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Resolution
Chemostratigraphy
of Amalgamated Paleosols
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