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Evidence for crustal recycling during the Archean: The parental magmas of the stillwater complexThe petrology and geochemistry of the Stillwater Complex, an Archean (2.7 Ga) layered mafic intrusion in the Beartooth Mountains of Montana is discussed. Efforts to reconstruct the compositions of possible parental magmas and thereby place some constraints on the composition and history of their mantle source regions was studied. A high-Mg andesite or boninite magma best matches the crystallization sequences and mineral compositions of Stillwater cumulates, and represents either a primary magma composition or a secondary magma formed, for example, by assimilation of crustal material by a very Mg-rich melt such as komatiite. Isotopic data do not support the extensive amounts of assimilation required by the komatiite parent hypothesis, and it is argued that the Stillwater magma was generated from a mantle source that had been enriched by recycling and homogenization of older crustal material over a large area.
Document ID
19880020842
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Mccallum, I. S.
(Washington Univ. Seattle, WA, United States)
Date Acquired
September 5, 2013
Publication Date
January 1, 1988
Publication Information
Publication: Lunar and Planetary Inst., Workshop on the Growth of Continental Crust
Subject Category
Geophysics
Accession Number
88N30226
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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