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Stirring in 3-d spherical models of convection in the Earth’s mantle

Gottschaldt, Klaus-Dirk and Walzer, U. and Hendel, Roland and Stegman, D. and Baumgardner, J. and Mühlhaus, H. (2006) Stirring in 3-d spherical models of convection in the Earth’s mantle. Philosophical Magazine, 86 (21-22), pp. 3175-3204. Taylor & Francis. ISSN 1478-6435

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Official URL: http://www.tandfonline.com/doi/pdf/10.1080/14786430500197991

Abstract

On a global scale basalts from mid-ocean ridges are strikingly more homogeneous than basalts from intraplate volcanism. The observed geochemical heterogeneity argues strongly for the existence of distinct reservoirs in the Earth’s mantle. It is an unresolved problem of Geodynamics as to how these findings can be reconciled with large-scale convection. We review observational constraints, and investigate stirring properties of numerical models of mantle convection. Conditions in the early Earth may have supported layered convection with rapid stirring in the upper layers. Material that has been altered near the surface is transported downwards by small-scale convection. Thereby a layer of homogeneous depleted material develops above pristine mantle. As the mantle cools over Earth history, the effects leading to layering become reduced and models show the large-scale convection favoured for the Earth today. Laterally averaged, the upper mantle below the lithosphere is least affected by material that has experienced near-surface differentiation. The geochemical signature obtained during the previous episode of small-scale convection may be preserved there for the longest time. Additionally, stirring is less effective in the high viscosity layer of the central lower mantle [1, 2], supporting the survival of medium-scale heterogeneities there. These models are the first, using 3-d spherical geometry and mostly Earth-like parameters, to address the suggested change of convective style. Although the models are still far from reproducing our planet, we find that proposal might be helpful towards reconciling geochemical and geophysical constraints.

Item URL in elib:https://elib.dlr.de/97041/
Document Type:Article
Title:Stirring in 3-d spherical models of convection in the Earth’s mantle
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Gottschaldt, Klaus-DirkDLR, IPA und Univ. Queensland, AustralienUNSPECIFIED
Walzer, U.Univ. JenaUNSPECIFIED
Hendel, RolandUniv. JenaUNSPECIFIED
Stegman, D.UNSPECIFIEDUNSPECIFIED
Baumgardner, J.UNSPECIFIEDUNSPECIFIED
Mühlhaus, H.University of Queensland, AustraliaUNSPECIFIED
Date:2006
Journal or Publication Title:Philosophical Magazine
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:86
Page Range:pp. 3175-3204
Publisher:Taylor & Francis
ISSN:1478-6435
Status:Published
Keywords:planetary dynamics, geochemisty, numerical modelling
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:other
DLR - Research area:Raumfahrt
DLR - Program:R - no assignment
DLR - Research theme (Project):R - no assignment
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics
Deposited By: Gottschaldt, Klaus-Dirk
Deposited On:07 Sep 2015 13:33
Last Modified:06 Sep 2019 15:18

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