scholarly journals Late Quaternary paleoclimatic and geomorphological evolution at the interface between the Menyuan basin and the Qilian Mountains, northeastern Tibetan Plateau

2013 ◽  
Vol 80 (3) ◽  
pp. 534-544 ◽  
Author(s):  
Xianyan Wang ◽  
Dimitri Vandenberghe ◽  
Shuangwen Yi ◽  
Jef Vandenberghe ◽  
Huayu Lu ◽  
...  

The Tibetan Plateau is regarded as an amplifier and driver of environmental change in adjacent regions because of its extent and high altitude. However, reliable age control for paleoenvironmental information on the plateau is limited. OSL appears to be a valid method to constrain the age of deposits of glacial and fluvial origin, soils and periglacial structures in the Menyuan basin on the northeastern Tibetan Plateau. Dating results show glaciers advanced extensively to the foot of the Qilian mountains at ~ 21 ka, in agreement with the timing of the global Last Glacial Maximum (LGM) recorded in Northern Hemisphere ice cores. Comparison with results from the eastern Tibetan Plateau suggests that the factor controlling glacial advance in both regions was decreased temperature, not monsoon-related precipitation increase. The areas of the Menyuan basin occupied by glacio-fluvial deposits experienced continuous permafrost during the LGM, indicated by large cryoturbation features, interpreted to indicate that the mean annual temperature was ≥ 7 °C lower than at present. Glacio-fluvial systems in the Menyuan basin aggraded and terraces formed during cold periods (penultimate glaciation, LGM, and possibly the Younger Dryas) as a response to increased glacial sediment production and meltwater runoff then.

2010 ◽  
Vol 40 (2) ◽  
pp. 200-211 ◽  
Author(s):  
Eryuan Liang ◽  
Xuemei Shao ◽  
Dieter Eckstein ◽  
Xiaohong Liu

Little is known about the spatial variability in tree growth and its responses to climate on the Tibetan Plateau; however, such information is essential for improving predictions of forest ecosystem response to climatic change. A network of 16 ring width chronologies was developed along a latitudinal transect in the Qilian Mountains, northeastern Tibetan Plateau. A principal components analysis revealed that the residual chronologies had a positive loading on the first unrotated principal component (PC1). After rotation, PC1 yielded the highest loadings on the driest sites in the northwest and decreased to the south and to the east. PC2 was negatively correlated with altitude. Moisture availability was a dominant limiting factor for tree growth, and this dominance increased northwards and westwards along the precipitation gradient. Loadings of the first two rotated principal components separated the 16 forest sites into three major groups corresponding to the three regions affected by the East Asian Monsoon, Westerlies, and their interaction. Thus, spatial variability in tree growth is an excellent bioindicator of regional climate.


2003 ◽  
Vol 22 (2) ◽  
pp. 137-138 ◽  
Author(s):  
Steffen Mischke ◽  
Ulrike Herzschuh ◽  
Harald Kürschner ◽  
Fahu Chen ◽  
Fei Meng ◽  
...  

Abstract. To our knowledge, the Qilian Mountains in NW China have been investigated with respect to Recent or sub-Recent ostracods for the first time. The Qilian Mountains (95–103°E/37–40°N) extend along the northeastern margin of the Tibetan Plateau reaching a maximum altitude of 5826 m above sea-level (m asl).In September 2001, surface mud from the bottom of various water bodies including brooks, rivers and small shallow meadow and oxbow pools were sampled at an altitude ranging from 2900 m to 3570 m asl. In addition, surface mud samples and short cores were obtained from the small (c. 1 km2) and shallow (<0.4 m) freshwater Lake Luanhaizi situated at about 3200 m asl.Ostracod valves were usually abundant in all of the 32 samples and comprised the taxa listed in Table 1, some of which are illustrated in Plate 1.The recorded taxa are mainly distributed in the holarctic realm but Fabaeformiscandona danielopoli and Ilyocypris echinata appear to be restricted to the cold mountainous regions in China (Huang, 1985; Wang &amp; Zhu, 1991; Sun et al., 1995; Yin &amp; Martens, 1997).Following the first survey, a 14 m long core was drilled in Lake Luanhaizi in January 2002 which is currently under multidisciplinary investigation to reconstruct the Holocene vegetation and climatic history of the Qilian Mountains.


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