Petrology of the Nepheline Syenites from Santuri Purulia District, West Bengal

A nepheline syenite pluton is reported from the area around Santuri, Purulia District. Microcline, phenocrystic mesoperthite, sodic oligoclase and nepheline are the predominant minerals. Biotite, barkevikite, apatite and calcite are the common accessory minerals. Nine rock samples have been chemically analysed. The nepheline syenites are miaskitic. Available data suggest a magmatic origin. The alkaline melt was emplaced latetectonically along fissures developed during the last stage of deformation. The alkaline rocks of the present area exhibit a striking resemblance to many of the nepheline syenites occurring along the Eastern Ghats.