--> ABSTRACT: Comparative Anatomy of Changes in Post-Jurassic Global Sea Level and Spreading Rates, by John D. Pigott, Michael N. Austin, and Larry A. Willis; #91030 (2010)

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Comparative Anatomy of Changes in Post-Jurassic Global Sea Level and Spreading Rates

John D. Pigott, Michael N. Austin, Larry A. Willis

Changes in global sea level are important forcing functions upon the quality and quantity of sedimentation within basins. Additional overprints are caused by local to global tectonism. An understanding of the intimate relationships between changes in global sea level and concomitant global tectonism is crucial to the accurate modeling and prediction of secular trends in basin sedimentary response.

Previous investigators have qualitatively hypothesized the temporal relationships between plate spreading rates and changes in sea level. In order to quantify and compare the major frequency components of the post-Jurassic global sea-level curve with that of global spreading rates, the published data were converted into the frequency domain by taking the discrete Fourier transform. The resulting power spectral densities delineate the major harmonics of the separate curves. Cross correlation reveals five frequencies common to both changes in global sea level and spreading rates. Two shared frequencies are the second and third harmonics of the fundamental 0.0275 cycles/m.y. (or a period of 36.4 m.y.). Reassembly of the signals into the wave equation approximates the original curves and urthermore provides an interesting, though hypothetical, prediction for global sea level and spreading rates for the next 100 m.y.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.