Has immiscibility occurred in the Bjerkreim-Sokndal layered intrusion (S. Norway)?

The Bjerkreim-Sokndal layered intrusion is made of a series of rocks of intermediate composition that result from fractional crystallization of a jotunite magma (Fe-Ti-rich diorite). The intermediate nature of the liquid line of descent makes possible the action of an immiscibility process that gives rise to conjugated Fe-rich and Si-rich melts. It is particularly plausible at the transition between gabbronorites and mangerite, where Fe-Ti-P-rich ultramafic layers are intercalated into norite and mangerite. The chemical compositions of a suite of rocks in a cross-section of the intrusion are here synthetized and compared to the recent experimental data of Charlier and Grove, 2012. It is shown that the ultramafic layers are not or do not derive from a Fe-rich immiscible melt. Moreover the reconstructed liquid line of descent of the intrusion by several methods does not enter into the two-immiscible melts domain. It is concluded that evidence of immiscibility in the evolution of the fractionation process is still lacking.