Enhanced microbial activity in carbon-rich pillow lavas, Ordovician, Great Britain and Ireland

Parnell, J., Boyce, A. J. , Davidheiser-Kroll, B., Brolly, C., Bowden, S. and Lindgren, P. (2015) Enhanced microbial activity in carbon-rich pillow lavas, Ordovician, Great Britain and Ireland. Geology, 43(9), pp. 827-830. (doi: 10.1130/G36937.1)

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There is extensive evidence for the microbial colonization of seafloor basalts in the modern ocean and in the geological record. The sulfur isotope composition of pyrite in the basalts commonly indicates marked isotopic fractionation due to microbial sulfate reduction. Sections through the Nemagraptus gracilis zone (Ordovician) in Great Britain and Ireland are characterized by both widespread pillow lavas and organic-rich seafloor sediment, allowing an exceptional opportunity to assess whether the availability of organic carbon influenced the extent of microbial activity in the basalts in deep geological time. Whole-rock data from basalts at 10 localities show that there is a relationship between sulfur isotopic composition and the carbon content of the basalt. At two localities where organic carbon was entrained in the basalt, isotopic compositions are heavy compared to compositions in carbon-poor basalt, implying that microbial activity exhausted the supply of seawater sulfate. In most basalt, microbial activity was limited by the supply of carbon, but where the basalt incorporated carbon during emplacement on the seafloor, microbial activity became sulfate limited.

Item Type:Articles
Additional Information:NERC supported the project through facility grant IP-1235- 0511. The Raman spectroscopy facility at the University of Aberdeen is funded by the Biotechnology and Biological Sciences Research Council.
Glasgow Author(s) Enlighten ID:Boyce, Professor Adrian and Lindgren, Dr Paula
Authors: Parnell, J., Boyce, A. J., Davidheiser-Kroll, B., Brolly, C., Bowden, S., and Lindgren, P.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Geology
Publisher:Geological Society of America
ISSN (Online):1943-2682
Published Online:28 July 2015
Copyright Holders:Copyright © 2015 Geological Society of America
First Published:First published in Geology 43(9):827-830
Publisher Policy:Reproduced under a Creative Commons License

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