The western margin of Yangtze block and southwestern Sanjiang region absorbed much attention from geologists. It has been proved that there occurred a series of plate subduction, collision, assembly, rifting and break...The western margin of Yangtze block and southwestern Sanjiang region absorbed much attention from geologists. It has been proved that there occurred a series of plate subduction, collision, assembly, rifting and breakup processes between them since Palaeozoic and the tectonic evolutionary relationship between them is clear. But in Proterozoic this kind of links between them became unclear. Did they undergo the assembly and breakup processes of the Rodinia super continent? This paper will take a primary discussion on this question on the basis of basement component, structure characteristics and magmatic activities.1\ Basement features\;(1) In western margin of Yangtze block its basement is composed of crystalline basement and folded basement, a so\|called double\|layer structure. The crystalline basement is made up of Kangding group, Pudeng Formation and Dibadu Formation, among them Kangding group is a representative and composed mainly of migmatite, compositing gneiss, hornblende schist and granulitite. The isotopic age of crystalline basement is older than 1900Ma, so its geological time is late Archaean to early Proterozoic. The folded basement is composed of Dahongshan group, Hekou group, Kunyang group, Huili group and Yanbian group. Their rock associations are made up mainly of spilite\|keratophyre formation, carbonate formation, clastic rock and clastic rock formation with some basic volcanic rocks. The folded basement is assigned to be early and middle Proterozoic (1000～1700M a).展开更多
This paper describes the aim and principle of element geochemical division, the source of samples and data processing, the choice of divisional indices and the division of index value ranges. According to the geologic...This paper describes the aim and principle of element geochemical division, the source of samples and data processing, the choice of divisional indices and the division of index value ranges. According to the geological structures and characteristic values (the accumulated value of enrichment coefficient) of the mantle-type elements (K T) this region can be divided into seven geochemical zones, i.e., the Yangtze basement, the Yangtze cover, the Jinshajiang paleo-Tethys, the Lancangjiang paleo-Tethys, the Lanping Mesozoic basin, the Indosinian granite, and the Himalayan granite. Again in accordance with the different characteristic values of high field strength elements (HFSE) (K Nb) or radiogenic elements (K Th) 16 geochemical sub-zones can be divided. Meanwhile, this paper also discusses the rules of variation in characteristic value of the various sub-zones and points out the characteristics of enrichment of ore-forming elements in some of the sub-zones.展开更多
[Objective] The study aimed at analysing the change characteristics of temperature in Jiamusi region of Sanjiang Plain.[Method] Based on temperature data of Jiamusi region in Sanjiang Plain from 1961 to 2010,including...[Objective] The study aimed at analysing the change characteristics of temperature in Jiamusi region of Sanjiang Plain.[Method] Based on temperature data of Jiamusi region in Sanjiang Plain from 1961 to 2010,including Jiamusi,Huanan,Fujin and Fuyuan station,we studied the change trends,abrupt climate change and abnormal years of temperature in Jiamusi region.[Result] Annual average temperature of Jiamusi region in Sanjiang Plain showed increasing trend,with the increase of 0.249-0.412 ℃/10 a.The order of annual average temperature in Jiamusi region was east> south> north> west.In addition,abrupt climate change of annual average temperature occurred in the early 1980s.Abrupt climate change of annual average temperature appeared in 1981 in Jiamusi,Huanan and Fujin,but in 1984 in Fuyuan.Annual average temperature in the mid-1960s and late 1960s was abnormally low in Jiamusi,Fujin and Huanan,while it was abnormally high in Huanan,Fuyuan and Jiamusi from 2007 to 2008,but Fujin in the early 1990s.Meanwhile,anomalies of seasonal average temperature in distinct regions appeared in various years.[Conclusion] The research could provide references for the prediction of temperature in Jiamusi region of Sanjiang Plain in furture.展开更多
Wetland is a kind of key natural resources. However, the wetlands have been shrinking rapidly in Sangjiang Plain and its functions have been degrading. These all hold back the sustainable development of human communit...Wetland is a kind of key natural resources. However, the wetlands have been shrinking rapidly in Sangjiang Plain and its functions have been degrading. These all hold back the sustainable development of human communities, and lead to great change in the land use /cover (LUCC), consequently caused global changes in climate, water cycling, etc.. Taken Fujin region as a case study, spatial and temporal dynamic processes of wetland and its driving forces were analyzed from 1954 to 2000 in this paper. It showed that the wetlands had been reduced from 52×104 ha to 11×104 ha in areas during the nearly 50 years . The percentage of wetland areas reduced from 61.27% to 12.39%. On the other hand, cultivated land increased from 22×104 ha to 60×104 ha in areas. The percentage of the areas increased from 25.31% to 70.45%. Further quantitative analysis of the wetland landscape conversion characteristics and the correlation analysis between the change of wetland areas and population increase were made. The results showed that 40×104 ha wetlands had been converted to cultivated land within half of a century; the correlation between the rate of wetland loss and that of population increased is nearly -0.922. So it was concluded that the main driving force of wetland shrinkage in Fujin region was the colonization of human being.展开更多
