Based on gas chromatography and gas chromatography mass spectrometry techniques, the authors examined biomarker characteristics of the Ganquan Formation source rocks in the area of Dahulishan, Ejina, and analyzed the ...Based on gas chromatography and gas chromatography mass spectrometry techniques, the authors examined biomarker characteristics of the Ganquan Formation source rocks in the area of Dahulishan, Ejina, and analyzed the information and petroleum geological significance that were indicated by the source of organic matter, sedimentary environment and maturity and so on. Gas chromatography peak of saturated hydrocarbons from the Ganquan Formation source rocks showed "the former peak" of the single peak distribution, the main peak of carbon being C18 , indicating the main sources of organic matter with marine organic matter. Pr/Ph ranges from 0.3 to 0.6, indicating a strongly reducing sedimentary environment. Biomarker assemblages of the Ganquan Formation source rocks are abundant in tricyclic terpane with long side chains, with a high level of gammacerane, showing dominant distribution of C27 sterane. High contents of gammacerane in organic matter show organic facies of source rocks in the saltwater sedimentary environment. That average hopane/sterane ratio is 0.59, showing that algae have made more contributions to organic matter than bacteria. And the high level of C27 steranes shows that algae are the main source of hydrocarbon precursors. The Ganquan Formation's methylphenanthrene index, which is an effective molecular parameter index to measure thermal evolution of organic matter, ranges from 0.35 to 0.50, and the conversion of vitrinite reflectance Rc from it is within the range of 2.00-2.09, indicating that the Ganquan Formation source rocks are in the over-mature stage of thermal evolution.展开更多
We conducted an investigation into the germination of seeds from individual Populus euphratica trees of different ages and growing conditions in order to discover the effect of intraspecific factors on their sexual re...We conducted an investigation into the germination of seeds from individual Populus euphratica trees of different ages and growing conditions in order to discover the effect of intraspecific factors on their sexual reproduction in the Ejina Oasis, Inner Mongolia of China. By carrying out germination experiments of seeds collected at various seed dispersal periods, we found that P. euphratica seeds could be germinated intensively within 8 h from the start of the experiments, that the germination percentage decreased with the time of seed dispersal and that the germination percentage of seeds collected at the early stage of seed dispersal was 1.86 times greater than those collected at the final stage. There was no significant difference in the germination percentage or the germination index between seeds collected at the early and peak stages. The vitality of seeds from the mature forest was clearly higher than that of the half-mature and near-mature forests. The rate of branch dieback only affected seed germination at the final stage. Therefore, we conclude that the mature P. euphratica forest was the main contributor to reproduction. The results show that both the time of seed harvest and stand age were the main factors affecting the germination percentage of P. euphratica seeds.展开更多
Radar remote sensing can acquire information of sub-surface covered by sand in arid area, detect surface roughness and vegetation coronet's layer and linear feature such as linear structure and channel sensitively...Radar remote sensing can acquire information of sub-surface covered by sand in arid area, detect surface roughness and vegetation coronet's layer and linear feature such as linear structure and channel sensitively. With sediment facies analysis, this paper studies the features of environmental evolution in mid-late Epipleistocene (60 ka BP-20 ka BP) in northeastern Ejin Banner. The conclusions are listed as follows: (1) The evolution of the three lakes, i.e. Gaxunnur, Sugunur and Tian'e lakes, are dominated by faults and regional climate. (2) By analyzing sedimentary section of old Juyanze Lake, the three lakes used to be a large outflow lake before 50 ka BP in northeastern Ejin Banner, and at 50 ka BP, temperature declined rapidly in northwestern China. The event caused the lake's shrinkage. (3) By fault activity uplift in the northern part of old Juyan Lake and depression in the southern part, the lake's water followed from north to south at around 35 ka BP, old Juyanze fluvial fan was formed. At the same time, Juyan Lake separated from Sugunur Lake and Wentugunr old channel was abandoned. (4) In recent 2000 years, Ruoshui River is a wandering river, sometimes it flows into Juyan Lake and sometimes Sugunur and Gaxunnur lakes. Due to human activities and over exploitation, the oasis ecosystem is rapidly degenerated in 15 years (1986-2000).展开更多
It is known that the exploitation of opencast coal mines has seriously damaged the environments in the semi-arid areas.Vegetation status can reliably reflect the ecological degeneration and restoration in the opencast...It is known that the exploitation of opencast coal mines has seriously damaged the environments in the semi-arid areas.Vegetation status can reliably reflect the ecological degeneration and restoration in the opencast mining areas in the semi-arid areas.Long-time series MODIS NDVI data are widely used to simulate the vegetation cover to reflect the disturbance and restoration of local ecosystems.In this study, both qualitative(linear regression method and coefficient of variation(CoV)) and quantitative(spatial buffer analysis, and change amplitude and the rate of change in the average NDVI) analyses were conducted to analyze the spatio-temporal dynamics of vegetation during 2000–2017 in Jungar Banner of Inner Mongolia Autonomous Region, China, at the large(Jungar Banner and three mine groups) and small(three types of functional areas: opencast coal mining excavation areas, reclamation areas and natural areas) scales.The results show that the