Fig. 3: Time series analysis of iron formation. | Nature Communications

Fig. 3: Time series analysis of iron formation.

From: Orbital forcing of ice sheets during snowball Earth

Fig. 3

a Fast-Fourier transform (FFT) of magnetic susceptibility at Holowilena. Red spectra are FFT recomputed after subtracting the strongest signal (~4 m; ~97 kyr). Two distinct signals in the ~100 kyr bandwidth are shown as two overlapping transparent dark blue bands. b Bandpass filters of significant cycles identified with FFT at Holowilena. Raw magnetic susceptibility data are shown in gray. c FFT of magnetic susceptibility at Oraparinna. d Bandpass filters of significant cycles identified with FFT at Oraparinna. Envelopes of bandpass filters exhibiting amplitude modulation characterized using the Hilbert transform (Methods). Raw detrended data are shown as the gray line.

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