Early Earth and Deep Time Processes

We constrain the nature of chemical exchanges and geochemical cycling for Earth formation and evolution

 

Cartoon depicting various possible deep-Earth processes that may have occurred in early in Earth's history to the current deep-Earth processes today, such as plate tectonics, and the effect on volatile elements. ( Dasgupta, 2013 RiMG )

Cartoon depicting various possible deep-Earth processes that may have occurred in early in Earth's history to the current deep-Earth processes today, such as plate tectonics, and the effect on volatile elements. (Dasgupta, 2013 RiMG)

A key question related to the budgets and distribution of life-essential elements in the modern Earth is how they got established and changed through time. Did the Earth acquire the volatiles and achieve their present distribution between the surface and the interior at the time of birth, i.e., at the main phase of accretion and growth, or is the present day budget (including ocean and atmosphere) shaped by later processes, such as late addition of materials (e.g., meteorites, comets)? Similarly, how did the surface chemistry of the planet such as carbon dioxide or oxygen content in the atmosphere, evolved from the Hadean through Phanerozoic and what roles, if any, Earth’s deep processes may have played in dictating it.

Our recent efforts are constraining the fate of life-essential volatile elements (e.g., C, N, S) during accretion and core-formation process of Earth (e.g., Dasgupta et al., 2013 – GCA; Li et al., 2016). Similarly, we also are investigating how Earth’s plate tectonic cycles may have modulated the surface-interior cycles of key elements such as carbon how such cycles might have had played a role in various deep time warm periods and oxygenation of the surface environment (e.g., Dasgupta, 2013 – RiMG; Duncan and Dasgupta, 2017 – Nat Geosci; Carter and Dasgupta, 2018 – Chem Geol).