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Satellite magnetic anomalies over subduction zones: The Aleutian Arc anomaly
Author(s) -
Clark Sherren C.,
Frey Herbert,
Thomas Herman H.
Publication year - 1985
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl012i001p00041
Subject(s) - subduction , geology , slab , magnetic anomaly , anomaly (physics) , geophysics , slab window , seismology , mantle (geology) , oceanic crust , tectonics , physics , condensed matter physics
Positive magnetic anomalies seen in MAGSAT average scalar anomaly data overlying some subduction zones can be explained in terms of the magnetization contrast between the cold subducted oceanic slab and the surrounding hotter, nonmagnetic mantle. Three‐dimensional modeling studies show that peak anomaly amplitude and location depend on slab length and dip. A model for the Aleutian Arc anomaly matches the general trend of the observed MAGSAT anomaly if a slab thickness of 7 km and a relatively high (induced plus viscous) magnetization contrast of 4 A/m are used. A second source body along the present day continental margin is required to match the observed anomaly in detail, and may be modeled as a relic slab from subduction prior to 60 m.y. ago.