Impact melting and vaporization of the Earth-Moon system.

Lead Research Organisation: University College London
Department Name: Earth Sciences

Abstract

The goal the project is to determine the thermodynamic properties of silicate liquids that control the response of rocky plants to large impacts using first principles molecular dynamics simulations. Such simulations have already had an important impact on our views of magma ocean evolution, for example, leading to the idea of the basal magma ocean. A coordinated suite of new simulations are needed to make progress. In particular the pressure-temperature regime relevant to large impacts remains unexplored: a symmetric impact at Keplerian velocity generates a peak pressure of 1000 GPa (1 TPa), 7 times the pressure at the base of Earth's mantle. Yet learning about material behavior at these conditions is essential for understanding the consequences if large impacts, including the depth of melting, and the amount and composition of vapor produced on release. The results will provide a rich source of information on the physical properties of silicate liquids, and will constrain the fundamental thermodynamic relation of silicate liquids over the entire pressure-temperature regime relevant to large impacts and the magma ocean.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
ST/N504476/1 01/10/2015 31/03/2021
1631737 Studentship ST/N504476/1 01/10/2015 18/03/2019 Alfred James Wilson
 
Description We have refined a relatively under developed method of calculating the entropy of liquids (in this case silicate liquids expected to be found in the early Earth system). This makes the calculation of free energies from individual simulations (FPMD) possible without external information.
We have calculated the melting curve for the dominant Earth mantle mineral phase (MgSiO3) to better accuracy than previously achieved. This was also done fore CaSiO3, these are the two main perovskite minerals of our mantle.
I have determined the structure and thermodynamic properties of carbonate liquids using FPMD simulations. This has not previously been done to this level of accuracy and allows properties of important magma transport phases to be understood.
Exploitation Route These findings will be published in the coming months/year allowing them to be used in mineral physics databases as well as informing the dynamical predictions of early earth magma ocean behaviour and further application of the 2PT method of entropy calculation of liquids.
Sectors Chemicals,Energy,Environment,Other