Bronze Age Human Communities in the Southern Urals Steppe: Sintashta-Petrovka Social and Subsistence Organization

Why and how exactly social complexity develops through time from small-scale groups to the level of large and complex institutions is an essential social science question. Through studying the Late Bronze Age Sintashta-Petrovka chiefdoms of the southern Urals (cal. 2050–1750 BC), this research aims to contribute to an understanding of variation in the organization of local communities in chiefdoms. It set out to document a segment of the Sintashta-Petrovka population not previously recognized in the archaeological record and learn about how this segment of the population related to the rest of the society. The Sintashta-Petrovka development provides a comparative case study of a pastoral society divided into sedentary and mobile segments. Subsurface testing on the peripheries of three Sintashta-Petrovka communities suggests that a group of mobile herders lived outside the walls of the nucleated villages on a seasonal basis. During the summer, this group moved away from the village to pasture livestock farther off in the valley, and during the winter returned to shelter adjacent to the settlement. This finding illuminates the functioning of the year-round settlements as centers of production during the summer so as to provide for herd maintenance and breeding and winter shelter against harsh environmental conditions. The question of why individuals chose in this context to form mutually dependent relationships with other families and thus give up some of their independence can be answered with a combination of two necessities: to remain a community in a newly settled ecological niche and to protect animals from environmental risk and theft. Those who were skillful at managing communal construction of walled villages and protecting people from military threats became the most prominent members of the society. These people formed the core of the chiefdoms but were not able to accumulate much wealth and other possessions. Instead, they acquired high social prestige that could even be transferred to their children. However, this set of relationships did not last longer than 300 years. Once occupation of the region was well established the need for functions served by elites disappeared, and centralized chiefly communities disintegrated into smaller unfortified villages

Strontium isotope ratios (87Sr/86Sr) analysis from various sources the southern Trans-Urals

The present dataset contains measurement of biovalable strontium isotopes (87Sr/86Sr) gathered in the southern Trans-Urals. There are four samples types, such as wormwood (n = 95), leached soil (n = 95), water (n = 93) and freshwater mollusks (n = 74), collected to measure bioavailable strontium isotopes. The analysis of Sr isotopic composition was carried out in the cleanrooms (6 and 7 ISO classes) of the Geoanalitik shared research facilities of the Institute of Geology and Geochemistry, the Ural Branch of the Russian Academy of Sciences (Ekaterinburg). Mollusk shell samples preliminarily cleaned with acetic acid, as well as vegetation samples rinsed with deionized water and ashed, were dissolved by open digestion in concentrated HNO 3 with the addition of H 2 O 2 on a hotplate at 150°C. Water samples were acidified with concentrated nitric acid and filtered. To obtain aqueous leachates, pre-ground soil samples weighing 1 g were taken into polypropylene containers, 10 ml of ultrapure water was added and shaken in for 1 hour, after which they were filtered through membrane cellulose acetate filters with a pore diameter of 0.2 μm. In all samples, the strontium content was determined by ICP-MS (NexION 300S). Then the sample volume corresponding to the Sr content of 600 ng was evaporated on a hotplate at 120°C, the precipitate was dissolved in 7M HNO 3 . Sample solutions were centrifuged at 6000 rpm and strontium was chromatographically isolated using SR resin (Triskem). The strontium isotopic composition was measured on a Neptune Plus multicollector mass spectrometer with inductively coupled plasma (MC-ICP-MS). To correct mass bias, a combination of bracketing and internal normalization according to the exponential law 88 Sr/ 86 Sr = 8.375209 was used. The results were additionally bracketed using the NIST SRM 987 strontium carbonate reference material using an average deviation from the reference value of 0.710245 for every two samples bracketed between NIST SRM 987 measurements. The long-term reproducibility of the strontium isotopic analysis was evaluated using repeated measurements of NIST SRM 987 during 2020-2022 and yielded 87 Sr/ 86 Sr = 0.71025, 2SD = 0.00012 (104 measurements in two replicates). The within-laboratory standard uncertainty (2σ) obtained for SRM-987 was ± 0.003 %

Strontium isotope ratios (87Sr/86Sr) from various sources of freshwater from the Southern Trans-Urals

The present dataset contains measurement of biovalable strontium isotopes (87Sr/86Sr) gathered in the southern Trans-Urals. There are four samples types, such as wormwood (n = 95), leached soil (n = 95), water (n = 93) and freshwater mollusks (n = 74), collected to measure bioavailable strontium isotopes. The analysis of Sr isotopic composition was carried out in the cleanrooms (6 and 7 ISO classes) of the Geoanalitik shared research facilities of the Institute of Geology and Geochemistry, the Ural Branch of the Russian Academy of Sciences (Ekaterinburg). Mollusk shell samples preliminarily cleaned with acetic acid, as well as vegetation samples rinsed with deionized water and ashed, were dissolved by open digestion in concentrated HNO 3 with the addition of H 2 O 2 on a hotplate at 150°C. Water samples were acidified with concentrated nitric acid and filtered. To obtain aqueous leachates, pre-ground soil samples weighing 1 g were taken into polypropylene containers, 10 ml of ultrapure water was added and shaken in for 1 hour, after which they were filtered through membrane cellulose acetate filters with a pore diameter of 0.2 μm. In all samples, the strontium content was determined by ICP-MS (NexION 300S). Then the sample volume corresponding to the Sr content of 600 ng was evaporated on a hotplate at 120°C, the precipitate was dissolved in 7M HNO 3 . Sample solutions were centrifuged at 6000 rpm and strontium was chromatographically isolated using SR resin (Triskem). The strontium isotopic composition was measured on a Neptune Plus multicollector mass spectrometer with inductively coupled plasma (MC-ICP-MS). To correct mass bias, a combination of bracketing and internal normalization according to the exponential law 88 Sr/ 86 Sr = 8.375209 was used. The results were additionally bracketed using the NIST SRM 987 strontium carbonate reference material using an average deviation from the reference value of 0.710245 for every two samples bracketed between NIST SRM 987 measurements. The long-term reproducibility of the strontium isotopic analysis was evaluated using repeated measurements of NIST SRM 987 during 2020-2022 and yielded 87 Sr/ 86 Sr = 0.71025, 2SD = 0.00012 (104 measurements in two replicates). The within-laboratory standard uncertainty (2σ) obtained for SRM-987 was ± 0.003 %