The occurrence of ramsayite,titan-låvenite and a fluorine-rich eucolite in a nepheline-syenite inclusion from Tenerife,Canary Islands

A nepheline syenite inclusion found in an ignimbritic sequence from Tenerife has revealed a variety of minerals which indicate the strongly peralkaline nature of the rock. The major mineral, alkali feldspar, encloses earlier crystallized biotite, Mn-rich magnetite, sphene and perovskite. The late-crystallizing minerals in the interstices include clinopyroxene (aegirine-augite to titanian-aegirine), F-rich arfvedsonite, ramsayite, nepheline, pyrophanite, apatite, sodalite and rare F-rich eucolite and titan-låvenite. The data illustrate the important role of volatiles in the sub-volcanic equivalent of the phonolitic lavas.