The Workshop 3 of the research programme ArchaeDyn II studies the mode of products diffusion between the sources of raw materials, places of manufacture and places of consumption. It takes benefit from the modellization of the changing of space and from the establishing qualitative and quantitative indicators permitting to measure, by chronological phases, the spatial dynamics.

In this aim it uses several pre-existing databases concerning essentially the period from the Neolithic to the Bronze Age. The fact that these data has been collected previously in order to meet other specific archaeological issues brings up the necessity to control the state of knowledge of the studied areas and the possible biases in the distributions to allow their correct analysis and the interpretation of the results. The circumstances of discoveries, the state of study, the preservation of vestiges, the accessibility of data and the choices made at the moment of the constitution of the corpus are very diversified concerning the different portions of space. This implies a high heterogeneity of data and a need for an evaluation of their “reliability” vis-à-vis the archaeological “reality”.

What are the factors that can create under- and over-representation in the distribution or can pose difficulties for the interpretation of the spatial analyses? Do these factors disturb or affect too profoundly the vision that we dispose of the “real” repartition of the studied objects? Can we finally say that the corpus is sufficiently reliable to realize a spatial study of the circulation and consummation of products?

Here, we present a case-study on the so-called Normand type palstave axes in the lower and middle Seine valley. This type was produced in series from 15^th c. to 14^th c. B.C. .  The axes found in the lower and middle Seine valley show different levels of finishing, made after the axe was taken out from the mould.  The majority of the app. 400 axes currently inventoried in the spatially referenced database was studied macroscopically. This dataset was involved in the analyses of ArchaeDyn’s Workshop 3 to examine whether the level of finishing depends or not on their distance from the production centres.

This corpus is particularly interesting for the elaboration of a method for the estimation of the reliability of distributions because it has some particularities: the metal finds are essentially known from hoards and isolated finds. The majority came from fortuitous discoveries so the corpus and the repartition of the data are above all influenced by the finds made at the occasion of agricultural activities, constructions, development work and exploitation of natural resources (dredging…).  From a comparison of data and discovery’s possibility (reliability map), we propose to examine the impact of the factor of the "conditions of discovery" on the archaeological data and we are going to see whether, in the present state of the research, it is possible to control it.