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1.
自2002年9月14日至2004年9月28日,在天山乌鲁木齐河源1号冰川积累区雪坑中连续观测取样,频率为1次/周。对表层雪样品和粒雪坑样品的pH值和电导率进行了分析。结果表明,表层雪的pH值和电导率具有明显的季节变化趋势,与本区域的主导山谷风风向NE和ENE密切相关。在春季,由于尘暴发生频率的增加,表层雪的pH值呈现较强碱性,电导率达到最大值;在冬季,由于原生气溶胶向次生气溶胶的转化,pH值呈现较弱碱性,电导率达到最小值。在后沉积过程中(2003年10月4日至2004年9月8日),雪坑中不同时期的pH值和电导率呈现不同的季节变化特征和淋溶过程。电导率的峰值P1进入粒雪冰的时间比与它相对应的大粒径(直径>10 μm)微粒的浓度峰值提前40天左右;在有的雪坑中,pH值和电导率的峰值出现在污化层附近,与污化层的位置有较好的一致性,说明污化层对可溶性离子的淋溶作用可能有一定的影响。相关分析表明,Ca2+是影响表层雪中pH值和电导率变化的最主要离子。  相似文献   

2.
Groundwater quality assessment in urban environment   总被引:1,自引:1,他引:0  
The assessment of environmental effects generated by urban areas (with various activities as agriculture, industry, human activities) on groundwater quality became essential for the use and conservation of the water resources. The main objective was to apply a water quality index to the groundwater sources using the specific methodology, establishing the suitability for drinking for groundwater. Water resources were monitored in October 2011, the samples were collected from 22 points for groundwater, and more parameters were analyzed: pH, electrical conductivity, turbidity, oxygen regime, hardness, alkalinity, nutrients regime (nitrates, ammonium, phosphates) which were considered important and utilized for water quality index computation that reveal poor quality for groundwater. The oxidability should be included in computation formula and the final results used for water management, taking into consideration the limits of the current model. Multivariate statistical analysis was used to indicate the influence of urban area on the quality of groundwater resources. Results of the analysis highlight an influence of geology and a contamination of agricultural origin.  相似文献   

3.
为了了解黄土高原中部全新世古气候演化特征,通过对陕西富平剖面的地质调查、密集采样和31个样品的孢粉分析,将孢粉图式划分为Ⅰ、Ⅱ、Ⅲ3个带,分别代表早、中、晚3个时期的孢粉带:Ⅰ带为松-菊-香蒲组合带,以草本植物花粉占优势、针叶树植物花粉含量较高为特征;Ⅱ带为松-栎-蒿-环纹藻组合带,以乔木花粉增加、草本植物花粉减少为特征;Ⅲ带为栎-松-蒿组合带,以草本植物花粉增加、乔木花粉减少为特征.结果表明,早全新世植被为森林草原-干草原,气候干凉-干冷;中全新世植被为森林草原与针阔叶混交林草原,气候温暖半湿润;晚全新世植被为森林草原或疏林草原,气候干旱偏暖-温凉干旱.  相似文献   

4.
慕士塔格卡尔塔马克冰川作用区的水文与水化学特征   总被引:7,自引:2,他引:7  
利用2003年6月1日~8月25日实测的水文数据,分析了慕士塔格峰卡尔塔马克冰川融水径流的变化特征.卡尔塔马克冰川融水径流主要集中在6~8月,其存在着明显的日变化过程,融水径流受控于温度及降水要素.同时,对8月10~23日采集的冰川径流样品及部分降水样品的pH、EC(电导率)和主要离子(Na+,K+,Ca2+,Mg2+,Cl-,NO3-,SO42-,未检测降水样品的离子含量)的测定结果进行了分析讨论.径流样品略偏碱性,pH和EC呈正相关关系.SO42-和Ca2+是所测离子中主导的阴阳离子.除NO3-外,样品中各离子含量具有一致的变化特征;各离子浓度与流量或水位具有相反的变化趋势.初步讨论了离子的来源,结果表明冰川融水中化学物质组分主要来源于地表.  相似文献   