rates of change in the average NDVI in the reclamation areas(20%–60%) and opencast coal mining excavation areas(10%–20%) were considerably higher than that in the natural areas(<7%).The vegetation in the reclamation areas experienced a trend of increase(3–5 a after reclamation)-decrease(the sixth year of reclamation)-stability.The vegetation in Jungar Banner has a spatial heterogeneity under the influences of mining and reclamation activities.The ratio of vegetation improvement area to vegetation degradation area in the west, southwest and east mine groups during 2000–2017 was 8:1, 20:1 and 33:1, respectively.The regions with the high CoV of NDVI above 0.45 were mainly distributed around the opencast coal mining excavation areas, and the regions with the CoV of NDVI above 0.25 were mostly located in areas with low(28.8%) and medium-low(10.2%) vegetation cover.The average disturbance distances of mining activities on vegetation in the three mine groups(west, southwest and east) were 800, 800 and 1000 m, respectively.The greater the scale of mining, the farther the disturbance distances of mining activities on vegetation.We conclude that vegetation reclamation will certainly compensate for the negative impacts of opencast coal mining activities on vegetation.Sufficient attention should be paid to the proportional allocation of plant species(herbs and shrubs) in the reclamation areas, and the restored vegetation in these areas needs to be protected for more than 6 a.Then, as the repair time increased, the vegetation condition of the reclamation areas would exceed that of the natural areas.展开更多
The evolvement of a vulnerable ecological region is a dynamic process, which is affected by various factors. During the evolvement process, human activities have a decisive effect. The purpose of studying vulnerable e...The evolvement of a vulnerable ecological region is a dynamic process, which is affected by various factors. During the evolvement process, human activities have a decisive effect. The purpose of studying vulnerable ecological region is to control human economic activities and to develop a negative feedback modulation mechanism.This paper established a model of vulnerable ecological region's evolvement by considering four synthetic variables.These synthetic variables are ecological carrying capacity, ecological resilience, economic development intensity, and economic development velocity. Finally, Ongniud Banner and Aohan Banner in North China were taken as study cases to simulate the evolvement processes of vulnerable ecological regions under different conditions of economic development. The results show that human activities have an important influence on the evolvement trend of vulnerable ecological region.展开更多
基金supported jointly by the China Geological Survey Project (Grant Nos. 1212011120972 and 1212010733506)Hubei Provincial Natural Science Foundation (Grant No. 2010CDB04305)CNPC Innovation Foundation (Grant No. 2010D-5006-0105)
文摘Based on gas chromatography and gas chromatography mass spectrometry techniques, the authors examined biomarker characteristics of the Ganquan Formation source rocks in the area of Dahulishan, Ejina, and analyzed the information and petroleum geological significance that were indicated by the source of organic matter, sedimentary environment and maturity and so on. Gas chromatography peak of saturated hydrocarbons from the Ganquan Formation source rocks showed "the former peak" of the single peak distribution, the main peak of carbon being C18 , indicating the main sources of organic matter with marine organic matter. Pr/Ph ranges from 0.3 to 0.6, indicating a strongly reducing sedimentary environment. Biomarker assemblages of the Ganquan Formation source rocks are abundant in tricyclic terpane with long side chains, with a high level of gammacerane, showing dominant distribution of C27 sterane. High contents of gammacerane in organic matter show organic facies of source rocks in the saltwater sedimentary environment. That average hopane/sterane ratio is 0.59, showing that algae have made more contributions to organic matter than bacteria. And the high level of C27 steranes shows that algae are the main source of hydrocarbon precursors. The Ganquan Formation's methylphenanthrene index, which is an effective molecular parameter index to measure thermal evolution of organic matter, ranges from 0.35 to 0.50, and the conversion of vitrinite reflectance Rc from it is within the range of 2.00-2.09, indicating that the Ganquan Formation source rocks are in the over-mature stage of thermal evolution.
基金supported by the National Natural Science Foundation of China (Grant Nos. 31070553, 30570332)the 11th Five-Year Plan of the National Scientific and Technological Support Projects of China (Grant No. 2008BAD-B0B05)
文摘We conducted an investigation into the germination of seeds from individual Populus euphratica trees of different ages and growing conditions in order to discover the effect of intraspecific factors on their sexual reproduction in the Ejina Oasis, Inner Mongolia of China. By carrying out germination experiments of seeds collected at various seed dispersal periods, we found that P. euphratica seeds could be germinated intensively within 8 h from the start of the experiments, that the germination percentage decreased with the time of seed dispersal and that the germination percentage of seeds collected at the early stage of seed dispersal was 1.86 times greater than those collected at the final stage. There was no significant difference in the germination percentage or the germination index between seeds collected at the early and peak stages. The vitality of seeds from the mature forest was clearly higher than that of the half-mature and near-mature forests. The rate of branch dieback only affected seed germination at the final stage. Therefore, we conclude that the mature P. euphratica forest was the main contributor to reproduction. The results show that both the time of seed harvest and stand age were the main factors affecting the germination percentage of P. euphratica seeds.
