Central Mongolian lake sediments reveal new insights on climate change and equestrian empires in the Eastern Steppes

Abstract

The repeated expansion of East Asian steppe cultures was a key driver of Eurasian history, forging new social, economic, and biological links across the continent. Climate has been suggested as important driver of these poorly understood cultural expansions, but paleoclimate records from the Mongolian Plateau often suffer from poor age control or ambiguous proxy interpretation. Here, we use a combination of geochemical analyses and comprehensive radiocarbon dating to establish the first robust and detailed record of paleohydrological conditions for Lake Telmen, Mongolia, covering the past ~ 4000 years. Our record shows that humid conditions coincided with solar minima, and hydrological modeling confirms the high sensitivity of the lake to paleoclimate changes. Careful comparisons with archaeological and historical records suggest that in the vast semi-arid grasslands of eastern Eurasia, solar minima led to reduced temperatures, less evaporation, and high biomass production, expanding the power base for pastoral economies and horse cavalry. Our findings suggest a crucial link between temperature dynamics in the Eastern Steppe and key social developments, such as the emergence of pastoral empires, and fuel concerns that global warming enhances water scarcity in the semi-arid regions of interior Eurasia.

Holocene Temperature Variations in Semi-Arid Central Mongolia—A Chronological and Sedimentological Perspective From a 7400-year Lake Sediment Record From the Khangai Mountains

“…The TSI controlled variation in growing season temperatures at Shireet Naiman Nuur during the Late Holocene was previously described for another high-altitude site from the Mongolian Altai (Bliedtner et al, 2021). Although the MCA is not that pronounced in both records, they well reflect the Late Holocene climate anomalies that were also regionally reported from pollen reconstructions (Yang et al, 2020;Rudaya et al, 2021), a glycerol dialkyl glycerol tetraether based temperature reconstruction (Dugerdil et al, 2021) and an isotope based moisture reconstruction (Struck et al, 2022).…”

“…This cooling phase includes the Dark Ages Cold Period (DACP) and/or Late Antique Little Ice Age (LALIA) from ~1.6 to 1.2 ka BP (Büntgen et al, 2016;Helama et al, 2017). Compared to Mongolian lowland records (Yang et al, 2020;Rudaya et al, 2021;Struck et al, 2022), the following Medieval Climate Anomaly (MCA) does not appear that pronounced as a warm period in the Shireet Naiman Nuur sediments. However, colder conditions are evident during the Little Ice Age (LIA) and growing season temperatures especially decrease during the Maunder Minima (Figure 6).…”

Resilient herders: A deeply stratified multiperiod habitation site in northwestern Mongolia

“…200 km northwest of our research area (Grunert et al, 2000;Walther, 2010), recently published data shows that palaeohydrological conditions at the closer Lake Telmen, situated ca. 150 km east of our research area, shifted toward humid conditions around 1200 BCE (Klinge and Sauer, 2019;Struck et al, 2022). Accordingly, it seems possible that things played out differently in different regions of Mongolia depending on specific local conditions, herd composition, mobility patterns, social arrangements, etc.…”

“…These layers could relate to a short episode during the dry and high-temperature Holocene Megathermal that has been dated for Inner Mongolia and Mongolia to the mid-Holocene (between ca. 8.0 and 4.3 kyr BP), with the duration of the dry intervals differing very locally (An et al, 2008;Chen et al, 2003;Fowell et al, 2003;Klinge and Sauer, 2019;Timireva et al, 2020;Struck et al, 2022). Thus, we believe that the fine and very organic sediments from layers 3 to 8, when the intensity of occupation was likely high, were deposited in a more humid environment when compared to layers 9-10.…”

Millennial‐ to centennial‐scale anti‐phase relationship between the Westerlies and the East Asian summer monsoon and its cultural response along the Silk Roads after a great earthquake in southern Altay ~ 3500 cal a BP

“…The climatic impacts on cultural exchange and evolution along the 'prehistoric Silk Roads' between Europe and Asia have been widely investigated (e.g. Bliedtner et al 2021, Dong et al 2017, 2021, Struck et al 2022, Tan et al 2021, van Geel et al 2004. Archeological data showed that wheat and barley domesticated in western Asia were spread into eastern Central Asia and northwestern China from 4500 to 4000 cal a BP, and broomcorn and foxtail millet domesticated in eastern Asia were spread into western Asia and Europe before 3500 cal a BP (Dong et al 2017).…”