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Seasonal and spatial variations in rare earth elements and yttrium of dissolved load in the middle,lower reaches and estuary of the minjiang river,southeastern China

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Journal of Oceanology and Limnology 2018年第3期36卷 700-716页

作者： ZHU Xuxu GAO Aiguo LIN Jianjie JIAN Xing YANG Yufeng ZHANG Yanpo HOU Yuting GONG Songbai College of Ocean and Earth Sciences Xiamen UniversityXiamen 361102China State Key Laboratory of Marine Environmental Sciences Xiamen 361102China Marine and Fisheries Technology Center of Fuzhou Fuzhou 350026China

A bstract With the aim of elucidating the spatial and seasonal behaviors of rare earth elements(REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower reaches and estuary of the minjiang river, southeastern China. The results display that the REE abundances in minjiang river, ranging from 3.3–785.9 ng/L, were higher than those of many of the major global rivers. The total REE concentrations(∑REE) were seasonally variable, averaging in 5 937.30, 863.79, 825.65 and 1 065.75 ng/L during second highest flow(SHF), normal flow(NF), low flow(LF) and high flow(HF) season, respectively. The R_(( L/M)) and R_((H/M)) ratios reveal the spatial and temporal variations of REE patterns, and particularly vary apparently in the maximum turbidity zone and estuary. REE patterns of dissolved loads are characterized by progressing weaker LREEs-enrichment and stronger HREEsenrichment downstream from middle reaches to estuary during all four seasons. Comparing with NF and LF seasons, in which REE patterns are relatively flat, samples of SHF season have more LREE-enriched and HREE-depleted patterns that close to parent rocks, while samples of HF season are more LREEs-depleted and HREE-enriched. REE fractionations from the middle to lower reaches are stronger in the SHF and HF seasons than those in NF and LF seasons. Generally, spatial and seasonal variations in REE abundance and pattern are presumably due to several factors, such as chemical weathering, mixture with rainfall and groundwater, estuarine mixing, runoff, biological production and mountain river characters, such as strong hydrodynamic forces and steep slopes. The highest Gd/Gd* always occurs at north ports during all four seasons, where most of the large hospitals are located. This suggests Gd anomalies are depended on the density of modern medical facilities. Y/Ho ratios fl uctuate and positively correlate to salinity in estuary, probably because of the geochem

关键词： rare earth elements(REEs) minjiang river estuarine mixing process dissolved load online pre-concentration system

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A Landscape Pattern Analysis Method Based on Boundaries and Nodes:A Case Study in Upper minjiang river,China

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Chinese Geographical Science 2014年第1期24卷 50-59页

作者： WEN Qingchun LI Xiuzhen HE Hongshi HU Yuanman CHEN Xin CHANG Yu WANG Wei BU Rencang Institute of Applied Ecology Chinese Academy of Sciences Liaoning Environmental Monitoring Center State Key Laboratory of Estuarine&Coastal Research East China Normal University University of Missouri-Columbia

Traditionally,patch-based analysis at the landscape scale fragmentation has been used in the study of landscape ecology while the study of boundary and node has not been considered as much detail until *** study investigated the possibility of applying boundary-and node-based methods in landscape pattern analysis to the upper reaches of the minjiang river in the southwestern ***-based and node-based landscape indices were selected to be used in analyzing changes in landscape patterns,and the results were compared with analysis using traditional pattern *** compared the responses of patch-area-based,boundary-length-based and node-number-based indices,and concluded that boundary-based and node-based indices are more sensitive to disturbance than patch-based indices with various patterns,and node-based indices are even more sensitive than boundary-based ***,the results suggest that boundary-based and node-based pattern analysis methods provide helpful supplementary information to traditional patch-based pattern analysis *** results about pattern dynamics of landscapes in the upper reaches of the minjiang river based on boundaries and nodes showed that with human disturbance,the dominance of forest landscape was weakened by other landscape types;thus the landscape pattern of the study area became more homogeneous and the boundary network became more *** changes further augmented disturbance interfaces in the landscape and increased the possibilities of further landscape fragmentation.

关键词： landscape pattern index patch boundary node minjiang river

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Late Pleistocene environmental information on the Diexi paleo-dammed lake of the upper minjiang river in the eastern margin of the Tibetan Plateau, China

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Journal of Mountain Science 2020年第5期17卷 1172-1187页

作者： WANG Lan-sheng WANG Xiao-qun SHEN Jun-hui YIN Guan CUI Jie XU Xiang-ning ZHANG Zhi-long WAN Tao WEN Li-wang State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China College of Environment geology and Civil Engineering Chengdu University of TechnologyChengdu 610059China College of Earth Sciences Chengdu University of TechnologyChengdu 610059China School of Environment and Resource Southwest University of Science and TechnologyMianyang 621010China Sichuan Bureau of Geology and Mineral Exploration Chengdu 610000China College of Water Resource and Hydropower Sichuan University Chengdu 610000China College of Materials and Chemistry&Chemical Engineering Chengdu University of TechnologyChengdu 610059China

In 1999, Diexi paleo-dammed lake(2349 m a.s.l.) was discovered around Diexi town along the minjiang river in Sichuan province. Diexi is located where the eastern edge of the Tibetan Plateau and the Sichuan Basin meet. The dammed lake was formed during the Last Glacial Maximum of the Late Pleistocene(~30,000 years ago) and began to empty about 15,000 years ago. The lacustrine sediments(up to 240 m thick) preserve abundant paleoenvironment information. In this paper, a mass of oxygen isotopes and 14 C dating from drilled cores are analyzed and discussed. The δ18 O curve on the paleo climate from this section is comparable with the coeval paleo climatic curves of ice cores and karsts in China and others. Furthermore, the physical model testing has confirmed that the disturbed zones in the core are caused by strong earthquakes occurred at least 10 times, which implies strong crustal deformation, as an important driving force, affecting climate change. This study provides a new window to observe East Asian monsoon formation, paleoenvironmental evolution and the global climate change.

