The Enigmatic Softstone Vessels of Northern Madagascar: Petrological Investigations of a Medieval Quarry

Abstract

The production of lathe-turned tripod vessels made from softstone is one of the major features of the so-called Rasikajy population that inhabited northern Madagascar from the ca. 8th to the late 15th century a.d. The raw material for the vessels was quarried in the hinterland, and over 30 quarries have recently been visited, documented and sampled. The quarry of Bobalila is the first to ever be excavated, and a large sample suite was taken for petrological analysis. The results reveal significant mineralogical and chemical variation that is almost as large as the variation between all other quarries in northern Madagascar. The underlying processes could affect other softstones and should be considered in provenance attempts. Nonetheless, the petrographic study has permitted us to understand and characterize the type of material that was sought-after by Rasikajy workers, which can now be easily distinguished from other softstone vessels in the Indian Ocean trade network.