文摘The western margin of Yangtze block and southwestern Sanjiang region absorbed much attention from geologists. It has been proved that there occurred a series of plate subduction, collision, assembly, rifting and breakup processes between them since Palaeozoic and the tectonic evolutionary relationship between them is clear. But in Proterozoic this kind of links between them became unclear. Did they undergo the assembly and breakup processes of the Rodinia super continent? This paper will take a primary discussion on this question on the basis of basement component, structure characteristics and magmatic activities.1\ Basement features\;(1) In western margin of Yangtze block its basement is composed of crystalline basement and folded basement, a so\|called double\|layer structure. The crystalline basement is made up of Kangding group, Pudeng Formation and Dibadu Formation, among them Kangding group is a representative and composed mainly of migmatite, compositing gneiss, hornblende schist and granulitite. The isotopic age of crystalline basement is older than 1900Ma, so its geological time is late Archaean to early Proterozoic. The folded basement is composed of Dahongshan group, Hekou group, Kunyang group, Huili group and Yanbian group. Their rock associations are made up mainly of spilite\|keratophyre formation, carbonate formation, clastic rock and clastic rock formation with some basic volcanic rocks. The folded basement is assigned to be early and middle Proterozoic (1000～1700M a).
文摘This paper describes the aim and principle of element geochemical division, the source of samples and data processing, the choice of divisional indices and the division of index value ranges. According to the geological structures and characteristic values (the accumulated value of enrichment coefficient) of the mantle-type elements (K T) this region can be divided into seven geochemical zones, i.e., the Yangtze basement, the Yangtze cover, the Jinshajiang paleo-Tethys, the Lancangjiang paleo-Tethys, the Lanping Mesozoic basin, the Indosinian granite, and the Himalayan granite. Again in accordance with the different characteristic values of high field strength elements (HFSE) (K Nb) or radiogenic elements (K Th) 16 geochemical sub-zones can be divided. Meanwhile, this paper also discusses the rules of variation in characteristic value of the various sub-zones and points out the characteristics of enrichment of ore-forming elements in some of the sub-zones.
文摘[Objective] The study aimed at analysing the change characteristics of temperature in Jiamusi region of Sanjiang Plain.[Method] Based on temperature data of Jiamusi region in Sanjiang Plain from 1961 to 2010,including Jiamusi,Huanan,Fujin and Fuyuan station,we studied the change trends,abrupt climate change and abnormal years of temperature in Jiamusi region.[Result] Annual average temperature of Jiamusi region in Sanjiang Plain showed increasing trend,with the increase of 0.249-0.412 ℃/10 a.The order of annual average temperature in Jiamusi region was east> south> north> west.In addition,abrupt climate change of annual average temperature occurred in the early 1980s.Abrupt climate change of annual average temperature appeared in 1981 in Jiamusi,Huanan and Fujin,but in 1984 in Fuyuan.Annual average temperature in the mid-1960s and late 1960s was abnormally low in Jiamusi,Fujin and Huanan,while it was abnormally high in Huanan,Fuyuan and Jiamusi from 2007 to 2008,but Fujin in the early 1990s.Meanwhile,anomalies of seasonal average temperature in distinct regions appeared in various years.[Conclusion] The research could provide references for the prediction of temperature in Jiamusi region of Sanjiang Plain in furture.
文摘Wetland is a kind of key natural resources. However, the wetlands have been shrinking rapidly in Sangjiang Plain and its functions have been degrading. These all hold back the sustainable development of human communities, and lead to great change in the land use /cover (LUCC), consequently caused global changes in climate, water cycling, etc.. Taken Fujin region as a case study, spatial and temporal dynamic processes of wetland and its driving forces were analyzed from 1954 to 2000 in this paper. It showed that the wetlands had been reduced from 52×104 ha to 11×104 ha in areas during the nearly 50 years . The percentage of wetland areas reduced from 61.27% to 12.39%. On the other hand, cultivated land increased from 22×104 ha to 60×104 ha in areas. The percentage of the areas increased from 25.31% to 70.45%. Further quantitative analysis of the wetland landscape conversion characteristics and the correlation analysis between the change of wetland areas and population increase were made. The results showed that 40×104 ha wetlands had been converted to cultivated land within half of a century; the correlation between the rate of wetland loss and that of population increased is nearly -0.922. So it was concluded that the main driving force of wetland shrinkage in Fujin region was the colonization of human being.
