Oasis landscape of the ancient Loulan on the west bank of Lake Lop Nur, Northwest China, inferred from vegetation utilization for architecture

Abstract

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.

New radiocarbon dating and archaeological evidence reveal the westward migration of prehistoric humans in the drylands of the Asian interior

“…Site 17JZ05: This site is located on a high yardang (height: 30 m, length: 350 m, width: 50 m) (Figure 6a) to the southwest of Tuyin Site (Li et al, 2019b) and in the vicinity of a former wetland and river channels. Mounds consisting of blocks of the remnants of the yardang platform were found.…”

“…The characteristics of the subsistence strategy of the inhabitants were preliminarily revealed based on materials from Xiaohe burials. The stable isotopes of carbon and nitrogen in human bones and hair suggest that their diet included animal products (Li et al, 2019b). 1, Gumugou (Wang, 2014); 2, Xiaohe Cemetery (Xinjiang Institute of Archaeology, 2007); 3, North Niya (Tang et al, 2013;Yue and Yu, 1999); 4, Northern Cemetery (Mair and Cheng, 2013;Wang, 2017a) (e.g.…”

“…The red star indicates the NLS prehistoric settlements. (b) Blue lines are rivers (vector file downloaded from http://bbs.3s001.com); white circles are Xiaohe cultural sites; and the black triangle shows the location of the ancient city of Loulan (Li et al, 2019b). 1, Gumugou (Wang, 2014); 2, Xiaohe Cemetery (Xinjiang Institute of Archaeology, 2007); 3, North Niya (Tang et al, 2013; Yue and Yu, 1999); 4, Northern Cemetery (Mair and Cheng, 2013; Wang, 2017a); DEM map downloaded from http://srtm.csi.cgiar.org.…”

“…Annual precipitation is approximately 20 mm, whereas potential evaporation exceeds 3000 mm; hence it is known as the core arid zone of Eurasia (Xia et al, 2007). The western bank of Lake Lop Nur has experienced an alternation of oasis and yardang-desert environments since the late Pleistocene, accompanied by varying levels of human activity (Li et al, 2018a, 2018b, 2019b). Landforms consisting of wind-eroded NE-SW-oriented yardang terrains, which vary greatly in morphology and chronology, are widespread on the western bank of Lake Lop Nur.…”

Inner Asian agro-pastoralism as optimal adaptation strategy of Wupu inhabitants (3000–2400 cal BP) in Xinjiang, China

“…Asitana (Chen et al, 2012; Li et al, 2013c); 21. Mohuchahangoukou (Li et al, 2019); 22. Bezikelike Grottoes (Yao et al, 2020).…”