This study examined spatial variations in the concentration,grain size and heavy mineral assemblages on Cedar Beach（Lake Erie,Canada）.Magnetic studies of heavy mineral-enriched,dark-reddish sands present on the beac...This study examined spatial variations in the concentration,grain size and heavy mineral assemblages on Cedar Beach（Lake Erie,Canada）.Magnetic studies of heavy mineral-enriched,dark-reddish sands present on the beach showed that magnetite（～150μm） is the dominant magnetic mineral.Surficial magnetic susceptibility values defined three zones：a lakeward region close to the water line（Zone 1）,the upper swash zone（Zone 2） and the region landwards of the upper swash zone （Zone 3）.Zone 2 showed the highest bulk and mass susceptibility（κ,χ） and the highest mass percentage of smaller grain-size（250μm） fractions in the bulk sand sample.Susceptibility（i.e.κandχ） values decreased and grain size coarsened from Zone 2 lakewards（into Zone 1） and landwards （into Zone 3）,and correlated with the distribution of the heavy mineral assemblage,most probably reflecting preferential separation of large,less dense particles by waves and currents both along and across the beach.The eroded western section of Cedar Beach showed much higher concentrations of heavy minerals including magnetite,and finer sand grain sizes than the accreting eastern section, suggesting that magnetic techniques could be used as a rapid,cost-effective way of examining erosion along sensitive coastline areas.展开更多
Environmental magnetic research on beaches and shoreline processes is limited.Therefore,we carried out environmental magnetic studies on the heavy mineral-enriched,dark-reddish sands on Cedar Beach of western Lake Eri...Environmental magnetic research on beaches and shoreline processes is limited.Therefore,we carried out environmental magnetic studies on the heavy mineral-enriched,dark-reddish sands on Cedar Beach of western Lake Erie(41.68°N,82.40°W).Magnetite has been identified as the dominant magnetic mineral of these sands.This study reveals a spatial variation in concentration of magnetite particles,distribution of展开更多
According to a long series of measured sediment data, the sedimentation effects of the Dongting Lake Area （DIP,） were studied in light of the relationship between sedimentation characteristics and resources and envi...According to a long series of measured sediment data, the sedimentation effects of the Dongting Lake Area （DIP,） were studied in light of the relationship between sedimentation characteristics and resources and environment. The result shows that the long-term deposition and the impact of human activities have led to a cycle of the evolution of sedimentation pattern, resulting in sediment disaster effects and resources effects in the DLA. The main features are as follows： 1） The water beach, silt beach, lake marsh beach, reed beach and other types of beach shaped by sedimentation effects constitute the main body of the giant lake system. 2） The disaster chains are induced, i.e., sedimentation → marshland expansion and reclamation → flood function decline, fish resource depletion, biodiversity reduction dis- aster chain, sedimentation → marshland expansion → floods, water pollution disaster chain, sedimentation → marshland floating vegetation rising → schistosomiasis, rodents virulence disaster chain, sedimentation → flood embankment bursting → land desertification disaster chain. 3） Sedimentation has created about 98.13×10^4 hm^2 of land in the past 55 years. Rational development and utilization of marshland resources have produced tremendous economic benefits.展开更多
The endorheic Lake Nam Co, south Eastern Tibetan Plateau, was selected to investigate the interrelationbetween drainage basin processes, especially post-glacial glacier decay, and lake level fluctuations. Landforms of...The endorheic Lake Nam Co, south Eastern Tibetan Plateau, was selected to investigate the interrelationbetween drainage basin processes, especially post-glacial glacier decay, and lake level fluctuations. Landforms of thedrainage basin are highly influenced by tectonics, superimposed by fluvial and periglacial processes, and locally by glacialand eolian processes. Thus,geomorphological features and hydrological characteristics were compiled for the lake-basin toprovide an overview of the landscape character. Data show that during the Last Glacial Maximum melt water from themountains accumulated fluvial deposits in the foreland. Concurrently, an increase of the lake level occurred which ispresently shown by a cliff line all around Nam Co with its base approximately 29m above the present lake level. TheHolocene decrease of the lake level is traced by beach ridges. As Nam Co is an endorheic lake post-glacial water loss has tobe primarily explained by evaporation and moisture conditions. However, more detailed conclusions on quantitative andchronological patterns of both factors, melt-water input and evaporation output, still remain to be drawn.展开更多
固定样地调查通过长期数据的积累和精准的时空对比获取生态系统动态特征,为长期的生态系统研究提供了坚实的基础。洞庭湖湿地生态系统观测研究站按中国生态系统研究网络(Chinese Ecosystem Research Network,CERN)统一的监测规范,对洞...固定样地调查通过长期数据的积累和精准的时空对比获取生态系统动态特征,为长期的生态系统研究提供了坚实的基础。洞庭湖湿地生态系统观测研究站按中国生态系统研究网络(Chinese Ecosystem Research Network,CERN)统一的监测规范,对洞庭湖水文情势变化下,湿地生态系统中典型洲滩植被的物种组成和群落特征等指标进行长期定位监测。通过东洞庭湖三种典型湿地植物群落(苔草,南荻和水蓼)长期监测样地的数据进行加工处理,获得2011-2015年洞庭湖洲滩植物群落长期监测数据集。本数据集包含有植物种名、拉丁名、株(丛)数(株或丛/样方)、叶层平均高度(cm)、生殖枝平均高度(cm)、盖度(%)、物候期、优势种、植物种数、密度(株或丛/m~2)、优势种叶层高度(cm)、优势种生殖枝高度(cm)、总盖度(%)、地上绿色部分总干重(g/m~2),共14个指标,同时附有完整的背景信息。本数据集实行全过程数据质量控制,并由专家审核验证,确保数据时空上的相对一致和准确可靠。本数据集可以为探究洞庭湖水文情势下,洲滩湿地生态系统过程和演替趋势提供本底资料,为洞庭湖植被的遥感监测、生物多样性保护和湿地生态修复及适应性管理等提供数据支撑。展开更多
基金supported by funding from the 111 Project B07011 of Ministry of Education of China,the China Scholarship Council(CSC) to SWZ (NCIS No.2007103928)an NSERC grant to MTC. D.Chevalier is thanked for her help in sampling. Laboratory assistance was provided bv K.Kawasaki and S.Joshi
文摘This study examined spatial variations in the concentration,grain size and heavy mineral assemblages on Cedar Beach（Lake Erie,Canada）.Magnetic studies of heavy mineral-enriched,dark-reddish sands present on the beach showed that magnetite（～150μm） is the dominant magnetic mineral.Surficial magnetic susceptibility values defined three zones：a lakeward region close to the water line（Zone 1）,the upper swash zone（Zone 2） and the region landwards of the upper swash zone （Zone 3）.Zone 2 showed the highest bulk and mass susceptibility（κ,χ） and the highest mass percentage of smaller grain-size（250μm） fractions in the bulk sand sample.Susceptibility（i.e.κandχ） values decreased and grain size coarsened from Zone 2 lakewards（into Zone 1） and landwards （into Zone 3）,and correlated with the distribution of the heavy mineral assemblage,most probably reflecting preferential separation of large,less dense particles by waves and currents both along and across the beach.The eroded western section of Cedar Beach showed much higher concentrations of heavy minerals including magnetite,and finer sand grain sizes than the accreting eastern section, suggesting that magnetic techniques could be used as a rapid,cost-effective way of examining erosion along sensitive coastline areas.
