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1.
Three discriminant function models are raised and cross-compared in order to distinguish geochemical patterns characteristic
for the Drava River floodplain sediments. Based on data representing total element concentrations in samples collected from
alluvium (A), terrace (T), and unconsolidated bedrock (B) at the border of a floodplain, four element clusters emerged accounting
for discrimination between the referred groups of sediments. The most prominent is contaminant/carbonate cluster characteristic
for alluvium. The other two are: silicate cluster typical for unconsolidated geological substrate (Neogene sedimentary rocks);
and naturally dispersed heavy metal cluster separating terrace from the former two groups. Models introducing depth intervals
and single profiles as grouping criteria reveal identical sediment-heavy metal matrices. The second important issue of this
paper is possibility of reclassification of samples originally assigned to one of the a priori defined groups of sediments,
based on established geochemical pattern. The mapped geological units can be reconsidered by the post hoc assignments to a
different group if geological border between alluvium and terrace or between terrace and bedrock can not be established geologically
with absolute certainty. 相似文献
2.
珠江三角洲第四纪沉积物Cd元素的分布特征及成因 总被引：2，自引：0，他引：2
根据珠江三角洲平原区44个钻孔揭示的第四系,对晚更新世以来沉积物的地球化学特征进行了系统分析,结合沉积物粒度,探讨了珠江三角洲平原区第四纪沉积物Cd的分布特征、高含量来源及迁移富集规律。研究结果表明：①珠江三角洲第四纪沉积物的Cd含量地区差异较大,西江、北江冲积区为主要富集区,而潭江和东江冲积区为背景区。②物质来源、沉积物粒度、沉积环境与有机质含量共同影响了珠江三角洲第四纪沉积物Cd的含量分布,西江、北江冲积区受控于富Cd的泥盆系、石炭系砂页岩,而东江、潭江冲积区主要由贫Cd的燕山期花岗岩等限定;沉积物平均粒径（φ值）与Cd含量存在显著正相关关系;另外,温暖湿润、海陆交互作用强烈的沉积环境与富含有机质的地区有利于Cd的聚积富集。③西江、北江流域相对富Cd岩石风化的产物,特别是具高强度Cd含量的铅锌多金属矿区,是西江、北江冲积区Cd高含量的主要来源。④珠江三角洲第四纪沉积物Cd的高含量区分成西江、北江西北部和东南濒海两大片区,究其原因,前者由区域发育的铅锌多金属矿控制,后者则受海陆交互作用沉积环境的影响。 相似文献
3.
4.
In order to examine the extent of the As enrichment and the factors influencing this enrichment in the groundwater of Eastern Croatia, groundwater samples were collected from 56 production wells in two counties, Osijek-Baranja and Vukovar-Srijem, suspected to be more affected. Hydrochemical analyses were performed at all locations including in situ As speciation at 32 locations. Arsenic was detected in 46 out of 56 groundwater samples with total As concentrations up to 491 μg/L. Thirty-six of the studied wells yielded groundwater with total As concentrations that exceeded the WHO Maximum Contaminant Level for arsenic in drinking water of 10 μg/L. Only inorganic As species were detected with arsenite As(III) as the predominant form. The spatial distribution of As in the groundwater was significantly linked with geological, geomorphological and hydrogeological development of the alluvial basin of the Drava and Sava rivers. The most probable groundwater As sources are deeper sediments from the Middle and Upper Pleistocene. The results obtained suggest that biogeochemical processes controlling As concentration in the groundwater are complex and location-specific. Reductive dissolution of Fe oxides, desorption of As from Fe oxides and/or clay minerals as well as competition for the sorption sites with organic matter and phosphate could be the principal mechanisms that control As mobilization. The extent of those processes vary in the different parts of the Drava and Sava depressions and could be linked to different site related parameters, such as lithology, mineralogy, local hydrology and hydrogeology; thus different processes of As mobilization have been proposed for the different types of water in relation to groundwater evolution. 相似文献
5.
D. Nenadić T. Gaudenyi K. Bogićević R. Tošović 《Stratigraphy and Geological Correlation》2016,24(4):427-437
The Quaternary sediments in the Danube and Sava riparian area near Belgrade have a considerable thickness. Several categories of deposits (fluvial-lacustrine, fluvial and aeolian) of Pliocene and Quaternary age have been identified. Their thickness, granulometric composition and paleontological features change depending on the distance from the recent Danube and Sava riverbeds. The Pleistocene fluvial deposits are underlain by sediments of the Late Miocene (Sarmatian and Pannonian) or the Plio-Pleistocene age, and are overlain by fluvial-palustrine deposits of the Pleistocene age and recent alluvial deposits. Pleistocene fluvial deposits that form a major part of the Quaternary sediments, have a great significance, since they are proved to be excellent collectors of ground water. Although these deposits are at lower altitudes in the area of Srem, they could be correlated with the high Danube and Morava terraces in Serbia and Drava in Croatia on the basis of their lithologic and paleontological features. 相似文献
6.
