Formation of river terraces in conditions of high seismicity

We have investigated the river terraces on the left bank of the Irkut river in the Torskaya depression a short distance from the village of Guzhiry. On the basis of lithological-geological findings and radiocarbon datings of buried soils from two sections of the second terrace (12–14 m), we identified nine formation stages of the terrace in the latter half of the Late Neopleistocene and in the Holocene. They reflect multiple changes of the leading exogenous process, implying a variety of the genetic types of deposits (soils, and aeolian and alluvial sediments) during the Early and Mid-Holocene. The formation stages of alluvium are correlated with periods of high water. It is found that the final transition of alluvial to cover deposits is associated with incision of the river to 2–4 m and is dated to 5.2–4.5 cal. ka. We examine the alternation of the natural factors for the formation of deposits of the second terrace of the Irkut river in the Late Neopleistocene and Holocene. One (hydroclimatic) factor implies accumulation of deposits of the alluvial and cover complex depending on climate and water runoff fluctuations, landscape changes, and on variation in the base level of erosion. The other (seismic) factor is correlated with data on high activity of the Tory paleoseismogenic structure, which seems to have caused the lowering as well as the rise of the bottom of the depression at the time of strong earthquakes and, as a consequence, erosion or accumulation of deposits of the channel facies of alluvium. It is established that the chief causes for the change of the terrace’s deposit types were the natural-climatic changes, the character and directedness of tectonic movements, the variations in the base levels of erosion, and the height of floo ds.     

Geochemical indicators of technogenic pollution of bottom sediments of small rivers in an urbanized environment

We have explored the possibility of using the geochemical characteristics of migration and accumulation of alkali metals (lithium, rubidium, and caesium) as the indicators of anthropogenic status of heavy metals in bottom sediments of small rivers of a technogenically disturbed (urbanized) environment. A study was made of the behavior of the above elements in bottom sediments of the rivers of Petrozavodsk (Republic of Karelia). The chemical composition of the sediments used in the study was determined with X-ray fluorescence spectrometer ARL ADVANT’X and mass spectrometer XSeries-2 ICP-MS; the content of organic matter in bottom sediments (from the LOI index) was estimated by the weighing method upon heating the samples under investigation to the temperature of 1100°C. As a result of the investigations, it was found that among the heavy metals, Co, Ni, Cu, Zn, Mo, Sb, W and Pb are of predominantly technogenic origin in river sediments, which Cr and Cs are of predominantly natural origin due to a high background of these elements in Quaternary formations of the study area. We determined a close association of the trace elements of technogenic status as well as of Li, Rb and Cs with content levels of iron-manganese formations and organic matter in river sediments, which does indicate a commonalty of the processes promoting their input into the urban water stream. It is established that the commonalty of accumulation of a number of heavy metals in bottom sediments with lithophylic elements (Li, Rb and Cs), due to the high chemical activity of these latter, makes it possible to use the geochemical characteristics of the alkali metals as the indicator of technogenic status of the main pollutants of the urban environment.     

澜沧江河床沉积物重金属污染评价

河床沉积物是河流水体与泥沙环境中重金属的主要积存载体,能反映水环境的重金属污染状况。本文选取澜沧江为对象,通过对澜沧江干流西藏和云南境内22个河段的河床沉积物重金属测定分析,得到了8种主要的重金属元素(Cr、Mn、Ni、Zn、As、Pb、Cu和Co)的含量,并采用沉积物富集系数法与地质积累指数法分别对所测得沉积物的重金属污染程度进行了评价。结果表明:①澜沧江干流大部分河段污染情况并不明显,但在中游的旧州和功果桥河段,因该区域的地质金属背景值和支流沘江流域铅锌矿开采,地表的重金属元素被雨水冲刷到该河段,导致沉积物重金属富集现象明显,出现了轻度到较强度污染;②澜沧江流域受人为干扰的区域集中于中游与下游,部分河段(功果桥附近)Cu、Pb和Zn等元素呈轻度或偏中度污染;③大坝对河流的阻隔效应使得干流沉积物重金属污染呈现片段化分布,河流沿岸城市化等人类活动对附近河段沉积物重金属污染状况也有较明显的影响。     

色楞格河三角洲重金属季节和空间分布

In order to estimate the present-day pollution levels in the ecosystem of the Selenga River Delta and to monitor the changes caused by the discharge of household refuse and industrial wastes,as well as the functioning of the agricultural and stock farming,a comprehensive study of the water and bottom sediments in the main branches of the Selenga River Delta was carried out.This study has determined the concentrations of heavy metals in river water and bottom sediments in its delta.     

