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The effect of post Pangea subduction on global mantle tomography and convection

Scrivner, Craig and Anderson, Don L. (1992) The effect of post Pangea subduction on global mantle tomography and convection. Geophysical Research Letters, 19 (10). pp. 1053-1056. ISSN 0094-8276. doi:10.1029/92GL00864. https://resolver.caltech.edu/CaltechAUTHORS:20140509-074802356

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Abstract

There is an excellent correlation between tomographic patterns and global tectonics in the upper 200 km of the mantle. Below this depth there is little relationship with present tectonic provinces. Most of the power in the tomography is in the longest wavelengths (ℓ=1–3) with ℓ=2 generally dominant. This is quite different from expectations based on mantle convection models. The question then arises, what causes the long wavelength variations mapped by seismic techniques? We investigate the hypotheses that past locations of supercontinents and subduction may control temperature variations in the mantle. We look for correlations between Pangea and post-Pangeatic subduction and seismic velocity variations at various depths. The best correlations with time integrated slab locations occur near the base of the uppermantle, suggesting that slabs bottom out in the mesosphere. The Pangea hemisphere has a colder than average uppermantle, probably due to circum- and intra-Pangea subduction. Hotspots and ridges avoid regions cooled by subduction over the past 180 Ma. The presence of large continents at the surface and large areas of cold slab at depth explain the dominance of long wavelengths in the mantle's thermal structure, despite the high Rayleigh number.


Item Type:Article
Related URLs:
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http://dx.doi.org/10.1029/92GL00864 DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/92GL00864/abstractPublisherArticle
Additional Information:© 1992 by the American Geophysical Union. We thank Scotese for maps of paleosubduction zones and Tanimoto for digital tomographic models. This work was supported by NSF Grants EAR 90-02947, 91-08246, and an NSF Graduate Fellowship. Contribution No. 5116, Division of Geological and Planetary Sciences, Caltech, Pasadena, CA 91125.
Funders:
Funding AgencyGrant Number
NSFEAR 90-02947
NSFEAR 91-08246
NSF Graduate FellowshipUNSPECIFIED
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Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences 5116
Issue or Number:10
DOI:10.1029/92GL00864
Record Number:CaltechAUTHORS:20140509-074802356
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140509-074802356
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45622
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 May 2014 17:16
Last Modified:10 Nov 2021 17:14

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