A 56 million year rhythm in North American sedimentation during the Phanerozoic

作者：Meyers Stephen R^*; Peters Shanan E

来源：Earth and Planetary Science Letters, 2011, 303(3-4): 174-180.

DOI：10.1016/j.epsl.2010.12.044

• macrostratigraphy
• cyclostratigraphy
• sedimentation
• spectral analysis
• biologic diversity

Long-term (> 10 Myr) fluctuations in climate, sea-level and sedimentation have been documented in the stratigraphic record, but the lack of well-constrained data series has made it difficult to rigorously evaluate cyclic (periodic or quasi-periodic) changes at this scale. Here we utilize a new compilation of the coverage area of sedimentary rocks in North America to investigate the dominant modes ("orders") of stratigraphic variability, and to evaluate potential long-period cyclic changes in sedimentation on the continent during the Phanerozoic. Our analysis resolves two principal temporal modes of variability: (1) a strongly sinusoidal mode with a periodicity of 56 Myr +/3-Myr, and (2) a longer-term Phanerozoic mode (the "M-curve", linked to the Wilson cycle), which is indistinguishable from a stochastic autoregressive process. The newly identified 56 myr cycle in sedimentation delineates most of the cratonic sequences that have previously been identified qualitatively in North America. but here we propose a quantitative redefinition that includes nine distinct units and two mega-sequences. The timing of the 56 Myr beat in sedimentation is consistent with an orogenic oscillator source or an oscillatory dynamic in mantle convection, and its tempo is statistically similar to a known rhythm in number of marine animal genera in the global fossil record. Thus, the identification of a significant periodic signal in the sedimentary record of North America provides new evidence for an important tectonic- and/or mantle-scale cyclic process that links both large-scale biological evolution and physical environmental change.

• 出版日期2011-3-1