Composition and State of the Core Kei Hirose, 1,2 St´ ephane Labrosse, 3,4 and John Hernlund 5 1 Department of Earth and Planetary Sciences and 2 Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan; email: kei@geo.titech.ac.jp 3 Laboratoire de G ´ eologie de Lyon, CNRS UMR 5276, Ecole Normale Sup´ erieure de Lyon, Universit ´ e Claude Bernard Lyon 1, 69364 Lyon Cedex 07, France; email: stephane.labrosse@ens-lyon.fr 4 Institut Universitaire de France, 75005 Paris, France 5 Department of Earth and Planetary Science, University of California, Berkeley, California 94720; email: hernlund@gmail.com Annu. Rev. Earth Planet. Sci. 2013. 41:657–91 First published online as a Review in Advance on March 28, 2013 The Annual Review of Earth and Planetary Sciences is online at earth.annualreviews.org This article’s doi: 10.1146/annurev-earth-050212-124007 Copyright c  2013 by Annual Reviews. All rights reserved Keywords ultrahigh pressure, phase relation, composition, thermal evolution, stratification Abstract The composition and state of Earth’s core, located deeper than 2,900 km from the surface, remain largely uncertain. Recent static experiments on iron and alloys performed up to inner core pressure and temperature conditions have revealed phase relations and properties of core materials. These mineral physics constraints, combined with theoretical calculations, continue to im- prove our understanding of the core, in particular the crystal structure of the inner core and the chemical composition, thermal structure and evolution, and possible stratification of the outer core. 657 Annu. Rev. Earth Planet. Sci. 2013.41:657-691. Downloaded from www.annualreviews.org by Ecole Normale Superieure de Lyon on 06/19/13. For personal use only.