Pressure-dependent isotopic composition of iron alloys

A Shahar; E A Schauble; R Caracas; A E Gleason; M M Reagan; Y Xiao; J Shu; W Mao

doi:10.1126/science.aad9945

Pressure-dependent isotopic composition of iron alloys

Science. 2016 Apr 29;352(6285):580-2. doi: 10.1126/science.aad9945.

Authors

A Shahar¹, E A Schauble², R Caracas³, A E Gleason⁴, M M Reagan⁵, Y Xiao⁶, J Shu⁷, W Mao⁵

Affiliations

¹ Geophysical Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA. ashahar@carnegiescience.edu.
² Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA 90095, USA.
³ CNRS, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Laboratoire de Géologie de Lyon, UMR 5276, 69364 Lyon Cedex 07, France.
⁴ Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
⁵ Department of Geological Sciences, Stanford University, Stanford, CA, USA.
⁶ High Pressure Collaborative Access Team (HPCAT), Carnegie Institution for Science, Argonne, IL, USA.
⁷ Geophysical Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA.

PMID: 27126042
DOI: 10.1126/science.aad9945

Abstract

Our current understanding of Earth's core formation is limited by the fact that this profound event is far removed from us physically and temporally. The composition of the iron metal in the core was a result of the conditions of its formation, which has important implications for our planet's geochemical evolution and physical history. We present experimental and theoretical evidence for the effect of pressure on iron isotopic composition, which we found to vary according to the alloy tested (FeO, FeH(x), or Fe3C versus pure Fe). These results suggest that hydrogen or carbon is not the major light-element component in the core. The pressure dependence of iron isotopic composition provides an independent constraint on Earth's core composition.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.