HDP09 core drilled in Lake Khuvsgul,Mongoria,at 50°52'48 'N,100°26'30' E where the water depth is 222.25 m reached to the depth of ~60 m below lake floor in 2006.The bottom part of the core c...HDP09 core drilled in Lake Khuvsgul,Mongoria,at 50°52'48 'N,100°26'30' E where the water depth is 222.25 m reached to the depth of ~60 m below lake floor in 2006.The bottom part of the core consists of alkali basalt.This basalt consists of the basement of the lake Khuvsgul based on its bulk chemistry and core position plotted on the seismic profile.K-Ar age of the basalt is(8.5±0.2) Ma,which is concordant with the on-land basalt distributed in the eastern part of the lake,and implies the maximum age of the Lake Khuvsgul formation.展开更多
A 13-m long sediment core from Borsog Bay of Lake Khuvsgul,northern Mongolia records hydro-environmental changes during the past 10000 years;three rapid environmental changes(ca.2700 a BP,ca.6000 a BP and ca.8000 a BP...A 13-m long sediment core from Borsog Bay of Lake Khuvsgul,northern Mongolia records hydro-environmental changes during the past 10000 years;three rapid environmental changes(ca.2700 a BP,ca.6000 a BP and ca.8000 a BP based on ^(14)C dates of organic carbon materials) are detected in depth profiles of sediment physical properties.Temporal changes in the physical properties of the core(grain size,grain density and water content) also suggest three periods of large discharge from outside and three periods of stable input(200-500 cm,800-980 cm and 1050-1200 cm).The sedimentation rates in the stable period are 0.102 cm·a^(-1),0.085 cm·a^(-1) and 0.139 cm·a^(-1),respectively.The periods of large discharge likely correspond to the intervals of the three rapid environmental changes,indicating that there were three rapid and high discharge periods related to melt water and/or heavy rainfall during the past 10000 years in this region.The analytical results also show that the physical properties are valuable in reconstructing past hydro-geomorphological fluctuations in the lake-catchment system.展开更多
Sediment information is closely related to a lake-catchment system.Lake Baikal and Lake Khuvsgul in the Baikal depression have shown different sedimentary trends during the past 800 ka;the sediment discharge(sedimenta...Sediment information is closely related to a lake-catchment system.Lake Baikal and Lake Khuvsgul in the Baikal depression have shown different sedimentary trends during the past 800 ka;the sediment discharge(sedimentation rate) in Baikal basically followed the global climatic change,whereas that in Khuvsgul did not always do so.An elementary mathematical model is used to explain the difference,considering changes in the catchment area and water level.Numerical calculations based on the model suggest that sedimentary conditions are closely related to changes in the water level and erosion area,which probably had a significant influence on Lake Khuvsgul and little influence on Lake Baikal.展开更多
基金The Research Fund from Kanazawa University and Grants-in-Aid for Scientific Research from Japanese Society for the promotion of Science(K.Kashiwaya[(A2)20253002])
文摘HDP09 core drilled in Lake Khuvsgul,Mongoria,at 50°52'48 'N,100°26'30' E where the water depth is 222.25 m reached to the depth of ~60 m below lake floor in 2006.The bottom part of the core consists of alkali basalt.This basalt consists of the basement of the lake Khuvsgul based on its bulk chemistry and core position plotted on the seismic profile.K-Ar age of the basalt is(8.5±0.2) Ma,which is concordant with the on-land basalt distributed in the eastern part of the lake,and implies the maximum age of the Lake Khuvsgul formation.
基金Grants-in-Aid for Scientific Research from Ministry of Education,Science and Culture(Japan)to K.Kashiwaya[(A2)20253002]
文摘A 13-m long sediment core from Borsog Bay of Lake Khuvsgul,northern Mongolia records hydro-environmental changes during the past 10000 years;three rapid environmental changes(ca.2700 a BP,ca.6000 a BP and ca.8000 a BP based on ^(14)C dates of organic carbon materials) are detected in depth profiles of sediment physical properties.Temporal changes in the physical properties of the core(grain size,grain density and water content) also suggest three periods of large discharge from outside and three periods of stable input(200-500 cm,800-980 cm and 1050-1200 cm).The sedimentation rates in the stable period are 0.102 cm·a^(-1),0.085 cm·a^(-1) and 0.139 cm·a^(-1),respectively.The periods of large discharge likely correspond to the intervals of the three rapid environmental changes,indicating that there were three rapid and high discharge periods related to melt water and/or heavy rainfall during the past 10000 years in this region.The analytical results also show that the physical properties are valuable in reconstructing past hydro-geomorphological fluctuations in the lake-catchment system.
基金Grants-in-Aid for Scientific Research from Ministry of Education,Science and Culture(Japan)to K.Kashiwaya[(A2)20253002]
文摘Sediment information is closely related to a lake-catchment system.Lake Baikal and Lake Khuvsgul in the Baikal depression have shown different sedimentary trends during the past 800 ka;the sediment discharge(sedimentation rate) in Baikal basically followed the global climatic change,whereas that in Khuvsgul did not always do so.An elementary mathematical model is used to explain the difference,considering changes in the catchment area and water level.Numerical calculations based on the model suggest that sedimentary conditions are closely related to changes in the water level and erosion area,which probably had a significant influence on Lake Khuvsgul and little influence on Lake Baikal.
