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Evidence of orbital forcing in 510 to 530 million year old shallow marine cycles, Utah and western CanadaSpectral analyses of two sequences of shallow marine sedimentary cycles that were deposited between 510 and 530 million years ago were completed. One sequence is from Middle Cambrian rocks in southern Utah and the other is from Upper Cambrian rocks in the southern Canadian Rockies. In spite of the antiquity of these strata, and even though there are differences in the age, location, and cycle facies between the two sequences, both records have distinct spectral peaks with surprisingly similar periodicities. A null model constructed to test for significance of the spectral peaks and circulatory in the methodology indicates that all but one of the spectral peaks are significant at the 90 percent confidence level. When the ratios between the statistically significant peaks are measured, we find a consistent relation to orbital forcing; specifically, the spectral peak ratios in both the Utah and Canadian examples imply that a significant amount of the variance in the cyclic records is driven by the short eccentricity (approximately 109 ky) and by the precessional (approximately 21 ky) components of the Earth's orbital variations. Neither section contains a significant component of variance at the period of the obliquity cycle, however.
Document ID
19930009786
Document Type
Conference Paper
Authors
Bond, Gerard C. (Lamont-Doherty Geological Observatory Palisades, NY, United States)
Beavan, John (Lamont-Doherty Geological Observatory Palisades, NY, United States)
Kominz, Michelle A. (Texas Univ. Austin., United States)
Devlin, William (Exxon Production Research Company Houston, TX., United States)
Date Acquired
September 6, 2013
Publication Date
December 1, 1992
Publication Information
Publication: NASA. Goddard Space Flight Center, Orbital, Rotational and Climatic Interactions
Subject Category
GEOPHYSICS
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19930009773Analytic PrimaryOrbital, Rotational, and Climatic Interactions