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:2020:10.1029/2019JB018734,
author = {Eeken, T and Goes, S and Petrescu, L and Altoe, I},
doi = {10.1029/2019JB018734},
journal = {Journal of Geophysical Research},
pages = {1--19},
title = {Lateral variations in thermochemical structure of the Eastern Canadian Shield},
url = {http://dx.doi.org/10.1029/2019JB018734},
volume = {125},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The origin of 3D seismic heterogeneity in Precambrian lithosphere has been enigmatic, because temperature variations in old stable shields are expected to be small and seismic sensitivity to majorelement compositional variations is limited. Previous studies indicate that metasomatic alteration may significantly affect average 1D structure below shields. Here, we perform a grid search for 3D thermochemical structure, including variations in alteration, to model published Rayleighwave phase velocities between 20 and 160 s for the eastern part of the Archean Superior and Canadian Proterozoic Grenville Provinces. We find that, consistent with constraints from surface heatflow and xenoliths, the lithosphere is coolest (Moho heatflow 1217 mW/m2) and the thermal boundary layer thickest (>250 km) in the northeastern Superior and warmest in the southeastern Grenville (Moho heatflow 2025 mW/m2, thermal boundary thickness 160200 km). Compositionally, the phase velocities for most of the Superior within our study region require little alteration, but in a few regions, fast velocities need to overlie slower velocities. These can be modelled with an eclogite layer in the mid lithosphere, consistent with activeseismic and xenolith evidence for remnants of subducted Archean crust. The phase velocities from the Grenville Province require significant metasomatic modification to explain the relatively low velocities of the shallow lithosphere, and the required intensity of alteration is highest in parts of the Grenville associated with arc accretion. Thus, composition of the northeastern Canadian Shield appears to reflect different stages and styles of craton assembly.
AU  - Eeken,T
AU  - Goes,S
AU  - Petrescu,L
AU  - Altoe,I
DO  - 10.1029/2019JB018734
EP  - 19
PY  - 2020///
SN  - 0148-0227
SP  - 1
TI  - Lateral variations in thermochemical structure of the Eastern Canadian Shield
T2  - Journal of Geophysical Research
UR  - http://dx.doi.org/10.1029/2019JB018734
UR  - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JB018734
UR  - http://hdl.handle.net/10044/1/80562
VL  - 125
ER  -
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