Sr isotopic variations along the Juan de Fuca Ridge

Journal of Geophysical Research Solid Earth
By: , and 

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Abstract

Sr isotopic ratios of 39 glass and microcrystalline basalt samples along the Juan de Fuca Ridge and 1 glass sample from Brown Bear Seamount are at the lower end of the range for normal mid-oceanic ridge basalt (MORB); the average 87Sr/86Sr ratio is 0.70249±0.00014 (2-σ). Although subtle variations exist along strike of the ridge, the Sr isotope data do not show systematic variation relative to the proposed Cobb Hotspot. The isotopic data are inconsistent with an enriched mantle-plume origin for the Cobb-Eickelberg Seamount chain, as has been proposed for Iceland, the Azores, and the Galapagos spreading center. Sr isotopic ratios of samples collected north and south of the Cobb offset are identical, although minor element ratios indicate that these regions have chemically distinct mantle sources. These distinct mantle sources may not have been separated long enough to develop isotopic differences.

Publication type Article
Publication Subtype Journal Article
Title Sr isotopic variations along the Juan de Fuca Ridge
Series title Journal of Geophysical Research Solid Earth
DOI 10.1029/JB089iB09p07883
Volume 89
Issue B9
Year Published 1984
Language English
Publisher American Geophysical Union
Description 8 p.
First page 7883
Last page 7890
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