5.
The high topographic complexity of the Alpine region is the origin of important climate differences that characterise the different areas of the Alps. These differences might have had a strong influence on vegetation and on migrations of human populations in the past. Based on an improved database containing about 3000 modern pollen samples, the standard “Modern Analogue Technique” has been applied to five pollen sequences from the subalpine belt of the South-western Italian Alps (Laghi dell’Orgials, 2240 m, Lago delle Fate, 2130 m, Torbiera del Biecai, 1920 m, Rifugio Mondovì, 1760 m, Pian Marchisio, 1624 m) to provide quantitative climate estimates for the Lateglacial and Holocene periods. Consistent climate trends are reconstructed for the different sequences. Sites recorded in detail the climate variations when they were located at the limit of two ecotones. Sites above the tree line recorded lower temperature values and less important variations. Climate was cold and dry during the Oldest and Younger Dryas and close to present-day values during the Bølling/Allerød interstadial. At the beginning of the Holocene, climate changed to warmer and moister conditions; a high number of climate fluctuations are recorded at several sites. A climate optimum is recorded in the Atlantic period, which caused a development of fir above its present-day altitudinal distribution. Climatic differences recorded at the various sites are discussed taking into account the limits of the method.  相似文献   

6.
水泥混合上海黏土pH值和电导率与强度特性研究   总被引:2,自引:0,他引:2  
车东日  罗春泳  沈水龙 《岩土力学》2012,33(12):3611-3615
针对目前钻芯取样、标准贯入试验、荷载试验等水泥搅拌桩的检测方法试验要求高、试验时间长、测试费用高等诸多缺点,提出联合测定水泥土初期pH值与电导率的方式来判断其后期无侧限抗压强度与混合土性状的方法。以上海地区第④层黏性土为研究对象、以水泥掺量为变量,对加固土体的化学性质与其强度增长特性做了试验研究;探讨了pH值和电导率与水泥掺量、养护时间、后期强度之间的关系。试验结果表明,当水泥土初期的pH值和电导率大于分别为11.5和0.09 s/m的临界值时开始产生强度。在此之后强度随着pH值的增长而缓慢增加,但当pH达到11.8时,强度开始随着pH值的增长而迅速增加。电导率与强度变化关系的这些特征可以避免用水泥土初期pH值单一化学指标来判定其后期无侧限抗压强度带来的误差与风险。为判定上海地区黏性土水泥搅拌桩的强度提供试验依据。  相似文献   

7.
Based on the pollen spectrum characteristics of 46 surface samples collected in the western Tianshan Mountains of Xinjiang and a plant community quadrat survey, we analyzed the relationship between pollen assemblages and modern climate and vegetation distribution in the region. The results showed the surface pollen assemblages were consistent with the distribution of modern vegetation. Based on the results of cluster analysis, the study area could be divided into three pollen assemblage zones(mountain steppe zone, desert vegetation zone and typical desert zone). In general, pollen assemblage can roughly reflect the main characteristics of local vegetation, but there are significant differences in the percentage of some pollen types and the coverage of related plants. The pollen of Picea and Pinus in arbor plants, Ephedra in shrub plants, Chenopodiaceae and Artemisia in herb plants were high represented due to the influence of natural wind, water flow and their own pollen yield. While Rosaceae pollen in shrubs and Poaceae in herbs were less representative in a modern plant community with its own dominant species;The Artemisia and Chenopodiaceae(A/C)ratio can distinguish the desert zone from the mountain steppe zone, and could clearly reflect the aridity level. However, when using this indicator to reconstruct the climate environment, it is necessary to combine the characteristics of pollen assemblage and the influence of changes in vegetation composition and other factors to distinguish;Altitude, average annual precipitation, and average annual temperature all affect the distribution of surface pollen in the area. © 2022 The authors.  相似文献   

8.
Comparative volcanological, mineralogical, petrological, and geochemical studies of blocks of Triassic submarine basalt occurrences hosted by the Jurassic mélange have been carried out. The studied localities are located in displaced parts of the Dinarides in NE-Hungary (Darnó Unit), in the Dinarides (Kalnik Mts., Croatia and Vare?-Smreka, Bosnia and Herzegovina), and in the Hellenides (Stragopetra, Greece). The common characteristic of the studied occurrences is the well observable result of the lava–water-saturated sediment mingling, i.e., the presence of the so-called carbonate peperitic facies. Mixing of the basaltic lava with pelagic lime mud (representing the unconsolidated stage of the red, micritic limestone), as well as fluid inclusion and chlorite thermometry data support that the carbonate peperite was formed above CCD and at the Bosnian locality, a shallower water, about 1.4?km depth is proven. The igneous rocks show mainly within-plate basalt geochemical characteristics; MORB signatures are not common. Low temperature (<200°C) hydrothermal alteration is characteristic to the pillow basalt blocks with peperitic facies. The similarities in the volcanological, geochemical, and textural characteristics observed at the different localities support a strong genetic connection among them. The results of this study suggest to the advanced rifting stage origin of the Triassic basaltic suits and their distinction from the true oceanic basalt pillow units of the Dinarides can be based on the occurrences of the peperite facies.  相似文献   

