1:45 PM - 2:00 PM
[HTT16-13] Climate changes and movement of people in central Asia during the Bronze Age
Keywords:Tienshan Mountains, ice core, central Asia, stable isotope
The Eurasian continent has a long history of movements of people and cultural transformations during the Holocene. Archeological evidence showed that Steppe pastoralists called Yamnaya, which originated in the northern part of the Black Sea, had moved to Central Asia around 5300 years before the present (yr BP). The Yamnaya people had moved south across Tienshan Mountains and Pamir Plateau about 3700 yr BP and finally reached India. The timing of their migration is possibly associated with climate change in Central Asia.
Ice cores have been drilled from mountain glaciers in central Asia to reconstruct past climate changes. An ice core was drilled in 2007 on Grigoriev Ice Cap in the Tianshan Mountains, located in the region where several archaeological remains of the settlements in the Bronze Age have been found. The ice core was 87 m long from the surface to the bottom bedrock and covered the last 12500 yr BP according to the radiocarbon dating.
In this study, we focused on the age of the movement of Yamnaya people in Central Asia, i.e. 2500-4500 cal yr BP, and analyzed water stable isotope ratios (δ18O and δD), the composition of major dissolved ions, pollen assemblages, mineral dust particles, and Sr stable isotopes of the ice core to explore the environmental factors associated with the movement of people. The age of ice core layers was determined by using radiocarbon dating. We compared the ice core records with the age of the settlements in this region.
Results showed that the oxygen-stable isotopes in the ice core fluctuated in a cycle of a hundred years during the period. Pollen records of the ice core suggested a significant vegetation change from tree to grass at 4700 yr BP in this region. Sr stable isotopes showed that the value increased at 5500 yr BP but were mostly stable afterward. Results suggest that aridification and vegetation changes in the middle Holocene may have induced the migration into the mountain region in central Asia.
Ice cores have been drilled from mountain glaciers in central Asia to reconstruct past climate changes. An ice core was drilled in 2007 on Grigoriev Ice Cap in the Tianshan Mountains, located in the region where several archaeological remains of the settlements in the Bronze Age have been found. The ice core was 87 m long from the surface to the bottom bedrock and covered the last 12500 yr BP according to the radiocarbon dating.
In this study, we focused on the age of the movement of Yamnaya people in Central Asia, i.e. 2500-4500 cal yr BP, and analyzed water stable isotope ratios (δ18O and δD), the composition of major dissolved ions, pollen assemblages, mineral dust particles, and Sr stable isotopes of the ice core to explore the environmental factors associated with the movement of people. The age of ice core layers was determined by using radiocarbon dating. We compared the ice core records with the age of the settlements in this region.
Results showed that the oxygen-stable isotopes in the ice core fluctuated in a cycle of a hundred years during the period. Pollen records of the ice core suggested a significant vegetation change from tree to grass at 4700 yr BP in this region. Sr stable isotopes showed that the value increased at 5500 yr BP but were mostly stable afterward. Results suggest that aridification and vegetation changes in the middle Holocene may have induced the migration into the mountain region in central Asia.