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The AAPG/Datapages Combined Publications Database

Kansas Geological Society

Abstract


Transactions of the 1999 AAPG Midcontinent Section Meeting (Geoscience for the 21st Century), 1999
Pages 221-221

ABSTRACT: An Application of High-Resolution Marine Chemostratigraphy as a Chronostratigraphic Control for "Mid" Cretaceous Oxygen-Isotope Records in Amalgamated Nonmarine Paleosols

T. S. White1, G. A. Ludvigson2, L. D. Young3

Ongoing sequence-stratigraphic reconstructions have led to correlation of Albian-Turonian nonmarine-marine strata in a transect perpendicular to the eastern-margin paleoshoreline of the Western Interior Seaway. In the nonmarine strata, we have developed a high-resolution palynostratigraphy and oxygen-isotope chemostratigraphy from amalgamated Albian–Cenomanian kaolinitic mudrock paleosols in Iowa and Nebraska. Our results suggest that meteorological conditions were stable in the late Albian/early Cenomanian of the midwestern U.S. However, an enrichment in δ18O values from −4.5 to −3.5‰ occurred in the late Albian, followed by a return to more depleted values of −4.5‰.

The sequence stratigraphy was used to tie detailed mid-basin geochemical profiles of %CaCO3,%TOC, HI, and Ol to nearshore geochemical profiles. Correlation of these profiles uses a model for the development of geochemically defined parasequences which provides ~100,000-year resolution. In Kansas, these parasequences interfinger with nonmarine paleosols. Here, oxygen-isotopic profiles generated from the paleosol sphaerosiderites allow us to tie the nonmarine oxygen-isotope chemostratigraphy to the geochemically defined marine parasequence. This approach allow us to better define the amalgamated nonmarine chronostratigraphy and therefore better interpret the paleoclimatological record.

Acknowledgments and Associated Footnotes

1 University of Iowa, Iowa City, Iowa

2 Iowa Department of Natural Resources–Geological Survey Bureau, Iowa City, Iowa

3 University of Iowa, Iowa City, Iowa

Copyright © 2006 by the Kansas Geological Society