years. The GIA process has been studied for decades, but most of the studies assume that the Earth’s viscoelastic structure be spherically symmetric, leaving unanswered the questions on the effects of realistic 3-D mantle structure including non-Newtonian rheology. In this presentation, I will discuss the development of an open-source modeling package CitcomSVE and its applications to the GIA process with 3-D mantle structure. I will focus on two problems. The first is the effects of non-Newtonian mantle viscosity on time-dependent mantle viscosity structure and its consequence on relative sea-level changes in the last 20,000 years. The second is the dynamic interplay between glacial forcing and plate tectonics including plate motions, seafloor spreading, mid-ocean ridge magmatism and degassing (e.g., CO2). I will also discuss the effort to understand the crustal motions of West Antarctica and northern Antarctica Peninsular in response to ongoing rapid ice melting in these regions and their implications for mantle rheology and stability of the Antarctica ice sheets.