[U-13] Advanced understanding of Quaternary and Anthropocene hydroclimate changes in East Asia:

[U13-P05] Bronze age megadrought and Trans-Eurasian culture exchange

★Invited Papers

*Liangcheng Tan^1,2,3,4, Guanghui Dong⁵, Zhisheng An^1,2,4, Lawrence R. Edwards^6,7, Haiming li⁸, Dong Li⁹, Robert Spengler¹⁰, Yanjun Cai³, Hai Cheng^3,1, Jianghu Lan^1,2, Rustam Orozbaev^11,12, Ruiliang Liu¹³, Jianhui Chen⁵, Hai Xu¹⁴, Fahu Chen¹⁵ (1. Institute of Earth Environment, Chinese Academy of Sciences, 2. Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, 3.Institute of Global Environmental Change, Xi’an Jiaotong University, 4.Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), 5. College of Earth and Environmental Sciences, Lanzhou University, 6.Department of Earth and Environmental Sciences, University of Minnesota, 7. School of Geography, Nanjing Normal University, 8.Institution of Chinese Agricultural Civilization, Nanjing Agricultural University, 9.Library of Chang’an University, 10. Max Planck Institute for the Science of Human History, 11.Research Center for Ecology and Environment of Central Asia (Bishkek), Chinese Academy of Sciences, 12. Institute of Geology, National Academy of Sciences of Kyrgyz Republic, 13. School of Archaeology, University of Oxford, 14.Institute of Surface-Earth System Science, Tianjin University, 15.Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences)

Keywords:Megadrought, Trans-Eurasian exchange, Silk Roads, Arid Central Asia, Mid-Holocene

Arid Central Asia (ACA), with its diverse landscapes of high mountains, oases, and deserts, hosted the central routes of the Silk Roads that linked trade centers from East Asia to the eastern Mediterranean. Ecological pockets and ecoclines in ACA are largely determined by local precipitation. However, little research has gone into the effects of hydroclimatic changes on trans-Eurasian cultural exchange. Here, we reconstruct precipitation changes in ACA, covering the mid-late Holocene with a U-Th dated, ~3 a resolution, multi-proxy time series of replicated stalagmites from the southeastern Fergana Valley, Kyrgyzstan. Our data reveal a 640-a megadrought between 5820 and 5180 a BP, which likely impacted cultural development in ACA and impeded the expansion of cultural traits along oasis routes. Instead, it may have diverted the earliest transcontinental exchange along the Eurasian steppe during the 5th millennium BP. With gradually increasing precipitation after the megadrought, settlement of peoples in the oases and river valleys may have facilitated the opening of the oasis routes, ‘‘prehistoric Silk Roads”, of trans-Eurasian exchange. By the 4th millennium BP, this process may have reshaped cultures across the two continents, laying the foundation for the organized Silk Roads.