A U-Pb zircon age constraint on the oldest-recorded air-breathing land animal
Identifieur interne : 000018 ( Pmc/Corpus ); précédent : 000017; suivant : 000019A U-Pb zircon age constraint on the oldest-recorded air-breathing land animal
Auteurs : Stephanie E. Suarez ; Michael E. Brookfield ; Elizabeth J. Catlos ; Daniel F. StöckliSource :
- PLoS ONE [ 1932-6203 ] ; 2017.
Abstract
The oldest-known air-breathing land animal is the millipede
Url:
DOI: 10.1371/journal.pone.0179262
PubMed: 28658320
PubMed Central: 5489152
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<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">A U-Pb zircon age constraint on the oldest-recorded air-breathing land animal</title><author><name sortKey="Suarez, Stephanie E" sort="Suarez, Stephanie E" uniqKey="Suarez S" first="Stephanie E." last="Suarez">Stephanie E. Suarez</name><affiliation><nlm:aff id="aff001"><addr-line>Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States of America</addr-line></nlm:aff></affiliation></author><author><name sortKey="Brookfield, Michael E" sort="Brookfield, Michael E" uniqKey="Brookfield M" first="Michael E." last="Brookfield">Michael E. Brookfield</name><affiliation><nlm:aff id="aff002"><addr-line>Environmental, Earth, and Ocean Sciences, University of Massachusetts at Boston, Boston, Massachusetts, United States of America</addr-line></nlm:aff></affiliation></author><author><name sortKey="Catlos, Elizabeth J" sort="Catlos, Elizabeth J" uniqKey="Catlos E" first="Elizabeth J." last="Catlos">Elizabeth J. Catlos</name><affiliation><nlm:aff id="aff001"><addr-line>Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States of America</addr-line></nlm:aff></affiliation></author><author><name sortKey="Stockli, Daniel F" sort="Stockli, Daniel F" uniqKey="Stockli D" first="Daniel F." last="Stöckli">Daniel F. Stöckli</name><affiliation><nlm:aff id="aff001"><addr-line>Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States of America</addr-line></nlm:aff></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">PMC</idno><idno type="pmid">28658320</idno><idno type="pmc">5489152</idno><idno type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5489152</idno><idno type="RBID">PMC:5489152</idno><idno type="doi">10.1371/journal.pone.0179262</idno><date when="2017">2017</date><idno type="wicri:Area/Pmc/Corpus">000018</idno><idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Corpus" wicri:corpus="PMC">000018</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a" type="main">A U-Pb zircon age constraint on the oldest-recorded air-breathing land animal</title><author><name sortKey="Suarez, Stephanie E" sort="Suarez, Stephanie E" uniqKey="Suarez S" first="Stephanie E." last="Suarez">Stephanie E. Suarez</name><affiliation><nlm:aff id="aff001"><addr-line>Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States of America</addr-line></nlm:aff></affiliation></author><author><name sortKey="Brookfield, Michael E" sort="Brookfield, Michael E" uniqKey="Brookfield M" first="Michael E." last="Brookfield">Michael E. Brookfield</name><affiliation><nlm:aff id="aff002"><addr-line>Environmental, Earth, and Ocean Sciences, University of Massachusetts at Boston, Boston, Massachusetts, United States of America</addr-line></nlm:aff></affiliation></author><author><name sortKey="Catlos, Elizabeth J" sort="Catlos, Elizabeth J" uniqKey="Catlos E" first="Elizabeth J." last="Catlos">Elizabeth J. Catlos</name><affiliation><nlm:aff id="aff001"><addr-line>Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States of America</addr-line></nlm:aff></affiliation></author><author><name sortKey="Stockli, Daniel F" sort="Stockli, Daniel F" uniqKey="Stockli D" first="Daniel F." last="Stöckli">Daniel F. Stöckli</name><affiliation><nlm:aff id="aff001"><addr-line>Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States of America</addr-line></nlm:aff></affiliation></author></analytic><series><title level="j">PLoS ONE</title><idno type="eISSN">1932-6203</idno><imprint><date when="2017">2017</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en"><p>The oldest-known air-breathing land animal is the millipede <italic>Pneumodesmus newmani</italic>, found in the Cowie Harbour Fish Bed at Stonehaven, Scotland. Here we report the youngest, most concordant <sup>238</sup>U-<sup>206</sup>Pb zircon age from ash below the fish bed of 413.7±4.4 Ma (±2σ), whereas the youngest age from a tuffaceous sandstone above the fish bed is statistically indistinguishable at 414.3±7.1 Ma. The Cowie Harbour Fish Bed thus appears to be lowermost Devonian (Lochkovian), contrary to the previously accepted mid-Silurian age based on palynomorphs from adjacent exposures. This has implications for the evolutionary timetable of land colonization, as the Cowie ages overlap late Lochkovian zircon ages reported elsewhere for andesite below the nearby (~50 mi) Rhynie Chert, which has more advanced terrestrial biota. The results postdate the possible late Silurian Ludford Lane locality in Shropshire, England. <italic>Pneumodesmus newmani</italic> is thus not the earliest air-breathing land animal, unless the Ludford Lane locality is younger than presently assigned.</p></div></front><back><div1 type="bibliography"><listBibl><biblStruct><analytic><author><name sortKey="Wilson, Hm" uniqKey="Wilson H">HM Wilson</name></author><author><name sortKey="Anderson, Li" uniqKey="Anderson L">LI Anderson</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Selden, P" uniqKey="Selden P">P Selden</name></author><author><name sortKey="Reid, H" uniqKey="Reid H">H Reid</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Marshall, Jea" uniqKey="Marshall J">JEA Marshall</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Wellman, Ch" uniqKey="Wellman C">CH Wellman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Dineley, Dl" uniqKey="Dineley D">DL Dineley</name></author><author><name sortKey="Dineley, Dl" uniqKey="Dineley D">DL Dineley</name></author><author><name sortKey="Metcalfe, Sj" uniqKey="Metcalfe S">SJ Metcalfe</name></author></analytic></biblStruct><biblStruct></biblStruct><biblStruct></biblStruct><biblStruct></biblStruct><biblStruct><analytic><author><name sortKey="Hallermeier, Rj" uniqKey="Hallermeier R">RJ Hallermeier</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Stacey, Js" uniqKey="Stacey J">JS Stacey</name></author><author><name sortKey="Kramers, Jd" uniqKey="Kramers J">JD Kramers</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Jackson, Se" uniqKey="Jackson S">SE Jackson</name></author><author><name sortKey="Pearson, Nj" uniqKey="Pearson N">NJ Pearson</name></author><author><name sortKey="Griffin, Wl" 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Evans</name></author><author><name sortKey="Mcdonald, B" uniqKey="Mcdonald B">B McDonald</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Suzuki, Y" uniqKey="Suzuki Y">Y Suzuki</name></author><author><name sortKey="Nagai, M" uniqKey="Nagai M">M Nagai</name></author><author><name sortKey="Maeno, F" uniqKey="Maeno F">F Maeno</name></author><author><name sortKey="Yasuda, A" uniqKey="Yasuda A">A Yasuda</name></author><author><name sortKey="Hokanishi, N" uniqKey="Hokanishi N">N Hokanishi</name></author><author><name sortKey="Shimano, T" uniqKey="Shimano T">T Shimano</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Guillong, M" uniqKey="Guillong M">M Guillong</name></author><author><name sortKey="Von Quadt, A" uniqKey="Von Quadt A">A von Quadt</name></author><author><name sortKey="Sakata, S" uniqKey="Sakata S">S Sakata</name></author><author><name sortKey="Peytcheva, I" uniqKey="Peytcheva I">I Peytcheva</name></author><author><name sortKey="Bachmann, O" uniqKey="Bachmann O">O Bachmann</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Bowring, Sa" uniqKey="Bowring S">SA Bowring</name></author><author><name sortKey="Schoene, B" uniqKey="Schoene B">B Schoene</name></author><author><name sortKey="Crowley, Jl" uniqKey="Crowley J">JL Crowley</name></author><author><name sortKey="Ramezani, J" uniqKey="Ramezani J">J Ramezani</name></author><author><name sortKey="Condon, Dj" uniqKey="Condon D">DJ Condon</name></author><author><name sortKey="Olszewski, T" uniqKey="Olszewski T">T Olszewski</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Cohen, Km" uniqKey="Cohen K">KM Cohen</name></author><author><name sortKey="Finney, Sc" uniqKey="Finney S">SC Finney</name></author><author><name sortKey="Gibbard, Pl" uniqKey="Gibbard P">PL Gibbard</name></author><author><name sortKey="Fan, J X" uniqKey="Fan J">J-X Fan</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Parry, Sf" uniqKey="Parry S">SF Parry</name></author><author><name sortKey="Noble, Sr" uniqKey="Noble S">SR Noble</name></author><author><name sortKey="Crowley, Qj" uniqKey="Crowley Q">QJ Crowley</name></author><author><name sortKey="Wellman, Ch" uniqKey="Wellman C">CH Wellman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Jeram, Aj" uniqKey="Jeram A">AJ Jeram</name></author><author><name sortKey="Selden, Pa" uniqKey="Selden P">PA Selden</name></author><author><name sortKey="Edwards, D" uniqKey="Edwards D">D Edwards</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Shear, Wa" uniqKey="Shear W">WA Shear</name></author><author><name sortKey="Jeram, Aj" uniqKey="Jeram A">AJ Jeram</name></author><author><name sortKey="Selden, Pa" uniqKey="Selden P">PA Selden</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Lavender, K" uniqKey="Lavender K">K Lavender</name></author><author><name sortKey="Wellman, Ch" uniqKey="Wellman C">CH Wellman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Marshall, Jea" uniqKey="Marshall J">JEA Marshall</name></author><author><name sortKey="Haughton, Pdw" uniqKey="Haughton P">PDW Haughton</name></author><author><name sortKey="Hillier, Sj" uniqKey="Hillier S">SJ Hillier</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Davies, Ns" uniqKey="Davies N">NS Davies</name></author><author><name sortKey="Turner, P" uniqKey="Turner P">P Turner</name></author><author><name sortKey="Sansom, Ij" uniqKey="Sansom I">IJ Sansom</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Smith, Ag" uniqKey="Smith A">AG Smith</name></author><author><name sortKey="Barry, T" uniqKey="Barry T">T Barry</name></author><author><name sortKey="Brown, P" uniqKey="Brown P">P Brown</name></author><author><name sortKey="Cope, J" uniqKey="Cope J">J Cope</name></author><author><name sortKey="Gale, A" uniqKey="Gale A">A Gale</name></author><author><name sortKey="Gibbard, P" uniqKey="Gibbard P">P Gibbard</name></author><author><name sortKey="Smith, Dg" uniqKey="Smith D">DG Smith</name></author><author><name sortKey="Bailey, Rj" uniqKey="Bailey R">RJ Bailey</name></author><author><name sortKey="Burgess, Pm" uniqKey="Burgess P">PM Burgess</name></author><author><name sortKey="Fraser, Aj" uniqKey="Fraser A">AJ Fraser</name></author></analytic></biblStruct></listBibl></div1></back></TEI><pmc article-type="research-article"><pmc-dir>properties open_access</pmc-dir>
