An animation of 210Pb dating. The black curve simulates an accumulating sediment record. Red is supported 210Pb, which varies a bit around 3 A. Flux of unsupported 210Pb is constant over time (10 A/yr) and produces the blue unsupported 210Pb record. Note how unsupported 210Pb decays over time, and that initial 210Pb levels are higher at deeper levels where sedimentation rates are slower. Vertical scale is depth in cm, horizontal scales are yr AD (top) and 210Pb 'activity'.
More to come, I hope!