From 2001 to 2019, at the Radiocarbon Laboratory of the IIMK RAS, 14C dating was carried out using the liquid- scintillation method of samples from the excavations of the Russian-Mongolian Archaeological Expedition led by A.A. Kovalev and D. Erdenebaatar, including those belonging to the firstly discovered cultures of the Bronze Age and complexes with deer stones. The materials obtained made it possible to construct a columnar sequence of Western Mongolian cultures, to clarify the period of construction of a different types of burial and ritual structures. The dates obtained by AMS-method in recent years for the same burials make the column older in parts and as a whole; the discrepancy with the previously obtained results is most likely due to the impossibility of complete purification of bulk samples for LSC analysis from modern organic contaminants.

The horizons of slash-and-burn agriculture were distinguished by pedological, anthracological, phytolithic and palynological features. Radiocarbon dates were obtained from the coals. Most of the dates refer to the time of the Great Migration and the Middle Ages. Some of the slash horizons are dated to the Early Iron Age, the earliest are from the Bronze Age and, presumably, the Neolithic.

This paper raises methodological issues of radiocarbon dating of historical events basing on the data obtained during the excavations in of the Russian medieval city of Yaroslavl. The city is of special interest to our study because of the precise time of its destruction by troops of Batu Khan mentioned in chronicles – the winter of 1238. To date in Yaroslavl there have been discovered nine sanitary mass-burials of citizens and domestics animals buried sometime after the Mongols massacre. To date in Yaroslavl there have been discovered nine sanitary mass-burials of citizens and domestics animals buried sometime after the Mongols massacre, of which we have dated sixty-five samples. A Bayesian chronological model of the AMS dates narrowed the interval to the range of 1233–1269 cal AD. The synchrony of all burials was confirmed with probability of 95.6%.

In Russian archaeology radiocarbon dating is used in very rare cases when antiquities from historical periods are studied based on coin finds and historical sources which have their own historical chronology. However, this arrangement does not always work, as some graves do not contain items that can be dated to a narrow time span while a great number of graves often have no funerary offerings at all. The State Historical Museum in Moscow houses archaeological materials from the Phanagoria necropolis excavated in 1936. Phanagoria is is the largest city of the Classical period and the early medieval period (540 BC–10th century). The collection from the necropolis excavations has preserved organic carbon-containing finds from grave 21 (the wood served to make a coffin – juniper, and sea algae). These materials were selected for AMS-dating. The following results were obtained: wood: 342–420 calAD, sea algae – 132–241 calAD. Of particular interest is the impression of the coin of the Roman Emperor Valens (364–378) found in this grave. The AMS-date of the coffin wood fully confirms the traditional archaeological dating of the finds whereas the coin offers an opportunity to narrow down the timeline of the grave to several decades (375–420). The older age of sea algae is caused by a marine reservoir effect which must be taken into account during the verification of the radiocarbon age of the consumers the food intake of which probably included algae.