Landscape evolution of the Ulan Buh Desert in northern China during the late Quaternary Fahu Chen a, ⁎, Guoqiang Li a , Hui Zhao b , Ming Jin a , Xuemei Chen a , Yuxin Fan a , Xiaokang Liu a , Duo Wu a , David Madsen a a MOE Key Laboratory of West China's Environmental System, Research School of Arid Environment and Climate Change, Lanzhou University, Lanzhou 730000, China b Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China abstract article info Available online xxxx Keywords: Arid landscape evolution Ulan Buh Desert Last glacial period Holocene China The evolution of arid environments in northern China was a major environmental change during the Quaternary. Here we present the dating and environmental proxy results from a 35 m long core (A-WL10ZK-1) collected from the Ulan Buh Desert (UBD), along with supplemental data from four other cores. The UBD is one of the main desert dune fields in China and our results indicate the UBD has undergone complex evolution during the late Quaternary. Most of the present UBD was covered by a Jilantai-Hetao Mega-paleolake lasting until ~90 ka ago. A sandy desert environment prevailed throughout the UBD during the last glacial period and early Holocene. A wetland environment characterized by the formation of numerous interdunal ponds in the northern UBD oc- curred at ~8–7 ka, although a dune field persisted in the southern UBD. The modern UBD landscape formed after these wetlands dried up. During the last 2000 years, eolian sand from the Badain Jaran Desert has invaded the northern UBD, while farming and overgrazing resulted in the formation of the eastern UBD. We suggest that the formation of UBD landforms is related to the disintegration of the megalake Jilantai-Hetao and to summer monsoon changes during the last glaciation and Holocene. © 2013 University of Washington. Published by Elsevier Inc. All rights reserved. Introduction Sand deserts are a major landscape feature of the arid and semi-arid areas of the world. Northwestern China contains the largest desert dune fields in the central-east Asian dryland zone, and these deserts form one of the main dust storm and dust source areas in the world (Biscaye et al., 1997; Sun et al., 2001). The evolution of the major deserts in China's drylands is very important in understanding environmental and climat- ic changes in arid central-east Asia, partly because these deserts provide huge amounts of atmospheric dust and aerosols which influence re- gional and even global climate changes (Uno et al., 2009). These deserts also contribute much of the silt to the Chinese Loess Plateau (Liu et al., 1994; Sun et al., 2008; Li et al., 2009). The Taklamakan Desert in western China, the largest desert dune field in China, was formed by ~5 Ma (Sun and Liu, 2006) or ~7 Ma (Sun et al., 2009). The Badain Jaran Desert, with the highest sand dunes on Earth (Yang et al., 2011), and the Tengger Desert on the southern Mongolian Plateau are thought to have formed since the Tertiary Period (Yan et al., 1992; Yang et al., 2006). However, it is generally believed that the sandy lands on the central and eastern Inner Mongolia Plateau and on the Ordos Plateau developed only during the late Holocene (Qin, 2002), possibly as recently as during the last 2000 yr, due to improper human land use including overgrazing and farming (Hou, 1979; Jing, 2001). The Ulan Buh Desert (UBD), on the western Inner Mongolia Plateau, one of the main desert dune fields in China, is located at the margin of the present Asian summer monsoon (Fig. 1), and the landscape there is thus sensitive to changes in the intensity and northern limit of the summer monsoon. This area experienced dramatic environmental changes during the late Quaternary (Chen et al., 2008a), as well as fre- quent human disturbances in the late Holocene (Hou and Yu, 1973). Chen et al. (2008a), Yang et al. (2008) and Fan et al. (2010a) have inves- tigated the serial shorelines and lacustrine deposits around Jilantai Salt Lake and the Hetao Plain. On the basis of Optically Stimulated Lumines- cence (OSL) dates, Chen et al. (2008a) proposed that a so-called Jilantai- Hetao Mega-paleolake (JH paleolake) covered the whole Jilantai Salt Lake basin, and most of the modern UBD and the Hetao Plain, with the highest water levels reaching ~ 1080 m above sea level (asl). OSL dating suggested that the megalake formed before 50–60 thousand yr ago (ka), with the UBD forming sometime after the paleolake disappeared. Using archeological methods and historical records, including the iden- tification of abandoned cultivated fields, the remains of ancient cities/ towns, and the location of tombs, Hou and Yu (1973) concluded that the UBD only formed after the Han Dynasty (beginning about 2200 yr ago) as the result of intensive human activity in the low wetlands of the eastern UBD. However, recent research indicates the UBD developed much earlier, before the historical period. Yang et al. (1991) believed that the desert formed during the late Pleistocene to early Holocene Quaternary Research xxx (2013) xxx–xxx ⁎ Corresponding author. Fax: +86 931 8912330. E-mail address: fhchen@lzu.edu.cn (F. Chen). YQRES-03470; No. of pages: 12; 4C: 0033-5894/$ – see front matter © 2013 University of Washington. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.yqres.2013.08.005 Contents lists available at ScienceDirect Quaternary Research journal homepage: www.elsevier.com/locate/yqres Please cite this article as: Chen, F., et al., Landscape evolution of the Ulan Buh Desert in northern China during the late Quaternary, Quaternary Research (2013), http://dx.doi.org/10.1016/j.yqres.2013.08.005