Basic techniques of mound construction of the Yamnaya culture in the Southern Urals

The aim of the study. To determine the material and basic techniques for constructing burial mounds (kurgans) of the Yamnaya culture of the Bronze Age in the Southern Urals based on a comprehensive analysis with an emphasis on meso- and micromorphological analysis. Location and time of the study. The research objects are located in the Orenburg region within the East European Plain. Security excavations were carried out in 2019-2022 at three burial mounds located in the Tashlinsky (mound burial grounds Boldyrevo IV and Tashla IV) and Grachevsky districts (kurgan burial ground Kalikino II) of the Orenburg region. Mound 1 in the Boldyrevo IV burial mound, due to its significant size of 4.2 m in height and 60 m in diameter was chosen as a key object for which a full survey was carried out. Additionally, the smaller in size mounds of the 1st burial mound Tashla IV, as well as 1, 4 and 5 of the Kalikino II burial mound were studied. Methods. To determine the source of building materials and the basic techniques of soil and ground subsoil substrates for mound construction, a comprehensive analysis was carried out with an emphasis on macro-, meso- and micromorphological properties of the substrates. For the analytical study, which was carried out only for the Boldyrevo IV mound 1, total carbon content, organic and inorganic (carbonates) carbon content, loss on ignition, particle size distribution, magnetic susceptibility and pH were determinied. Results. The structure and materials of five burial mounds of the Yamnaya culture of the Bronze Age (5500 - 4300 years ago) were studied. The kurgans were proven to have been built from the local soils with the addition of anthropogenic material (silt, bones, shells). Representatives of the Yamnaya culture created variegated flowers using the construction techniques such as kneading, ramming, and the inclusion of anthropogenic material. At the micromorphological level, these techniques produces patterns of light loose and more compacted dark microzones in construction materials. Conclusions. Based on meso- and micromorphological analysis of the studied mound structures, we conclude that the representatives of the Yamnaya culture had knowledge of construction technologies and used them appropriately. The main method of mound constructing was creating a variegated mixed soil from humus or carbonate horizons with admixtures of anthropogenic and carbonate material. When building small mounds, people used rough kneading and tamping, but for larger mounds, either more complex construction was used, or more thorough kneading and tamping, as well as longer exposure to water.