Seasonal and spatial distribution of heavy metals in the Selenga River Delta

In order to estimate the present-day pollution levels in the ecosystem of the Se-lenga River Delta and to monitor the changes caused by the discharge of household refuse and industrial wastes, as well as the functioning of the agricultural and stock farming, a comprehensive study of the water and bottom sediments in the main branches of the Selenga River Delta was carried out. This study has determined the concentrations of heavy metals in river water and bottom sediments in its delta.     

Assessing the Influence of the Mining Operations on the State of Streams in the Northern Part of the Red River Basin (Viet Nam)

A study was made of the influence of extraction of lead and zinc ores in the northern part of Vietnam (the Red river basin, Chodon district of Bac Can Province, and the basins of the Dai, Ban Thi, Ta Dieng and Cau rivers). Background concentrations of macro- and microelements and biogenic elements are determined in the river waters and water extracts from bottom sediments of small streams of the study area. A significance exceedance of background concentrations was revealed in stretches of the headwaters of the Ban Thi and Dai rivers caused by a combination of natural and anthropogenic factors. It is established that the river waters near the pollution sources contain increased (compared with the geochemical background) concentrations of Zn, Pb, Fe, Ni, Co, As, Bi, Cd, Cs, Sb, Ag,NO₂^? and SO₄^2?. The waters are estimated as moderately and heavily polluted, and at the other points as minimally polluted. It is determined that the level of accumulation of matter in water extracts from bottom sediments with respect to the geochemical background in the vicinity of the ore dressing factories corresponds to weakly and heavily polluted bottom sediments, and further downstream, to thy minimum level of pollution. It is shown that the influence of extraction of lead and zinc ores on the state of small streams is observed in stretches as long as 11–12 km (with a maximum in stretches of up to 4.5 km). The mathematical model of Pb and Zn distribution in the river waters of the study area has been developed and tested.     

Influence of large tributaries on biogeochemical processes in the Amur river

Presented are the results from experimental investigations into the influence of large tributaries (the Zeya, Bureya and Sungari rivers) on the water quality formation in the Amur river during the transformation of organic matter in bottom sediments. A spectral method and biochemical indication were used to show that toxic heavy metals (mercury, lead, and cadmium) accumulate in river sections of sedimentation of suspended load forming along the right bank from the mouth of the Sungari river to the city of Komsomolsk-on-Amur, and to substantiate the risk of emergence of hydrogen sulfide zones on the lower Amur.     

北京地区河流沉积物的金属元素背景值研究

本文检验,表征了北京地区河流沉积物的金属元素背景值。并应用多元分析法探讨了金属元素背景值的地球化学活动性、相关组合、区域差异等地球化学特征以以环境要素对形成背景值的影响。     

长江口南港的水文泥沙环境及污染物输移

南港河道水域宽广,水体量大,动力条件强,悬沙含量较高且都是细颗粒物质,纳污容量大,具有较强的输运、稀释和自净能力。污水进入南港以后,污染物在河道中迁移转化,主要吸附在泥沙上。在外泄过程中污染物质在南港中往返逗留,循环输移,向底层、滩地、涨潮沟等地迁移,并在河海相接地带富集。     

Influence of the interactions within the water – earth materials system on the formation of river water composition in the Ob basin

Physicochemical calculations of the abundance of a number of minerals and organo-mineral compounds in the river waters of the Ob basin revealed that the river waters throughout a year are able to actively interact with bottom sediments and river loads. The most active interactions occur in areas and during periods with increased moduli of river flow. It is shown that the increase in concentrations of dissolved organic matter in the river waters, including in the case of waste water discharges, is limited to a relatively low solubility of a number of compounds of metals with carbonates and humic acids.     

Preliminary reconstruction of sediment-source linkages for the past 6000 yr at the Petit Lac d'Annecy, France, based on mineral magnetic data