9.
对天山哈密庙尔沟平顶冰川和奎屯河哈希勒根51号冰川的雪层剖面及雪坑中pH值和电导率的变化特征进行了初步研究.结果表明:哈密庙尔沟平顶冰川以渗浸-冻结成冰作用为主,一年成冰,成冰带由消融带和渗浸-冻结带组成,渗浸-冻结带的垂直高度在60 m左右或者更大一点;奎屯河哈希勒根51号冰川的成冰作用以暖型为主,成冰带由消融带、渗浸-冻结带和渗浸带组成,渗浸-冻结带的垂直高度不大于70 m.雪坑中pH值和电导率的较高值一般出现在冰片和污化层附近,这与冰的阻碍、引起可溶性离子在冰面上部的高浓度值和可溶性离子的淋溶过程与污化物的迁移过程密切联系直接相关.哈密庙尔沟平顶冰川雪坑中pH值和电导率之间的相关性异于奎屯河哈希勒根51号冰川,由于雪坑的资料有限,有待进一步的深入研究.  相似文献   

10.
漓江水系汞的分布和污染研究   总被引:1,自引:0,他引:1  
对漓江水系干流、支流、连体湖泊、较大的孤立湖塘和近岸水井设置40个采样点。水样采样周期为2个水文年,分枯水季和丰水季两次采样,现场测定水温、电导率、pH值等理化参数。系统采集水样112件、底泥样40件、水草样40件、近岸土壤样40件。底泥样用逐步浸提法进行不同形态汞分析。研究结果显示,干流河水、底泥和水草中汞的平均含量分别为0.12μg/L、0.20μg/g和0.032μg/g;主要支流河水、底泥和水草中汞的平均含量高于干流,分别为0.15—0.23μg/L、0.38~1.7μg/g和0.028—0.044μg/g。底泥中汞含量均高于近岸土壤汞含量。无论是干流还是支流,河水汞含量与底泥、水草汞含量有明显的相关关系。由上游至下游,漓江水系干流、主要支流河水样汞含量均不断增高,可高出源头河水汞含量的1.5—5倍。相应地指示重金属离子污染的参考指标——电导率值不断增高,河水的pH值亦逐渐增高。丰水期(5月至6月)河水中的汞含量(0.12—0.28μg/L)明显高于枯水期(9月至11月)河水中的汞含量(0.091—0.28μg/L)。不同断面河水汞含量均高于相应近岸井水汞含量。不同水体底泥中汞的形态分布一般顺序为:残渣态〉难氧化降解有机质结合态〉腐殖酸结合态〉碳酸盐和铁锰氧化物吸附态〉交换态〉易氧化降解有机质结合态〉水溶态。综合各项资料分析,认为漓江干流是桂林城市汞污染最大的汇。根据地表水环境质量标准(GB3838--2002),仅汞而言,漓江水系均达到Ⅳ类水质标准(河水中汞含量≤1μg/L)。漓江支流汞污染高于干流,对干流存在较大的污染风险。  相似文献   

11.
The aim of this study was to investigate the water and sediment quality in the mid-Black Sea coast of Turkey. The samples were collected from six stations during 2007. Investigated parameters were total carbon (TC), total inorganic carbon (TIC), total organic carbon (TOC), ammonium-nitrogen (NH4-N), nitrate-nitrogen (NO3-N), nitrite-nitrogen (NO2-N), total phosphorus (TP), sulphate, total hardness, methylene blue active substances (MBAS), phenol, adsorbable organic halogens (AOX), dissolved oxygen (DO), pH and electrical conductivity (EC) in water samples and TC, TIC, TOC, TP, pH, electrical conductivity (EC), redox potential (Eh) and water content (WC) in sediment samples. Different multivariate statistical techniques were used to evaluate variations in surface water and sediment quality. Principal component analysis helped in identifying the factors or sources responsible for water and sediment quality variations. Five factors were found responsible for 87.63% of the total variance in the surface waters. In sediments, three factors explained 84.73% of the observed total variance. Cluster analysis classified the monitoring sites into two groups based on similarities of water and sediment quality characteristics.  相似文献   

