Sadiman Volcano, Crater Highlands, Tanzania; does it really contain melilitites and carbonatites or its is just a phonolite-nephelinite volcano?

Abstract

Sadiman is 4.8-4.0 Ma old volcano located in the Crater Highlands area in northern Tanzania. Limited published data and field observations show that it consists of interlayered phonolitic tuffs and nephelinitic lavas. Rare xenoliths of phonolite and ijolite were observed in the nephelinites. It was suggested that Sadiman volcano contains melilititic and carbonatitic rocks. These also occur as tuffs in the Laetoli area where fossilised footprints from human ancestors are known which is why Sadiman is of special interest as a possible source of them.