January 30 @ 4:00 pm - 5:00 pm CST
“The early Earth evolution during and after the solidification of magma ocean”
The early Earth experienced large-scale melting owing to giant impacts during the last phase of accretion. This indicates the possibility of substantial differentiation during the subsequent solidification of magma ocean, and its aftermath has likely been crucial for characterizing the surface environment of the Hadean. How differentiation proceeds, however, is controversial because a number of parameters are unconstrained, including density contrast, viscosity, grain size, and permeability. In this study, instead of exploring the most likely scenario, I aim to bound the degree of chemical differentiation by calculating the thermochemical structure of end-member cases. A new model is developed that is consistent with both thermal and compositional aspects, and a potential differentiation mechanism is assumed to take full effect in each calculation. I show that the length scale of heterogeneity differs significantly depending on a mechanism driving the differentiation. I will further present contrasting surface evolution scenarios for two different differentiated mantle structures. If crystal settling were the only mechanism, the Hadean may have been habitable within 10 Myr after the solidification of magma ocean.