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Effect of Glacial Buzzsaw during Quaternary in Puland, Tibet
GUO Hao, LIU Gengnian
Acta Scientiarum Naturalium Universitatis Pekinensis    2020, 56 (6): 1065-1072.   DOI: 10.13209/j.0479-8023.2020.075
Abstract1494)   HTML    PDF(pc) (4710KB)(187)       Save
In order to verify the effect of glacial buzzsaw on the evolution of landform in Pulan region of Tibet, three areas of Gurla Mandhata (Naimon’anyi), Himalayas and Gangdese are selected. Based on digital elevation model (DEM) data, remote sensing images, the equilibrium line altitude (ELA) of modern glacier and last glacial maximum (LGM) glacier, the relationship between slope and elevation and the elevation distribution are calculated and analyzed. We conclude that the areas with significant glacier erosion and the most obvious slope reduction are located in the area near LGM glacial equilibrium line and the heights of the mountains are limited in some degree. Based on the glacial landform characteristics and previous investigations, we believe that climate is the most important factor influencing the effectiveness of glacial buzzsaw. During glacial periods, the westerly jets moved southward, wind speed and precipitation increased, and the precipitation increased, resulting in favorable conditions for the development of glaciers and the effect of glacial buzzsaw. For mountains with strong tectonic uplift, such as Gurla Mandhata in the study area, although the effect of glacial buzzsaw is strengthened, the height increase caused by tectonic uplift is not completely offset by glacial buzzsaw.
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Equilibrium Line Altitude Distribution Characteristics and Influencing Factors of Modern Glaciers in Yadong-Kangmar, Himalaya Range
LIU Junnan, LIU Gengnian, PENG Xu, LIU Beibei, CUI Zhijiu
Acta Scientiarum Naturalium Universitatis Pekinensis    2018, 54 (2): 398-406.   DOI: 10.13209/j.0479-8023.2017.103
Abstract970)   HTML2)    PDF(pc) (33858KB)(191)       Save

The second China glacier inventory results and satellite images, combined with field observation of the landscape, are used to discuss the glacier equilibrium-line altitude (ELA) distribution characteristics and influencing factors of Yadong-Kangmar, Himalaya Range. The result shows that the average of modern glacier ELA of study area is 5717 m, Kuragon District on average is 5840?5957 m, Baima Ling Kangri area is relatively low, 5333?5373 m, reflecting the control of climate and terrain trend to glacier ELAs. In addition, there are varying degrees of effects on glacier ELAs on account of the factors like direction, slope, glacier moraine cover, and avalanche.

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Prediction of Tibetan Plateau Permafrost Distribution in Global Warming
JIAO Shihui, WANG Lingyue, LIU Gengnian
Acta Scientiarum Naturalium Universitatis Pekinensis    2016, 52 (2): 249-256.   DOI: 10.13209/j.0479-8023.2015.112
Abstract1327)   HTML    PDF(pc) (5599KB)(1350)       Save

Area and condition variation of three kinds of permafrost in 2099 are simulated by integration of temperature data and modern permafrost distribution in Tibetan Plateau. The conclusions shows that in condition of 1.8ºC rising of annual average air temperature, the total area of permafrost will be 83.4% of today, the continuous permafrost will shrink to the east of 76.6°E, the sporadic permafrost melts greatly in southeast of plateau, and the mountainous permafrost has obvious degeneration in Pamirs and Himalaya Mountain area. While in condition of 4ºC rising of annual average air temperature, the total area of permafrost will be 73% of today, the continuous permafrost will shrink to the east of 77.4°E, the sporadic permafrost degenerates slightly in middle area, the mountainous permafrost melts greatly in Qilian Mountain, and it only could be found in some high altitude places such as Pamirs, Himalaya Mountain and Hengduan Mountain. In condition of 6ºC rising of annual average air temperature, the total area of permafrost will be 50.8% of today, the continuous permafrost will shrink to 78°E, the sporadic permafrost only could be found in middle-west area, the mountainous permafrost appeares in some extremely high area slightly.

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Analysis of Particle Characteristics and Differentiation Processes of Glacial Sediment in Tianshan and Eolian Sediment in the Taklimakan Desert
PAN Renyi,LI Chuanchuan,ZHANG Mei,SUN Caiqi,LIU Gengnian
Acta Scientiarum Naturalium Universitatis Pekinensis   
Quartz Grain SEM Microtextures Analyses of Sub-Glacial Deposits at Hailuogou Glacier
SHI Lei,ZHANG Yue,CHEN Yixin,FU Hairong,LIU Gengnian
Acta Scientiarum Naturalium Universitatis Pekinensis   
Abstract761)            Save
The SEM microtextures of glacial sediments samples taken from Hailuogou Glacier are analyzed. The major microtextures are listed as follows: sharp angular features with sharp edges and high relief; large-medium conchoidal fractures, parallel cleavage and terraced fractures, indicating mechanical fragmentation; stria, crescentic gouges and crushed deep hole, indicating abrasion; dissolution pits and grooves, siliceous sphere and clay minerals, indicating chemical dissolution and precipitation. These results indicate that there are intensive erosion processes and chemical dissolution processes under Hailuogou Glacier. The statistical analyses show that the quartz grain SEM microtextures of maritime glacial deposits are different fromthat of fluvial, lacustrine, coastal and eolian deposits, as well as that of continental glacial deposits in Antarctic and inside Tibetan Plateau.
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