Earthen constructions of the Yamnaya culture kurgans in the Orenburg region: a case study of applying soil science approaches to archaeological challenges

Abstract

This article compares the earthen kurgan constructions and building technologies of seven kurgans of the Bronze Age Yamnaya culture in the Orenburg region. We conducted a comprehensive analysis to determine the source materials for kurgan construction and the primary earthen building techniques used to create kurgans, focusing on macro-, meso-, and micromorphological properties. It made it possible to prove that ancient people did not simply pile up earthen materials in a chaotic manner but always used specific building plans, skills, and technologies available. We have noted the similarities and differences in the structure of earthen constructions, using the results of studying the kurgans of the Yamnaya culture from the beginning of the developed stage A to the end of the developed stage B (3300–2600 cal BC). Some of the identified differences are because of even slight changes in environmental conditions and, consequently, in the available raw materials that affect construction materials and technologies. Based on the analysis of all the kurgans, the primary way of their building has been identified — the creation of a “pestrotsvet” (patchy-colored material) and the techniques used for this — kneading, tamping, and inclusion of artificially introduced material. Local soils formed the primary material, to which various inclusions were added (river silt, bones, coals, etc.). Kurgan size, the original material's particle-size pattern, and its resulting cementing properties determined whether the material was extensively kneaded and tamped, or if a more complex design was employed.