Recently, the degradation of permafrost and marsh environments in the Da and Xiao Hinggan Mountains has become a great concern as more human activities and pronounced climate warming were observed during the past 30 y...Recently, the degradation of permafrost and marsh environments in the Da and Xiao Hinggan Mountains has become a great concern as more human activities and pronounced climate warming were observed during the past 30 years and projected for the near future. The distr/bution patterns and development mechanisms of the permafrost and marshes have been examined both in theories and in field observations, in order to better understand the symbiosis of permafrost and marshes. The permafrost and marshes in the Da and Xiao Hinggan Mountains display discernible zonations in latitude and elevation. The marsh vegetation canopy, litter and peat soil have good thermal insulation properties for the underlying permafrost, resulting in a thermal offset of 3 ℃ to 4℃ and subsequently suppressing soil temperature. In addition, the much higher thermal conductivity of frozen and ice-rich peat in the active layer is conducive to the development or in favor of the protection of permafrost due to the semi-conductor properties of the soils overlying the permafrost. On the other hand, because permafrost is almost impervious, the osmosis of water in marsh soils can be effectively reduced, timely providing water supplies for helophytes growth or germination in spring. In the Da and Xiao Hinggan Mountains, the permafrost degradation has been accelerating due to the marked climate warming, ever increasing human activities, and the resultant eco-environmental changes. Since the permafrost and marsh environments are symbiotic and interdependent, they need to be managed or protected in a well-coordinated and integrated way.展开更多
This paper studied the soil animals of four type forests of broad leaved pine forests in the southern slope of the Xiao Hinggan Mountains. The samples were extracted from four forest types in every first week of June,...This paper studied the soil animals of four type forests of broad leaved pine forests in the southern slope of the Xiao Hinggan Mountains. The samples were extracted from four forest types in every first week of June, August, October, and every forest type was chosen out three plots. Since there are different soil animals in different depths, every plot was divided into four partitions with the same vertical distance: litter, 0－ 10 cm, 10－ 20 cm, 20－ 30 cm. Using hand sorting out large soil animals, Tullgren method (to middle and small soil animals) and Baermann method (to moist soil animals) to collect soil animals. Among the four type forests, insecta has the largest amount of groups of 54. Oribatida has the most number of individual, which is 1547, occupying 21.73 percent of total collectings. There are 81 groups of soil animals, totalling 7118 belonging to 8 Class 24 Order 57 Family, in which there are 54 groups of big sized soil animals totalling 2370, 41 groups of middle and small sized soil animals totalling 4808. Among all the soil animals,their dominant group is 3 ones, usual growp is 14 ones, and rare group is 64 ones. The results show that among the four type forests, the groups of soil animal in Tilia pine forest are much more than the others, with the highest variety index, and the individual number of the soil animals is also very large. The numbers of group and individual in Picea Abies Pine forest are both small.Among the four forest types, the soil animals in Tilia pine forest are most similar to Betula costata pine forest. There is so little similarity between the soil animals in Picea Abies pine forest and in the other three forest types.展开更多
晨明岩体位于小兴安岭东南段,其岩石组合为花岗闪长岩和二长花岗岩。所测定样品中的锆石均具有振荡生长环带,结合Th/U比值,表明这些锆石为岩浆成因,LA-ICP MS U-Pb测年结果显示,其形成时代分别为432.8±1.2 Ma和431.9±1.7 Ma,...晨明岩体位于小兴安岭东南段,其岩石组合为花岗闪长岩和二长花岗岩。所测定样品中的锆石均具有振荡生长环带,结合Th/U比值,表明这些锆石为岩浆成因,LA-ICP MS U-Pb测年结果显示,其形成时代分别为432.8±1.2 Ma和431.9±1.7 Ma,即早志留世。晨明岩体的地球化学特征显示,其属于高钾钙碱性系列,ACNK值为1.16～1.40,属于过铝质花岗岩;微量元素表现出富集大离子亲石元素(Rb、Ba、U和Th)和轻稀土元素,亏损高场强元素(Nb、Ta、Ti)和P、Sr以及重稀土元素。上述地球化学特征暗示其主要来源于下地壳物质的部分熔融,样品的过铝质特征暗示其形成于陆壳加厚环境。结合前人研究成果,认为晨明岩体形成于松嫩地块和佳木斯地块的碰撞拼合环境,即松嫩地块和佳木斯地块可能在早志留世碰撞拼合。展开更多