<front><journal-meta><journal-id journal-id-type="nlm-ta">PLoS One</journal-id><journal-id journal-id-type="iso-abbrev">PLoS ONE</journal-id><journal-id journal-id-type="publisher-id">plos</journal-id><journal-id journal-id-type="pmc">plosone</journal-id><journal-title-group><journal-title>PLoS ONE</journal-title></journal-title-group><issn pub-type="epub">1932-6203</issn><publisher><publisher-name>Public Library of Science</publisher-name><publisher-loc>San Francisco, CA USA</publisher-loc></publisher></journal-meta><article-meta><article-id pub-id-type="pmid">28658320</article-id><article-id pub-id-type="pmc">5489152</article-id><article-id pub-id-type="doi">10.1371/journal.pone.0179262</article-id><article-id pub-id-type="publisher-id">PONE-D-17-00711</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Geology</subject><subj-group><subject>Geologic Time</subject><subj-group><subject>Paleozoic Era</subject><subj-group><subject>Devonian Period</subject></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Engineering and Technology</subject><subj-group><subject>Equipment</subject><subj-group><subject>Optical Equipment</subject><subj-group><subject>Lasers</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Geology</subject><subj-group><subject>Geologic Time</subject><subj-group><subject>Paleozoic Era</subject><subj-group><subject>Silurian Period</subject></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Physical Sciences</subject><subj-group><subject>Physics</subject><subj-group><subject>Particle Physics</subject><subj-group><subject>Composite Particles</subject><subj-group><subject>Atoms</subject><subj-group><subject>Isotopes</subject></subj-group></subj-group></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Paleontology</subject><subj-group><subject>Fossils</subject><subj-group><subject>Marine Fossils</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Paleontology</subject><subj-group><subject>Fossils</subject><subj-group><subject>Marine Fossils</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Natural Disasters</subject><subj-group><subject>Volcanoes</subject></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Geology</subject><subj-group><subject>Volcanology</subject><subj-group><subject>Volcanoes</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Geology</subject></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Paleontology</subject><subj-group><subject>Palynology</subject><subj-group><subject>Palynomorphs</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Earth Sciences</subject><subj-group><subject>Paleontology</subject><subj-group><subject>Palynology</subject><subj-group><subject>Palynomorphs</subject></subj-group></subj-group></subj-group></subj-group><subj-group subj-group-type="Discipline-v3"><subject>Biology and Life Sciences</subject><subj-group><subject>Plant Science</subject><subj-group><subject>Palynology</subject><subj-group><subject>Palynomorphs</subject></subj-group></subj-group></subj-group></subj-group></article-categories><title-group><article-title>A U-Pb zircon age constraint on the oldest-recorded air-breathing land animal</article-title><alt-title alt-title-type="running-head">Age of the oldest recorded air-breathing land animal</alt-title></title-group><contrib-group><contrib contrib-type="author"><name><surname>Suarez</surname><given-names>Stephanie E.</given-names></name><xref ref-type="aff" rid="aff001"><sup>1</sup></xref></contrib><contrib contrib-type="author"><name><surname>Brookfield</surname><given-names>Michael E.</given-names></name><xref ref-type="aff" rid="aff002"><sup>2</sup></xref></contrib><contrib contrib-type="author"><contrib-id authenticated="true" contrib-id-type="orcid">http://orcid.org/0000-0001-6043-3498</contrib-id><name><surname>Catlos</surname><given-names>Elizabeth J.</given-names></name><xref ref-type="aff" rid="aff001"><sup>1</sup></xref><xref ref-type="corresp" rid="cor001">*</xref></contrib><contrib contrib-type="author"><name><surname>Stöckli</surname><given-names>Daniel F.</given-names></name><xref ref-type="aff" rid="aff001"><sup>1</sup></xref></contrib></contrib-group><aff id="aff001"><label>1</label><addr-line>Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States of America</addr-line></aff><aff id="aff002"><label>2</label><addr-line>Environmental, Earth, and Ocean Sciences, University of Massachusetts at Boston, Boston, Massachusetts, United States of America</addr-line></aff><contrib-group><contrib contrib-type="editor"><name><surname>Wong</surname><given-names>William Oki</given-names></name><role>Editor</role><xref ref-type="aff" rid="edit1"></xref></contrib></contrib-group><aff id="edit1"><addr-line>Institute of Botany, CHINA</addr-line></aff><author-notes><fn fn-type="COI-statement" id="coi001"><p><bold>Competing Interests: </bold>The authors have declared that no competing interests exist.</p></fn><fn fn-type="con"><p><list list-type="simple"><list-item><p><bold>Conceptualization:</bold> SES MEB.</p></list-item><list-item><p><bold>Data curation:</bold> EJC DFS.</p></list-item><list-item><p><bold>Formal analysis:</bold> SES DFS.</p></list-item><list-item><p><bold>Funding acquisition:</bold> SES MEB EJC.</p></list-item><list-item><p><bold>Investigation:</bold> SES MEB.</p></list-item><list-item><p><bold>Methodology:</bold> SES MEB DFS.</p></list-item><list-item><p><bold>Project administration:</bold> SES EJC MEB.</p></list-item><list-item><p><bold>Resources:</bold> MEB DFS.</p></list-item><list-item><p><bold>Software:</bold> DFS.</p></list-item><list-item><p><bold>Supervision:</bold> EJC.</p></list-item><list-item><p><bold>Validation:</bold> EJC MEB SES.</p></list-item><list-item><p><bold>Visualization:</bold> MEB EJC.</p></list-item><list-item><p><bold>Writing – original draft:</bold> MEB EJC SES.</p></list-item><list-item><p><bold>Writing – review & editing:</bold> MEB EJC SES.</p></list-item></list></p></fn><corresp id="cor001">* E-mail: <email>ejcatlos@jsg.utexas.edu</email></corresp></author-notes><pub-date pub-type="epub"><day>28</day><month>6</month><year>2017</year></pub-date><pub-date pub-type="collection"><year>2017</year></pub-date><volume>12</volume><issue>6</issue><elocation-id>e0179262</elocation-id><history><date date-type="received"><day>6</day><month>1</month><year>2017</year></date><date date-type="accepted"><day>27</day><month>5</month><year>2017</year></date></history><permissions><copyright-statement>© 2017 Suarez et al</copyright-statement><copyright-year>2017</copyright-year><copyright-holder>Suarez et al</copyright-holder><license xlink:href="http://creativecommons.org/licenses/by/4.0/"><license-p>This is an open access article distributed under the terms of the <ext-link ext-link-type="uri" xlink:href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution License</ext-link>, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</license-p></license></permissions><self-uri content-type="pdf" xlink:href="pone.0179262.pdf"></self-uri><abstract><p>The oldest-known air-breathing land animal is the millipede <italic>Pneumodesmus newmani</italic>, found in the Cowie Harbour Fish Bed at Stonehaven, Scotland. Here we report the youngest, most concordant <sup>238</sup>U-<sup>206</sup>Pb zircon age from ash below the fish bed of 413.7±4.4 Ma (±2σ), whereas the youngest age from a tuffaceous sandstone above the fish bed is statistically indistinguishable at 414.3±7.1 Ma. The Cowie Harbour Fish Bed thus appears to be lowermost Devonian (Lochkovian), contrary to the previously accepted mid-Silurian age based on palynomorphs from adjacent exposures. This has implications for the evolutionary timetable of land colonization, as the Cowie ages overlap late Lochkovian zircon ages reported elsewhere for andesite below the nearby (~50 mi) Rhynie Chert, which has more advanced terrestrial biota. The results postdate the possible late Silurian Ludford Lane locality in Shropshire, England. <italic>Pneumodesmus newmani</italic> is thus not the earliest air-breathing land animal, unless the Ludford Lane locality is younger than presently assigned.</p></abstract><funding-group><award-group id="award001"><funding-source><institution>Geological Society of America South Central Section</institution></funding-source><principal-award-recipient><name><surname>Suarez</surname><given-names>Stephanie E.</given-names></name></principal-award-recipient></award-group><funding-statement>Funding was provided to Stephanie Suarez from the Geological Society of America South Central Section. This was an undergraduate research award. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.