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Joint inversion of shear wave travel time residuals and geoid and depth anomalies for long-wavelength variations in upper mantle temperature and composition along the Mid-Atlantic RidgeMeasurements were carried out for SS-S differential travel time residuals for nearly 500 paths crossing the northern Mid-Atlantic Ridge, assuming that the residuals are dominated by contributions from the upper mantle near the surface bounce point of the reflected phase SS. Results indicate that the SS-S travel time residuals decrease linearly with square root of age, to an age of 80-100 Ma, in general agreement with the plate cooling model. A joint inversion was formulated of travel time residuals and geoid and bathymetric anomalies for lateral variation in the upper mantle temperature and composition. The preferred inversion solutions were found to have variations in upper mantle temperature along the Mid-Atlantic Ridge of about 100 K. It was calculated that, for a constant bulk composition, such a temperature variation would produce about a 7-km variation in crustal thickness, larger than is generally observed.
Document ID
19920032046
Document Type
Reprint (Version printed in journal)
Authors
Sheehan, Anne F. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Solomon, Sean C. (MIT Cambridge, MA, United States)
Date Acquired
August 15, 2013
Publication Date
November 10, 1991
Publication Information
Publication: Journal of Geophysical Research
Volume: 96
ISSN: 0148-0227
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSF EAR-90-04750
CONTRACT_GRANT: NAG5-814
Distribution Limits
Public
Copyright
Other