Imperial College London
Alternate

Dr Ian Bastow

Faculty of Engineering, Department of Earth Science & Engineering

Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7594 2974i.bastow Website

 
 
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Location

 

4.45Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Boyce:2023:10.1029/2022JB025745,
author = {Boyce, A and Liddell, M and Pugh, S and Brown, J and McMurchie, E and Parsons, P and Clement, E and Burdick, S and Darbyshire, F and Cottaar, S and Bastow, I and Schaeffer, A and Audet, P and Schutt, D and Aster, R},
doi = {10.1029/2022JB025745},
journal = {Journal of Geophysical Research: Solid Earth},
pages = {1--34},
title = {A new P-wave tomographic model (cap22) for North America: implications for the subduction and cratonic metasomatic modification history of western Canada and Alaska},
url = {http://dx.doi.org/10.1029/2022JB025745},
volume = {128},
year = {2023}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Our understanding of the present-day state and evolution of the Canadian and Alaskan mantle is hindered by a lack of absolute P-wavespeed constraints that provide complementary sensitivity to composition in conjunction with existing S-wavespeed models. Consequently, cratonic modification, orogenic history of western North America and complexities within the Alaskan Proto-Pacific subduction system remain enigmatic. One challenge concerns the difficulties in extracting absolute arrival-time measurements from often-noisy data recorded by temporary seismograph networks required to fill gaps in continental and global databases. Using the Absolute Arrival-time Recovery Method (AARM), we extract >180,000 new absolute arrival-time residuals from seismograph stations across Canada and Alaska and combine these data with USArray and global arrival-time data from the contiguous US and Alaska. We develop a new absolute P-wavespeed tomographic model, CAP22, spanning North America that significantly improves resolution in Canada and Alaska over previous models. Slow wavespeeds below the Canadian Cordillera sharply abut fast wavespeeds of the continental interior at the Rocky Mountain Trench in southwest Canada. Slow wavespeeds below the Mackenzie Mountains continue farther inland in northwest Canada, indicating Proterozoic-Archean metasomatism of the Slave craton. Inherited tectonic lineaments colocated with this north-south wavespeed boundary suggest that both the crust and mantle may control Cordilleran orogenic processes. In Alaska, fast upper mantle wavespeeds below the Wrangell Volcanic Field favor a conventional subduction related mechanism for volcanism. Finally, seismic evidence for the subducted Kula and Yukon slabs indicate tectonic reconstructions of western North America may require revision.
AU  - Boyce,A
AU  - Liddell,M
AU  - Pugh,S
AU  - Brown,J
AU  - McMurchie,E
AU  - Parsons,P
AU  - Clement,E
AU  - Burdick,S
AU  - Darbyshire,F
AU  - Cottaar,S
AU  - Bastow,I
AU  - Schaeffer,A
AU  - Audet,P
AU  - Schutt,D
AU  - Aster,R
DO  - 10.1029/2022JB025745
EP  - 34
PY  - 2023///
SN  - 2169-9313
SP  - 1
TI  - A new P-wave tomographic model (cap22) for North America: implications for the subduction and cratonic metasomatic modification history of western Canada and Alaska
T2  - Journal of Geophysical Research: Solid Earth
UR  - http://dx.doi.org/10.1029/2022JB025745
UR  - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022JB025745
UR  - http://hdl.handle.net/10044/1/103475
VL  - 128
ER  -
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