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Geochemistry of Precambrian carbonates. IV - Early Paleoproterozoic (2.25 +/- 0.25 Ga) seawaterThe mineralogy, chemistry, and isotopic composition of the Malmani Dolomite, Duck Creek Dolomite, and Bruce 'Limestone' Member of the Espanola Formation are studied in an effort to restrict the first- and second-order variations in isotopic composition of Early Paleoproterozoic seawater. The diagenetic rank is found to increase in the order Duck Creek less than Bruce less than Malmani. The interpolation of alteration trends to 'best' value yields an estimate of 0.70550 for Sr-87/Sr-86. For delta C-13, the measured range of 0 +/- 1.5 percent PDB is similar to that observed for Phanerozoic marine carbonates, while the 'best' delta O-18 value for dolostones is -5 percent PDB, depleted in O-18 relative to Phanerozoic counterparts but comparable to estimates obtained for Archean facies. The isotope geochemistry and mineralogy of Bruce 'Limestone' Member is consistent with the proposition that the sequence was deposited in a lacustrine environment.
Document ID
19920053677
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Veizer, Jan
(Ottawa, University Canada; Bochum, Ruhr-Universitaet, Federal Republic of Germany, United States)
Clayton, R. N.
(NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Hinton, R. W.
(Chicago, University IL, United States)
Date Acquired
August 15, 2013
Publication Date
March 1, 1992
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 56
Issue: 3 Ma
ISSN: 0016-7037
Subject Category
Geophysics
Accession Number
92A36301
Funding Number(s)
CONTRACT_GRANT: NSF EAR-83-13579
CONTRACT_GRANT: NAG9-51
Distribution Limits
Public
Copyright
Other

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