文摘Environmental magnetic research on beaches and shoreline processes is limited.Therefore,we carried out environmental magnetic studies on the heavy mineral-enriched,dark-reddish sands on Cedar Beach of western Lake Erie(41.68°N,82.40°W).Magnetite has been identified as the dominant magnetic mineral of these sands.This study reveals a spatial variation in concentration of magnetite particles,distribution of
基金Key Discipline Building Program on Physical Geography of Hunan ProvinceProject for Science & Tech-nology of Hunan Province,No.2007Fj302
文摘According to a long series of measured sediment data, the sedimentation effects of the Dongting Lake Area （DIP,） were studied in light of the relationship between sedimentation characteristics and resources and environment. The result shows that the long-term deposition and the impact of human activities have led to a cycle of the evolution of sedimentation pattern, resulting in sediment disaster effects and resources effects in the DLA. The main features are as follows： 1） The water beach, silt beach, lake marsh beach, reed beach and other types of beach shaped by sedimentation effects constitute the main body of the giant lake system. 2） The disaster chains are induced, i.e., sedimentation → marshland expansion and reclamation → flood function decline, fish resource depletion, biodiversity reduction dis- aster chain, sedimentation → marshland expansion → floods, water pollution disaster chain, sedimentation → marshland floating vegetation rising → schistosomiasis, rodents virulence disaster chain, sedimentation → flood embankment bursting → land desertification disaster chain. 3） Sedimentation has created about 98.13×10^4 hm^2 of land in the past 55 years. Rational development and utilization of marshland resources have produced tremendous economic benefits.
基金supported by the Deutsche Forschungsgemeinschaft(DFG)part of the DFG bundle project Schw 674/5-1,2, Schu 949/10-1,2 )
文摘The endorheic Lake Nam Co, south Eastern Tibetan Plateau, was selected to investigate the interrelationbetween drainage basin processes, especially post-glacial glacier decay, and lake level fluctuations. Landforms of thedrainage basin are highly influenced by tectonics, superimposed by fluvial and periglacial processes, and locally by glacialand eolian processes. Thus,geomorphological features and hydrological characteristics were compiled for the lake-basin toprovide an overview of the landscape character. Data show that during the Last Glacial Maximum melt water from themountains accumulated fluvial deposits in the foreland. Concurrently, an increase of the lake level occurred which ispresently shown by a cliff line all around Nam Co with its base approximately 29m above the present lake level. TheHolocene decrease of the lake level is traced by beach ridges. As Nam Co is an endorheic lake post-glacial water loss has tobe primarily explained by evaporation and moisture conditions. However, more detailed conclusions on quantitative andchronological patterns of both factors, melt-water input and evaporation output, still remain to be drawn.
文摘固定样地调查通过长期数据的积累和精准的时空对比获取生态系统动态特征,为长期的生态系统研究提供了坚实的基础。洞庭湖湿地生态系统观测研究站按中国生态系统研究网络(Chinese Ecosystem Research Network,CERN)统一的监测规范,对洞庭湖水文情势变化下,湿地生态系统中典型洲滩植被的物种组成和群落特征等指标进行长期定位监测。通过东洞庭湖三种典型湿地植物群落(苔草,南荻和水蓼)长期监测样地的数据进行加工处理,获得2011-2015年洞庭湖洲滩植物群落长期监测数据集。本数据集包含有植物种名、拉丁名、株(丛)数(株或丛/样方)、叶层平均高度(cm)、生殖枝平均高度(cm)、盖度(%)、物候期、优势种、植物种数、密度(株或丛/m~2)、优势种叶层高度(cm)、优势种生殖枝高度(cm)、总盖度(%)、地上绿色部分总干重(g/m~2),共14个指标,同时附有完整的背景信息。本数据集实行全过程数据质量控制,并由专家审核验证,确保数据时空上的相对一致和准确可靠。本数据集可以为探究洞庭湖水文情势下,洲滩湿地生态系统过程和演替趋势提供本底资料,为洞庭湖植被的遥感监测、生物多样性保护和湿地生态修复及适应性管理等提供数据支撑。
