Paleocene-Eocene carbon isotope excursion in organic carbon and pedogenic carbonate; direct comparison in a continental stratigraphic section

Online Access: Get full text
doi: 10.1130/G20476.1
Author(s): Magioncalda, Roberto; Dupuis, Christian; Smith, Thierry; Steurbaut, Etienne; Gingerich, Philip D.
Author Affiliation(s): Primary:
Faculté Polytechnique de Mons, Laboratoire de Géologie Fondamentale et Appliquée, Mons, Belgium
Royal Belgian Institute of Natural Sciences, Belgium
University of Michigan at Ann Arbor, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 32(7), p.553-556. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. With GSA Data Repository Item 2004089. 40 refs.; sects., sketch map
Summary: The negative carbon isotope excursion at the Paleocene-Eocene boundary is a chemostratigraphic marker widely used for correlation of marine and continental stratigraphic sections. It is linked to massive dissociation of sedimentary methane hydrates and helps to explain an important greenhouse thermal event (Paleocene-Eocene thermal maximum), marine extinctions, and mammalian faunal change on three continents. We show that the carbon isotope excursion recorded in dispersed organic carbon (DOC) from fine-grained terrestrial sedimentary rocks at Polecat Bench, Wyoming, is very similar to that described in two high-resolution studies of pedogenic soil-nodule carbonate from the same section. All show a rapid onset, an ∼40 m series of excursion values, and a slower recovery. However, the carbon isotope excursion in soil-nodule carbonate starts and ends ∼3-5 m lower stratigraphically than that in DOC. We hypothesize that enhanced diffusion of atmospheric CO2 and subsurface diagenesis in an environment of good drainage and elevated temperature and pCO2 may explain this offset. The reliability of δ13C in DOC is attributed to mixing and averaging of isotopic signals from different organic compounds and tissues.
Year of Publication: 2004
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Bighorn Basin; C-13/C-12; Carbon; Cenozoic; Chemostratigraphy; Correlation; Diagenesis; Eocene; Fine-grained materials; Geochemistry; Greenhouse effect; Isotope ratios; Isotopes; Leg 113; Lower Eocene; Ocean Drilling Program; Organic carbon; Organic compounds; Paleocene; Paleocene-Eocene boundary; Paleoclimatology; Paleogene; Paleotemperature; Park County Wyoming; Polecat Bench; Sedimentary rocks; Stable isotopes; Stratigraphic boundary; Tertiary; United States; Upper Paleocene; Wyoming
Coordinates: N444500 N450000 W1084000 W1090000
Record ID: 2004056719
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States