关键词： Late Pleistocene Paleo-dammed lake Paleo climate Earthquake minjiang river Diexi

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Restoring Mountain Slope Forests by Strip-cutting Shrubs in the Upper Reaches of minjiang river,Sichuan, China: A Biodiversity-oriented Silvicuture Experiment

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Chinese Forestry Science and Technology 2004年第1期3卷 7-16页

作者： SUNShucun BAOWeikai PANKaiwen GAOXianming DepartmentofBiology NanjingUnversityNanjing210093P.R.China ChengduInstituteofBiology ChineseAcademyofSciencesChengdu610041P.R.China LaboratoryofQuantitativeVegetationEcology InstituteofBotanyChineseAcademyofSciencesBeijing10093P.R.China

The aims of forest restorationRestoration on of mountain slopes forests is often used to achieveone or a combination of the following aims, should be diverse, and includeincluding increased production, soilprotection and wildlife conservation, .and each development scheme should have a combination of thepurposes In this paper, we proposed biodiversity-oriented silviculture was proposed as a design principle inforest restoration design principle to meet the requirements and then described from which strip-cutting ofshrubs was used as the restoring technology of restoring forests by strip-cutting shrubs that developed formthe design principle. More than 10-year-observations, and experimentals and results of from more than 10years research on the afforestation practices in the upper reaches of minjiang river, Sichuan, China, indicatedthat the technology was feasible and had many advantages. In the technology, sStrip-cutting of shrubsameliorated microclimate conditions, and improved soil nutrient level for the growth of target tree speciesand. increased The the physical survival of pine species was increased. Structural diversity, in terms ofspecies, was did not much increased, but a shrub species was observed to differentiate from shrub layer andtended to form mixed forests. Preserve belts of the technology were supposed to cover meet public demandsincluding biodiversity conservation and soil protection, and lay a foundation foract as a basic stage inecologically progressive succession. Although it is too early to conclude that this approach is successful in allfunctions, The promising initial resultslook promising indicate that strip-cutting of shrubs may be an effectivepractice for forest restoration in the upper reaches of minjiang river, Sichuan, China.

关键词： forest restoration mountains silvicultural technology minjiang river

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Journal of Mountain Science 2020年第10期17卷 2497-2511页

作者： WANG Xiao-qun HUANG Xin SHEN Man ZHOU Zhou WEI Jie State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China College of Environment and Civil Engineering Chengdu University of TechnologyChengdu610059China Anhui Xinhua University Hefei230088China

The Diexi ancient dammed lake is in the upper reaches of the minjiang *** terraces with lacustrine sediments occur at the *** terraces are the products of the graded outburst of the Diexi ancient dammed *** outburst of the ancient dammed lake would certainly have had an impact on the Chengdu Plain in the lower reaches of the minjiang *** this paper,on-site sampling and laboratory analysis were used to analyze the sediments of the Diexi ancient dammed lake and the Jinsha site in Chengdu Plain,and the environmental indicators of each sediment layer were *** a comparative analysis of the environmental indicators in the sediments at the two locations,the following results were obtained:the palaeoclimatic and palaeoenvironmental characteristics at the two locations generally show consistent *** most important finding is that the types and content of the major pollen taxa at the two locations are *** Pinus content strongly proves that the soil layers at the Jinsha site was sourced from the upper reaches of the minjiang *** that the demise of the ancient culture at the Jinsha site occurred close in time to the outburst of the ancient dammed lake,this similarity suggests that the cultural change at the Jinsha site may have been related to the outburst of the Diexi ancient dammed lake.

关键词： minjiang river Diexi ancient dammed lake Jinsha site Palaeoclimate Palaeoenvironment

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Reproduction of the Sedimentary Disturbance Phenomenon of the Diexi Ancient Landslide-Dammed Lake under Earthquake

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Journal of Mountain Science 2015年第5期12卷 1181-1188页

作者： WEI Yu-feng WANG Xiao-qun SHENG Man ZHOU Zhou YUAN Yong State Key Laboratory of Geohazard Prevention & Geoenvironment Protection Chengdu University of Technology

Valuable geological and environmental information can be obtained from the 200 m thick lacustrine sediments in the Diexi lake(an ancient landslide-dammed lake) of the minjiang river. The shaking table test method was employed to study the disturbance phenomena which occurred in the Diexi lake sediments. The results show that the disturbance phenomena were caused by liquefaction-induced flows in the unconsolidated lacustrine sediments, due to triggering by earthquakes. The deformations only occurred in unconsolidated sediment layers and not in consolidated layers. This means that a consolidated layer cannot be liquefied and disturbed again by an earthquake for a second time. The disturbance on one layer corresponds to only one earthquake. The temporal occurrence of earthquakes could be determined by disturbance layers generated at different ages. In total, 10 disturbed layers were found in the lacustrine sediments of the Diexi lake. The experiments showed that there were more than 10 earthquakes between 30 ka B.P. and 15 ka B.P. in the Diexi lake area based on the dating of the disturbed sediment layers.

关键词： minjiang river Diexi lake Landslide Earthquake disturbance deformation Simulatingexperiment

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