An 8 m core from the central plain of the Petit Lac d'Annecy, France, two floodplain cores, river bedload sediments and several hundred soil samples from the catchment have been studied using magnetic techniques. The soils, mainly developed on limestones and local glacial tills, show widespread magnetic enhancement with higher ferrimagnetic concentrations and contents of SP grains than found in the lake sediments. Some soils show significant concentrations of canted antiferromagnetic minerals (mainly haematite). Using magnetic quotient parameters the surface soils are classified into four mineralogical types. The lake and floodplain sediment properties over the past 6000 yrs can largely be explained by the erosion and deposition of these sources, with a smaller superimposed biogenic (magnetosomes) signal. Derived sediment-source linkages allow the construction of several hypotheses about geomorphological changes in the catchment system: (i) the long-term erosion of high altitude unweathered substrates has gradually increased towards the present day; (ii) the erosion of high altitude soils has increased within the last 1000 yrs, possibly during the period of the 'Little Ice Age'; (iii) shifts towards an increased erosion of surface lowland soil occurred ~2000 and 1000 yrs ago and may be linked to an accelerated accretion of floodplain overbank deposits; (iv) there has been a significant storage of surface soil within floodplains, which leads to an underestimation of the importance of soil erosion in the lake sediment records; (v) the sediment transported by high magnitude, low frequency flood events has shifted in source from high altitude soils before ~1000 cal. yr BP to lowland and mid-altitude free draining soils after ~1000 cal. yr BP.     

Sediment runoff,transporting capacity of flows and their role in river channel formation

An analysis is made of the sediment runoff as a determining factor of channel processes and as a set of phenomena arising due to the flow-channel interaction. The amount of sediments transported by the flow is determined by its transporting capacity that is changing constantly according to hydraulic characteristics of the flow undergoing changes across space and time. The relationships between them are responsible for the directedness of vertical channel deformations, i.e. incisions and accumulations of sediments leading to an increase or decrease in bottom elevations. In this case, the leading role in channel development is played by the runoff of entrained sediments. Its proportion governs changes in morphometric characteristics of the channel and its stability and influences the development of river branches and braids of the channel.     

柴达木盆地那棱格勒河流域表层沉积物微量元素组成及其对流域内锂的物源制约意义

柴达木盆地那棱格勒河流域是我国目前最大的盐湖型锂矿区和工业设施最为完备的卤水锂工业基地,长期以来关于其尾闾盐湖区锂的物源问题备受关注。尽管目前的众多研究已经对流域内地表水体及尾闾区盐湖中锂的物源有了较为一致的看法,但盆地周缘围岩风化过程在其中起到的作用仍缺乏系统性认识。基于部分保守性微量元素在物源示踪研究中的重要作用,本文通过对流域内河流表层沉积物中的REEY、Li、Sc、Co、Nb、Ta、Th等微量元素开展其地球化学行为方面的分析,讨论了沉积物的物源属性特征及其中锂的来源特征,为深入认识盐湖区游离态锂资源的物源提供了新的证据。结果表明,那棱格勒河流域与毗邻的东、西对比区河流沉积物有着相似的化学风化背景和基岩类型,源岩具有显著的长英质岩和基性岩的二元混合特征,且基性源岩所占比重更大;而沉积物中的锂除尾闾盐湖区明显受到富锂孔隙水体夹带的影响外,其它地区锂的来源特征与沉积物的物源特征相同,表明地表迁移过程对介质中锂的通量影响较弱,沉积物中的锂更多的是以赋存在相关矿物结构中的形式存在;研究区来自源岩风化作用提供的游离态锂的量较为有限,尾闾盐湖中的锂资源主要以昆仑山深大断裂带涌出的热泉水的长年补给为主。     

毛乌素沙地西南缘灌丛沙丘沉积物的粒度和元素特征

对毛乌素沙地白刺(Nitraria tangutorum)灌丛沙丘沉积物粒度和元素特征进行了采样分析.结果表明:灌丛沙丘沉积物来源单一,几乎全部由丘间地物质组成,其粒度和元素特征与丘间地物质极其相似;相对而言,灌丛沙丘沉积物比丘间地物质含有更多粗颗粒物,主要因丘间地可做跃移运动的中沙和细沙更易被灌丛阻挡而堆积;灌丛沙丘沉积物中大部分元素含量比丘间地物质低,主要因这些元素易被淋溶迁移到丘间地富集;灌丛沙丘发育以来,虽然其沉积环境存在波动,但相对稳定,未发生过显著变化.     

A geomorphological approach to the management of rivers contaminated by metal mining

As the result of current and historical metal mining, river channels and floodplains in many parts of the world have become contaminated by metal-rich waste in concentrations that may pose a hazard to human livelihoods and sustainable development. Environmental and human health impacts commonly arise because of the prolonged residence time of heavy metals in river sediments and alluvial soils and their bioaccumulatory nature in plants and animals. This paper considers how an understanding of the processes of sediment-associated metal dispersion in rivers, and the space and timescales over which they operate, can be used in a practical way to help river basin managers more effectively control and remediate catchments affected by current and historical metal mining. A geomorphological approach to the management of rivers contaminated by metals is outlined and four emerging research themes are highlighted and critically reviewed. These are: (1) response and recovery of river systems following the failures of major tailings dams; (2) effects of flooding on river contamination and the sustainable use of floodplains; (3) new developments in isotopic fingerprinting, remote sensing and numerical modelling for identifying the sources of contaminant metals and for mapping the spatial distribution of contaminants in river channels and floodplains; and (4) current approaches to the remediation of river basins affected by mining, appraised in light of the European Union's Water Framework Directive (2000/60/EC). Future opportunities for geomorphologically-based assessments of mining-affected catchments are also identified.     

