Figure 12. Comparison of measured (m) abundances of
4He and
3He and those
calculated (c) assuming closed system evolution.
While
4He(m)/
4He(c) ratios are similar to or less than 1 in all samples, a great excess
of
3He(m) is observed implying a contribution of mantle fluid retained by almost all
samples. Carbonatites and alkaline rocks from Khibiny show small excess of
3He in
contrast to ultrabasic rocks and carbonatites from Kovdor and Seblyavr. Av - the
average values, Me- the medians.