Estimation of the scale of spatiotemporal variability in the lithological and geochemical characteristics of suspended particulate matter and bottom sediments at the mouth of the Volga River and the adjacent zone of the northern Caspian

Based on the data of synchronous observations of hydrophysical and biogeochemical parameters in the near-mouth and shallow-water areas of the northern Caspian in 2000–2001, the scale of spatiotemporal variability in the following characteristics of the water-bottom system was estimated (1) flow velocity and direction within vortex structures formed by the combined effect of wind, discharge current, and the presence of higher aquatic plants; (2) dependence of the spatial distribution of the content and composition of suspended particulate matter on the hydrodynamic regime of waters and development of phytoplankton; (3) variations in the grain-size, petrographic, mineralogical, and chemical compositions of the upper layer of bottom sediments at several sites in the northern Caspian related to the particular local combination of dominant natural processes; and (4) limits of variability in the group composition of humus compounds in bottom sediments. The acquired data are helpful in estimating the geochemical consequences of a sea level rise and during the planning of preventive environmental protection measures in view of future oil and gas recovery in this region.     

临洪河口现代沉积环境及重金属元素的分布特征

对江苏北部临洪河口不同区域的表层与柱状沉积物进行了粒度分析、石英颗粒表面微细结构和沉积物的测年分析以及沉积物中的重金属含量分析．将河口划分为不同的沉积环境区．探讨了不同沉积环境中沉积物的粒度分布、石英颗粒表面微细结构、沉积速率以及重金属元素分布差异的原因。结果显示,临洪河口可以划分为低潮滩上的波浪与潮流强烈混合作用区、高潮滩上的弱潮流作用区、口门附近的潮流与河流强烈混合作用区和河道内河流与潮流弱混合作用区。重金属的含量在柱样的30～40cm深度呈现向表层递增的趋势,Hg的污染比较严重．其他元素基本无污染,整个河口区域的生态危害性严重;沉积物粒度分布不是该区域重金属分布的主要影响因素,城市污水排放量增加、氧化还原层位、沉降方式和不同沉积区的水动力环境是影响本区域重金属元素分布和累积的主要原因。     

Application of discriminant analysis and manova to grain-size data on a study of the distribution and movement of dredged sediment

A dredged material disposal operation was monitored at a location in Lake Erie, 8 km offshore at Ashtabula, Ohio, in 1975. Approximately 200 sediment cores were collected from 12 experimental and 4 control locations before and after dredging and analyzed for the grain-size distribution and related heavy-metal content. The dredged sediments were similar to those from the lake bottom at the disposal and control sites. Because of this similarity, it was extremely difficult to distinguish between the dredged material and the lake bottom sediments without tagging the material with dyes or radioactive isotopes. A sequence consisting of a linear discriminant analysis followed by a univariate and multivariate analysis of variance was successfully applied to discriminate between the dredged and the original lake sediments. Results indicate that 4 months after the disposal operation some stations had returned to predisposal conditions, a probable result of currents stripping dredged material off the lake bottom. The analysis of variance indicated that the clay-size fraction was responsible for initial changes in the grain-size distribution. Storm induced scouring caused an eventual return of the grain-size distribution to predisposal conditions. In support of this observation, the concentrations of iron and zinc, which were statistically correlated to the clay size fraction, also exhibited the same trends.     

Facies Variability of Recent Sediments in the Hornsunn Fjord,Western Spitsbergen

The study of bottom sediments and suspended matter (SM) in the Hornsunn Fjord of western Spitsbergen reveals that SM is largely deposited in its central part. The model of recent sedimentation in the fjord is proposed based on the analysis of grain-size distribution, petrographic-mineralogical composition, physical properties of recent sediments, and benthic foraminiferal communities therein.     

陕西潼关金矿区太峪河底泥重金属元素的含量及污染评价

通过对潼关金矿区太峪河和太峪水库底泥中重金属元素总量的调查,探讨了金矿开发活动中重金属元素对河流底泥的污染程度。研究结果表明,除As外,河流底泥中重金属元素的含量与尾矿渣中重金属元素的含量变化一致,表明其主要来源于尾矿渣,但又明显高于尾矿渣。在同一地点河流底泥中重金属元素的含量平均高出河水中的1048.61～666030.08倍,呈显著富集。以邻近地区不受工矿活动影响的河流底泥重金属元素的含量均值作为评价参比值,太峪河底泥受到了Hg、Pb、Cd、Cu、Zn元素的极度污染,单项污染超标倍数及综合污染指数法评价结果表明,Hg、Pb、Cd平均污染超标倍数达366.90、217.42和149.97,是底泥中最主要的污染元素。河流底泥重金属元素的综合污染指数高达278.97,表明河流的复合污染亦呈极度状态。太峪河底泥受重金属元素极度污染的现实提示,矿区的环境防治工作已刻不容缓。     