</funding-statement></funding-group><counts><fig-count count="4"></fig-count><table-count count="2"></table-count><page-count count="10"></page-count></counts><custom-meta-group><custom-meta id="data-availability"><meta-name>Data Availability</meta-name><meta-value>All relevant data are within the paper and its Supporting Information files.</meta-value></custom-meta></custom-meta-group></article-meta><notes><title>Data Availability</title><p>All relevant data are within the paper and its Supporting Information files.</p></notes></front><body><sec sec-type="intro" id="sec001"><title>Introduction</title><p>Evaluating the rate and character of land colonization requires precise dating of early land biotas—but this is often difficult because of the problem of correlating and dating non-marine deposits. The supposed oldest air-breathing land animal found to date, the millipede <italic>Pneumodesmus newmani</italic>, is from the Cowie Harbour Fish Bed at Cowie, Aberdeenshire, Scotland [<xref rid="pone.0179262.ref001" ref-type="bibr">1</xref>, <xref rid="pone.0179262.ref002" ref-type="bibr">2</xref>] (<xref ref-type="fig" rid="pone.0179262.g001">Fig 1</xref>). It is currently assigned a late Wenlock to early Ludlow age (mid-Silurian, ~427 Ma) based on plant spores from supposedly correlative, but tectonically isolated, and undescribed small exposures of sediment at Carron wood and Carron water inland (<xref ref-type="fig" rid="pone.0179262.g001">Fig 1</xref>) [<xref rid="pone.0179262.ref001" ref-type="bibr">1</xref>, <xref rid="pone.0179262.ref003" ref-type="bibr">3</xref>, <xref rid="pone.0179262.ref004" ref-type="bibr">4</xref>]. Fish and arthropod fossils from the Cowie Harbour Fish Bed itself suggest a Pridoli (latest Silurian) age of 423–419 Ma [<xref rid="pone.0179262.ref005" ref-type="bibr">5</xref>]. No spores are recorded from the Cowie Harbour Fish Bed, which is unexpected if correlative with the inland exposures due to its close proximity.</p><fig id="pone.0179262.g001" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0179262.g001</object-id><label>Fig 1</label><caption><title>Location map of samples at Cowie Harbor, Scotland.</title><p>The top left onset shows the location of Stonehaven. The bottom right highlights the relationship of inland exposures to Cowie and location of large map after [<xref rid="pone.0179262.ref005" ref-type="bibr">5</xref>]. Fig 1 is based on [<xref rid="pone.0179262.ref005" ref-type="bibr">5</xref>], which is included as <xref ref-type="supplementary-material" rid="pone.0179262.s002">S1 Fig</xref>.</p></caption><graphic xlink:href="pone.0179262.g001"></graphic></fig><p>No radiometric dates exist from the succession, thus we applied U-Pb Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to zircon grains extracted from adjacent beds above and below the Cowie Harbour Fish Bed (<xref ref-type="fig" rid="pone.0179262.g002">Fig 2</xref>). Zircon ages from these units have important implications for the development and rate of evolution of early land communities. The results suggest rapid evolution of integrated invertebrate-plant land communities in the earliest Devonian.</p><fig id="pone.0179262.g002" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0179262.g002</object-id><label>Fig 2</label><caption><title>Stratigraphic section at Cowie and location of samples (16COW1, 16COW2, and 16COW3, indicated by 1, 2, and 3 respectively) based on information in [<xref rid="pone.0179262.ref005" ref-type="bibr">5</xref>] and [<xref rid="pone.0179262.ref006" ref-type="bibr">6</xref>].</title><p>Descriptions of the rock assemblages are included.</p></caption><graphic xlink:href="pone.0179262.g002"></graphic></fig></sec><sec id="sec002"><title>Setting and methods</title><p>The Cowie Harbour Fish Bed occurs in the tectonically isolated, but unmetamorphosed, non-marine succession of the Cowie Sandstone Formation, the older of two formations within the Stonehaven Group (Figs <xref ref-type="fig" rid="pone.0179262.g001">1</xref> and <xref ref-type="fig" rid="pone.0179262.g002">2</xref>). The Cowie Sandstone Formation is composed of six members [<xref rid="pone.0179262.ref006" ref-type="bibr">6</xref>] and the youngest, the Cowie Harbour Siltstone, contains the Cowie Harbour Fish Bed at its base. The Stonehaven Group is characterized by alternating grey sandstones and mudstones interpreted as a river and floodplain complex [<xref rid="pone.0179262.ref003" ref-type="bibr">3</xref>, <xref rid="pone.0179262.ref005" ref-type="bibr">5</xref>]. We collected three hand-sized samples for zircon U-Pb geochronology using LA-ICP-MS. Note that no specific permissions are required for sampling the rocks at the Cowie site. We followed the Scottish Outdoor Access Code published by Scottish Natural Heritage [<xref rid="pone.0179262.ref007" ref-type="bibr">7</xref>], and responsible collecting of material from the area is permitted. This is also stated specifically in [<xref rid="pone.0179262.ref008" ref-type="bibr">8</xref>]. The field studies did not involve endangered or protected species.</p><p>Sample 16COW1 is from a fine-grained green tuff at the top of the Cowie Harbour Conglomerate member, whereas sample 16COW2 is from a coarse bed within the Red Sandstone member directly below the fish bed. Sample 16COW3 is from a fine-grained tuffaceous sandstone located within the Cowie Harbour Siltstone member 20m above the fish bed. Using standard heavy-mineral separation methods, sample 16COW2 surprisingly contained no zircons, but the others supplied >100 grains that are typically 50–100μm in length (<xref ref-type="fig" rid="pone.0179262.g003">Fig 3</xref>). One explanation for the absence of zircon in 16COW2 is that small, fine sand-sized zircons remained in suspension in the higher energy environment indicated by the coarse grain-size of the red sandstone [<xref rid="pone.0179262.ref009" ref-type="bibr">9</xref>]. The zircon absence in 16COW2 and the abundant small grain sizes seen in 16COW1 and 16COW3, also suggest that only fine-grained zircons may have been available for transport, and thus Cowie may have been a long distance from the eruption source.</p><fig id="pone.0179262.g003" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0179262.g003</object-id><label>Fig 3</label><caption><title>Secondary electron images of selected zircons from samples (A) 16COW1 and (B) 16COW3.</title><p>Grain number and ages are indicated.</p></caption><graphic xlink:href="pone.0179262.g003"></graphic></fig><p>Forty zircon grains each from sample 16COW1 and 16COW3 were selected and dated using an Element2 High Resolution (HR)-ICP-MS with an Excimer (192 nm) laser ablation system instrumentation in the Geo-Thermochronometry lab at the University of Texas at Austin. Each zircon was mounted on double-sided tape, and was examined optically during the mounting process to select euhedral grains and eliminate analysis of cracked or metamict zircons (<xref ref-type="fig" rid="pone.0179262.g003">Fig 3</xref>). In this dating method, an ablated dry aerosol is introduced into the High Resolution ICP-MS using ultra-high purity He carrier gas for <sup>238</sup>U, <sup>235</sup>U, <sup>232</sup>Th and <sup>206</sup>Pb-<sup>208</sup>Pb isotopic measurements using ion-counting. Each analysis consisted of a 2-pulse cleaning ablation, a background measurement taken with the laser off, a 30 sec measurement with the laser firing, and a 30 sec cleaning cycle. The laser beam was 30μm diameter. Common Pb was corrected using the measured <sup>204</sup>Pb (Hg-corrected) and assuming initial composition reported by [<xref rid="pone.0179262.ref010" ref-type="bibr">10</xref>]. Elemental and isotopic fractionation of Pb/U and Pb isotopes, respectively, is corrected by interspersed analysis of primary and secondary zircon standards with a known age (GJ1 and Plesovice) [<xref rid="pone.0179262.ref011" ref-type="bibr">11</xref>, <xref rid="pone.0179262.ref012" ref-type="bibr">12</xref>]. The common unknown to standard measurement ratio was generally 3:1 or 4:1. Uncertainty resulting from calibration correction is 1–2% for both <sup>206</sup>Pb/<sup>207</sup>Pb and <sup>206</sup>Pb/<sup>238</sup>U. We attempted to date the youngest grains in each sample a second time, but the results were discordant. The youngest grains in <xref ref-type="fig" rid="pone.0179262.g003">Fig 3</xref> have two laser ablation spots.</p><p>Data is summarized in Tables <xref ref-type="table" rid="pone.0179262.t001">1</xref> and <xref ref-type="table" rid="pone.0179262.t002">2</xref>, with details provided in <xref ref-type="supplementary-material" rid="pone.0179262.s001">S1 Table</xref>. We report the <sup>238</sup>U-<sup>206</sup>Pb age if the zircon was less than 850 Ma, and the <sup>207</sup>Pb-<sup>206</sup>Pb age if the grain was older than 850 Ma. Ages were filtered for concordance, and <sup>238</sup>U-<sup>206</sup>Pb ages that are >10% discordant are not reported (N = 9 out of 83 total). In addition to the age data, U (ppm) and U/Th for each analysis were obtained. Note that the whole zircon grains, as opposed to exposed zircon cross sections, were analyzed due to their small size. The time-resolved laser ablation technique allows us to evaluate data that is obtained as the laser drills continuously into the grain, thus identifying zones of different age and limiting the possibility of mixed ages. This process allows us to distinguish between zircon cores and rims, as different age populations as easily identified. All ages are reported with ±2σ uncertainty.</p><table-wrap id="pone.0179262.t001" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0179262.t001</object-id><label>Table 1</label><caption><title>LA-ICP-MS results from zircons dated in upper bed sample 16COW3.