Peter Olson - University of New Mexico

May 28, 2019, 3:30 p.m. - 4:30 p.m.
3656 Geology

Presented By:
Peter Olson,
University of New Mexico

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Nebular atmosphere to magma ocean: water and other volatiles captured during Earth’s accretion.

The origin and abundance of mantle volatiles, including water, present major questions for Earth's evolution. In this talk I explorecauses and consequences of volatile capture from a massive hydrogen-helium rich atmosphere derived from the solar nebula during Earth’s accretion. I use a model of magma ocean dynamics coupled to a nebular atmosphere model adapted to Earth’s formation that includes (i) atmosphere winds based on the dynamics of deep rotating fluids; (ii) water production at the magma surface; and (iii) gas transfer between magma and atmosphere based on the systematics of air-sea gas exchange. Provided the Earth accreted to 30% or more of its final mass in the presence of the solar nebula, the mantle is expected to have ingassed one or more oceans of water along with many petagrams of helium-3 and other light noble gases. This model also predicts that thermal insulation by the nebular atmosphere led to very hot conditions in Earth's interior during accretion, with temperatures above 6000 K in the core and the possibility of an early Hadean dynamo.