Contrasting microfossil preservation and lake chemistries within the 1200-1000 Ma Torridonian Supergroup of NW Scotland

David Wacey, Martin Brasier, John Parnell, Timothy Culwick, Stephen Bowden, Sam Spinks, Adrian J. Boyce, Brett Davidheiser-Kroll, Heejin Jeon, Martin Saunders, Matt R. Kilburn

Research output: Chapter in Book/Conference paperChapter

4 Citations (Scopus)
454 Downloads (Pure)

Abstract

Oxygenation of the Proterozoic atmosphere caused the progressive build-up of dissolved sulphate on the continents and in marine environments. However, oxygen levels in the Proterozoic were low enough to allow the early burial of biological material into low redox potential environments where permineralization and the authigenic replacement of organic material, including micro-organisms, occurred by a range of minerals. Consequently, microbial sulphate reduction caused the widespread degradation of organic matter and, where iron was available, the precipitation of pyrite. By contrast, where sulphate levels were low, early preservation by other minerals (e. g. phosphate or silica) could be excellent. We show, using two Proterozoic lake sequences with low and high sulphate chemistries, but with otherwise similar characteristics, that microbial sulphate reduction caused a profound loss of morphological detail and diversity within preserved microfossils. The results could imply that there is a significant bias in the Proterozoic fossil record towards low sulphate environments, which were in reality relatively scarce.

Original languageEnglish
Title of host publicationEarth System Evolution and Early Life: A Celebration of the Work of Martin Brasier
EditorsA.T Braisier, D McIlroy, N McLoughlin
Place of PublicationUnited Kingdom
PublisherThe Geological Society Publishing House
Pages105-119
Number of pages15
Volume448
ISBN (Print)9781786202796
DOIs
Publication statusPublished - 2016

Publication series

NameGeological Society Special Publication
PublisherGeological Society of London
ISSN (Print)0305-8719

Cite this