The ancient Loulan, situated on the west bank of Lake Lop Nur, Xinjiang, Northwest China, was an important town on the Silk Road connecting China to Europe. However, this once-prosperous kingdom has been a depopulated zone filled with wind-eroded mounds since approximately AD 500–600. A comprehensive understanding of the environmental setting of the flourishing Loulan civilization is a prerequisite for assessing environment–human interaction there. Here, we present our survey, chronology, and archaeobotany (the identification of plant remains) of vegetation use for architecture from eight ancient ruins of the Loulan kingdom to clarify the ecological landscape on the west bank of Lake Lop Nur and to assess paleoenvironmental conditions when the Loulan kingdom flourished. Our results suggest that Populus euphratica, tamarisk (Tamarix Linn), and reed (Phragmites Trin.) were most widely used as building materials in this period. Wood utilization for buildings depended entirely on indigenous vegetation rather than that of the mountains in the Loulan kingdom, even though the Loulan was a predominant transportation hub on the prosperous Silk Road. Our reconstruction indicates that the west bank of Lake Lop Nur was sufficiently wetter than present conditions to support riparian forest growth composed mainly of P. euphratica, tamarisk shrubs, and reed meadows, until approximately AD 500. These wetter conditions and flourishing civilization accompanied an increase in precipitation in arid central Asia. Conversely, combined evidence of both archeological and paleoclimatic records from the water sources of Lake Lop Nur and ancient oases suggest that abrupt decreased mountain precipitation could be considered a significant environmental factor in the decline of Loulan kingdom.

The discovery of the ancient city of Loulan in Xinjiang, China, at the beginning of the 20th century was of great significance for understanding the evolution of culture and civilization in Inner Asia. However, due to the lack of systematic chronological studies, the history of this ancient city remains unclear, particularly the date of its construction and abandonment. Here, we present the results of the first systematic radiocarbon (¹⁴C) dating carried out on artifacts from ancient Loulan. Our results show that human activity began as early as 350 cal BC, flourished during the interval from the 1st to 4th centuries AD, and completely disappeared around 600 AD. Most of the buildings in the city were constructed during the Eastern Han Dynasty rather than in Wei/Jin Dynasty, as previously indicated by excavated documents and letters (Hedin 1898; Xiao 2006). The development and flourishing of Loulan coincided with the interval of high ice accumulation and meltwater supply from surrounding mountains. The city began to decline and was finally abandoned following an abrupt decrease in ice accumulation and meltwater supply (Yao et al. 1996; Lauterbach et al. 2014), suggesting that natural climate change was the major factor responsible for the abandonment of Loulan.

Prehistoric Holocene eruptions of Changbaishan volcano in Northeast China are poorly dated, with the exception of the 946 CE Millennium eruption. Poorly refined age estimates for the earlier eruptions present problems for the reconstruction of the eruptive history of the volcano. The Qixiangzhan eruption (QE) is a major controversial event in terms of its eruptive timing (ranging from ~88 to ~4 kyr) and style (effusive or explosive). As a result of the imprecise age estimates for the eruption, a geomagnetic field excursion recorded within the QE comendite has been variably correlated with a number of different excursion events observed elsewhere. In this study, a visible early Holocene tephra was identified in Yuanchi Lake, ~30 km east of the Changbaishan volcanic vent, and was dated to 8831‐8100 cal yr BP using Bayesian age modelling. Glass shard compositions enable the correlation of this tephra with the poorly dated QE, as well as with a tephra (SG14‐1058) recorded in Lake Suigetsu, in central Japan. These correlations confirm that the QE was explosive and that the ash from the QE can serve as an important early Holocene marker bed across East Asia. In addition, we propose an age of ~8100 cal yr BP for the QE based on the precise date of the Suigetsu SG14‐1058 tephra. Our results also confirm that the geomagnetic field excursion recorded in the Qixiangzhan comendite dates to ~8100 cal yr BP.