Micro-chemical evaluation of ancient potsherd by mean of Micro-Libs-Scanning on thin section negatives

In the study of ancient pottery fragments, thin section analysis represents the basic approach to obtain preliminary information about origin of archaeological ceramic finds[1]. In fact, composition of aggregates and clays usually reflects the geological context of artifacts production. However, even if thin section analysis allows investigating the textural and structural characteristics of archeological ceramics, peculiar features related to clay paste and temper composition can be detailed addressed only by quantitative mineralogical and chemical studies. In some cases, the relevance of artifacts prevents the sampling of large amount of materials to analyse by different analytical techniques and only fragments to preliminary study under microscopy light can be obtained. In the realization of thin sections,often a negative face is produced, similar to the thin section itself, which can be used for additionally analysis, such as high spatial resolution micro-chemical studiesusing a micro-laser -LIBS) scanner. LIBS is a spectroscopic technique that, exploiting the laser radiation, is able to bring into the plasma state micrometric portions of the sample, and to analyse its content through the study of the optical emission of the plasma itself [2]. Unlike other techniques,LIBS can detect and quantify light elements such asaluminium and magnesium, as well as add other elements, relevant in potteries studies [3]. -LIBS instrument show the spatial distribution of the chemical elements within a portion of the sample, which may have dimensionsfrom a few hundred microns up to several centimeters. The combination of these images with algorithms derived from image processing techniques may return interesting information and supporting data to go in-depth investigate potteries components detected by petrographic observations. Thus, in this contribute we present the results of an experimental study performed on thin sections negatives coming from some important Neolithic Italian sites different for grain size, surface treatments and aggregates, exploring the potential of the method in micro-chemical studies of ancient potsherd.