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Subduction-zone magnetic anomalies and implications for hydrated forearc mantle

Geology

By:
, , and
DOI: 10.1130/G21447.1

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Abstract

Continental mantle in subduction zones is hydrated by release of water from the underlying oceanic plate. Magnetite is a significant byproduct of mantle hydration, and forearc mantle, cooled by subduction, should contribute to long-wavelength magnetic anomalies above subduction zones. We test this hypothesis with a quantitative model of the Cascadia convergent margin, based on gravity and aeromagnetic anomalies and constrained by seismic velocities, and find that hydrated mantle explains an important disparity in potential-field anomalies of Cascadia. A comparison with aeromagnetic data, thermal models, and earthquakes of Cascadia, Japan, and southern Alaska suggests that magnetic mantle may be common in forearc settings and thus magnetic anomalies may be useful in mapping hydrated mantle in convergent margins worldwide. ?? 2005 Geological Society of America.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Subduction-zone magnetic anomalies and implications for hydrated forearc mantle
Series title:
Geology
DOI:
10.1130/G21447.1
Volume
33
Issue:
6
Year Published:
2005
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geology
First page:
445
Last page:
448
Number of Pages:
4