The 206-year cycle in tree ring radiocarbon data and in the thermoluminescence profile of a recent sea sediment

We study the secular variations observed (1) in the thermoluminescence (TL) profile of a recent sea sedimentary core, (2) in the Δ14C time series from tree rings, and (3) in the mean annual sunspot number Rz. We show that a regular oscillation with a period of approximately 206 years is present in the radiocarbon signal. The comparison between the Δ14C secular oscillation and the 206-year TL modulation produced by the beats of two TL waves with close-by decennial periods is considered. The role of the 206-year radiocarbon wave and its possible relationships with the solar activity (as represented by the annual sunspot number Rz) are finally discussed.