文摘Radar remote sensing can acquire information of sub-surface covered by sand in arid area, detect surface roughness and vegetation coronet's layer and linear feature such as linear structure and channel sensitively. With sediment facies analysis, this paper studies the features of environmental evolution in mid-late Epipleistocene (60 ka BP-20 ka BP) in northeastern Ejin Banner. The conclusions are listed as follows: (1) The evolution of the three lakes, i.e. Gaxunnur, Sugunur and Tian'e lakes, are dominated by faults and regional climate. (2) By analyzing sedimentary section of old Juyanze Lake, the three lakes used to be a large outflow lake before 50 ka BP in northeastern Ejin Banner, and at 50 ka BP, temperature declined rapidly in northwestern China. The event caused the lake's shrinkage. (3) By fault activity uplift in the northern part of old Juyan Lake and depression in the southern part, the lake's water followed from north to south at around 35 ka BP, old Juyanze fluvial fan was formed. At the same time, Juyan Lake separated from Sugunur Lake and Wentugunr old channel was abandoned. (4) In recent 2000 years, Ruoshui River is a wandering river, sometimes it flows into Juyan Lake and sometimes Sugunur and Gaxunnur lakes. Due to human activities and over exploitation, the oasis ecosystem is rapidly degenerated in 15 years (1986-2000).
基金supported by the National Key Research and Development Program of China (2016YFC0501107)the Project of Ordos Science and Technology Program (2017006)the Special Project of Science and Technology Basic Work of Ministry of Science and Technology of China (2014FY110800)
文摘It is known that the exploitation of opencast coal mines has seriously damaged the environments in the semi-arid areas.Vegetation status can reliably reflect the ecological degeneration and restoration in the opencast mining areas in the semi-arid areas.Long-time series MODIS NDVI data are widely used to simulate the vegetation cover to reflect the disturbance and restoration of local ecosystems.In this study, both qualitative(linear regression method and coefficient of variation(CoV)) and quantitative(spatial buffer analysis, and change amplitude and the rate of change in the average NDVI) analyses were conducted to analyze the spatio-temporal dynamics of vegetation during 2000–2017 in Jungar Banner of Inner Mongolia Autonomous Region, China, at the large(Jungar Banner and three mine groups) and small(three types of functional areas: opencast coal mining excavation areas, reclamation areas and natural areas) scales.The results show that the rates of change in the average NDVI in the reclamation areas(20%–60%) and opencast coal mining excavation areas(10%–20%) were considerably higher than that in the natural areas(<7%).The vegetation in the reclamation areas experienced a trend of increase(3–5 a after reclamation)-decrease(the sixth year of reclamation)-stability.The vegetation in Jungar Banner has a spatial heterogeneity under the influences of mining and reclamation activities.The ratio of vegetation improvement area to vegetation degradation area in the west, southwest and east mine groups during 2000–2017 was 8:1, 20:1 and 33:1, respectively.The regions with the high CoV of NDVI above 0.45 were mainly distributed around the opencast coal mining excavation areas, and the regions with the CoV of NDVI above 0.25 were mostly located in areas with low(28.8%) and medium-low(10.2%) vegetation cover.The average disturbance distances of mining activities on vegetation in the three mine groups(west, southwest and east) were 800, 800 and 1000 m, respectively.The greater the scale of mining, the farther the disturbance distances of mining activities on vegetation.We conclude that vegetation reclamation will certainly compensate for the negative impacts of opencast coal mining activities on vegetation.Sufficient attention should be paid to the proportional allocation of plant species(herbs and shrubs) in the reclamation areas, and the restored vegetation in these areas needs to be protected for more than 6 a.Then, as the repair time increased, the vegetation condition of the reclamation areas would exceed that of the natural areas.
基金Under the auspices of the National Natural Science Foundation of China (No. 40301052)the 10th Five-year National Key Technology R&D Program of Ministry of Science and Technology (No. 2001BA606A-01)
文摘The evolvement of a vulnerable ecological region is a dynamic process, which is affected by various factors. During the evolvement process, human activities have a decisive effect. The purpose of studying vulnerable ecological region is to control human economic activities and to develop a negative feedback modulation mechanism.This paper established a model of vulnerable ecological region's evolvement by considering four synthetic variables.These synthetic variables are ecological carrying capacity, ecological resilience, economic development intensity, and economic development velocity. Finally, Ongniud Banner and Aohan Banner in North China were taken as study cases to simulate the evolvement processes of vulnerable ecological regions under different conditions of economic development. The results show that human activities have an important influence on the evolvement trend of vulnerable ecological region.
