Imperial College London
Alternate

Saskia Goes

Faculty of Engineering, Department of Earth Science & Engineering

Professor of Geophysics
 
 
 
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Contact

 

+44 (0)20 7594 6434s.goes

 
 
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Location

 

4.47Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Eeken:2018:10.1016/j.epsl.2018.03.018,
author = {Eeken, T and Goes, S and Pedersen, H and Arndt, N and Bouilhol, P},
doi = {10.1016/j.epsl.2018.03.018},
journal = {Earth and Planetary Science Letters},
pages = {148--159},
title = {Seismic evidence for depth-dependent metasomatism in cratons},
url = {http://dx.doi.org/10.1016/j.epsl.2018.03.018},
volume = {491},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The long-term stability of cratons has been attributed to low temperatures and depletion iniron and water, which decrease density and increase viscosity. However, steady-state thermalmodels based on heat flow and xenolith constraints systematically overpredict the seismicvelocity-depth gradients in cratonic lithospheric mantle. Here we invert for the 1-D thermalstructure and a depth distribution of metasomatic minerals that fit average Rayleigh-wavedispersion curves for the Archean Kaapvaal, Yilgarn and Slave cratons and the ProterozoicBaltic Shield below Finland. To match the seismic profiles, we need a significant amount ofhydrous and/or carbonate minerals in the shallow lithospheric mantle, starting between theMoho and 70 km depth and extending down to at least 100-150 km. The metasomaticcomponent can consist of 0.5-1 wt% water bound in amphibole, antigorite and chlorite, ~0.2wt% water plus potassium to form phlogopite, or ~5 wt% CO2 plus Ca for carbonate, or acombination of these. Lithospheric temperatures that fit the seismic data are consistent withheat flow constraints, but most are lower than those inferred from xenolithgeothermobarometry. The dispersion data require differences in Moho heat flux betweenindividual cratons, and sublithospheric mantle temperatures that are 100-200°C less beneathYilgarn, Slave and Finland than beneath Kaapvaal. Significant upward-increasingmetasomatism by water and CO2-rich fluids is not only a plausible mechanism to explain theaverage seismic structure of cratonic lithosphere but such metasomatism may also lead to theformation of mid-lithospheric discontinuities and would contribute to the positive chemicalbuoyancy of cratonic roots.
AU  - Eeken,T
AU  - Goes,S
AU  - Pedersen,H
AU  - Arndt,N
AU  - Bouilhol,P
DO  - 10.1016/j.epsl.2018.03.018
EP  - 159
PY  - 2018///
SN  - 0012-821X
SP  - 148
TI  - Seismic evidence for depth-dependent metasomatism in cratons
T2  - Earth and Planetary Science Letters
UR  - http://dx.doi.org/10.1016/j.epsl.2018.03.018
UR  - http://hdl.handle.net/10044/1/58030
VL  - 491
ER  -
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