Grain-size characteristics of fine-grained unflocculated sediments I:'one-round' distributions

A simple physical model of gravitational settling from an unsorted, unflocculated source suspension is presented and an equation derived to describe the grain-size spectra of the resulting bottom sediment. Results of grain-size analyses of sediments from a variety of environments and geographical locations are shown to conform with the postulated model. The characteristic size spectrum, termed ‘one-round’ sediment, identifies a deposit which has settled from suspension with no subsequent reworking resulting in modification of the grain-size distribution. The distribution of settling rates of grains in the suspension may be inferred from an analytical form fit to the bottom sediment grain-size spectrum, along with knowledge of certain physical characteristics of the fluid (e.g. mean velocity profile).     

钱塘江南岸ＳＥ２孔晚第四纪以来沉积物粒度特征及环境演化

利用钱塘江南岸萧山地区SE2孔的粒度资料,分析了粒度参数、频率分布曲线和概率累积曲线的 特征,并结合沉积物的岩性、沉积构造和有孔虫的分布特点,探讨了该区自晚第四纪以来的沉积环境演化。结 果表明,晚第四纪以来,钱塘江南岸地区依次接受了河床相、河漫滩相、潮坪相、近岸浅海相和河口湾相5种 沉积。河床相沉积物以砂砾为主,粒度参数变化较大,概率分布曲线为3段式,频率分布曲线为不对称的双峰 式,主要发育块状层理,生物化石稀少。河漫滩相以细砂、粉砂级沉积物为主,频率分布曲线为单峰式,富含 生物壳体碎屑和植物根茎。潮坪相沉积物表现为粉砂和黏土互层沉积,粒度参数变化频繁,频率分布曲线多为 双峰式,韵律层理发育。近岸浅海相沉积物主要为淤泥质黏土,粒度参数稳定,概率分布曲线为2段式,以悬 浮组分为主,频率分布曲线为单峰式,有孔虫含量丰富。河口湾相沉积物以粉砂和细砂组成的韵律性沉积为主, 粒度参数富于变化,概率分布曲线为3段式,频率分布曲线为双峰式。     

江苏典型地区河流沉积物重金属元素分布特征及其污染来源

通过对河流沉积物等地表沉积物中重金属元素分布等环境地球化学调查数据的统计分析,总结了江苏典型地区河流沉积物中重金属元素的分布特点与规律:江苏局部地区河流沉积物中,Cd、Pb、Zn、Cr、Cu、Ni、Hg等相对富集趋势明显,Cd最大富集倍数 100;不同河流沉积物的重金属元素分布存在差异,与其污染来源密切相关;工业排放是导致河流重金属污染的主要原因,使用含Cd的颜料作为调色剂导致部分河流出现严重Cd污染;与土壤等其他地表沉积物相比,河流沉积物中重金属元素的分布更不均衡。查明河流沉积物的重金属元素分布可为相关农产品安全性预测、确定重金属污染来源、追踪涉重产业的发展历程、防治局部耕地重金属污染等提供科学依据。     

Heavy metal distribution in the surface layer of bottom sediments of the Kara Sea

This paper addresses the distribution of heavy metals (Co, Ni, Cu, Zn, Cd, Sn, Sb, Pb, and Bi) as well as Si, Al, Fe, and Mn in the surface (0–2 cm) layer of bottom sediments of the Kara Sea. The contents of these elements are determined in each of the previously distinguished facies-genetic types of terrigenous sediments: fluvial, glacial, estuarine, shallow water–marine, “background” marine, and relict sediments. It is shown that these types reflect the modern conditions of accumulation of river discharge material, which forms fans of two greatest Siberian rivers, Ob and Yenisei. The main stages are distinguished in heavy metal accumulation. The first stage is related to the avalanche sedimentation of terrigenous sediments in the estuary and characterized by the elevated contents of Co, Ni, Cu, Zn, Cd, Sb, and Bi. The second stage reflects the mechanical differentiation of sedimentary material by waves and bottom currents in a shallow-water sea part adjacent to the estuarine zone, with accumulation of Pb- and Sn-bearing “heavy” ore minerals. The deepwater background terrigenous–marine sediments accumulate mainly Ni, Zn, and Cd, as well as Mn. The relict sediments differ in the high contents of Si, Mn, and Sn.     

Ecological-geochemical evaluation of the state of surface water streams in the impact area of the tailing dump of the Urupsky Ore Mining

Surface waters are subject to intense contamination with trace elements in ore mining areas. A complex study was performed for the state of waters and bottom sediments from the Bogachukha and Urup Rivers in the area of the abandoned tailing dump of the Urupsky Ore Mining. The impact exerted by the tailing dump on the concentration of elements in the water, suspended particulate matter, and bottom sediments of the rivers is evaluated. The major contaminants of surface waters and bottom sediments, as well as the forms of their element distribution are revealed.     

