Figure 3

Time series analyses of proxy records: left panels: spectral power diagrams of (a) δ¹⁸O, (b) δ¹³C and (c) Mg/Ca calculated with REDFIT³⁹). Colored lines indicate the calculated AR(1) false-alarm levels of 80% (blue), 90% (green), and 95% (red), respectively. Right panels: continuous wavelet transform spectra computed for the continuous growth period of NAH14 for (d) δ¹⁸O, (e) δ¹³C and (f) Mg/Ca records down-sampled to 5a-equidistant time series. Red (blue) colors correspond to high (low) values of the transform coefficients (power). Contour lines indicate the 90% significance levels calculated using an AR(1) spectrum with autocorrelation coefficients ρ derived with REDFIT for each proxy record individually (ρ_δ13C = 0.75, ρ_δ18O = 0.85, ρ_Mg = 0.45). The white line indicates the cone of influence where edge effects are not negligible.