</title></caption><alternatives><graphic id="pone.0179262.t001g" xlink:href="pone.0179262.t001"></graphic><table frame="hsides" rules="groups"><colgroup span="1"><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col></colgroup><thead><tr><th align="left" rowspan="1" colspan="1">Grain #(-Rim or core)<xref ref-type="table-fn" rid="t001fn001"><sup>a</sup></xref></th><th align="left" rowspan="1" colspan="1">U (ppm)</th><th align="left" rowspan="1" colspan="1">U/Th</th><th align="left" rowspan="1" colspan="1">Age (Ma)<xref ref-type="table-fn" rid="t001fn002"><sup>b</sup></xref></th><th align="left" rowspan="1" colspan="1">±2σ</th><th align="left" rowspan="1" colspan="1">% Discordance<xref ref-type="table-fn" rid="t001fn003"><sup>c</sup></xref></th></tr></thead><tbody><tr><td align="center" colspan="6" rowspan="1">Devonian zircon ages</td></tr><tr><td align="left" rowspan="1" colspan="1">4</td><td align="right" rowspan="1" colspan="1">190</td><td align="right" rowspan="1" colspan="1">0.9</td><td align="right" rowspan="1" colspan="1">414.3</td><td align="right" rowspan="1" colspan="1">7</td><td align="char" char="." rowspan="1" colspan="1">0.65</td></tr><tr><td align="left" rowspan="1" colspan="1">9-Rim</td><td align="right" rowspan="1" colspan="1">241.7</td><td align="right" rowspan="1" colspan="1">1.27</td><td align="right" rowspan="1" colspan="1">415.0</td><td align="right" rowspan="1" colspan="1">12</td><td align="char" char="." rowspan="1" colspan="1">0.97</td></tr><tr><td align="left" rowspan="1" colspan="1">26</td><td align="right" rowspan="1" colspan="1">275</td><td align="right" rowspan="1" colspan="1">0.82</td><td align="right" rowspan="1" colspan="1">418.7</td><td align="right" rowspan="1" colspan="1">4.4</td><td align="char" char="." rowspan="1" colspan="1">1.48</td></tr><tr><td align="center" colspan="6" rowspan="1">Older zircon ages</td></tr><tr><td align="left" rowspan="1" colspan="1">3</td><td align="right" rowspan="1" colspan="1">287</td><td align="right" rowspan="1" colspan="1">1.19</td><td align="right" rowspan="1" colspan="1">426.0</td><td align="right" rowspan="1" colspan="1">10</td><td align="char" char="." rowspan="1" colspan="1">2.52</td></tr><tr><td align="left" rowspan="1" colspan="1">37</td><td align="right" rowspan="1" colspan="1">118.6</td><td align="right" rowspan="1" colspan="1">1.12</td><td align="right" rowspan="1" colspan="1">447.7</td><td align="right" rowspan="1" colspan="1">7.8</td><td align="char" char="." rowspan="1" colspan="1">0.61</td></tr><tr><td align="left" rowspan="1" colspan="1">23</td><td align="right" rowspan="1" colspan="1">525</td><td align="right" rowspan="1" colspan="1">1.5</td><td align="right" rowspan="1" colspan="1">454.0</td><td align="right" rowspan="1" colspan="1">13</td><td align="char" char="." rowspan="1" colspan="1">2.78</td></tr><tr><td align="left" rowspan="1" colspan="1">22</td><td align="right" rowspan="1" colspan="1">351</td><td align="right" rowspan="1" colspan="1">1</td><td align="right" rowspan="1" colspan="1">457.6</td><td align="right" rowspan="1" colspan="1">9.7</td><td align="char" char="." rowspan="1" colspan="1">1.17</td></tr><tr><td align="left" rowspan="1" colspan="1">17</td><td align="right" rowspan="1" colspan="1">243</td><td align="right" rowspan="1" colspan="1">1.21</td><td align="right" rowspan="1" colspan="1">470.5</td><td align="right" rowspan="1" colspan="1">4.6</td><td align="char" char="." rowspan="1" colspan="1">3.13</td></tr><tr><td align="left" rowspan="1" colspan="1">9-Core</td><td align="right" rowspan="1" colspan="1">172.1</td><td align="right" rowspan="1" colspan="1">1.85</td><td align="right" rowspan="1" colspan="1">651</td><td align="right" rowspan="1" colspan="1">18</td><td align="char" char="." rowspan="1" colspan="1">7.26</td></tr><tr><td align="left" rowspan="1" colspan="1">11</td><td align="right" rowspan="1" colspan="1">83.3</td><td align="right" rowspan="1" colspan="1">1.13</td><td align="right" rowspan="1" colspan="1">940</td><td align="right" rowspan="1" colspan="1">76</td><td align="char" char="." rowspan="1" colspan="1">0.53</td></tr><tr><td align="left" rowspan="1" colspan="1">19</td><td align="right" rowspan="1" colspan="1">123</td><td align="right" rowspan="1" colspan="1">1.62</td><td align="right" rowspan="1" colspan="1">1027</td><td align="right" rowspan="1" colspan="1">68</td><td align="char" char="." rowspan="1" colspan="1">4.77</td></tr><tr><td align="left" rowspan="1" colspan="1">10</td><td align="right" rowspan="1" colspan="1">265</td><td align="right" rowspan="1" colspan="1">2.5</td><td align="right" rowspan="1" colspan="1">1041</td><td align="right" rowspan="1" colspan="1">32</td><td align="char" char="." rowspan="1" colspan="1">1.06</td></tr><tr><td align="left" rowspan="1" colspan="1">18</td><td align="right" rowspan="1" colspan="1">298</td><td align="right" rowspan="1" colspan="1">1.99</td><td align="right" rowspan="1" colspan="1">1080</td><td align="right" rowspan="1" colspan="1">30</td><td align="char" char="." rowspan="1" colspan="1">1.81</td></tr><tr><td align="left" rowspan="1" colspan="1">31</td><td align="right" rowspan="1" colspan="1">816</td><td align="right" rowspan="1" colspan="1">2.2</td><td align="right" rowspan="1" colspan="1">1106</td><td align="right" rowspan="1" colspan="1">30</td><td align="char" char="." rowspan="1" colspan="1">1.36</td></tr><tr><td align="left" rowspan="1" colspan="1">7</td><td align="right" rowspan="1" colspan="1">377</td><td align="right" rowspan="1" colspan="1">1.8</td><td align="right" rowspan="1" colspan="1">1108</td><td align="right" rowspan="1" colspan="1">25</td><td align="char" char="." rowspan="1" colspan="1">2.71</td></tr><tr><td align="left" rowspan="1" colspan="1">34</td><td align="right" rowspan="1" colspan="1">143.8</td><td align="right" rowspan="1" colspan="1">1.15</td><td align="right" rowspan="1" colspan="1">1125</td><td align="right" rowspan="1" colspan="1">41</td><td align="char" char="." rowspan="1" colspan="1">3.64</td></tr><tr><td align="left" rowspan="1" colspan="1">28</td><td align="right" rowspan="1" colspan="1">580</td><td align="right" rowspan="1" colspan="1">7.71</td><td align="right" rowspan="1" colspan="1">1132</td><td align="right" rowspan="1" colspan="1">50</td><td align="char" char="." rowspan="1" colspan="1">2.74</td></tr><tr><td align="left" rowspan="1" colspan="1">1</td><td align="right" rowspan="1" colspan="1">227.2</td><td align="right" rowspan="1" colspan="1">1.33</td><td align="right" rowspan="1" colspan="1">1156</td><td align="right" rowspan="1" colspan="1">47</td><td align="char" char="." rowspan="1" colspan="1">2.94</td></tr><tr><td align="left" rowspan="1" colspan="1">2</td><td align="right" rowspan="1" colspan="1">200</td><td align="right" rowspan="1" colspan="1">2.31</td><td align="right" rowspan="1" colspan="1">1176</td><td align="right" rowspan="1" colspan="1">49</td><td align="char" char="." rowspan="1" colspan="1">1.45</td></tr><tr><td align="left" rowspan="1" colspan="1">38</td><td align="right" rowspan="1" colspan="1">313</td><td align="right" rowspan="1" colspan="1">2.72</td><td align="right" rowspan="1" colspan="1">1298</td><td align="right" rowspan="1" colspan="1">35</td><td align="char" char="." rowspan="1" colspan="1">22.34</td></tr><tr><td align="left" rowspan="1" colspan="1">8</td><td align="right" rowspan="1" colspan="1">116</td><td align="right" rowspan="1" colspan="1">0.67</td><td align="right" rowspan="1" colspan="1">1331</td><td align="right" rowspan="1" colspan="1">51</td><td align="char" char="." rowspan="1" colspan="1">19.16</td></tr><tr><td align="left" rowspan="1" colspan="1">5</td><td align="right" rowspan="1" colspan="1">74.9</td><td align="right" rowspan="1" colspan="1">1</td><td align="right" rowspan="1" colspan="1">1345</td><td align="right" rowspan="1" colspan="1">51</td><td align="char" char="." rowspan="1" colspan="1">1.49</td></tr><tr><td align="left" rowspan="1" colspan="1">14</td><td align="right" rowspan="1" colspan="1">320</td><td align="right" rowspan="1" colspan="1">2.43</td><td align="right" rowspan="1" colspan="1">1363</td><td align="right" rowspan="1" colspan="1">30</td><td align="char" char="." rowspan="1" colspan="1">4.99</td></tr><tr><td align="left" rowspan="1" colspan="1">16</td><td align="right" rowspan="1" colspan="1">278</td><td align="right" rowspan="1" colspan="1">1.2</td><td align="right" rowspan="1" colspan="1">1385</td><td align="right" rowspan="1" colspan="1">24</td><td align="char" char="." rowspan="1" colspan="1">0.07</td></tr><tr><td align="left" rowspan="1" colspan="1">33</td><td align="right" rowspan="1" colspan="1">153.9</td><td align="right" rowspan="1" colspan="1">2.09</td><td align="right" rowspan="1" colspan="1">1454</td><td align="right" rowspan="1" colspan="1">40</td><td align="char" char="." rowspan="1" colspan="1">0.41</td></tr><tr><td align="left" rowspan="1" colspan="1">35</td><td align="right" rowspan="1" colspan="1">336</td><td align="right" rowspan="1" colspan="1">3.05</td><td align="right" rowspan="1" colspan="1">1509</td><td align="right" rowspan="1" colspan="1">27</td><td align="char" char="." rowspan="1" colspan="1">1.59</td></tr><tr><td align="left" rowspan="1" colspan="1">20</td><td align="right" rowspan="1" colspan="1">369</td><td align="right" rowspan="1" colspan="1">2.29</td><td align="right" rowspan="1" colspan="1">1518</td><td align="right" rowspan="1" colspan="1">34</td><td align="char" char="." rowspan="1" colspan="1">10.67</td></tr><tr><td align="left" rowspan="1" colspan="1">29</td><td align="right" rowspan="1" colspan="1">258</td><td align="right" rowspan="1" colspan="1">2.18</td><td align="right" rowspan="1" colspan="1">1545</td><td align="right" rowspan="1" colspan="1">41</td><td align="char" char="." rowspan="1" colspan="1">1.94</td></tr><tr><td align="left" rowspan="1" colspan="1">24</td><td align="right" rowspan="1" colspan="1">399</td><td align="right" rowspan="1" colspan="1">2.64</td><td align="right" rowspan="1" colspan="1">1549</td><td align="right" rowspan="1" colspan="1">26</td><td align="char" char="." rowspan="1" colspan="1">5.81</td></tr><tr><td align="left" rowspan="1" colspan="1">39</td><td