R. E. Jackson 《Hydrogeology Journal》1998,6(1):144-155
The migration, dissolution, and subsequent fate of spilled chlorinated solvents in the urban alluvial valleys of the southwestern
U.S. appear to be governed by a unique set of hydrogeologic and geochemical processes occurring within terrigeneous clastic
depositional systems. The alluvial and lacustrine fill of the basins, the trapping of solvents in fine-grained sediments beneath
the urbanized valley centers, the oxic conditions typical of the deeper alluvium, and the contaminant-transport patterns produced
by large-scale basin pumping combine to produce long aqueous-phase plumes derived from the dissolution of trapped chlorinated
solvents. Although of limited aqueous solubility, these dense solvents are sufficiently mobile and soluble in the southwestern
alluvial valleys to have produced aqueous plumes that have migrated several kilometers through the deeper alluvium and have
contaminated valuable water-supply well fields in California, Arizona, and New Mexico. The typical length of these plumes
and the presence of oxic groundwater indicate that it is unlikely that natural attenuation will be a practical remedial option
in the southwestern alluvial valleys or in other alluvial systems in which similar hydrogeologic and geochemical conditions
exist.
Received, December 1996 · Revised, October 1997 · Accepted, November 1997 相似文献
7.
Delineation of geochemical blocks for undiscovered large ore deposits using deep-penetrating methods in alluvial terrains of eastern China 总被引：1，自引：0，他引：1
Many large ore deposits have been discovered in eastern China along the Circum-Pacific Rim. However, alluvium, which covers most of the terrain, prevents a complete assessment of the mineralization potential by geological and conventional geochemical approaches. Two deep-penetrating geochemical methods—collection of nanoscale metals in earthgas (NAMEG) and selective leaching of mobile forms of metals in overburden (MOMEO) have been used to investigate the possibility to delineate geochemical blocks generated from large ore deposits buried by alluvial terrains. A wide-spaced sampling was carried out in an area of approximately 250 000 km2 at density of one sample per 400–800 km2. The soil samples were subjected to MOMEO leaching and were analyzed for Au, Ag, Cu, Pb, Zn, Fe, and Mn by atomic absorption spectrometry (AAS). The earthgas samples were analyzed for 17 elements by INNA. The results show that water-extractable metals by MOMEO processing can give prominent expression to concealed deposits and can delineate large-scale geochemical anomalies in the alluvial terrains. The distribution of gold in earthgas is situated along the largest deep fault systems and the concentration centers distribute in the secondary faults on the both sides of the deep fault systems. 相似文献
8.
Alpa Sridhar L.S. Chamyal 《Proceedings of the Geologists' Association. Geologists' Association》2010,121(2):195-202
The rivers of western India are monsoon dominated and have been so throughout the late Quaternary. Sediment accumulation in these river basins has been controlled by climatic and tectonic changes over a time span from the Late Pleistocene to the recent. The lithofacies assemblages associated with the various sediment archives in the Narmada basin range from the boulders of the alluvial fans to overbank fines on the alluvial plains. Estimates, based on clast size, of stream power and competence, bed shear stress and discharge reveal that hydrological conditions during the Late Pleistocene (∼90 ka) were comparable to the present day. The size of the transported clasts and the thickness of the accumulated sediment indicate the influence of basin subsidence rather than an increase in discharge. Discharge estimates based on sedimentary structures preserved in the alluvial-plain facies suggest that the channel had a persistent flow, with a low width-depth ratio and large meander wavelength. The hydrological changes during the Holocene are more pronounced where the early Holocene is marked by a high-intensity hydrological regime that induced erosion and incision of the earlier sediments. The mid-Holocene stream channel was less sinuous and had a higher width-depth ratio and a higher meander amplitude in comparison with the present-day channel. Palaeo-fluvial reconstructions based on the sediment archives in the alluvial reach of the river basin are important tools in understanding the long-term hydrological changes and the intricate fluvial architecture preserved in the Narmada River basin ensures scope for detailed studies to identify phases of weak and enhanced hydrological regimes. 相似文献
9.
Marcin Słowik Tadeusz Sobczyński Zygmunt Młynarczyk 《Environmental Earth Sciences》2010,59(5):957-966
Research concerning chemical constitution of alluvial sediments was done in the lower course of the Obra river (Western Poland).
