Fig. 3: Spectral analysis of the cyclostratigraphic series. | Nature Communications

Fig. 3: Spectral analysis of the cyclostratigraphic series.

From: Astronomical tuning of the Aptian stage and its implications for age recalibrations and paleoclimatic events

Fig. 3

a Magnetic susceptibility (MS); b anhysteretic remanent magnetization (ARM); c δ13C; d δ18O. Top: 2π multitaper power spectra, with the AR(1) red noise spectral model and 90%, 95%, 99%, and 99,9% confidence levels (c.l.) for null hypothesis testing. Wavelengths of spectral peaks are labeled in cm. Bottom: evolutionary fast Fourier transform (eFFT) spectrograms with a 4 m sliding window, with each calculated eFFT spectrum normalized to 1. MSB million-year scale band, E long eccentricity, e125 and e95 125-kyr and 95-kyr short eccentricity, TA and TB are referred to periodicities of ~60–70 kyr, O obliquity, P1 and P2 precession.

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