align="right" rowspan="1" colspan="1">190.6</td><td align="right" rowspan="1" colspan="1">0.51</td><td align="right" rowspan="1" colspan="1">1605</td><td align="right" rowspan="1" colspan="1">23</td><td align="char" char="." rowspan="1" colspan="1">2.49</td></tr><tr><td align="left" rowspan="1" colspan="1">13</td><td align="right" rowspan="1" colspan="1">161</td><td align="right" rowspan="1" colspan="1">1.11</td><td align="right" rowspan="1" colspan="1">1609</td><td align="right" rowspan="1" colspan="1">32</td><td align="char" char="." rowspan="1" colspan="1">7.27</td></tr><tr><td align="left" rowspan="1" colspan="1">15</td><td align="right" rowspan="1" colspan="1">527</td><td align="right" rowspan="1" colspan="1">5.18</td><td align="right" rowspan="1" colspan="1">1620</td><td align="right" rowspan="1" colspan="1">33</td><td align="char" char="." rowspan="1" colspan="1">14.01</td></tr><tr><td align="left" rowspan="1" colspan="1">32</td><td align="right" rowspan="1" colspan="1">204</td><td align="right" rowspan="1" colspan="1">1.29</td><td align="right" rowspan="1" colspan="1">1654</td><td align="right" rowspan="1" colspan="1">23</td><td align="char" char="." rowspan="1" colspan="1">0.36</td></tr><tr><td align="left" rowspan="1" colspan="1">12</td><td align="right" rowspan="1" colspan="1">227.4</td><td align="right" rowspan="1" colspan="1">1.63</td><td align="right" rowspan="1" colspan="1">1657</td><td align="right" rowspan="1" colspan="1">21</td><td align="char" char="." rowspan="1" colspan="1">1.27</td></tr><tr><td align="left" rowspan="1" colspan="1">27</td><td align="right" rowspan="1" colspan="1">85.1</td><td align="right" rowspan="1" colspan="1">2.33</td><td align="right" rowspan="1" colspan="1">1684</td><td align="right" rowspan="1" colspan="1">50</td><td align="char" char="." rowspan="1" colspan="1">2.02</td></tr><tr><td align="left" rowspan="1" colspan="1">40</td><td align="right" rowspan="1" colspan="1">203.9</td><td align="right" rowspan="1" colspan="1">1.15</td><td align="right" rowspan="1" colspan="1">1688</td><td align="right" rowspan="1" colspan="1">27</td><td align="char" char="." rowspan="1" colspan="1">4.32</td></tr></tbody></table></alternatives><table-wrap-foot><fn id="t001fn001"><p><sup>a.</sup> Number is the zircon grain that was dated, “-core” or “-rim” indicates that an age gradient is found through depth profiling.</p></fn><fn id="t001fn002"><p><sup>b.</sup> We report the <sup>238</sup>U-<sup>206</sup>Pb age if the zircon is <850 Ma, and the <sup>207</sup>Pb-<sup>206</sup>Pb age if the grain is >850 Ma.</p></fn><fn id="t001fn003"><p><sup>c.</sup> Reports the percent discordance, and is the <sup>206</sup>Pb/<sup>238</sup>U discordance if the age is younger than 850 Ma and is the <sup>207</sup>Pb/<sup>206</sup>Pb discordance age if grain is older than 850Ma</p></fn></table-wrap-foot></table-wrap><table-wrap id="pone.0179262.t002" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0179262.t002</object-id><label>Table 2</label><caption><title>LA-ICP-MS results from zircons dated in lower bed sample 16COW1.</title></caption><alternatives><graphic id="pone.0179262.t002g" xlink:href="pone.0179262.t002"></graphic><table frame="hsides" rules="groups"><colgroup span="1"><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col><col align="left" valign="middle" span="1"></col></colgroup><thead><tr><th align="left" rowspan="1" colspan="1">Grain #</th><th align="left" rowspan="1" colspan="1">U (ppm)</th><th align="left" rowspan="1" colspan="1">U/Th</th><th align="left" rowspan="1" colspan="1">Age (Ma)<xref ref-type="table-fn" rid="t002fn001"><sup>a</sup></xref></th><th align="left" rowspan="1" colspan="1">±2σ</th><th align="left" rowspan="1" colspan="1">% Discordance</th></tr></thead><tbody><tr><td align="center" colspan="6" rowspan="1">Devonian zircon ages</td></tr><tr><td align="left" rowspan="1" colspan="1">34</td><td align="right" rowspan="1" colspan="1">570</td><td align="char" char="." rowspan="1" colspan="1">2.96</td><td align="right" rowspan="1" colspan="1">410.4</td><td align="right" rowspan="1" colspan="1">7.2</td><td align="right" rowspan="1" colspan="1">3.37</td></tr><tr><td align="left" rowspan="1" colspan="1">6</td><td align="right" rowspan="1" colspan="1">596</td><td align="char" char="." rowspan="1" colspan="1">2.8</td><td align="right" rowspan="1" colspan="1">413.7</td><td align="right" rowspan="1" colspan="1">4.4</td><td align="right" rowspan="1" colspan="1">0.72</td></tr><tr><td align="left" rowspan="1" colspan="1">1</td><td align="right" rowspan="1" colspan="1">628</td><td align="char" char="." rowspan="1" colspan="1">2.54</td><td align="right" rowspan="1" colspan="1">413.8</td><td align="right" rowspan="1" colspan="1">6.3</td><td align="right" rowspan="1" colspan="1">5.11</td></tr><tr><td align="left" rowspan="1" colspan="1">12</td><td align="right" rowspan="1" colspan="1">713</td><td align="char" char="." rowspan="1" colspan="1">2.5</td><td align="right" rowspan="1" colspan="1">414.0</td><td align="right" rowspan="1" colspan="1">13</td><td align="right" rowspan="1" colspan="1">1.9</td></tr><tr><td align="left" rowspan="1" colspan="1">14</td><td align="right" rowspan="1" colspan="1">934</td><td align="char" char="." rowspan="1" colspan="1">2.65</td><td align="right" rowspan="1" colspan="1">414.0</td><td align="right" rowspan="1" colspan="1">12</td><td align="right" rowspan="1" colspan="1">3.72</td></tr><tr><td align="left" rowspan="1" colspan="1">27</td><td align="right" rowspan="1" colspan="1">411</td><td align="char" char="." rowspan="1" colspan="1">2.67</td><td align="right" rowspan="1" colspan="1">415.0</td><td align="right" rowspan="1" colspan="1">9.2</td><td align="right" rowspan="1" colspan="1">2.58</td></tr><tr><td align="left" rowspan="1" colspan="1">19</td><td align="right" rowspan="1" colspan="1">468</td><td align="char" char="." rowspan="1" colspan="1">1.36</td><td align="right" rowspan="1" colspan="1">418.8</td><td align="right" rowspan="1" colspan="1">4.6</td><td align="right" rowspan="1" colspan="1">0.88</td></tr><tr><td align="center" colspan="6" rowspan="1">Older zircon ages</td></tr><tr><td align="left" rowspan="1" colspan="1">2</td><td align="right" rowspan="1" colspan="1">513</td><td align="char" char="." rowspan="1" colspan="1">2.7</td><td align="right" rowspan="1" colspan="1">420.0</td><td align="right" rowspan="1" colspan="1">15</td><td align="right" rowspan="1" colspan="1">0.47</td></tr><tr><td align="left" rowspan="1" colspan="1">8</td><td align="right" rowspan="1" colspan="1">137</td><td align="char" char="." rowspan="1" colspan="1">1.81</td><td align="right" rowspan="1" colspan="1">422.9</td><td align="right" rowspan="1" colspan="1">6.7</td><td align="right" rowspan="1" colspan="1">0.73</td></tr><tr><td align="left" rowspan="1" colspan="1">15</td><td align="right" rowspan="1" colspan="1">651</td><td align="char" char="." rowspan="1" colspan="1">2.14</td><td align="right" rowspan="1" colspan="1">425.2</td><td align="right" rowspan="1" colspan="1">5.4</td><td align="right" rowspan="1" colspan="1">0.86</td></tr><tr><td align="left" rowspan="1" colspan="1">11</td><td align="right" rowspan="1" colspan="1">682</td><td align="char" char="." rowspan="1" colspan="1">1.14</td><td align="right" rowspan="1" colspan="1">426.0</td><td align="right" rowspan="1" colspan="1">5.5</td><td align="right" rowspan="1" colspan="1">0.88</td></tr><tr><td align="left" rowspan="1" colspan="1">30</td><td align="right" rowspan="1" colspan="1">594</td><td align="char" char="." rowspan="1" colspan="1">2.42</td><td align="right" rowspan="1" colspan="1">427.2</td><td align="right" rowspan="1" colspan="1">7.8</td><td align="right" rowspan="1" colspan="1">5.13</td></tr><tr><td align="left" rowspan="1" colspan="1">3</td><td align="right" rowspan="1" colspan="1">596</td><td align="char" char="." rowspan="1" colspan="1">2.57</td><td align="right" rowspan="1" colspan="1">428.1</td><td align="right" rowspan="1" colspan="1">5.8</td><td align="right" rowspan="1" colspan="1">0.83</td></tr><tr><td align="left" rowspan="1" colspan="1">17</td><td align="right" rowspan="1" colspan="1">429.8</td><td align="char" char="." rowspan="1" colspan="1">2.32</td><td align="right" rowspan="1" colspan="1">428.7</td><td align="right" rowspan="1" colspan="1">4.9</td><td align="right" rowspan="1" colspan="1">0.42</td></tr><tr><td align="left" rowspan="1" colspan="1">7</td><td align="right" rowspan="1" colspan="1">443</td><td align="char" char="." rowspan="1" colspan="1">2.44</td><td align="right" rowspan="1" colspan="1">437.5</td><td align="right" rowspan="1" colspan="1">5.4</td><td align="right" rowspan="1" colspan="1">5.32</td></tr><tr><td align="left" rowspan="1" colspan="1">28</td><td align="right" rowspan="1" colspan="1">379</td><td align="char" char="." rowspan="1" colspan="1">2.29</td><td align="right" rowspan="1" colspan="1">439.0</td><td align="right" rowspan="1" colspan="1">12</td><td align="right" rowspan="1" colspan="1">0.45</td></tr><tr><td align="left" rowspan="1" colspan="1">10</td><td align="right" rowspan="1" colspan="1">188.7</td><td align="char" char="." rowspan="1" colspan="1">1.49</td><td align="right" rowspan="1" colspan="1">442.0</td><td align="right" rowspan="1" colspan="1">11</td><td align="right" rowspan="1" colspan="1">0</td></tr><tr><td align="left" rowspan="1" colspan="1">20</td><td align="right" rowspan="1" colspan="1">896</td><td align="char" char="." rowspan="1" colspan="1">2.78</td><td align="right" rowspan="1" colspan="1">451.1</td><td align="right" rowspan="1" colspan="1">9.6</td><td align="right" rowspan="1" colspan="1">1.46</td></tr><tr><td align="left" rowspan="1" colspan="1">16</td><td align="right" rowspan="1" colspan="1">2340</td><td align="char" char="." rowspan="1" colspan="1">3.18</td><td align="right" rowspan="1" colspan="1">460.1</td><td align="right" rowspan="1" colspan="1">7.7</td><td