Organic matter in the bottom sediments of the Ob Bay: Distribution,nature, and sources

The lateral variability of main geochemical parameters of dispersed organic matter (DOM) in the bottoms sediments of the Ob Bay was studied using materials of areal geological survey. It was found that they correspond to background compositions of estuarine-delta facies of the Western Arctic shelf, being mainly determined by the influx of river run-off and coastal abrasion. The distribution of DOM and its components is controlled by the hydrodynamic regime of the water area and grain-size composition of sediments. The molecular composition of hydrocarbon markers (n-alkanes, cyclanes, and arenes) confirms the dominant role of terrigenous humic material in the formation of DOM of the bottom sediments, while temporal stability of quantitative and qualitative geochemical characteristics indicates the stability of the Ob Bay ecosystem.     

Transformations of pollutants in the river water-pore solution-solid phase of the bottom sediments system in small rivers (using the example of waterways in the Losinyi Ostrov (Elk Island) National Park)

The distribution of heavy metals has been examined in water and bottom sediments of small streams within the Losinyi Ostrov (Elk Island) National Park (Moscow) that are undergoing manmade impacts. We demonstrated that pollution caused by motor vehicles causes seasonal changes in the general composition of the river water and pore solutions in bottom sediments. The strongest pollution of water and sediments was found near the CMHW (Circum-Moscow Highway) (Zn, Pb, Cu). This is expressed in the growth of mobile forms of metals in sediments. We have shown, using Zn as an example, the pollution transformation in the snow-river water-suspension-bottom sediment system.     

大冶铁山地区河流水体及水系沉积物中重金属元素分布特征

矿产资源的长期勘探、开采和冶炼活动给大冶铁山地区的自然生态环境造成了严重破坏.对该区西港河、东港河河水和水系沉积物中重金属元素分布特征的研究结果表明,该区矿山开采和冶炼活动形成的重金属污染元素主要为Cd、As、Zn;其主要污染源为冶炼厂排放的废水,其次是采矿废弃物堆积渗漏水;重金属元素在河水与水系沉积物中的空间分布特征较相似,但水系沉积物中元素质量分数比河水中的普遍增高,元素变化的剧烈程度加剧.     

山西应县护驾岗冲沟阶地地层粒度特征与沉积环境

山西应县护驾岗冲沟阶地地层形成于66.46～33.62 ka,根据该剖面地层的粒度分布特征对该地区冲沟阶地的沉积环境进行了探讨。护驾岗冲沟阶地剖面的粒度分布特征显示:(1)剖面地层总体表现为自下而上由粗到细的正韵律沉积特征,结合野外观察将其分为4段(A—D段);(2)A段粒度分布特征变化不大,均以细砂为主,频率曲线为不对称单峰,概率累积曲线为2段式,以跃移搬运为主,分选相对较好,水动力较强,沉积环境稳定;(3)B—C段粒度分布特征变化较大,以粉砂和细砂为主,频率曲线为不对称双峰,概率累积曲线为2段式,以跃移搬运为主,分选较差,水动力较强,沉积环境不稳定;(4)D段粒度分布特征变化不大,以粉砂为主,频率曲线为不对称单峰,概率累积曲线为2段式,以悬移搬运为主,分选相对较好,水动力较弱,沉积环境稳定。总体来说,冲沟阶地形成于河流沉积环境,顶部为河漫滩沉积环境。粒度分布特征与古里雅冰芯氧同位素变化基本一致,因此护驾岗冲沟阶地粒度特征与沉积环境的变化归因于气候变化。     

中国大陆架海底沉积物中的稀土元素

选择渤海、黄海、东海和南海有代表性的大陆架沉积物样品,利用X射张荧光光谱法测定了15个稀土元素。中国大陆架沉积物稀土元素的丰度为156ppm,相对接近于中国黄土和花岗岩的丰度,而与太平洋沉积物的丰度相差较远,具有明显的“亲陆性”。稀土的配分模式旦显著的负斜率,属陆壳稀土的典型特征。稀土含量受沉积物粒度控制。实验表明稀土主要以类质同像存在于粘土矿物之晶体构造中。根据数理统计,稀土与亲陆源粘土矿物的元素为一类,彼此呈正相关;与亲海洋生物的元素为负相关。事实说明中国大陆岩石的风化和搬运,是中国海大陆架沉积物中稀土的主要物质来源。     

History of Holocene Sedimentation in the Southern Kara Sea

Two bottom sediment cores (BP00-23/7 and BP00-7/6) recovered from the Yenisei transect in the southern Kara Sea are described. Data on their grain size composition, clay and heavy mineral assemblages, and distribution of a large group of chemical elements are presented. Radiocarbon dates based on AMS C-14 method suggest the Holocene age of sediments in the cores. Literature data on physical properties and foraminifers have also been analyzed. The facies affiliation of the lithostratigraphic subdivisions has been unraveled. History of the Yenisei River runoff in the Holocene has been reconstructed on the basis of different indicators.     

