Petrology, Petrochemistry and Genesis of the Alkaline Rocks Associated With the Ambadungar Carbonatite Complex, Baroda District, Gujarat, India

The present paper describes the petrology, protochemistry and genesis of alkaline rocks related to the Ambadungar Carbonatite Complex. These alkaline rocks have been classified as tinguaite, phonolite/phononephelinite, melanephelinite and syenite/nepheline syenite. The porphyritic variety dominates in the area and important phenocrysts are aegirine/aegirine-augite. feldspars, nepheline, hauyene, analcite, and minor mealnite. Chemically they are undersaturated. In the tight of new petrological and chemical data presented. the alkaline rocks of Ambadungar are shown to be genetically related to the Carbonalite-Nephelinite magmatism. These are inferred as products of liquid immiscibility from a parental carbonated nephelinilic magma.