Na,Rb and T1 distributions between phlogopite and sanidine by direct synthesis in a common vapour phase

Using a double-capsule technique, phlogopite and sanidine were equilibrated directly in a common aqueous vapour phase to study the distributions of Na, Rb and T1 at 700°C and 1.5 Kbar. Behaviour of these elements approaches ideality for wt.% concentrations of up to Na = 0.18, Rb = 0.55 and T1 = 0.065 in phlogopite and 0.19, 0.33 and 0.063 respectively in sanidine. The following partition coefficients and K_D values for phlogopite/sanidine were obtained: D (Na) = 0.83, D (Rb) = 2.3 rmand D (T1) = 1.3; K_D(Na/K) = 1.2, K_D(Rb/K) = 3.2 and K_D(T1/K) = 1.8. Although these results are preliminary and in some cases marred by analytical uncertainty, they nevertheless demonstrate the feasibility of the technique as applied to studies of multielement distribution between two or more coexisting solid phases.