align="right" rowspan="1" colspan="1">1.65</td></tr><tr><td align="left" rowspan="1" colspan="1">33</td><td align="right" rowspan="1" colspan="1">1362</td><td align="char" char="." rowspan="1" colspan="1">3.3</td><td align="right" rowspan="1" colspan="1">469.8</td><td align="right" rowspan="1" colspan="1">5</td><td align="right" rowspan="1" colspan="1">0.82</td></tr><tr><td align="left" rowspan="1" colspan="1">26</td><td align="right" rowspan="1" colspan="1">489</td><td align="char" char="." rowspan="1" colspan="1">2.11</td><td align="right" rowspan="1" colspan="1">500.4</td><td align="right" rowspan="1" colspan="1">6.5</td><td align="right" rowspan="1" colspan="1">3.86</td></tr><tr><td align="left" rowspan="1" colspan="1">13</td><td align="right" rowspan="1" colspan="1">1874</td><td align="char" char="." rowspan="1" colspan="1">61.6</td><td align="right" rowspan="1" colspan="1">580.6</td><td align="right" rowspan="1" colspan="1">7.5</td><td align="right" rowspan="1" colspan="1">9.8</td></tr><tr><td align="left" rowspan="1" colspan="1">41</td><td align="right" rowspan="1" colspan="1">20.49</td><td align="char" char="." rowspan="1" colspan="1">0.23</td><td align="right" rowspan="1" colspan="1">728</td><td align="right" rowspan="1" colspan="1">18</td><td align="right" rowspan="1" colspan="1">7.96</td></tr><tr><td align="left" rowspan="1" colspan="1">29</td><td align="right" rowspan="1" colspan="1">77.1</td><td align="char" char="." rowspan="1" colspan="1">1.26</td><td align="right" rowspan="1" colspan="1">875</td><td align="right" rowspan="1" colspan="1">85</td><td align="right" rowspan="1" colspan="1">0.57</td></tr><tr><td align="left" rowspan="1" colspan="1">23</td><td align="right" rowspan="1" colspan="1">111.2</td><td align="char" char="." rowspan="1" colspan="1">1.14</td><td align="right" rowspan="1" colspan="1">1016</td><td align="right" rowspan="1" colspan="1">45</td><td align="right" rowspan="1" colspan="1">1.77</td></tr><tr><td align="left" rowspan="1" colspan="1">5</td><td align="right" rowspan="1" colspan="1">317</td><td align="char" char="." rowspan="1" colspan="1">3.96</td><td align="right" rowspan="1" colspan="1">1060</td><td align="right" rowspan="1" colspan="1">45</td><td align="right" rowspan="1" colspan="1">7.64</td></tr><tr><td align="left" rowspan="1" colspan="1">18</td><td align="right" rowspan="1" colspan="1">186</td><td align="char" char="." rowspan="1" colspan="1">1.4</td><td align="right" rowspan="1" colspan="1">1077</td><td align="right" rowspan="1" colspan="1">32</td><td align="right" rowspan="1" colspan="1">0.2</td></tr><tr><td align="left" rowspan="1" colspan="1">25</td><td align="right" rowspan="1" colspan="1">374.6</td><td align="char" char="." rowspan="1" colspan="1">13.72</td><td align="right" rowspan="1" colspan="1">1093</td><td align="right" rowspan="1" colspan="1">38</td><td align="right" rowspan="1" colspan="1">6.22</td></tr><tr><td align="left" rowspan="1" colspan="1">32</td><td align="right" rowspan="1" colspan="1">282</td><td align="char" char="." rowspan="1" colspan="1">2.43</td><td align="right" rowspan="1" colspan="1">1095</td><td align="right" rowspan="1" colspan="1">31</td><td align="right" rowspan="1" colspan="1">2.19</td></tr><tr><td align="left" rowspan="1" colspan="1">35</td><td align="right" rowspan="1" colspan="1">68.1</td><td align="char" char="." rowspan="1" colspan="1">0.68</td><td align="right" rowspan="1" colspan="1">1120</td><td align="right" rowspan="1" colspan="1">110</td><td align="right" rowspan="1" colspan="1">17.32</td></tr><tr><td align="left" rowspan="1" colspan="1">21</td><td align="right" rowspan="1" colspan="1">461</td><td align="char" char="." rowspan="1" colspan="1">1.03</td><td align="right" rowspan="1" colspan="1">1316</td><td align="right" rowspan="1" colspan="1">26</td><td align="right" rowspan="1" colspan="1">0.08</td></tr><tr><td align="left" rowspan="1" colspan="1">40</td><td align="right" rowspan="1" colspan="1">135</td><td align="char" char="." rowspan="1" colspan="1">0.92</td><td align="right" rowspan="1" colspan="1">1463</td><td align="right" rowspan="1" colspan="1">46</td><td align="right" rowspan="1" colspan="1">5.26</td></tr><tr><td align="left" rowspan="1" colspan="1">36</td><td align="right" rowspan="1" colspan="1">634</td><td align="char" char="." rowspan="1" colspan="1">8.4</td><td align="right" rowspan="1" colspan="1">1481</td><td align="right" rowspan="1" colspan="1">29</td><td align="right" rowspan="1" colspan="1">0.2</td></tr><tr><td align="left" rowspan="1" colspan="1">24</td><td align="right" rowspan="1" colspan="1">364</td><td align="char" char="." rowspan="1" colspan="1">1.13</td><td align="right" rowspan="1" colspan="1">1499</td><td align="right" rowspan="1" colspan="1">45</td><td align="right" rowspan="1" colspan="1">10.21</td></tr><tr><td align="left" rowspan="1" colspan="1">42</td><td align="right" rowspan="1" colspan="1">284.9</td><td align="char" char="." rowspan="1" colspan="1">3.04</td><td align="right" rowspan="1" colspan="1">1635</td><td align="right" rowspan="1" colspan="1">33</td><td align="right" rowspan="1" colspan="1">0.43</td></tr><tr><td align="left" rowspan="1" colspan="1">37</td><td align="right" rowspan="1" colspan="1">131.7</td><td align="char" char="." rowspan="1" colspan="1">3.18</td><td align="right" rowspan="1" colspan="1">1569</td><td align="right" rowspan="1" colspan="1">39</td><td align="right" rowspan="1" colspan="1">19.95</td></tr><tr><td align="left" rowspan="1" colspan="1">38</td><td align="right" rowspan="1" colspan="1">272</td><td align="char" char="." rowspan="1" colspan="1">1.17</td><td align="right" rowspan="1" colspan="1">1651</td><td align="right" rowspan="1" colspan="1">34</td><td align="right" rowspan="1" colspan="1">7.45</td></tr><tr><td align="left" rowspan="1" colspan="1">22</td><td align="right" rowspan="1" colspan="1">450</td><td align="char" char="." rowspan="1" colspan="1">11.3</td><td align="right" rowspan="1" colspan="1">2684</td><td align="right" rowspan="1" colspan="1">32</td><td align="right" rowspan="1" colspan="1">5.66</td></tr></tbody></table></alternatives><table-wrap-foot><fn id="t002fn001"><p><sup>a.</sup> We report the <sup>238</sup>U-<sup>206</sup>Pb age if the zircon is <850 Ma, and the <sup>207</sup>Pb-<sup>206</sup>Pb age if the grain is >850 Ma.</p></fn><fn id="t002fn002"><p><sup>b.</sup> Reports the percent discordance, and is the <sup>206</sup>Pb/<sup>238</sup>U discordance if the age is younger than 850 Ma and is the <sup>207</sup>Pb/<sup>206</sup>Pb discordance age if grain is older than 850Ma.</p></fn></table-wrap-foot></table-wrap></sec><sec sec-type="results" id="sec003"><title>Results</title><p>Overall, 38 zircon ages are reported from sample 16COW1 and 36 ages from 16COW3. Ages from 16COW1 range from 2684±32 Ma (5.66% discordant) to 410.4±7.2 Ma (3.37% discordant), whereas those from 16COW3 range from 1688±27 (4.32% discordant) to 414.3±7.1 Ma (0.65% discordant). We found ten Devonian zircon ages (N = 7 from 16COW1 and N = 3 from 16COW3) and eleven that yield Silurian results (N = 10 from 16COW1 and N = 1 from 16COW3). The average Devonian ages from 16COW1 is 414.2±8.7 Ma (MSWD = 0.82), whereas the Devonian results from sample 16COW3 average 416.0±8.4 Ma (MSWD = 0.64). One Devonian age in sample 16COW3 (415.0±12.0 Ma) is found as a rim on a 651±18 Ma core. This is the only zircon that contains an older core and younger rim; the remainder of the grains did not show age gradients using our filters for discordance. The majority of the zircon grains analyzed are older than Silurian (55% of all results from 16COW1 and 89% of all results in 16COW3). We find no correlation between zircon age and U (ppm) or U/Th. The U/Th data is consistent with igneous zircons (e.g., [<xref rid="pone.0179262.ref013" ref-type="bibr">13</xref>]).</p></sec><sec sec-type="conclusions" id="sec004"><title>Discussion</title><p>The weighted means of zircon ages from volcanic ashes, which are frequently used to define bed ages, are averages of the ages of zircons blown out by the explosive eruption which produced the ash, and must include some older material from the volcanic pile and country rock. Ultimately, they do not give the age of the eruption, but only an older age, depending on the amount of earlier material incorporated [<xref rid="pone.0179262.ref014" ref-type="bibr">14</xref>, <xref rid="pone.0179262.ref015" ref-type="bibr">15</xref>]. They are meaningless in terms of the age of eruption of the ash that contains them [<xref rid="pone.0179262.ref015" ref-type="bibr">15</xref>]. Thus, we use the youngest, most concordant zircon ages as the maximum age of each bed, since a bed cannot be older than the youngest thing in it, although it can be younger (<xref ref-type="fig" rid="pone.0179262.g004">Fig 4</xref>; Tables <xref ref-type="table" rid="pone.0179262.t001">1</xref> and <xref ref-type="table" rid="pone.0179262.t002">2</xref>). The youngest, most concordant U-Pb zircon age from the lowermost bed is 413.7±4.4 Ma (grain 6, <xref ref-type="table" rid="pone.0179262.t002">Table 2</xref>), whereas the uppermost bed is 414.3±7.1 Ma (grain 4, <xref ref-type="table" rid="pone.0179262.t002">Table 2</xref>). These are statistically indistinguishable, indicating rapid sedimentation, consistent with the paleo-environment.</p><fig id="pone.0179262.g004" orientation="portrait" position="float"><object-id pub-id-type="doi">10.1371/journal.pone.0179262.g004</object-id><label>Fig 4</label><caption><p>Concordia diagrams for zircon ages between 510 and 400 Ma for samples (A) 16COW1 and (B) 16COW3. (C) and (D) are plots of the ages in ascending order.