(a) log(K/Rb) versus log(Cs) relationship in white-mica composing granite, greisen and the mineralized veins of Panasqueira. (b) Modelled compositional evolution trend of white-mica formed during fractional crystallization of the Panasqueira granite (F gives the fraction of remaining liquid). This trend is calculated applying the Rayleigh equation(Hulsbosch et al., 2014) and assuming a starting composition of granitic melt () of 370 ppm Rb, 70 ppm Cs and 44 900 ppm K. Modal proportion of minerals (x^j) composing the Panasqueira two-mica granite and mineral/melt partition coefficients () for K, Rb and Cs used for calculation of distribution coefficients (D_i) are summarized in table below diagram (b). References for k_d: ^aIcenhower and London (1996); ^bIcenhower and London (1995); ^cPhilpotts and Schnetzler (1970); ^dJolliff et al. (1992); ^eNash and Crecraft (1985).