12.
《Applied Geochemistry》1999,14(6):787-805
Water samples were taken from 120 lakes spread over the western half of the Kola Peninsula, NW Russia. The samples were analysed for 37 elements, pH and electrical conductivity. Lake water chemistry appears in most cases to be dominated by a Ca/Na–HCO3 signature, characteristic of natural carbonate/silicate weathering. Input of elements from marine derived salts and from the Ni industry (roasting plant at Zapoljarnij, smelter at Nikel and smelter/refinery at Monchegorsk) emissions are restricted to limited regions. Considering that 3 of the world's largest point source emitters of SO2 are located within the area, the median lake water pH is surprisingly close to neutral (6.6, range 4.2–7.4). Indeed some of the apparently SO4 contaminated lakes nearest to the smelters yield the highest pH values. Changes in climate and vegetation from north to south within the survey area probably have an influence on element concentrations and pH as observed in the lake waters. Proton displacement by sea salt cation input provides an explanation of low pH lakes in coastal areas.  相似文献   

13.
对青海共和盆地内的达连海湖泊流域54个样点进行植被调查及表土花粉分析,研究了植被与表土花粉之间的关系. 结果显示: 表土花粉组合可反映出该区植被的总体特征;达连海湖泊流域花粉沉积来源于整个流域植被,花粉与主要植被类型之间相关性良好,但不能完全反映出群落的建群种、优势种和盖度等. 蒿属和藜科花粉具有超代表性,禾本科表现为低代表性,蒿/藜比具有区域植被生态特点与气候指示意义,在不同的植被区域A/C变化明显;影响达连海湖泊流域表土花粉组合的主要控制因素是风力作用.  相似文献   

14.
小南屯砂砾石层成因争论较大。通过孢粉学研究表明:该孢粉组合是以草本植物花粉为主,木本植物花粉为辅。在草本植物花粉中,又以蒿属占绝对优势,加上藜科、禾本科为特征的干燥寒冷气候带的孢粉组合,表明该砂砾石层为冰水堆积物。  相似文献   

15.
The Qaidam Basin is one of the most sensitive areas to climate change in China, owing to its unique geographical position and ecological condition. In this study, 32 surface‐soil pollen samples were collected to reveal the relationship between modern pollen assemblages, vegetation and precipitation in the eastern region of the Qaidam Basin. The results show that Chenopodiaceae (3.8–87%, average 48%), Artemisia (1.7–64.2%, average 17.5%) and Ephedra (0–90%, average 16.3%) are the dominant pollen types in all samples, and that different pollen assemblages correspond to different vegetation types. DCA and CCA of major pollen types demonstrate that precipitation is an important factor in the control of the distribution of vegetation in the study area. The content and concentration of the three major pollen types (Artemisia, Chenopodiaceae and Ephedra) change with the mean annual precipitation, and the optimum mean annual precipitation for Ephedra, Chenopodiaceae and Artemisia is <80, 80–200 and >160 mm, respectively. Correlation analysis between the variation in grain size of the three major pollen types and the main environmental variables shows that the grain size of the three pollen types is positively correlated with precipitation in the Qaidam Basin. The results confirm that precipitation is the most important environmental factor in the Qaidam Basin, and that it has an important effect on pollen grain size in the study area.  相似文献   

16.
电磁感应仪EM38用于土壤盐渍剖面分类与评价研究   总被引:9,自引:0,他引:9  
结合电磁感应仪EM38测量与田间采样,文章分析了黄河三角洲典型区域土壤电导率的剖面分布特征,建立了磁感式表观电导率与土壤电导率间的(多元)回归解译模型,探讨了不同分类方法对土壤盐渍剖面分类结果的准确性,并对典型盐渍剖面类型进行了评价。结果表明:研究区土壤盐分具有较强的表聚性与变异强度;土壤电导率与磁感表观电导率EMh、EMv间呈极显著的相关关系,EMh对浅层土壤电导率的解译精度较高,而EMv对深层土壤电导率的解译精度较高;EMv/EMh法和理论函数法对土壤盐渍剖面的分类结果均具有较高的精度,且理论函数法分类结果的准确性明显优于EMv/EMh法;研究区土壤盐渍剖面可划分为表聚型、底聚型与均匀型,在数量上以表聚型及底聚型为主,其中表聚型与均匀型属于积盐型剖面,底聚型属于脱盐型剖面。该结果对研究黄河三角洲地区土壤盐渍化的发生、机理、预测与评估该地区土壤盐渍化的发生、发展具有重要意义。  相似文献   

