Linking geology and archeology: investigations of Corded Ware and contemporary Hunter-Gatherer pottery from SE Lithuania by micro-invasive spectroscopic methods

Twelve potsherds from the 3rd millennium BCE pottery in southeastern Lithuania were analyzed using X-ray fluorescence (XRF), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) to obtain the bulk geochemical and mineralogical characteristics of the ceramic paste. Microstructures and geochemical variability of the clay matrix and temper were studied by Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS). The purpose of this study was to characterize the pottery attributed to the foreign Corded Ware Culture and local Hunter-Gatherers, to imply possible sources of raw material and to evaluate technology choices.

The main clusters of major and trace elements in the bulk compositions (XRF; Šatavičė et al., 2022) reflect the five technological styles identified by the manipulation, shaping, and firing conditions of the ceramic raw material. The XRD and FTIR analysis (Šatavičė et al., 2022) indicated a predominance of iron-rich illite clay, quartz, and alkali feldspar minerals. The early coarse pottery was fired at low to medium temperatures, accompanied by a decrease in the firing temperature of both the cord-decorated and hunter-gatherer pottery. The FTIR and XRD results are not indicative of firing in a reducing atmosphere.

The SEM-EDS with SE and BSE imaging and point analysis allowed to determine the detail mineral chemical composition of the ceramic pastes and tempers. The SEM SE and BSE images showed textural differences in the clay matrix, some of which may be explained by intentionally mixing the clay or a specific pottery surface treatment. The other may be attributed to internal differences in glacial till formation. No grog temper characteristic for the classic Corded Ware was detected, only clay pellets, ferruginous nodules and weathered minerals, which may look like grog to the naked eye. The SEM-EDS point analysis allowed us to investigate the gradual changes in the chemical composition of the clay matrix and to evaluate weathering process. To sum up, both the Corded Ware and the local Hunter-Gatherer pottery were made from the same hydro-micaceous variegated clay from the local Quaternary glacial sediments, which contain weathered granitoid fragments, but display different technological choices for the clay paste preparation, surface treatment, and firing strategies.

The study provided a lot of hitherto unknown information on glacial till, glacial lacustrine and post-glacial lacustrine sediments in SE Lithuania. Their composition, textural properties, susceptibility to weathering were evaluated for the first time in this region.

Šatavičė, E. et al., 2022. Minerals 12, 1006. https://doi.org/10.3390/min12081006.