Stacks and sheets: The microstructure of nacreous shell and its merit in the field of archaeology

Abstract

Inspired by archaeological finds from Kilise Tepe in southern Turkey, this paper explains how the internal structure of nacreous shell can indicate which type of shell was its source. Previous work in the biological sciences demonstrated that it is possible to distinguish between gastropods/cephalopods and bivalves by observing the arrangement of the aragonite tablets in the nacreous layer, and that the thickness of these tablets is fairly constant within taxa but can differ between them. This study verifies these properties by scanning electron microscopy on modern and ancient material, and discusses the benefit in the field of archaeology. The text is not the result of full-scale research but rather a proof of concept to explore the potential of the topic. It is shown that the difference between gastropods/cephalopods and bivalves can indeed be established by looking at the internal architecture of their mother-of-pearl, but that it is problematic to further discriminate between taxa. The thickness of the aragonite tablets is not a reliable distinctive feature. The microstructure of the overlying prismatic layer is a useful parameter when it is preserved.