Sr Isotopic Variations along the Juan de Fuca Ridge

Authors

Jacqueline Eaby, U.S. Geological SurveyFollow
David A. Clague, U.S. Geological Survey
John R. Delaney, University of Washington

Document Type

Article

Publication Date

9-1984

Digital Object Identifier (DOI)

https://doi.org/10.1029/JB089iB09p07883

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.

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Was this content written or created while at USF?

No

Citation / Publisher Attribution

Journal of Geophysical Research: Solid Earth, v. 89, issue B9, p. 7883-7890

Published in 1984 by the American Geophysical Union.

Scholar Commons Citation

Eaby, Jacqueline; Clague, David A.; and Delaney, John R., "Sr Isotopic Variations along the Juan de Fuca Ridge" (1984). Marine Science Faculty Publications. 1321.
https://digitalcommons.usf.edu/msc_facpub/1321