Abstract
A sequence of 1337 laminae of cyclically varying thickness, interpreted as periglacial varves, obtained from drill cores of the late Precambrian Elatina Formation may record by proxy an ancient solar activity cycle similar to that of the present epoch Sun. This inferred ancient activity cycle, represented by a sequence of 110 varve-cycles, has a variable period which approximates a normal distribution (chi square = 3.5), with mean and median values of 12 varve years, standard deviation 1.6 varve years, and maximum variability of ± 4 varve years. The time-sequence of varve-cycle periods consists of both deterministic and stochastic elements. The intrinsic period of the varve-cycle is modulated principally by a longer period of ∼ 160 varve years, during which the varve-cycle period displays superimposed stochastic variation. The power spectral density of the varve thickness sequence is endowed with a strong multiplet of spectral lines centered on the median period, a second weaker multiplet at ∼ 22–25 varve years, and several very long periods. The line spacing within the multiplets favors a separation of period mainly of about 160 varve years, while the superimposed random variability of the varve-cycle period is expressed in the amplitude of the sideband envelope. Running autocorrelation of the varve sequence supports the interpretation of frequency modulation (deviation ratio ∼ 1.5) of the late Precambrian solar activity cycle principally by a period of ∼ 160 varve years.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bartlett, M. S.: 1946, J. Roy. Stat. Soc. B8, 27.
Bracewell, R. N.: 1978, The Fourier Transform and its Applications (second ed.), McGraw-Hill, New York.
Bracewell, R. N.: 1985, Australian J. Phys. 38, 1009.
Dicke, R. W.: 1978, Nature 276, 676.
Noyes, R. W., Weiss, N. O., and Vaughan, A. H.: 1984, Astrophys. J. 287, 769.
Papoulis, A.: 1984, Probability, Random Variables, and Stochastic Processes (second ed.), McGraw-Hill Intl. Book Co., New York.
Rabin, D., Wilson, R. M., and Moore, R. L.: 1986, Geophys. Res. Letters 13, 352.
Sonett, C. P.: 1986, Nuovo Cimento (in press).
Williams, G. E.: 1981, Nature 291, 624.
Williams, G. E.: 1983, in B. M. McCormac (ed.), ‘Precambrian Varves and Sunspot Cycles’, Weather and Climate Responses in Solar Variations, Colorado Assoc. Universities Press, Boulder, p. 517.
Williams, G. E.: 1985, Australian J. Phys. 38, 1027.
Williams, G. E.: 1986, Sci. Amer. 255, No. 2, 88.
Williams, G. E. and Sonett, C. P.: 1985, Nature 318, 523.
Williams, G. E. and Sonett, C. P.: 1986, in D. J. Schove and R. W. Fairbridge (eds.), ‘Periglacial Varve-Cycles in the Late Precambrian Elatina Formation’, Ice Cores, Varves, and Tree-Rings, Balkema, Rotterdam (in press).
Williams, G. E. and Tonkin, D. G.: 1985, Australian J. Earth Sci. 32, 287.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Sonett, C.P., Williams, G.E. Frequency modulation and stochastic variability of the elatina varve record: A proxy for solar cyclicity?. Sol Phys 110, 397–410 (1987). https://doi.org/10.1007/BF00206434
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00206434