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Early Archean Spherule Beds-Confirmation of Impact OriginThe oldest record of major impact events on Earth may be a number of early Archean (3.5 to 3.2 Ga) spherule beds that have been identified in the Barberton Greenstone Belt, South Africa. Several field, petrographic, and geochemical criteria distinguish these beds from typical volcanic and clastic sediments. These criteria include the wide geographic distribution of two beds in a variety of depositional environments, the presence of relict quench textures, absence of juvenile volcaniclastic debris within the beds, and extreme enrichment of Ir and other platinum group elements (PGE) as compared to surrounding sediments. Some researchers, however, argued for a terrestrial origin for spherule bed formation, possibly related to volcanism and gold mineralization.
Document ID
20030063269
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Shukolyukov, A.
(Scripps Institution of Oceanography La Jolla, CA, United States)
Kyte, F. T.
(California Univ. Los Angeles, CA, United States)
Lugmair, G. W.
(Scripps Institution of Oceanography La Jolla, CA, United States)
Lowe, D. R.
(Stanford Univ. Stanford, CA, United States)
Byerly, G. R.
(Louisiana State Univ. Baton Rouge, LA, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2000
Publication Information
Publication: Met. Plan. Science
Volume: 35
Subject Category
Geophysics
Funding Number(s)
CONTRACT_GRANT: NAG5-9441
Distribution Limits
Public
Copyright
Other

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