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Probable microbial origin of Ordovician (Arenig) phosphatic pebble coats (‘ Bolopora ’) from North Wales, U.K.

Published online by Cambridge University Press:  01 May 2009

R.-O. Niedermeyer  and
R. Langbein
R.-O. Niedermeyer
Affiliation:
Department of Geological Sciences, Ernst-Moritz-Arndt-University, Friedrich-Ludwig-Jahn Strasse, 17a, Greifswald 2200, German Democratic Republic
R. Langbein
Affiliation:
Department of Geological Sciences, Ernst-Moritz-Arndt-University, Friedrich-Ludwig-Jahn Strasse, 17a, Greifswald 2200, German Democratic Republic
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Abstract

Results are presented of thin-section, SEM, X-ray and microprobe investigations on problematical phosphatic accretions (‘ Bolopora ’) from the St Tudwal's area of North Wales. The data supplement investigations made by H. J. Hofmann on the genesis of the accretions, and indicate a microbial (bacteriogenic) origin. The bacteriogenic pebble coats are of dahllite. Microbial relics suggest water–sediment interface-linked formation of the coatings under subtidal, and oxic to anoxic, environmental conditions during a sedimentary hiatus.

Type
Articles
Information
Geological Magazine , Volume 126 , Issue 6 , November 1989 , pp. 691 - 698
Copyright
Copyright © Cambridge University Press 1989

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