. Bulletins of American paleontology. Frequency |T= minimum wavelength]. E < Frequency [T= minimum wavelength] Text-figure 3.—Power spectra showing the results of the "'Fast Fourier Transform (FFT)" executed on carbonate proxy data from the early Famennian sections at Coumiac (A) and La Serre (B). Arrows indicating "'dominant'" waveform used for inverse Fourier transformation. 3. Only integer frequencies are calculated. Fourier methods are aimed to decompose a time se- ries into a suite of waveforms, the sum of which are regarded to form the sequence of data. The resulti
. Bulletins of American paleontology. Frequency |T= minimum wavelength]. E < Frequency [T= minimum wavelength] Text-figure 3.—Power spectra showing the results of the "'Fast Fourier Transform (FFT)" executed on carbonate proxy data from the early Famennian sections at Coumiac (A) and La Serre (B). Arrows indicating "'dominant'" waveform used for inverse Fourier transformation. 3. Only integer frequencies are calculated. Fourier methods are aimed to decompose a time se- ries into a suite of waveforms, the sum of which are regarded to form the sequence of data. The resulting power spectra (Text-fig. 3) show the amplitude of each of the integer frequencies. The cyclicity in a time se- ries will normally be represented by a significant spike in the power spectra. As can be seen from Text-figure 3, both power spectra show that the possible cyclicity in the sections results from a variety of waveforms of similar and comparatively low amplitude, one of which has a slightly elevated spike. This means that even the most influential cyclical process in the sedi- mentation of the early Famennian deposits produces only a weak signal. For both sections the highest spike, indicating the most powerful single waveform, has been used to carry out an inverse Fourier transform in order to single out the most dominant cyclicity (Text- fig. 2) and remove noise from time series data. POSSIBLE FREQUENCIES AND MISTAKES The major processes forming marl-limestone alter- nations and black shale-carbonate alternations were summarized by Einsele and Ricken (1991) as follows: 1) Productivity cycles that are formed entirely by changes in organic surface water carbonate produc- tivity. 2) Dilution cycles that are triggered by oscillating ter- rigenous input. 3) Dissolution cycles that are produced by rhythmic oscillation of lysocline and CCD. 4) Calcareous redox cycles indicate fluctuating oxy- genation of bottom waters, which coincides with primary organic carbon producti
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