Fig 1.
The extent of the Xiongnu Empire (ca 250 BCE– 150 AD) indicated in red and the location of Baga Gazaryn Chuluu, a Xiongnu intermediate elite ring burial cemetery located in the Gobi desert steppe, Mongolia.
Red circles indicate major ring burial cemeteries supporting 100+ burials. Black icons indicate distribution of aristocratic elite terrace tombs.
Fig 2.
Example of a Xiongnu intermediate elite burial.
Burial Ex08.04b containing the disrupted skeletal remains of a male individual, 20–40 years in age. Burial chamber and artifacts include: (1) ceremonial alcove containing herd animal offerings; (2) iron arrowheads; (3) item made of birch bark; (4) stones comprising the internal cist structure of the burial chamber. Ex08.04 also included a later intrusive interment not shown here.
Fig 3.
Geology of the greater Baga Gazaryn Chuluu showing the relationship between the volcanic sedimentary country rocks and the granitoid massifs.
The granites are of similar but not identical composition due to the terrane boundary between the two areas [33, 34].
Fig 4.
Map of the Baga Gazaryn Chuluu granite ridge system and the locations of Xiongnu period cemeteries where excavations provided samples for isotope analyses.
Areas marked in dark gray range in elevation from 1600 to 1770 m a.s.l., light gray indicates 1600 and 1530 m a.s.l., and white represents landscape below 1530 m a.s.l.
Table 1.
Strontium isotope values (87Sr/86Sr) measured from the tooth enamel of modern domesticated sheep (Ovis aries), wild sheep (Ovis ammon), and archaeological sheep recovered from Xiongnu burials establishing local bioavailable strontium isotope values.
M/2 = second mandibular molar.
Fig 5.
Strontium isotope values for single and paired teeth for Xiongnu individuals from Baga Gazaryn Chuluu.
Yellow bars indicate range of local bioavailable strontium isotope values (light yellow = 2σ) measured from modern sheep grazing in BGC and sheep interred in Xiongnu graves. For paired teeth from the same individual, the arrow indicates the later forming tooth. Red shapes indicate tooth type (circle = molar, diamond = premolar, square = incisor, triangle = canine).
Table 2.
Strontium (87Sr/86Sr), and carbon (δ13C) and oxygen (δ18O) isotope values measured from Xiongnu intermediate elites buried at BGC as well as calibrated radiocarbon determinations.
Additional information reported in S1 Table.
Fig 6.
Oxygen (δ18Oapa) and strontium isotope values for BGC Xiongnu individuals.
Blue circles indicate individuals yielding carbon isotope values consistent with dietary intake from a C3 environment and yellow circles indicating individuals yielding high δ13C values consistent with millet consumption in a C3/C4 environment (see Fig 8). Ex08.19 was measured only for strontium isotopes. For paired teeth from the same individual, the arrow indicates the later forming tooth.
Fig 7.
Strontium isotope results (n = 30) categorized as ‘local’ or ‘non-local’ to BGC for each Xiongnu individual (n = 15) and also displaying which individuals yielded multiple values from different teeth (see Table 2).
Red or blue circles are plotted approximately in line with the mean radiocarbon year (cal BP) represented by a circle within the 95% probability distribution for the radiocarbon determination associated with each individual.
Fig 8.
Carbon (δ13Capa) and strontium isotope values measured from Xiongnu individuals.
Orange bar indicates the estimated seasonal distribution of carbon isotope values in the C3/C4 biome of the BGC area based on seasonal minimum and maximum δ13Capa values measured from the incrementally sampled teeth of modern sheep local to BGC [62]. Yellow bars indicate range of local bioavailable strontium isotope values (light yellow = 2σ). For paired teeth from the same individual, the arrow indicates the later forming tooth.