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Mineral compositions of plutonic rocks from the Lewis Hills massif, Bay of Islands ophioliteMineral compositions of residual and cumulate rocks from the Lewis Hills massif of the Bay of Islands ophiolite complex are reported and interpreted in the context of magnetic processes involved in the geochemical evolution of spatially associated diabase dikes. The mineral compositions reflect greater degrees of partial melting than most abyssal peridotites do and appear to represent the most depleted end of abyssal peridotite compositions. Subsolidus equilibration between Cr-Al spinal and olivine generally has occurred at temperatures of 700 to 900 C. The spinel variations agree with the overall fractionation of basaltic magmas producing spinels with progressively lower Cr numbers. The compositions of clinopyroxenes suggest that the fractionation of two different magma series produced the various cumulate rocks.
Document ID
19880045372
Document Type
Reprint (Version printed in journal)
Authors
Smith, Susan E. (Houston Univ. TX, United States)
Elthon, Don (Houston, University TX, United States)
Date Acquired
August 13, 2013
Publication Date
April 10, 1988
Publication Information
Publication: Journal of Geophysical Research
Volume: 93
ISSN: 0148-0227
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NASW-4066
CONTRACT_GRANT: NSF EAR-80-26445
CONTRACT_GRANT: NSF EAR-83-09535
Distribution Limits
Public
Copyright
Other