  We have measured the equivalent width (EW) of the K I 7699 A line in a sample
of G and K-type members of the ~35 Myr old cluster IC 2602 for which a
dispersion in Li EWs had been reported by previous studies. Active cluster
stars with 0.75 < (B-V)o < 1 are characterized by a dispersion in the EW of the
K I 7699 A, while earlier and later-type stars do not show any significant
scatter. Cluster stars at all colors show potassium EW excesses with respect to
field inactive stars; furthermore, a statistically significant relationship is
found between differential potassium EWs and log Lx/Lbol ratios, indicating
that the EWs of the potassium feature are altered by activity. Our results
suggest that the dispersion in Li EWs observed among cluster stars later than
(B-V)o ~ 1 cannot be fully explained by the effects of activity. No final
conclusion can instead be drawn for earlier-type stars.
