HR: 17:30h
AN: PP34A-07    [Abstracts]
TI: The Cenomanian-Turonian Boundary Event: Linkage of High-Resolution Terrestrial and Marine Records of a Major Climate Perturbation During Peak Greenhouse Conditions.
AU: * Sageman, B B
EM: brad@earth.northwestern.edu
AF: Northwestern University, Department of Geological Sciences 1850 Campus Drive, Evanston, IL 60208 United States
AU: Arthur, M A
EM: arthur@geosc.psu.edu
AF: Penn State University, Department of Geosciences 503 Deike Building, University Park, PA 16802 United States
AU: Kenig, F
EM: fkenig@uic.edu
AF: University of Illinois at Chicago, Department of Earth and Environmental Sciences 845 West Taylor Street, Chicago, IL 60607-7059 United States
AU: Laurin, J
EM: laurin@ig.cas.cz
AF: Academy of Sciences of the Czech Republic, Institute of Geophysics Bocni II/1401, Prague, 141 31 Czech Republic
AU: McElwain, J C
EM: mcelwain@fieldmuseum.org
AF: The Field Museum of Natural History, Department of Geology 1400 S. Lake Shore Drive, Chicago, IL 60605-2496 United States
AU: Meyers, S R
EM: stephen.meyers@yale.edu
AF: Yale University, Department of Geology and Geophysics P.O. Box 208109, New Haven, CT 06520-8109 United States
AB: Interdisciplinary studies of paleoclimate provide a critical source of information about the nature and magnitude of changes in the natural climate system, of thresholds and feedbacks in the biogeochemical cycles that modulate climate, and of the biological consequences of extreme climate transitions and states. Unfortunately, many studies of ancient climate are constrained by low temporal resolution, diminished reliability of proxy data, and a lack of information about linkages between different components of the climate system. This talk will summarize recent improvements in the temporal resolution of biogeochemical and paleobiological data across the marine record of the Cenomanian-Turonian Boundary Event (CTBE), and extension of that record into the terrestrial realm of the Western Interior of North America. The CTBE is hypothesized to represent a brief interval of global marine organic carbon burial that occurred during the peak Cretaceous greenhouse. It is thought to have caused an oscillation in pCO$_{2}$ comparable to, or greater in magnitude than glacial-interglacial cycles. This is believed to have caused transient cooling followed by return to maximum Cretaceous warmth with major impacts on the ecology and evolution of terrestrial ecosystems. Efforts to quantify the pCO$_{2}$ effect, to assess available paleoclimate indicators, and to evaluate changes in terrestrial ecosystems across this event have been limited by the constraints mentioned above. However, a number of recent advances are facilitating a new generation of paleoclimatic analysis of the CTBE : 1) development of an orbital time scale for the C-T stratotype in central Colorado with average temporal resolution of 8 kyrs; 2) use of this time scale to calculate burial fluxes for key paleoenvironmental proxies; 3) export of the time scale to a coeval terrestrial section containing fossil whole plant and cuticle material based on high-resolution lithostratigraphic, biostratigraphic and chemostratigraphic correlation; 4) development of new high-resolution d13Corg records for both the marine (average 5 cm resolution; bulk TOC) and terrestrial (average 40 cm resolution; coal, charcoal, and cuticle) sections; and 5) preliminary pCO$_{2}$ estimates based on stomatal index analysis of fossil plant cuticle collected across the CTBE interval. These linked, high-resolution data provide new constraints on the timing and response of terrestrial and marine biogeochemical cycles and ecosystems during the CTBE and thus allow leading mechanistic hypotheses for the event to be re-evaluated.
DE: 3344 Paleoclimatology
DE: 4267 Paleoceanography
DE: 4802 Anoxic environments
DE: 1615 Biogeochemical processes (4805)
DE: 1620 Climate dynamics (3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting