V.G. Dirksen

Mid to Late Holocene Climate Change and ITS Influence on Cultural Development in South Central Siberia

The emergence and the cultural blooming of the Scythian cultures in the steppe of South Central Siberia occurred from the 9th century BC (ca. 2700 cal yr BP), much earlier than in the western part of Eurasia. To understand a possible climatic cause of this cultural phenomenon, we have studied sediment cores from the Kutuzhekovo Lake in the Minusinsk depression (Southern Siberia) and the White Lake in the Uyuk depression (Tuva, Central Asia). Both pollen records indicated an arid climate during the mid-Holocene up to ca. 4 kyr BP; increased moisture but still predominantly dry conditions at 4-3 kyr BP interval; a sudden change to more-humid-than-present climate in relatively cold conditions since ca. 3 kyr BP, and a return to drier/warmer climate after ca. 1.6 kyr BP. The reconstructed climate changes correlate well with cultural changes reported for both depressions. The scarcity of Mesolithic-Neolithic (10-5 ka) findings there is in good agreement with the mid-Holocene aridity, which did not provide favorable living conditions for the ancient tribes. By contrast, wet climate establishment since ca. 3 kyr BP corresponds to the Scythian cultures expansion to the Asian steppe which started in the 9th century BC. The data obtained suggest the close relationship between climatic and cultural changes within these arid areas. We conjecture that increased effective moisture balance changed initially arid areas into attractive steppe with a higher biomass production which may have launched the cultural development and blooming of the Scythian cultures.

Chronology of Holocene climate and vegetation changes and their connection to cultural dynamics in Southern Siberia

Two sediment sequences from Big Kyzykul Lake and the Shushenskoe paleolake in the Minusinsk depression, Southern Siberia, were studied by pollen, microfossil, and geochemical analyses, as well as radiocarbon dating. The records indicate the persistence of an arid period between ~11.77.6 cal kyr BP, increased effective moisture since ~7.6 cal kyr BP, 2 humid impulses at ~5.1 and 2.8 cal kyr BP separated by a dry interval, and the return to generally drier conditions after ~1.5 cal kyr BP. This is contrary to the findings noted for the Eurasian temperate zone, but agrees with proxy data reported for arid and semi-arid zones of Central Asia. Reconstructed changes in climate and environment are in good agreement with archaeological data. Almost no evidence of the Mesolithic-Neolithic cultures has been reported for the depression, which is consistent with a dry early and mid-Holocene. Effective moisture started to rise from ~7.6 cal kyr BP, followed by the beginning of human occupation at ~6 cal kyr BP. Two maxima of humidity are recorded in the late Holocene, corresponding to the arrival of trees in the depression. No gap was to be found from the Early Bronze to the Iron ages cultures at this time, with the exception of a dry interval at ~3.63.3 cal kyr BP, when the Minusinsk depression was sparsely occupied. The data obtained suggest a close relationship between climate change and cultural dynamics in the steppe zone of Southern Siberia.

The Sun, Climate Change and the Expansion of the Scythian Culture After 850 BC

The climate shift towards wetter conditions at the transition from Subboreal to Subatlantic in NW-Europe (ca 850 cal. yrs BC; caused by a decline of solar activity), is also evident in South Siberia. Areas that initially were hostile semi-deserts changed into attractive steppe landscapes with a high biomass production, and therefore high carrying capacity. We focus on south-central Siberia where an acceleration of cultural development and an increase in the density of nomadic Scythian populations took place shortly after 850 BC. We hypothesize a causal relationship between the Scythian expansion and migration, and the early Subatlantic shift towards increased humidity.