fig20.htm

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].


This document was generated by TeXWeb (Win32, v.1.0) on March 28, 1999.