Osl dating of sediments from deserts in northern china
In the middle-to-late Holocene, Earth’s monsoonal regions experienced catastrophic precipitation decreases that produced green to desert state shifts.Resulting hydrologic regime change negatively impacted water availability and Neolithic cultures.Whereas mid-Holocene drying is commonly attributed to slow insolation reduction and subsequent nonlinear vegetation–atmosphere feedbacks that produce threshold conditions, evidence of trigger events initiating state switching has remained elusive. 4,200 years ago in the Hunshandake Sandy Lands of Inner Mongolia, northern China, associated with groundwater capture by the Xilamulun River.This process initiated a sudden and irreversible region-wide hydrologic event that exacerbated the desertification of the Hunshandake, resulting in post-Humid Period mass migration of northern China’s Neolithic cultures.In the early and middle Holocene, northern China’s eastern deserts, including much of the currently sparsely vegetated and semistabilized Hunshandake (Figs.1 and 2), were covered by forests (8), reflecting significantly wetter climate associated with intensification of monsoon precipitation by up to 50% (6). 3) is on the southern margin, and the site Bayanchagan marks the coring site of ref. Rivers with headwaters in the Hunshandake likely formed by groundwater sapping are marked in blue.Totally 900 zircon grains from 9 samples, including 3 surface aeolian sand, 2 lake shore sand, 2 modern river bed sand and 2 Mesozoic sandstone, were collected to correlate the U-Pb ages provenance to trace the possible source of the Hobq Desert.The 2 samples from paleo-lake were dated by OSL and have age of 62.1±8.9ka for KD-2 and 22.4±2.4ka for KD-4, which can be compared to the Hetao paleo-lake exposed below the desert.
The Tengger Desert in China is sensitive to the waxing and waning of the monsoonal system.years old, our multidisciplinary investigation in the Hunshandake Sandy Lands, located in the eastern portion of China’s desert belt, shows that this desert is ca. This study documents dramatic environmental and landscape changes in this desert during the last 10,000 years.For the first time to our knowledge we present a case of desertification mainly triggered by changes in the hydrological and geomorphological system, associated with climate change at ca. Our research on the human–environment interactions in the Hunshandake suggests Chinese civilization may be rooted in the marginal areas in the north, rather than in the middle reaches of the Yellow River.State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061 Abstract Hobq Desert is located at the north of Yimeng Uplift of Ordos Plateau, facing the Hetao Plain.So the terrain is relative low in the north and high in the south.