17.
Salt mining induced ground subsidence is a major hazard in the city of Tuzla (Northeastern sector of Bosnia and Herzegovina) and its surroundings since 1950, when solution mining of salt deposits by boreholes began. An analysis of the large (and never before processed) amount of topographical data collected during two periods: from 1956 to the Balkan War, and from 1992 to 2003 has been made. The analysis reveals a cumulative subsidence as high as 12 m during the whole period, causing damage to buildings and infrastructures within an area that includes a large portion of the historical town. Human-induced subsidence, (with rates up to 40 cm/year in the most developed area), has been investigated to recognize the areas affected by the sinking phenomenon and to produce a subsidence hazard. The time series of topographical observations have been enlarged by conducting new surveys in the urban area by modern space-geodesy methodologies, such as static relative GPS (Global Positioning System) and high resolution satellite imageries. The GPS monitoring started in 2004 and detected a decrease in the subsidence rates to 20 cm/year related to the reduction of salt exploitation. There is close correlation between the average subsidence rate and the annual amount of salt extracted.  相似文献   

18.
琼东南盆地深水区是21世纪南海北部大陆架地区天然气勘探的重点区带之一。为了划分该盆地WN-A井的地层时代及探明其沉积物所记录的古气候条件,笔者对该井分布于3 261.25~5 079.00 m井段共计108份岩屑样品进行了孢粉分析。研究结果显示,该井孢粉化石种类较丰富且分布连续,由下至上可划分为4个孢粉组合: Pinuspollenites-Polypodiaceoisporites-Juglanspollenites-Quercoidites E-Quercoidites D组合、Pinuspollenites-Juglanspollenites-Polypodiaceoisporites-Dicolpopollis kockelii组合、Quercoidites E-Polypodiaceoisporites-Pinuspollenites-Polypodiisporites组合和Pinuspollenites-Polypodiaceoisporites-Randiapollis reticulatus-Quercoidites E组合。其中:4 425.00~5 079.00 m井段孢粉组合的优势组分是Pinuspollenites、Juglanspollenites和Quercoidites D,指示热带、亚热带针叶、常绿、落叶阔叶混交林,气候较温凉;3 261.25~4 425.00 m井段孢粉组合中Quercoidites E占优势,指示热带、亚热带常绿、落叶阔叶混交林,气候温暖湿润。WN-A井孢粉组合记录了一次明显的由温凉转为温暖的气候变化,与全球渐新世—中新世的气候变化可以对比,其发生位置,即4 425.00 m可以作为WN-A井渐新统和中新统的界线。  相似文献   

19.
第四纪孢粉分析的时间序列与空间模型   总被引:4,自引:0,他引:4  
郑卓 《地球科学进展》1998,13(3):300-305
论述了第四纪孢粉时间序列和孢粉空间模型在不同尺度上的时空代表性,同时介绍了一些相关的研究方法和主要成果。利用数理统计方法来定量恢复古气候已成为目前第四纪孢粉时间序列研究的一个发展趋势。各种尺度的第四纪孢粉空间模型图可以反映植被对第四纪气候变化的响应。根据孢粉数据与气候变量之间的函数关系还可换算成古气候图。此外,在全球气候模拟和植被模拟中,孢粉数据成为必不可少的诊断工具。  相似文献   

20.
Forty-one water samples in each season(both pre-and post-monsoon) were collected from different for-mations of the Kadiri schist belt located in the Anantapur district,Andhra Pradesh.The specific electrical conductiv-ity(EC) of these water samples was measured at 25℃ by using specific conductivity bridge.The specific conductiv-ity values of the water samples were also calculated by multiplying ionic concentrations with conductivity factor.It is found that the observed EC values of all water samples collected in both the seasons are different from the esti-mated EC values because of the electro-chemical properties of ions in water.  相似文献   

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