A Possible Connection of the Tethyan and Boreal Seas between the Albian Kiowa-Skull Creek Cycle and the Cenomanian Greenhorn Cycle

S. L. Akins
Southeast Missouri State University, Dept. of Geoscience, Cape Girardeau, MO

This study tests the hypothesis that a previously unrecognized connection between the Tethyan and Boreal Seas at the early/late Cretaceous boundary existed. The traditional belief is that there were five third order transgressive/regressive cycles that dominated the western interior during the Cretaceous Period. A previously proposed hypothesis suggested a brief connection of theWestern Interior Seaway during latest Albian-earliest Cenomanian, based on the introduction of Tethyan (Metengonoceras) ammonites mixing with Boreal endemic (Neogastrophliets) in the Boreal Mowry shale.

Evidence for the hypothesized connection would greatly help to illuminate the current complicated mid-Cretaceous biostratigraphic, lithostratgraphic and sequence stratigraphic correlation between mid-Cretaceous rocks deposited in the Tethyan and Boreal realms. This study could also explain the unexpected marine faunal migrations addressed by other geologists.

Any connection between Mowry (Boreal) and the equivalentTethyan marine strata in Texas must pass through the mid-Cretaceous strata of the southern high plains. This study examines mid- Cretaceous Muddy Sandstones and overlying Graneros Shale, in northeastern New Mexico, southeastern Colorado, extreme western Kansas and the Oklahoma panhandle, for chemical evidence of marine influences. The approach to studying the target sample sites is detailed chemofacies analysis. Samples from various sites of the Muddy Strata will be collected and processed for Carbon and Sulfur. Carbon isotope data will be obtained by Mass Spectrometry. The influence of fresh versus marine water will be shown in the carbon content of the shaly strata samples of the target interval.

AAPG Search and Discovery Article #90902©2001 AAPG Foundation Grants-in-Aid