Outer-core compositional stratification from observed core wave speed profiles

George Helffrich () and Satoshi Kaneshima
Additional contact information
George Helffrich: Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
Satoshi Kaneshima: Earth and Planetary Sciences, University of Kyushu, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan

Nature, 2010, vol. 468, issue 7325, 807-810

Abstract: Abstract Light elements must be present in the nearly pure iron core of the Earth to match the remotely observed properties of the outer and inner cores1,2. Crystallization of the inner core excludes light elements from the solid, concentrating them in liquid near the inner-core boundary that potentially rises and collects at the top of the core3, and this may have a seismically observable signal. Here we present array-based observations of seismic waves sensitive to this part of the core whose wave speeds require there to be radial compositional variation in the topmost 300 km of the outer core. The velocity profile significantly departs from that of compression of a homogeneous liquid. Total light-element enrichment is up to five weight per cent at the top of the core if modelled in the Fe–O–S system. The stratification suggests the existence of a subadiabatic temperature gradient at the top of the outer core.

Date: 2010
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/nature09636 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:468:y:2010:i:7325:d:10.1038_nature09636

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/nature09636

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().