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Rb-Sr ages of the Archean rocks from the Vermilion district, northeastern MinnesotaThe Vermilion district in Northeastern Minnesota is a classic example of a lower Precambrian greenstone-granite terrane in the Superior Province of the Canadian Shield. The present study presents new Rb-Sr isotopic data for the Ely Greenstone, the Newton Lake Formation, granitic pebbles that occur within the Ely Greenstone, a graywacke composite of the Knife Lake Group, and some Algoman granites whose data are complementary to those of Peterman et al. (1972). The isochron ages obtained are statistically indistinguishable and therefore cannot be used to resolve the timing of specific geologic events. Volcanic extrusion, granitic intrusion, and metamorphism are shown to be less contemporaneous events which probably took place within a time span of less than 50 m.y. A major conclusion is that a granitic basement probably did not underlie the Ely Greenstone.
Document ID
19760032825
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Jahn, B.-M.
(Minnesota Univ. Minneapolis, MN, United States)
Murthy, V. R.
(Minnesota, University Minneapolis, Minn., United States)
Date Acquired
August 8, 2013
Publication Date
December 1, 1975
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 39
Subject Category
Geophysics
Accession Number
76A15791
Funding Number(s)
CONTRACT_GRANT: NSR-09-051-001
CONTRACT_GRANT: NSF GA-14950
Distribution Limits
Public
Copyright
Other

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