Fig. 3: Bicoherence spectra based on the WOSA method (the contour plots).
From: Precession-induced millennial climate cycles in greenhouse Cretaceous
A Periodogram power spectra (upper panel) and p-values for the null hypothesis (middle panel), as well as the bicoherence spectra (bottom panel) of grayscale datasets from the SK2 borehole. B, C Same as (A) but for log (Ca/Ti) from the SK2 borehole and L* datasets from the DSDP–16 F borehole. The bicoherence spectral analysis uses four segments with 50% overlap and a Hanning taper. Thick black contours highlight bicoherence results exceeding the 95% confidence level. Because the FDR-corrected p-values for the power peaks at ~1.8–2.5 kyr in Rb/Sr are larger than 0.2, the Rb/Sr bicoherence plot is shown in Fig. S5 instead.
