Ongoing lithostratigraphic and sequence stratigraphic work at the University of Iowa has led to correlation of Cretaceous (Albian-Turonian) non-marine to marine strata along a transect approximately perpendicular to the paleoshoreline of the Western Interior Seaway. This work has been undertaken in support of paleoclimatologic studies of non-marine strata where chronostratigraphy is based primarily on palynostratigraphy.
The lithologic correlations have been tied to detailed coeval, mid-basin geochemical profiles completed by other workers. Correlations of these geochemical profiles are based on a parasequence model for the development of geochemical facies which provides chronostratigraphic resolution of ~100,000 years. The high resolution chronostratigraphy revealed by the parasequence model can be applied to non-marine chronstratigraphy in places where the geochemically defined parasequences interfinger with non-marine paleosols. Oxygen isotope chemostratigraphic profiles have been established for the amalgamated paleosols in Northwestern Iowa and Nebraska, and high resolution geochemical reference sections are established for the mid-basin, marine strata in Colorado, Kansas, Iowa, and Saskatchewan. The goals of this project are to generate an oxygen isotope chemostratigraphy from paleosols and a geochemical record from marine strata (Rockeval, carbon coulometry), found in the Kenyon core from North-central Kansas where the two facies are interfingered.
This approach will allow me to generate a higher resolution non marine chronostratigraphy by tying oxygen isotope records and the parasequence model for geochemical facies in the transitional interfingered facies.
AAPG Search and Discovery Article #90925©1999 AAPG Foundation Grants-in-Aid