Pyrite discs in coal: Evidence for fossilized bacterial colonies

Abstract

Research Article| January 01, 2001 Pyrite discs in coal: Evidence for fossilized bacterial colonies Gordon Southam; Gordon Southam 1Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011-5640, USA Search for other works by this author on: GSW Google Scholar Ravin Donald; Ravin Donald 1Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011-5640, USA Search for other works by this author on: GSW Google Scholar Astrid Röstad; Astrid Röstad 1Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011-5640, USA Search for other works by this author on: GSW Google Scholar Cyndi Brock Cyndi Brock 2U.S. Geological Survey, Water Resources Division, 3215 Marine Street, Boulder, Colorado 80303-1066, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Gordon Southam 1Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011-5640, USA Ravin Donald 1Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011-5640, USA Astrid Röstad 1Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011-5640, USA Cyndi Brock 2U.S. Geological Survey, Water Resources Division, 3215 Marine Street, Boulder, Colorado 80303-1066, USA Publisher: Geological Society of America Received: 08 Jun 2000 Revision Received: 06 Oct 2000 Accepted: 06 Oct 2000 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2001) 29 (1): 47–50. https://doi.org/10.1130/0091-7613(2001)029<0047:PDICEF>2.0.CO;2 Article history Received: 08 Jun 2000 Revision Received: 06 Oct 2000 Accepted: 06 Oct 2000 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Gordon Southam, Ravin Donald, Astrid Röstad, Cyndi Brock; Pyrite discs in coal: Evidence for fossilized bacterial colonies. Geology 2001;; 29 (1): 47–50. doi: https://doi.org/10.1130/0091-7613(2001)029<0047:PDICEF>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Discs of pyrite from 1 to 3 mm in diameter and ∼100 μm thick were observed within fracture planes in coal from the Black Mesa coal deposit in northeastern Arizona. The pyrite discs were composed of aggregates of crystals, which suggested that sulfide mineral diagenesis had initiated at multiple nucleation sites and occurred prior to the compaction forces occurring during coal formation. Stable sulfur isotope analysis of the discs (δ34S = −31.7‰) supports a bacterial origin resulting from dissimilatory sulfate reduction. Fossilized bacteria on the disc surfaces (average = 27/100 μm2) appeared as halos when viewed using reflected light microscopy, but were lenticular by scanning electron microscopy, each microfossil being 2–3 μm in length. A fossilized bacterial colony (pyrite disc), 1 mm in diameter, would contain ∼2.1 × 107 microfossils. These microfossils were not observed on hydrothermal pyrite. Coating and in-filling of sulfate-reducing bacteria with iron disulfide during in vitro sulfide mineral diagenesis provide mechanisms to explain the preservation of the three-dimensional lenticular microfossils observed on the pyrite discs. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.