Title: Differentiation trends in the Ice River complex, British Columbia
Abstract: Four phases of the complex (jacupirangite, ijolite, nepheline syenite, and sodalite syenite) were studied from the viewpoint of their chemical variation. If one goes from the first-formed jacupirangite to the last-formed sodalite syenite, CaO, FeO, Fe ~2~ O ~3~ , MgO, and TiO ~2~ decrease, whereas SiO ~2~ , Al ~2~ O ~3~ , Na ~2~ O, K ~2~ O, and volatile content increase. A tentative diagram for the system SiO ~2~ -NaAlSiO ~4~ -KAlSiO ~4~ at a water pressure of 1,000 kg ^2^ /cm. ^2^ is used to study the differentiation path. Jacupirangite lies well above the diagram due to its high CaO and MgO content. Ijolite is at or near the liquidus of the system, and nepheline syenite falls in the cotectic trough between the feldspar and nepheline fields. Sodalite syenite does not appear to lie at the ternary eutectic in the position expected of the last differentiate.