Fig. 4

Stalagmite MAJ-1 stable isotope datasets. (a) Stable isotopes of carbon time series. (b) Stable isotopes of oxygen time series. (c) Sunspot number time series. (d) Spectral analysis results for δ¹⁸O dataset. The sunspot numbers are annual means of the corrected international/Zurich/Wolf number defined by Lockwood et al.^41,42.