Chronologies of glacial advances during the last glacial period in the Nyainqentanglha mountain range may provide constraints on the past climate in a transition zone of the Asian monsoon. We present 15 new Be exposur...Chronologies of glacial advances during the last glacial period in the Nyainqentanglha mountain range may provide constraints on the past climate in a transition zone of the Asian monsoon. We present 15 new Be exposure ages from two moraines in the Payuwang valley, on the north slope of the range. The inner moraine has exposure ages ranging from 18.0±1.7 to 30.6±2.8 ka （n=10）, with a mean age of 23.8±4.0 ka, corresponding to the global Last Glacial Maximum （LGM）. The outer moraine yields exposure ages ranging from 18.0±1.6 to 39.9±3.7 ka （n=5）. Evidence for weathering leads us to view the oldest age as a mini mum age, placing moraine formation during MIS3. Chronologies from the last glacial period from south slope of the Nyainqentanglha support this interpretation. Thus, there appears to have been a local LGM （LLGM） during MIS3 and a more limited glacial advance during the global LGM. Glacial advances during MIS3 in the Nyainqentanglha may correlate with mil lennialscale climate change （Heinrich events）.展开更多
Glaciers in the western Nyainqentanglha Range are an important source of water for social and economic development. Changes in their area were derived from two Chinese glacier inventories; one from the 197o 1：5o,ooo ...Glaciers in the western Nyainqentanglha Range are an important source of water for social and economic development. Changes in their area were derived from two Chinese glacier inventories; one from the 197o 1：5o,ooo scale Chinese Topographic Maps series and the other from Landsat TM/ETM＋ images acquired in 2009. Analyses also included boundaries from 2000 and 2014 Landsat TM/ETM＋ images. A continuing and accelerating shrinkage of glaciers occurred here from 1970 to 2014, with glacier area decreasing by 244.38±29.48 km^2 （27.4%±3.3%） or 0.62%±0.08% a^-1. While this is consistent with a changing climate, local topographic parameters, such as altitude, slope, aspect and debris cover, are also important influences. Recession is manifested by a rise in the elevation of the glacier terminus. The shrinkage of glaciers with NE, N and NW orientations exceeded that of other aspects, and glaciers with SE and S orientations experienced less shrinkage. Changes in the average positive difference of glaciation （PDG） show that the western Nyainqentanglha Range has unfavorable conditions for glacier maintenance which is being exacerbated by a warming climate since 1970.展开更多
基金supported by National Natural Science Foundation of China(Key Program)(Grant No.41230523)Strategic Priority Research Program(B) of the Chinese Academy of Sciences(Grant No.XDB01020300)National Natural Science Foundation of China(General Program)(Grant No.40971017)
文摘Chronologies of glacial advances during the last glacial period in the Nyainqentanglha mountain range may provide constraints on the past climate in a transition zone of the Asian monsoon. We present 15 new Be exposure ages from two moraines in the Payuwang valley, on the north slope of the range. The inner moraine has exposure ages ranging from 18.0±1.7 to 30.6±2.8 ka （n=10）, with a mean age of 23.8±4.0 ka, corresponding to the global Last Glacial Maximum （LGM）. The outer moraine yields exposure ages ranging from 18.0±1.6 to 39.9±3.7 ka （n=5）. Evidence for weathering leads us to view the oldest age as a mini mum age, placing moraine formation during MIS3. Chronologies from the last glacial period from south slope of the Nyainqentanglha support this interpretation. Thus, there appears to have been a local LGM （LLGM） during MIS3 and a more limited glacial advance during the global LGM. Glacial advances during MIS3 in the Nyainqentanglha may correlate with mil lennialscale climate change （Heinrich events）.
基金supported by the fundamental program from the Ministry of Science and Technology of China(MOST)(Grant No.2013FY111400)the National Natural Science Foundation of China(Grant No.41190084)+1 种基金the MOST Technology Oriented Project(Grant No.2012BAC19B07)The second Chinese Glacier Inventory was a product of the previous MOST Project(Grant No.2006FY110200)
文摘Glaciers in the western Nyainqentanglha Range are an important source of water for social and economic development. Changes in their area were derived from two Chinese glacier inventories; one from the 197o 1：5o,ooo scale Chinese Topographic Maps series and the other from Landsat TM/ETM＋ images acquired in 2009. Analyses also included boundaries from 2000 and 2014 Landsat TM/ETM＋ images. A continuing and accelerating shrinkage of glaciers occurred here from 1970 to 2014, with glacier area decreasing by 244.38±29.48 km^2 （27.4%±3.3%） or 0.62%±0.08% a^-1. While this is consistent with a changing climate, local topographic parameters, such as altitude, slope, aspect and debris cover, are also important influences. Recession is manifested by a rise in the elevation of the glacier terminus. The shrinkage of glaciers with NE, N and NW orientations exceeded that of other aspects, and glaciers with SE and S orientations experienced less shrinkage. Changes in the average positive difference of glaciation （PDG） show that the western Nyainqentanglha Range has unfavorable conditions for glacier maintenance which is being exacerbated by a warming climate since 1970.
