Fig. 3.

Comparison between untuned depth rank data from core and reflection coefficient (60) data (derived from borehole sonic velocity and density measurements from Rutgers and Somerset cores and holes of the NBCP; ref. 38) (SI Appendix) showing similarity in periods. The interval from ∼1,530 to ∼1,640 m lacks structure in depth ranks but shows clear periodicities similar to surrounding strata in the reflection coefficient data. (A) Comparison of wavelet spectra showing similar structure and periodicities. (B) MTM spectra of depth rank and reflection coefficient data showing similar cyclicity attributed to orbital eccentricity as well as the “F test” (f statistic values greater than 0.7 for both datasets; Analyseries 2.0 default: 6, 4pi tapers) and Blackman–Tukey coherence between the datasets (Analyseries 2.0 default: 30% autocorrelation; 80% confidence level). Note the close correspondence between frequencies with high coherence, high statistical significance, and high power.