Planetary Science

We explore how rocky planets form and geochemically evolve over time.

 

To understand how Earth distinguished itself as the only known inhabited planet among the Solar System bodies, there are lessons to be learnt from geologic evolution of other terrestrial planetary bodies, such as Mars, the Moon, Venus, and Mercury and even exoplanets. We do not know why these planets have drastically different atmosphere. Is it owing to accretion from vastly different compositions, or is it because of the difference in conditions of early evolution (e.g., thermal and oxidation state and depth of core-mantle separation) that caused very different fractionation of fluids between the interior and the exosphere? Our goal is to compare and contrast the origin and cycling of volatiles and fluids, magmatic history of various known and plausible rocky planets through time.

Some of the current sub-themes (see more details below) are:

  • Accretion and core-mantle differentiation of terrestrialrocky planets
  • Rocky Bodies in our Solar System and Beyond

Accretion and core-mantle differentiation of rocky planets

Massive global events such as the moon-forming impact may have affected the composition of Earth and its internal layers. ( Li et al., 2015 – Nat Geo )

Massive global events such as the moon-forming impact may have affected the composition of Earth and its internal layers. (Li et al., 2015 – Nat Geo)

We are not only interested in the origin of volatile elements on Earth but also aim to constrain how the processes of accretion and early differentiation might have shaped the starting condition for other rocky bodies in our Solar System and other solar systems. We have been learning how the difference in conditions of early differentiation may lead to very different initial budget of life-essential elements such as carbon in the silicate portion of the planet (e.g., Chi et al., 2014 – GCA; Li et al., 2016 – Nat Geocsi; Tsuno et al., 2018 – GCA). In the coming years we would look to expand our work on the fate of all life-essential elements (COHNSP) during early history of rocky planets.

Rocky Bodies in our Solar System and Beyond 

There is a growing amount of data on the compositions of the crust for Mars and Mercury through orbiter data and/or from meteorites or rovers. We try to reconcile these observations with the estimated compositions of the planetary mantles through laboratory experiments. For example, in this theme, we worked on thermal vigor of magma generation through the geologic history of Mars (Filiberto and Dasgupta, 2011 — EPSL; Filiberto and Dasgupta, 2015 – JGR-Planets). We have also worked on constraining the efficiency of sulfur extraction through mantle melting on Mars and the Moon (e.g., Ding et al., 2015 – EPSL; Ding et al., 2018 – GCA). Similarly, we have also investigated the efficiency of carbon extraction via mantle melting of reduced planetary bodies such as Mercury and Mars (Li et al., 2017 – JGR-Planets). These studies are useful to link the interior compositions of these distant bodies to the plausible compositions of their atmospheres that maybe influenced by magmatic degassing. As more and more exoplanets are being discovered, it is important to ask what the atmospheric signatures from these distant bodies may tell us in terms of their interior structure or magmatic history.