Our article, “Late Pleistocene paleoenvironments and episodic human occupations in the Orkhon Valley of central Mongolia,” describing early Upper Pleistocene climatic and environmental conditions associated with the Middle Paleolithic in Mongolia is now available in Archaeology, Ethnology & Anthropology of Eurasia, Volume 49, Number 2: 3-22 (2021). [A Russian-language version of this article is available as “Природная среда и эпизоды заселения Центральной Монголии в позднем плейстоцене: по материалам памятников в долине реки Орхон,” Археология, этнография и антропология Евразии, Том 49, № 2: 3-22 (2021)].
Here, we report our analysis of geological profiles at three sites in the Orkhon Valley containing cultural sequences spanning the Final Middle Paleolithic through Late Upper Paleolithic. Here, we present the first results of our work on paleoclimatic conditions that may have impacted human occupation and abandonment of this major valley.
This research is based mostly on geochemical analysis (Rare Earth Elements, Strontium, and various geochemical indices) and the interpretation of faunal remains.
Collectively, our data indicate gradual aridification of a semi-arid to semi-humid climate in the Orkhon Valley during Marine Isotope Stages-3 and -2. This conclusion is supported by the faunal complex reconstructed for the Khangai Mountains, representing the mammoth fauna of the steppe and forest-steppe ecozones. Taking into account radiometric dates of culture-bearing layers and features of the identified lithic industries and their deposition, we conclude that human occupation of the Orkhon Valley was episodic, sporadic and of variable duration. Two discrete occurrences of human occupation have been established thus far at Moiltyn-am; one for the geological unit including Layers 4–6, in which Layer 4 is redeposited, and one for Layer 3.
Remains of the large bovid – horse – sheep triad are most often found in these sites, while the occurrence of bovids, most likely represented by the Baikal yak, decreases with the period of aridification lasting from the Middle Paleolithic to the Early Upper Paleolithic. The diversity of human material culture documented in the study area is obviously associated with paleoecological and paleoclimatic parameters, the fluctuating availability of water resources supporting predictable availability of prey animals, and lithic raw materials suitable for stone tool production, as well as with a favorable geographical location on the pathways of migratory game. The available chronostratigraphic characteristics of sites in the Orkhon Valley are still insufficient for conclusions to be confidently drawn about the coexistence of different hominin groups exhibiting varying cultural characteristics. It is possible that ancestral human populations migrating through the valley did not often encounter one another due to what we perceive as short-term habitation of the currently-known archaeological sites.
More data, including new Optically Stimulated Luminescence and radiocarbon dates, are in process, to be published later this year.