An atmospheric pCO2 threshold for glaciation in the Late Ordovician

Research Article| May 01, 1997 An atmospheric pCO2 threshold for glaciation in the Late Ordovician Mark T. Gibbs; Mark T. Gibbs 1Department of Geosciences and Earth System Science Center, Pennsylvania State University, University Park, Pennsylvania 16802 Search for other works by this author on: GSW Google Scholar Eric J. Barron; Eric J. Barron 1Department of Geosciences and Earth System Science Center, Pennsylvania State University, University Park, Pennsylvania 16802 Search for other works by this author on: GSW Google Scholar Lee R. Kump Lee R. Kump 1Department of Geosciences and Earth System Science Center, Pennsylvania State University, University Park, Pennsylvania 16802 Search for other works by this author on: GSW Google Scholar Author and Article Information Mark T. Gibbs 1Department of Geosciences and Earth System Science Center, Pennsylvania State University, University Park, Pennsylvania 16802 Eric J. Barron 1Department of Geosciences and Earth System Science Center, Pennsylvania State University, University Park, Pennsylvania 16802 Lee R. Kump 1Department of Geosciences and Earth System Science Center, Pennsylvania State University, University Park, Pennsylvania 16802 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1997) 25 (5): 447–450. https://doi.org/10.1130/0091-7613(1997)025<0447:AAPCTF>2.3.CO;2 Article history 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 Mark T. Gibbs, Eric J. Barron, Lee R. Kump; An atmospheric pCO2 threshold for glaciation in the Late Ordovician. Geology 1997;; 25 (5): 447–450. doi: https://doi.org/10.1130/0091-7613(1997)025<0447:AAPCTF>2.3.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 The Late Ordovician glaciation differs from other major Phanerozoic glaciations because of its short duration (∼1 m.y.). A satisfactory explanation for this glaciation must be able to account for its sudden initiation, short duration, and rapid termination; mechanisms operating on tectonic time scales appear to be precluded. Given recent studies of a major perturbation in the carbon cycle during the glaciation, a climate model investigation of the sensitivity of the Late Ordovician climate to changes in atmospheric pCO2 was undertaken. Under the condition of a 4.5% reduction in solar luminosity, permanent snow cover (taken as a key indicator of potential for glaciation) is dramatically different between five experiments. The range of 18X present atmospheric level CO2 (ice free) to 8X ("runaway" icehouse) lies within the uncertainty of previous geochemical estimates of Late Ordovician atmospheric pCO2. The strong sensitivity to the modest direct forcing from pCO2 changes is due to the ice-albedo feedback. A plausible increase in organic carbon burial could have drawn down enough atmospheric CO2 to have briefly lowered the climate system below a critical glacial inception threshold at the end of the Ordovician. Conversely, a high pCO2 is required for the rest of the early Paleozoic, which was essentially ice free. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.