Holocene environmental changes around Xiaohe Cemetery and its effects on human occupation, Xinjiang, China

Abstract

The Xiaohe Cemetery archaeological site (Cal. 4-3.5 ka BP) is one of the most important Bronze Age sites in Xinjiang, China. Although the surrounding environment is an extremely arid desert now, abundant archaeological remains indicate that human occupation was common during certain periods in the Holocene. Field investigations and laboratory analyses of a sediment profile near the Xiaohe Cemetery indicate that while the regional environment was arid desert throughout the Holocene there were three episodes of lake formation near the site in the periods 4.8-3.5 ka BP, 2.6-2.1 ka BP and 1.2-0.9 ka BP. Geomorphic and hydrological investigations reveal that a lake or lakes formed in a low-lying area when water was derived initially from the Kongque River and then shunted into the Xiaohe River basin. Low amounts of active chemical elements in lacustrine sediment between 4.8-3.5 ka BP indicate abundant and continuous water volume in the lake; the content of active chemical elements increased between 2.6-2.1 ka BP but was still at a relatively low level, suggesting a declining amount of water and diminished inflow. Between 1.2-0.9 ka BP there was a very high content of active elements, suggesting decreased water volume and indicating that the lake was stagnate. In contrast, the general climate condition shows that there had a warm-humid stage at 8-6 ka BP, a cool-humid stage at 6-2.9 ka BP and a warm-dry stage at 2.9-0.9 ka BP in this region. The hydrological evolutions around Xiaohe Cemetery did not have one-to-one correspondence with climate changes. Regional comparison indicates that broad-scale climatic conditions played an important role through its influences on the water volume of the Tarim River and Kongque River. But, the formation of the lakes and their level were controlled by geomorphic conditions that influenced how much water volume could be ZHANG Yifei et al.: Holocene environmental changes around Xiaohe Cemetery and its effects on human occupation 753 shunted to Xiaohe River from Kongque River. Human occupation of the Xiaohe Cemetery and nearby regions during the Bronze Age and Han-Jin period (202 BC-420 AD) corresponded to the two earlier lake periods, while no human activities existed in the third lake period because of the decreased water volume.

The genomic origins of the Bronze Age Tarim Basin mummies

“…The southern part of Xinjiang consists of the Tarim Basin, a dry inland sea that now forms the Taklamakan Desert. Although mostly uninhabitable, the Tarim Basin also contains small oases and riverine corridors, fed by runoff from thawing glacier ice and snow from the surrounding high mountains 4 , 10 , 11 .

Fig.

…”

Moisture Changes in the Northern Xinjiang Basin Over the Past 2400 years as Documented in Pollen Records of Jili Lake

“…There is evidence for a widespread prehistoric culture in Xinjiang area, associated with a relatively wetter climate during the late Holocene (An et al, 2019). However, abrupt climate and environment changes might have led to the collapse of some civilizations, such as Xiaohe Culture (Zhang et al, 2017) and Loulan civilization (Fontana et al, 2019;Hao et al, 2019). A diatom record from Bosten Lake indicated that changes in hydro-climate was the main reason for the collapse of the Loulan Kingdom (Fontana et al, 2019).…”

The study of early human settlement preference and settlement prediction in Xinjiang, China

“…Especially when compared to the Palaeolithic period conditions under the influence of Younger Dryas impact hypothesis 28 , 88 , the Neolithic moisture and temperature conditions were superior and were conducive to human space expansion and settlement. The cold and dry climate (4.3–3.8 ka BP, 4.3 ka event) and its lagged influence on the early late Holocene in Xinjiang restricted the development of the Bronze Age in Xinjiang to some extent 89 – 91 . This climatic influence is also an important reason why the maximum elevation of settlements in the Bronze Age was 814 m lower than that during the Neolithic and why the settlement preference for rivers was different from that in the Neolithic, as evidenced by the decline of the Xiaohe Culture in Xinjiang 91 .…”