Tracing grog and pots to reveal neolithic Corded Ware Culture contacts in the Baltic Sea region (SEM-EDS, PIXE)

The Neolithic Corded Ware Culture (CWC) complex spread across the Baltic Sea region ca. 2900/2800-2300/2000 BCE. Whether this cultural adaptation was driven by migration or diffusion remains widely debated. To gather evidence for contact and movement in the CWC material culture, grog-tempered CWC pots from 24 archaeological sites in southern Baltoscandia (Estonia and the southern regions of Finland and Sweden) were sampled for geochemical and micro-structural analyses. Scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) and particle-induced X-ray emission (PIXE) were used for geochemical discrimination of the ceramic fabrics to identify regional CWC pottery manufacturing traditions and ceramic exchange. Major and minor element concentrations in the ceramic body matrices of 163 individual vessels and grog temper (crushed pottery) present in the ceramic fabrics were measured by SEM-EDS. Furthermore, the high-sensitivity PIXE technique was applied for group confirmation. The combined pot and grog matrix data reveal eight geochemical clusters. At least five geochemical groups appeared to be associated with specific find locations and regional manufacturing traditions. The results indicated complex inter-site and cross-Baltic Sea pottery exchange patterns, which became more defined through the grog data, i.e., the previous generations of pots. The CWC pottery exhibited high technological standards at these latitudes, which, together with the identified exchange patterns and the existing evidence of mobility based on human remains elsewhere in the CWC complex, is indicative of the relocation of skilled potters, possibly through exogamy. An analytical protocol for the geochemical discrimination of grog-tempered pottery, and its challenges and possibilities, is presented. (C) 2018 Elsevier Ltd. All rights reserved.