Powder diffraction of yellow and red natural earths from Lessini Mountains in NE Italy

Abstract

A first attempt to differentiate goethite- and hematite-based natural materials, used for several purposes during the Late Palaeolithic in the Lessini Mountains (Italy), is here proposed. All raw materials were collected from known geological sites within a distance of about 20 km from archaeological excavations (Tagliente and Fumane caves) where ochre fragments were found. X-ray powder diffraction allowed the mineralogical composition of samples collected from carbonate and volcanic geological host and parent rocks to be inferred; in addition, a preliminary distinction based on the different mineral assemblages, on the presence of distinctive mineral phases and on the degree of crystallinity of some compounds such as hematite, became possible. The acquired data thus represent a sort of preliminary inventory for provenance studies on archaeological samples originating in the same region, for which ancillary micro-analytical and geochemical techniques are planned.