Abstract
AbstractEvaluating carbon’s candidacy as a light element in the Earth’s core is critical to constrain the budget and planet-scale distribution of this life-essential element. Here we use first principles molecular dynamics simulations to estimate the density and compressional wave velocity of liquid iron-carbon alloys with ~4-9 wt.% carbon at 0-360 gigapascals and 4000-7000 kelvin. We find that for an iron-carbon binary system, ~1-4 wt.% carbon can explain seismological compressional wave velocities. However, this is incompatible with the ~5-7 wt.% carbon that we find is required to explain the core’s density deficit. When we consider a ternary system including iron, carbon and another light element combined with additional constraints from iron meteorites and the density discontinuity at the inner-core boundary, we find that a carbon content of the outer core of 0.3-2.0 wt.%, is able to satisfy both properties. This could make the outer core the largest reservoir of terrestrial carbon.
Funder
National Science Foundation
National Aeronautics and Space Administration
Publisher
Springer Science and Business Media LLC
Subject
General Earth and Planetary Sciences,General Environmental Science
Cited by
7 articles.
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