Resolution of a sign (1). Regarding a Neolithic slab in the petit mont passage grave (Arzon, France)

Our communication will make use of the word “resolution” in order to address both the original meanings of prehistoric signs and the new technical capabilities that make it possible to detect ancient engravings on stone. An interpretation of an iconographic program belonging to such an old period (6500 BP) relies on a precise inventory of material removals on the rock surface so that all the signs can be detailed and labelled. For this, we will focus on one of the two passage graves preserved in the Neolithic cairn of PetitMont (Arzon, France). There, an engraved orthostat displaying a figure of a so-called “solar wheel” has been known for a long time; however, this type of motif neither fits the chronological context nor the usual corpus of signs in the megaliths of Brittany. A careful recording combining a compilation of images under oblique lighting and 3D modelling makes it possible to produce a graphical synthesis at several levels of information (contours, removal of material from the rock surface, chromatic and morphological alterations). All the signs identified on the basis of their hollow layouts allow us to recognize four main motifs: a circular composition consisting of 17 polished axe blades; a representation of a liquid element; two depictions of boats, one with crew, the other unmanned.