Understanding Mercury's Thermochemical Evolution Using a Geochemical and Geophysical Lens

Mercury is the most mysterious planet in the inner Solar System, suggested by observations from the MESSENGER mission. These observations shine a light on potential processes occurring within Mercury as it evolved over time. Scientific instruments aboard MESSENGER indicate that Mercury has a very thin surface layer of broken rocks, a thin crustal layer covered by lavas erupted from a melt formed in a relatively thin, FeO poor mantle, and a large metal rich core made from Fe and some quantity of a light element. These conditions are different than those seen on Earth: a thick crust covered by a layer of varied thickness made up of loose unconsolidated rocks and dust, a large mantle with more FeO, and a smaller core to planet ratio. To understand how these non-Earth like conditions affect how the planet's interior changes with time, a modified evolution model was created to track the changes in heat and chemistry within Mercury. This model accounts for complications like a dynamic core density that changes with a growing inner core, the formation method of the inner core, and the FeO poor mantle composition. Using this model offers illumination on the conditions Mercury experienced after it formed. This model is limited, but results suggest that Mercury's mantle began at an initial mantle temperature of 1600 K, and a mantle reference viscosity of 1021–1022 Pa s, indicating the mantle was less likely to flow easily. Model results also suggest the core contained some sulfur from 0.05–8.9 wt.% S, derived from the MESSENGER data. BepiColombo, a new Mercury mission, will provide some perspectives on the interior of Mercury, leading to more detailed information about conditions present after planetary formation and the effect of non-Earth like conditions on a planet's interior as it cools.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Geosciences

Department dc:contributor.department

Geosciences

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2024

Author dc:creator

• Bose, Priyanka

Chairs dc:contributor.committeechair

• Duncan, Megan S.
• King, Scott D.

Committee members dc:contributor.committeemember

• Caddick, Mark James
• Spotila, James A.
• Pollyea, Ryan

• Mercury
• Thermochemical Evolution
• Mantle Melt Parameterization
• Inner Core Formation
• Top-Down Core Crystallization
• Bottom-Up Core Crystallization

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:40378

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/119032