Figure 20. Generally samples from Kola UACC (excepting those from the Dyke
Complex) show whole-rock
4He/40Ar* ratios lower than those predicted by parent
elements.
These relationships imply a preferential loss of radiogenic
4He. Some carbonatites
show especially low
4He/40Ar* resulted from insufficient ability to preserve helium
(see Figure 15). A correlation between
4He/40Ar*melt and
4He/40Ar*mill (not presented
in this paper) indicates a contribution of the in-situ produced species into the trapped
fluid (see Figure 23).
In contrast, the ratios in host rocks of the Dyke Complex are below the concordia,
whereas these in several samples from dykes themselves are above this line indicating
that the dykes could be considered as a complementary reservoir to the host rocks
[Mamyrin and Tolstikhin, 1984; Tolstikhin et al., 1996].