The fragment of vertical profile, which consisted of various alluvial sediments (fine sands, peats, and sandy silts) was chosen
for detailed analysis. The main research problem was to determine if lithology and chemical constitution of alluvial deposits
are interconnected in a distinct way within studied section of the Obra river valley, and, if changes of chemical elements’
concentration could be used to illustrate depositional processes, which take place in riverbed and floodplain. Concentrations
of Fe, Mn, Cu, Zn, Ca, Mg, and K were determined in collected sediment samples. Next, geochemical groups of alluvial sediments
were distinguished using cluster analysis. Investigated changes of chemical elements’ concentration show that there is a distinct
border between the environment of organic sediments, which marks the place of former functioning of the Obra riverbed, and
sandy silts, which were deposited within floodplain during floods. Besides, floodplain sediments, riverbed sediments, and
reductive environment within peat deposits were singled out on the basis of the analysis. 相似文献
10.
青藏高原东缘龙门山北东段山前涪江冲积扇在武都盆地内的覆盖面积约为25 km2,区域构造上为江油断层、香水-让水断层等组成的江油断裂带右旋走滑构造域。通过宇宙核素成因埋藏年龄测试技术精确地测定发源于龙门山北东段主要河流-涪江自第四纪以来发育的三期冲积扇形成年代,即早更新世冲积扇（1.84 Ma）、中更新世冲积扇（0.54 Ma）和全新世冲积扇。由于龙门山北东段-江油断裂的右旋走滑兼逆冲运动,导致涪江早更新世冲积扇扇头右旋错动约3.2 km,之后形成新的冲积扇（中更新世积扇）。随着江油断裂继续的继续活动,中更新世冲积扇扇头又被右旋错动了约0.8 km,之后形成全新世的冲积扇。涪江形成以来总共右旋错动距离约为4 km。同时,早、中更新世冲积扇褶皱隆升了约50 m,早更新世冲积扇总共褶皱隆升了约100 m。这在一定程度上反映了龙门山构造带北东段第四纪以来沉积对构造演化的响应过程。 相似文献
11.
以长江中下游1∶20万铜区域地球化学数据为基础,研究了铜元素地球化学异常特征,认为不同尺度的地球化学异常图具有不同的研究意义:(1)1∶20万地球化学异常可以圈定矿床异常,用于大型矿床预测。研究区内13个大型矿床中有12个落在具有三层套合结构的地球化学异常中,已知矿床储量与异常面金属量、异常面积之间的相关系数分别为0.94、0.95,显示区域地球化学异常规模与储量之间的较好相关性。(2)1∶50万地球化学异常可以圈定矿区异常,用于在成矿带中预测有利成矿区。(3)1∶100万地球化学异常可以圈定大型矿集区或成矿带,用于矿集区预测。如果把研究区内面积大于1 000km2且含有3个以上已知矿床的异常作为矿集区的话,则长江中下游存在3个大型矿集区:马鞍山—南京矿集区、九江—瑞昌—大冶矿集区和德兴—黄山—安庆—铜陵矿集区(实际上包含德兴和铜陵2个矿集区)。大型矿床多产于多层套合的地球化学异常中,大型矿集区所形成的异常具有至少3层套合结构,浓集中心与大型矿床存在对应关系,这些规律的发现为在不同成矿域预测新的大型矿集区提供了重要地球化学标志。 相似文献
12.
Hydrogeochemical evolution of groundwaters with excess fluoride concentrations from Dashtestan, South of Iran 总被引：2，自引：2，他引：0
S. Battaleb-Looie F. Moore H. Jafari G. Jacks D. Ozsvath 《Environmental Earth Sciences》2012,67(4):1173-1182
Hydrogeochemical investigations were carried out in the Dashtestan, the eastern part of Borazjan, with a focus on fluoride content. The study area is underlain by a complex geology that is dominated by three lithological units, namely marl, alluvial sediments, and carbonate rocks. To assess the major geochemical factors controlling the fluoride enrichment in water, 37 groundwater and 12 surface water samples were collected from the three lithological units. Fluoride concentrations ranged up to 3?mg/L, and average concentrations varied from 1.12 (in carbonate aquifers) to 1.73 (in alluvial aquifers) to 1.82?mg/L (in marl aquifers). To study the influence of rocks and soils on groundwater quality, an additional 41 soil and rock samples were also taken and analyzed for fluoride. The order of average fluoride content in both rocks and soils is: marl?>?alluvial sediments?>?limestone, which confirms that marl is a likely source of fluoride. 相似文献
13.