沅江下游入湖段河床沉积物重金属污染特征

对沅江入湖沉积物进行钻探取样,利用等离子质谱仪（ICP-MS）对沉积物重金属进行分析。结果表明：重金属Ba、Sc、V、Th、U、Cu、Co、Ni、Cr等在沉积物中含量变化相对稳定,分布相对均匀;而Mn、Zn、Pb、Mo、Cd、Tl、Bi等重金属的含量变化大,分布不均匀。重金属含量柱状剖面变化特征及富集系数（EF值）的计算结果显示：沉积物中Cd达显著富集,而Sc、V、Mn、Pb、Bi等为中等富集程度。沉积物中存在3个重金属富集层,即中下部Pb、Tl、Bi富集层;中上部Pb、Cr、Ni、Cu富集层;浅表部V、Cr、Mn、Ni、Cu、Zn、Pb、Cd、Tl、Bi等多种重金属富集层。地累积指数（I_geo）和综合富集指数（EI）评价结果显示：沅江入湖沉积物重金属污染程度自河床深部向浅部,污染程度趋于增强,污染元素组合趋于由Pb-Bi的单一元素组合向由V-Cr-Mn-Ni-Cu-Zn-Pb-Cd-Bi组成的复合元素组合变化。且自上游向下游,沉积物重金属污染程度趋于降低。这种重金属污染空间变化特征与区域人为活动有关,值得进一步研究。     

黄河中游悬移质泥沙粒径与流域环境的关系

以黄河中游多沙粗沙区为研究区，在流域泥沙粒径、降雨、地面物质组成、地面形态、植被和高含沙水流等资料采集的基础上，采用“环境要素法”和多元回归分析来阐明泥沙粒径空间分异的机理。研究表明，随降雨不均匀系数的减小，断面最大含沙量的减小，流域内黄土覆盖面积的增大，以及植被盖度的增大和沟谷密度的减小，悬移质泥沙粒径趋于变细，反之，趋于变粗。其中，流域地面物质对泥沙粒径组成起最重要的控制作用，其次是植被，高含沙水流、沟谷密度和降雨影响作用相对较小。     

Using cosmogenic beryllium–7 as a tracer in sediment budget investigations

Recent advances in the use of the environmental radionuclides caesium–137 and unsupported lead–210 to quantify medium– and longer–term rates of erosion and sediment accumulation have proved of considerable value in catchment sediment budget investigations. However, there remains a need to explore the potential for using other shorter–lived radionuclides to provide evidence of sediment mobilisation, transport and storage over shorter timescales and particularly for individual events. This contribution reports the results of a study aimed at exploring the potential for using beryllium–7 (⁷Be, t _½= 53.3 days) to meet this requirement. The study investigated the use of ⁷Be as a sediment tracer in three key components of the sediment budget, namely, soil erosion and sediment mobilisation from slopes, the transport, storage and remobilisation of fine sediment in river channels and overbank deposition on river floodplains. The results presented clearly demonstrate the potential for using ⁷Be to obtain information on short–term and event–based sediment redistribution rates for use in catchment sediment budget investigations.     

贝加尔地区萨彦山东部Jom-Bolok火山谷湖泊古环境研究（英文）

This article describes the lake basins of the Jom-Bolok volcanic region in the East Sayan(the largest manifestation of the Holocene eruptions in Central Asia). The geomorphological position, origins, aspects of the structure and development are reviewed considering its sedimentary filling. The limnic morphogenesis here develops under the conditions of contrasting relief, high energy of neotectonic and exogenous processes. We established that Lake Khara-Nur, formed as a result of lava-damming of the Jom-Bolok river valley, emerged in its present form approximately 6500 years ago. A complex record on the environment and climatic changes, acquired from its sediments, made it possible to determine for the first time in this region the long-term trends in the development of the Middle and Late Holocene mountain geosystems and also the distinction of several paleogeographic stages of the formation of the natural environment. An average geochemical record resolution for the bottom sediments of the lake was made uniquely for the East Siberian lake records and is equal to 35 years, while the palynological record approximates 110 years.