Calcareous nannofossils in medieval mortar and mortar-based materials: A powerful tool for provenance analysis

摘要

Calcareous nannofossils-very small-scaled marine microfossils-occur in many archaeological materials. Foremost, these include limestones used in masonry, material which has not experienced significant modification by humans. Poorly documented are nannofossils in mortars, because the burning process of quicklime requires the heating of the raw material to > 800 degrees C. Here we focus on calcareous nannofossils in mortar and mortar-based samples of four medieval buildings in northern Germany. The study documents the presence of nannofossils in historic mortars. It supplies evidence for the provenance of the mortars used, thereby introducing a new tool for mortar provenance studies.