基金Under the auspices of National Natural Science Foundation of China (No. 40701031,40225001,J0630966)3rd-term Knowledge Innovation Program of Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences (No. O650445)
文摘Recently, the degradation of permafrost and marsh environments in the Da and Xiao Hinggan Mountains has become a great concern as more human activities and pronounced climate warming were observed during the past 30 years and projected for the near future. The distr/bution patterns and development mechanisms of the permafrost and marshes have been examined both in theories and in field observations, in order to better understand the symbiosis of permafrost and marshes. The permafrost and marshes in the Da and Xiao Hinggan Mountains display discernible zonations in latitude and elevation. The marsh vegetation canopy, litter and peat soil have good thermal insulation properties for the underlying permafrost, resulting in a thermal offset of 3 ℃ to 4℃ and subsequently suppressing soil temperature. In addition, the much higher thermal conductivity of frozen and ice-rich peat in the active layer is conducive to the development or in favor of the protection of permafrost due to the semi-conductor properties of the soils overlying the permafrost. On the other hand, because permafrost is almost impervious, the osmosis of water in marsh soils can be effectively reduced, timely providing water supplies for helophytes growth or germination in spring. In the Da and Xiao Hinggan Mountains, the permafrost degradation has been accelerating due to the marked climate warming, ever increasing human activities, and the resultant eco-environmental changes. Since the permafrost and marsh environments are symbiotic and interdependent, they need to be managed or protected in a well-coordinated and integrated way.
基金Under the auspices of the National Natural Science Foundation of China(49471045).
文摘This paper studied the soil animals of four type forests of broad leaved pine forests in the southern slope of the Xiao Hinggan Mountains. The samples were extracted from four forest types in every first week of June, August, October, and every forest type was chosen out three plots. Since there are different soil animals in different depths, every plot was divided into four partitions with the same vertical distance: litter, 0－ 10 cm, 10－ 20 cm, 20－ 30 cm. Using hand sorting out large soil animals, Tullgren method (to middle and small soil animals) and Baermann method (to moist soil animals) to collect soil animals. Among the four type forests, insecta has the largest amount of groups of 54. Oribatida has the most number of individual, which is 1547, occupying 21.73 percent of total collectings. There are 81 groups of soil animals, totalling 7118 belonging to 8 Class 24 Order 57 Family, in which there are 54 groups of big sized soil animals totalling 2370, 41 groups of middle and small sized soil animals totalling 4808. Among all the soil animals,their dominant group is 3 ones, usual growp is 14 ones, and rare group is 64 ones. The results show that among the four type forests, the groups of soil animal in Tilia pine forest are much more than the others, with the highest variety index, and the individual number of the soil animals is also very large. The numbers of group and individual in Picea Abies Pine forest are both small.Among the four forest types, the soil animals in Tilia pine forest are most similar to Betula costata pine forest. There is so little similarity between the soil animals in Picea Abies pine forest and in the other three forest types.
文摘晨明岩体位于小兴安岭东南段,其岩石组合为花岗闪长岩和二长花岗岩。所测定样品中的锆石均具有振荡生长环带,结合Th/U比值,表明这些锆石为岩浆成因,LA-ICP MS U-Pb测年结果显示,其形成时代分别为432.8±1.2 Ma和431.9±1.7 Ma,即早志留世。晨明岩体的地球化学特征显示,其属于高钾钙碱性系列,ACNK值为1.16～1.40,属于过铝质花岗岩;微量元素表现出富集大离子亲石元素(Rb、Ba、U和Th)和轻稀土元素,亏损高场强元素(Nb、Ta、Ti)和P、Sr以及重稀土元素。上述地球化学特征暗示其主要来源于下地壳物质的部分熔融,样品的过铝质特征暗示其形成于陆壳加厚环境。结合前人研究成果,认为晨明岩体形成于松嫩地块和佳木斯地块的碰撞拼合环境,即松嫩地块和佳木斯地块可能在早志留世碰撞拼合。