周老镇钻孔砾石层重矿物特征及地质意义

利用江汉平原周老镇钻孔的岩心样品,分析研究了钻孔岩心沉积物10层砾石层中填充物的重矿物组分及分布特征。结果显示周老镇钻孔10个砾石层自下而上可以分为3个矿物段。对比3个阶段稳定重矿物、非稳定重矿物的变化特征:阶段Ⅰ、阶段Ⅱ,沉积物主要以近源物质为主,含有少量的远源物质;而阶段Ⅲ,沉积物主要以远源物质为主,含有少量的近源物质。结合周老镇钻孔岩性及钻孔砾石含量和江汉平原第四系岩相剖面特征,判断在阶段Ⅲ,深度112.30～109.05m(1.17～1.12MaB.P.)处,钻孔沉积环境发生了重大改变,江汉平原水系发生重要调整,长江三峡贯通形成。     

Preference ratios for mercury and other chemical elements in the Madeira River, Brazil

Samples of water, suspended solids, and bottom sediments from the Madeira River, Rondônia state, Brazil, were physically and chemically analyzed to investigate the actual Hg mobilization in the aquatic environment and compare it with that of other heavy metals and elements in the area. Two dimensionless Hg preference ratios were defined, expressing (1) the ratio of Hg and other elements in the liquid phase divided by the ratio of Hg and other elements in bottom sediments (P_l.phase) and (2) the ratio of Hg and other elements in the particulate matter divided by the ratio of Hg and other elements in bottom sediments (P_s.solids). These preference ratios are useful for comparing Hg transport in three different phases (liquid, particulate matter, and bottom sediments). They also were applicable to any analyzed element in the area studied, because they generated an almost constant value when the maximum calculated was divided by the minimum (P_l.phase=2931; P_s.solids=84) and because of their sensitivity to the dominance of sorption processes by Fe oxides and hydroxides. Mercury could be transported preferentially to other analyzed elements in the particulate phase only if its concentration reached values at least 10⁴-fold higher than those expected or quantified in the area.     

江汉盆地ZL钻孔微量元素含量的粒度效应与环境意义

江汉盆地是长江出三峡后第一个大型卸载区,近2.77 Ma以来堆积了近300m的碎屑沉积物,主要由河流相和湖沼相组成,形成了多个沉积旋回。选择江汉盆地中心位置的ZL钻孔,利用ICP-MS方法展开微量元素组成分析,细粒组分中微量元素含量与各粒组含量相关性并不明显,主要是5~7粒级组分表现出微弱的相关性.可见,粒度并非ZL钻孔微量元素丰度的主控因素。钻孔岩心中大部分亲石元素、亲硫元素相对上部陆壳均出现明显富集,亲铁元素总体低于上部陆壳,可能与江汉盆地总体上更多地接受了来自上游而非扬子古陆本地深源物质风化碎屑沉积有关。Sr、V/Ni和Sr/Ba值的变化则表明江汉盆地在2.6~2.43 Ma B.P.时可能有咸化湖的发育,而在2.1 Ma B.P.左右存在过一段大湖发育期。     

Assessment of clay content from the analysis of K,U, and Th distribution in different grain-size fractions of the productive sediments of the Lovin Field,Western Siberia

During the calculation of the oil and gas resources of Western Siberia, especially in the sediments of the Tyumen Formation, the presence of thin nonreservoir clay intercalations must be accounted for. However, the resolution of standard geophysical methods that are used to identify productive sequences is insufficient, and the clay intercalations are included into the total thickness of reservoir rocks, which leads to considerable errors during resource assessment. The most efficient method for the estimation of clay mineral content in sedimentary rocks is the gamma method or gamma-ray well logging, which is typically used for this purpose. However, its application requires the knowledge of correlations between the abundance of clay minerals in the sediments; the contents of K, U, and Th; and total radioactivity. To solve this problem, four grain-size fractions (sand, coarse silt, fine silt, and clay) were separated from the sediments of the Tyumen Formation at the Lovin Field and were analyzed for naturally radioactive elements (NRE), total radioactivity, and mineral composition. The tendencies found in the distribution of NRE and total radioactivity in different grain-size fractions provided a methodical basis for the determination of clay mineral contents in the productive sediments of the Tyumen Formation at the Lovin Field using gamma-spectrometric data.