AbstractThe melting relations of a group of ultra alkali lavas are determined. They include a range of types rich in melilite and nepheline (melilite nephelinites) from the Nyiragongo volcano of the Congo and a group rich in olivine (olivine nephelinites).The liquidi of these assemblages range from 1100°C (the melilite nephelinite of the lava lake of Nyiragongo) through the Cameroons etindite (clinopyroxene nephelinite, 1118°C to 1300°C for the olivine nephelinites.For the most part the liquidi follow a course dependent on iron‐enrichmcnt. Notable departures are examples rich in leu