HR: 08:30h
AN: MR41A-03    [Abstracts]
TI: Seismological Constraints on Core Composition From Core Liquid Immiscibility
AU: * Helffrich, G
EM: george@gly.bris.ac.uk
AF: Earth Sciences, University of Bristol, Wills Mem. Bldg., Queen's Road, Bristol, BS8 1RJ United Kingdom
AU: Kaneshima, S
AF: Earth and Planetary Science, Titech, 1-2-1 Ookayama, Meguro-ku, Tokyo, 152-6551 Japan
AB: Liquid immiscibility in iron-rich liquids at atmospheric pressure forms the basis of smelting, which separates an iron-rich liquid from a second liquid in which contaminating elements are concentrated. The earth's core is a similar iron-rich system that contains light elements that progressively enrich the outer core liquid as the core cools and the inner core crystallizes. Thermodynamic modelling of Fe-O-S liquids shows that immiscible liquids can exist at outer core pressures at temperatures less than 5000$^\circ$K. However, there is no evidence for liquid layers in the outer core in the travel times and waveforms of seismic waves that reflect internally in the core, P4KP. The absence of layers therefore constrains core compositions in the Fe-O-S system to be no richer than 4 wt.% oxygen and 2-11 wt.% sulfur, the remainder being iron.
DE: 7207 Core and mantle
SC: Mineral and Rock Physics [MR]
MN: 2004 AGU Fall Meeting