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The AAPG/Datapages Combined Publications Database

CSPG Special Publications

Abstract


Shelf Sands and Sandstones — Memoir 11, 1986
Pages 346-346
Symposium Abstracts: Tide-Dominated Shelves

Prediction of Tides in Epeiric Seas with a Numerical Model: The Cretaceous Seaway of North America: Abstract

Richard D. Slater1

Abstract

A numerical model of the tides in the North American Cretaceous seaway was designed and the lunar semidiurnal tide calculated for a variety of possible controlling parameters. The most important parameters are the bathymetry and boundary conditions. Separate runs were made for uniform-depth models of 100, 200 and 600 m in a completely closed basin. The largest response is for the 200 m depth, because of a resonance of the seaway at 211 m.

Additional runs were made for different combinations of tidal forcing, according to whether the tidal force acted directly on the seaway (independent tide) or indirectly, through the seaway’s possible connection with the Arctic Ocean or Gulf of Mexico (co-oscillating tide). The co-oscillating tide from the Arctic Ocean was very small with respect to the independent tide. However, a co-oscillating tide from the Gulf of Mexico could have had a significant effect on the seaway. In contrast, if the Gulf of Mexico had not been tidally connected to the seaway, a radiation condition along the southern boundary would have been appropriate. This reduces the independent tide by about 20%.

A spectral analysis of unforced oscillations of the seaway shows closely spaced peaks throughout the diurnal and semidiurnal tide bands for a 200 m deep basin. This indicates the likelihood of a tidal resonance occurring in the seaway. These peaks in the frequency spectrum are more closely spaced for models with shallower depth.

The maximum tidal range for the most “realistic” case (independent tide with a radiation condition on the southern boundary and co-oscillating tide at the north) is 86 cm, and the maximum current speed is 10 cm/s.


 

Acknowledgments and Associated Footnotes

1 The University of Chicago, Department of the Geophysical Sciences, Chicago, Illinois 60637, U.S.A.

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