Conodont faunas, age and correlation of the Alas Formation (Carboniferous), Sumatra

Abstract

Summary. The Alas Formation (shelf limestones) of Sumatra is reinterpreted to be of late Visean age, on the basis of conodonts and brachiopods, rather than of Permian age as previously thought. It is, therefore, the oldest dated formation in Sumatra. The Alas Formation probably underlies or is equivalent to the lower part of the Kluet Formation within the Tapanuli Group.