</p></caption><graphic xlink:href="pone.0179262.g004"></graphic></fig><p>The Cowie Harbour Fish Bed thus appears to be ~414 Ma in age, almost 13 million years younger than the currently accepted age. The younger zircon ages have the potential to be due to Pb loss from original mid-Silurian grains. However, zircons are often used to time major events in Earth’s history because they retain their daughter isotopes under a range of extreme conditions. If the ~414 Ma zircons were originally ~427 Ma, the zircons would have had to experience ~4% radiogenic Pb loss. Although this is a remote possibility, we selected clear, prismatic grains that lacked metamict features or textures suggestive of Pb loss. In addition, <xref ref-type="fig" rid="pone.0179262.g004">Fig 4C and 4D</xref> shows that a significant number of zircons yield the younger results, which requires they be considered when evaluating the age of <italic>Pneumodesmus newmani</italic>.</p><p>The uncertainty in the ages obtained using LA-ICP-MS is larger than ages that would be obtained using other approaches, such as isotope dilution thermal ionization mass spectrometry (ID-TIMS) analyses. The ID-TIMS approach applied to the youngest zircons would yield more precise ages since the two-sigma precision of individual ID-TIMS analyses is 0.1–0.3% compared with about 1–3% of individual LA-ICP-MS [<xref rid="pone.0179262.ref016" ref-type="bibr">16</xref>]. However, the only zircons available in the age range are small and aliquots of multiple grains would likely include the higher amounts of older material. We attempted a second LA-ICP-MS analysis of the youngest grains in the samples, but these yielded only discordant results. We anticipate that the TIMS analysis is almost certain to incorporate material from more than one zone and it is impossible to mechanically separate these in such small grains.</p><p>The Silurian-Devonian boundary is dated at 419.2±3.2 Ma [<xref rid="pone.0179262.ref017" ref-type="bibr">17</xref>]. Therefore, the Cowie Harbour Fish Bed and its air-breathing millipede are lowermost Devonian (Lochkovian) in age, contrary to the previously accepted Silurian age—on the current time scale. This has important implications for the evolutionary timetable of land colonization, as the Cowie age range statistically overlaps a U-Pb zircon age of 411.5±1.3 Ma (late Lochkovian, average of N = 4 grains, TIMS) for an andesite just below the Rhynie Chert with its more advanced and better preserved terrestrial biota [<xref rid="pone.0179262.ref018" ref-type="bibr">18</xref>] and is possibly younger than the supposed land centipedes and arachnid recorded from the Ludford Lane bone bed [<xref rid="pone.0179262.ref019" ref-type="bibr">19</xref>, <xref rid="pone.0179262.ref020" ref-type="bibr">20</xref>], which is correlated with the basal Pridoli (423±2.3 Ma). However, the biostratigraphic inferred ages of such early freshwater and land biotas are based on correlation with marine sections whose radiometric dating requires revision.</p><p>The fish/arthropod fauna of the Stonehaven Group, within which the Cowie Fish Bed is located, differs dramatically from those at structurally shallower levels of the Arbuthnott Group in the Midland Valley (see [<xref rid="pone.0179262.ref021" ref-type="bibr">21</xref>] for cross-section). Fault systems and unconformities may exist throughout the section in <xref ref-type="fig" rid="pone.0179262.g002">Fig 2</xref> that are currently not exposed, and the Stonehaven Group may be of a separate provenance and depositional succession and structurally juxtaposed into its current position [<xref rid="pone.0179262.ref022" ref-type="bibr">22</xref>]. This observation leaves the significance of the dates here unaffected, but should be considered in interpretations for the structural development of the region.</p><p>Although attention has been paid to ascertaining ages to successions in <xref ref-type="fig" rid="pone.0179262.g002">Fig 2</xref> via other means, consensus on the age of the units has not been achieved (e.g., [<xref rid="pone.0179262.ref023" ref-type="bibr">23</xref>], see <xref ref-type="sec" rid="sec004">Discussion</xref> regarding dating exposures of the Ringerike Group (Old Red Sandstone) in Norway). Many recent calibrations of the geological time scale have relied heavily on statistical techniques on conjunction with best-fit line techniques for estimating numerical ages for chronostratigraphic boundaries. For example, the Silurian time scale is based on calibrating a constrained optimization (CONOP) composite graptolite zonation to selected radiometric ages (e.g., [<xref rid="pone.0179262.ref024" ref-type="bibr">24</xref>]). But this, while useful, is no substitute for precise radiometric dating of ashes in fossiliferous sections if available.</p></sec><sec sec-type="supplementary-material" id="sec005"><title>Supporting information</title><supplementary-material content-type="local-data" id="pone.0179262.s001"><label>S1 Table</label><caption><title>Description of the excel file: Detailed U-Pb LA-ICP-MS data.</title><p>The first tab (Explanation) is a detailed key for the raw data presented under the second tab (Data).</p><p>(XLSX)</p></caption><media xlink:href="pone.0179262.s001.xlsx"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material><supplementary-material content-type="local-data" id="pone.0179262.s002"><label>S1 Fig</label><caption><title>Geological sketch-map of the coast of north of Stonehaven from [<xref rid="pone.0179262.ref005" ref-type="bibr">5</xref>].</title><p>(TIF)</p></caption><media xlink:href="pone.0179262.s002.tif"><caption><p>Click here for additional data file.</p></caption></media></supplementary-material></sec></body><back><ref-list><title>References</title><ref id="pone.0179262.ref001"><label>1</label><mixed-citation publication-type="journal"><name><surname>Wilson</surname><given-names>HM</given-names></name>, <name><surname>Anderson</surname><given-names>LI</given-names></name>. <article-title>Morphology and taxonomy of Paleozoic millipedes (Diplopoda: Chilognatha: Archipolypoda) from Scotland</article-title>. <source>J Micropalaeontol</source>. <year>2004</year>;<volume>78</volume>: <fpage>169</fpage>–<lpage>184</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref002"><label>2</label><mixed-citation publication-type="journal"><name><surname>Selden</surname><given-names>P</given-names></name>, <name><surname>Reid</surname><given-names>H</given-names></name>. <article-title>The oldest land animals: Silurian millipedes from Scotland</article-title>. <source>Bull British Myriapod Isopod Group</source>. <year>2008</year>;<volume>23</volume>: <fpage>36</fpage>–<lpage>37</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref003"><label>3</label><mixed-citation publication-type="journal"><name><surname>Marshall</surname><given-names>JEA</given-names></name>. <article-title>Palynology of the Stonehaven Group, Scotland: evidence for a mid-Silurian age and its geological implications</article-title>. <source>Geol Mag</source>. <year>1991</year>;<volume>128</volume>: <fpage>283</fpage>–<lpage>286</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref004"><label>4</label><mixed-citation publication-type="journal"><name><surname>Wellman</surname><given-names>CH</given-names></name>. <article-title>A land plant microfossil assemblage of mid-Silurian age from the Stonehaven Group, Scotland</article-title>. <source>J Micropalaeontol</source>. <year>1993</year>;<volume>12</volume>: <fpage>47</fpage>–<lpage>66</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref005"><label>5</label><mixed-citation publication-type="book"><name><surname>Dineley</surname><given-names>DL</given-names></name>. <chapter-title>Silurian fossil fishes sites of Scotland</chapter-title> In: <name><surname>Dineley</surname><given-names>DL</given-names></name>, <name><surname>Metcalfe</surname><given-names>SJ</given-names></name>, editors. <source>Fossil fishes of Great Britain</source>. <publisher-loc>Peterborough, UK</publisher-loc>: <publisher-name>Joint Nature Conservation Committee</publisher-name>; <year>1999</year> pp. <fpage>131</fpage>–<lpage>145</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref006"><label>6</label><mixed-citation publication-type="other">Browne MAE, Smith RA, Aitken AM. Stratigraphical framework for the Devonian (Old Red Sandstone) rocks of Scotland south of a line from Fort William to Aberdeen. British Geological Survey Research Report RR/01/04. 2002;67: 1–19.</mixed-citation></ref><ref id="pone.0179262.ref007"><label>7</label><mixed-citation publication-type="other">Scottish Outdoor Access Code: Scottish Natural Heritage; 2005 [cited 2017 May 31]. <ext-link ext-link-type="uri" xlink:href="http://www.snh.org.uk/pdfs/publications/access/full%20code.pdf">http://www.snh.org.uk/pdfs/publications/access/full%20code.pdf</ext-link>.</mixed-citation></ref><ref id="pone.0179262.ref008"><label>8</label><mixed-citation publication-type="other">Scottish Earth Science Education Forum: Earth Science Outdoors Teachers' Guide: Cowie, Stonehaven, Aberdeenshire. 2009 [cited 2017 May 31]. <ext-link ext-link-type="uri" xlink:href="http://www.geowalks.co.uk/eso/CowieTeachersGuide-v4.pdf">http://www.geowalks.co.uk/eso/CowieTeachersGuide-v4.pdf</ext-link>.