| Outer-core compositional stratification from observed core wave speed profiles. | |
| | |
MedLine Citation:
|
PMID: 21150995 Owner: NLM Status: PubMed-not-MEDLINE |
Abstract/OtherAbstract:
|
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 cores. 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 core, 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. |
| | |
Authors:
|
George Helffrich; Satoshi Kaneshima |
Related Documents
:
|
16592585 - Colored lattices. 17873955 - Frustrated-total-internal-reflection-based thin-film color separator. 7123855 - Color discrimination at threshold: the approach through increment threshold sensitivity. 20386355 - Images perceived after chromatic or achromatic contrast sensitivity losses. 2689795 - Wavelike isomorphic prepatterns in development. 7637565 - Dietary deficiency of docosahexaenoic acid impairs vision at low light intensities in j... |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: Nature Volume: 468 ISSN: 1476-4687 ISO Abbreviation: Nature Publication Date: 2010 Dec |
Date Detail:
|
Created Date: 2010-12-14 Completed Date: 2011-01-26 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 0410462 Medline TA: Nature Country: England |
Other Details:
|
Languages: eng Pagination: 807-10 Citation Subset: - |
Affiliation:
|
Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan. george.helffrich@bris.ac.uk |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Ice-sheet acceleration driven by melt supply variability.
Next Document: Gene expression divergence recapitulates the developmental hourglass model.