</mixed-citation></ref><ref id="pone.0179262.ref009"><label>9</label><mixed-citation publication-type="journal"><name><surname>Hallermeier</surname><given-names>RJ</given-names></name>. <article-title>Terminal velocity of commonly occurring sand grains</article-title>. <source>Sedimentology</source>. <year>1981</year>:<volume>28</volume>: <fpage>859</fpage>–<lpage>865</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref010"><label>10</label><mixed-citation publication-type="journal"><name><surname>Stacey</surname><given-names>JS</given-names></name>, <name><surname>Kramers</surname><given-names>JD</given-names></name>. <article-title>Approximation of terrestrial lead isotope evolution by a 2-stage model</article-title>. <source>Earth Planet Sc Lett</source>. <year>1975</year>;<volume>26</volume>: <fpage>207</fpage>–<lpage>221</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref011"><label>11</label><mixed-citation publication-type="journal"><name><surname>Jackson</surname><given-names>SE</given-names></name>, <name><surname>Pearson</surname><given-names>NJ</given-names></name>, <name><surname>Griffin</surname><given-names>WL</given-names></name>, <name><surname>Belousova</surname><given-names>EA</given-names></name>. <article-title>The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U–Pb zircon geochronology</article-title>. <source>Chem Geol</source>. <year>2004</year>:<volume>211</volume>: <fpage>47</fpage>–<lpage>69</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref012"><label>12</label><mixed-citation publication-type="journal"><name><surname>Sláma</surname><given-names>J</given-names></name>, <name><surname>Kosler</surname><given-names>J</given-names></name>, <name><surname>Condon</surname><given-names>DJ</given-names></name>, <name><surname>Crowley</surname><given-names>JL</given-names></name>, <name><surname>Gerdes</surname><given-names>A</given-names></name>, <name><surname>Hanchar</surname><given-names>JM</given-names></name>, <etal>et al</etal><article-title>Plesovice zircon—a new natural reference material for U-Pb and Hf isotopic microanalysis</article-title>. <source>Chem Geol</source>. <year>2008</year>;<volume>249</volume>: <fpage>1</fpage>–<lpage>35</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref013"><label>13</label><mixed-citation publication-type="journal"><name><surname>Kirkland</surname><given-names>CL</given-names></name>, <name><surname>Smithies</surname><given-names>RH</given-names></name>, <name><surname>Taylor</surname><given-names>RJM</given-names></name>, <name><surname>Evans</surname><given-names>N</given-names></name>, <name><surname>McDonald</surname><given-names>B</given-names></name>. <article-title>Zircon Th/U ratios in magmatic environs</article-title>. <source>Lithos</source>. <year>2015</year>;<volume>212–215</volume>: <fpage>397</fpage>–<lpage>414</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref014"><label>14</label><mixed-citation publication-type="journal"><name><surname>Suzuki</surname><given-names>Y</given-names></name>, <name><surname>Nagai</surname><given-names>M</given-names></name>, <name><surname>Maeno</surname><given-names>F</given-names></name>, <name><surname>Yasuda</surname><given-names>A</given-names></name>, <name><surname>Hokanishi</surname><given-names>N</given-names></name>, <name><surname>Shimano</surname><given-names>T</given-names></name>, <etal>et al</etal><article-title>Precursory activity and evolution of the 2011 eruption of Shinmoe-dake in Kirishima volcano—insights from ash samples</article-title>. <source>Earth Planets Space</source>. <year>2013</year>;<volume>65</volume>: <fpage>591</fpage>–<lpage>607</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref015"><label>15</label><mixed-citation publication-type="journal"><name><surname>Guillong</surname><given-names>M</given-names></name>, <name><surname>von Quadt</surname><given-names>A</given-names></name>, <name><surname>Sakata</surname><given-names>S</given-names></name>, <name><surname>Peytcheva</surname><given-names>I</given-names></name>, <name><surname>Bachmann</surname><given-names>O</given-names></name>. <article-title>LA-ICP-MS Pb-U dating of young zircons from the Kos-Nisyros volcanic centre, SE Aegean arc</article-title>. <source>J Anal Atom Spectrom</source>. <year>2014</year>;<volume>29</volume>: <fpage>863</fpage>–<lpage>970</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref016"><label>16</label><mixed-citation publication-type="book"><name><surname>Bowring</surname><given-names>SA</given-names></name>, <name><surname>Schoene</surname><given-names>B</given-names></name>, <name><surname>Crowley</surname><given-names>JL</given-names></name>, <name><surname>Ramezani</surname><given-names>J</given-names></name>, <name><surname>Condon</surname><given-names>DJ</given-names></name>. <chapter-title>High-precision U-Pb zircon geochronology and the stratigraphic record: Progress and promise</chapter-title> In: <name><surname>Olszewski</surname><given-names>T</given-names></name>, editor. <source>Geochronology: Emerging Opportunities, Paleontological Society Short Course</source>, <month>10</month><day>21</day>, <year>2006</year><publisher-loc>Philadelphia, PA</publisher-loc>: <publisher-name>Paleontological Society Papers</publisher-name>; 2006. pp. <fpage>23</fpage>–<lpage>43</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref017"><label>17</label><mixed-citation publication-type="journal"><name><surname>Cohen</surname><given-names>KM</given-names></name>, <name><surname>Finney</surname><given-names>SC</given-names></name>, <name><surname>Gibbard</surname><given-names>PL</given-names></name>, <name><surname>Fan</surname><given-names>J-X</given-names></name>. <article-title>The ICS international chronostratigraphic chart</article-title>. <source>Episodes</source>. <year>2004</year>;<volume>36</volume>: <fpage>199</fpage>–<lpage>204</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref018"><label>18</label><mixed-citation publication-type="journal"><name><surname>Parry</surname><given-names>SF</given-names></name>, <name><surname>Noble</surname><given-names>SR</given-names></name>, <name><surname>Crowley</surname><given-names>QJ</given-names></name>, <name><surname>Wellman</surname><given-names>CH</given-names></name>. <article-title>A high-precision U–Pb age constraint on the Rhynie Chert Konservat-Lagerstätte: time scale and other implications</article-title>. <source>J Geol Soc London</source>. <year>2001</year>;<volume>168</volume>: <fpage>863</fpage>–<lpage>872</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref019"><label>19</label><mixed-citation publication-type="journal"><name><surname>Jeram</surname><given-names>AJ</given-names></name>, <name><surname>Selden</surname><given-names>PA</given-names></name>, <name><surname>Edwards</surname><given-names>D</given-names></name>. <article-title>Land animals in the Silurian: arachnids and myriapods from Shropshire, England</article-title>. <source>Science</source>. <year>1990</year>;<volume>250</volume>: <fpage>658</fpage>–<lpage>666</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1126/science.250.4981.658">10.1126/science.250.4981.658</ext-link></comment><pub-id pub-id-type="pmid">17810866</pub-id></mixed-citation></ref><ref id="pone.0179262.ref020"><label>20</label><mixed-citation publication-type="journal"><name><surname>Shear</surname><given-names>WA</given-names></name>, <name><surname>Jeram</surname><given-names>AJ</given-names></name>, <name><surname>Selden</surname><given-names>PA</given-names></name>. <article-title>Centipede legs (Arthropoda, Chilopoda, Scutigeromorpha) from the Silurian and Devonian of Britain and the Devonian of North America</article-title>. <source>Am Mus Novit</source>. <year>1998</year>;<volume>3231</volume>: <fpage>1</fpage>–<lpage>16</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref021"><label>21</label><mixed-citation publication-type="journal"><name><surname>Lavender</surname><given-names>K</given-names></name>, <name><surname>Wellman</surname><given-names>CH</given-names></name>. <article-title>Lower Devonian spore assemblages from the Arbuthnott Group at Canterland Den in the Midland Valley of Scotland</article-title>. <source>Rev Palaeobot Palyno</source>. <year>2002</year>;<volume>118</volume>: <fpage>157</fpage>–<lpage>180</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref022"><label>22</label><mixed-citation publication-type="journal"><name><surname>Marshall</surname><given-names>JEA</given-names></name>, <name><surname>Haughton</surname><given-names>PDW</given-names></name>, <name><surname>Hillier</surname><given-names>SJ</given-names></name>. <article-title>Vitrinite reflectivity and the structure and burial history of the Old Red Sandstone of the Midland Valley of Scotland</article-title>. <source>J Geol Soc London</source>. <year>1994</year>;<volume>151</volume>: <fpage>425</fpage>–<lpage>438</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref023"><label>23</label><mixed-citation publication-type="journal"><name><surname>Davies</surname><given-names>NS</given-names></name>, <name><surname>Turner</surname><given-names>P</given-names></name>, <name><surname>Sansom</surname><given-names>IJ</given-names></name>. <article-title>A revised stratigraphy for the Ringerike Group (Upper Silurian, Oslo Region)</article-title>. <source>Norw J Geol</source>. <year>2005</year>;<volume>85</volume>: <fpage>193</fpage>–<lpage>201</lpage>.</mixed-citation></ref><ref id="pone.0179262.ref024"><label>24</label><mixed-citation publication-type="book"><name><surname>Smith</surname><given-names>AG</given-names></name>, <name><surname>Barry</surname><given-names>T</given-names></name>, <name><surname>Brown</surname><given-names>P</given-names></name>, <name><surname>Cope</surname><given-names>J</given-names></name>, <name><surname>Gale</surname><given-names>A</given-names></name>, <name><surname>Gibbard</surname><given-names>P</given-names></name>, <etal>et al</etal><chapter-title>GSSPs, global stratigraphy and correlation</chapter-title> In: <name><surname>Smith</surname><given-names>DG</given-names></name>, <name><surname>Bailey</surname><given-names>RJ</given-names></name>, <name><surname>Burgess</surname><given-names>PM</given-names></name>, <name><surname>Fraser</surname><given-names>AJ</given-names></name>, editors. <source>Strata and time: probing the gaps in our understanding</source>. <publisher-name>Geol Soc Spec Publ</publisher-name><year>2015</year>;<volume>404</volume>: <fpage>37</fpage>–<lpage>67</lpage>.</mixed-citation></ref></ref-list></back></pmc></record>Pour manipuler ce document sous Unix (Dilib)
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