A depositional model of the lower Pliocene Hagul formation, which is exposed in the East Cairo district (Egypt), is proposed with more than 10 depositional cycles recognized. Field occurrence, detailed petrographic investigation and geochemical analysis revealed that the sediments within each cycle are the result of three sequential sedimentological processes: (1) alluvial sedimentation, (2) calcretization, and (3) precipitation of palustrine carbonate. It was concluded that Hagul formation has been deposited within the distal part of an alluvial plain during three successive climatic conditions: a humid climate during which alluvial sediments were deposited, a semi-arid climate with episodic precipitation which was favorable for pedogenic calcrete development, and a sub-humid climate during which groundwater level was gradually elevated and groundwater calcrete accumulated. Rising groundwater level continued until shallow wetlands covered the area and palustrine limestone was precipitated. Variations in the thickness and the nature of the host sediment, calcrete and palustrine limestone cycle suggest that each of the sedimentation processes varied from cycle to cycle. 相似文献
14.
A conceptual isotopic/geochemical model is presented to explain the variation of major, trace and rare earth element (REE)
geochemistry and Sr isotope systematics in suspended particulate matter (SPM) as a function of particle/colloid size. This
conceptual model is an extension of a previous investigation of the origin of SPM in the Murray-Darling River system (MDRS)
that utilised Sr isotope systematics to examine aspects of SPM (particle/colloid) origin, structure and mineralogy. The geochemical
processes that give rise to the often coherent trends in major, trace and REE geochemistry and Sr isotopic signature as a
function of particulate (<1 μm) and colloidal (>1 μm) size in the MDRS have been identified using an enhanced SPM size fractionation
technique as a basis to not only obtain a broad range of particle/colloid size ranges, but also to provide sufficient material
for subsequent geochemical and isotopic analysis. The conceptual isotopic/geochemical model proposed here contains three major
components: (i) the differential weathering of micas and alkali (K-) feldspars to form the majority of the particulate (<1
μm) fractions (high 87Sr/86Sr ratio), which have a geochemical and Sr isotopic signature that closely resembles precursor
mineralogies, (ii) the differential weathering of Na, Ca-feldspars (plagioclase) which decompose to form clay minerals in
the colloidal (>1 μm) fractions (low 87Sr/86Sr ratio), with a range of geochemical signatures related to the relative proportions
of inorganic and organic constituents, and (iii) the presence of natural organic matter as coatings on the particulate (<1
μm) and colloidal (>1 μm) matter and possibly as organo-colloids which exert an increasing influence in particular on bulk
colloid geochemistry with decreasing colloid size. This conceptual isotopic/geochemical model also accounts for the distinct
variation in major, trace and REE geochemistry and Sr isotopic systematics between the particulate (<1 μm) and colloidal (>1
μm) fractions, the variation being primarily a function of the distinctly different precursor mineralogies of the SPM fractions
and geochemical fractionation during the weathering and transport. Additionally, this model explains a systematic fractionation
of REE apparent within colloidal (>1 μm) fractions. Statisitcal (hierachical cluster) analysis of two particulate and three
colloidal fractions from 23 samples from the MDRS is used as a basis to investigate geochemical and mineralogical associations
within the particulate and colloidal size fractions and to provide additional supporting evidence for the conceptual isotopic/geochemical
model.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
The influence of geomorphological factors to Hg contamination of the Idrijca River alluvial sediments because of the historical mining and ore roasting activities has been studied. Main source of Hg in alluvial sediments was dumping of ore roasting residues and mining waste into the river channel and its erosion downstream. The position of the material in relation to the geomorphological properties is highly related with its Hg content. Floodplains were found to be the most contaminated geomorphological units (mean Hg content 335 mg/kg), with Hg concentration rapidly dropping in the first terrace (155 mg/kg). The least contaminated material was found in the higher terraces (3.8 mg/kg). Sampling upstream Idrija (average Hg content is 22.1 mg/kg) shows that not only mine and ore roasting plant increased Hg levels in alluvial deposits but also contaminated sites upstream Idrija contribute to Hg contamination. Geochemical background for alluvial sediments for this area is estimated to be 0.75 mg/kg. Downstream Idrija, 9 hotspots were determined where highly contaminated material is actively eroded and carries a high risk of further contamination of the So?a River and northern Adriatic Sea ecosystems. 相似文献
16.
Md. Salah U. Sharif Ralph K. DavisKenneth F. Steele Burmshik KimPhillip D. Hays Tim M. KresseJohn A. Fazio 《Applied Geochemistry》2011,26(4):496-504
The potential health impact of As in drinking water supply systems in the Mississippi River Valley alluvial aquifer in the state of Arkansas, USA is significant. In this context it is important to understand the occurrence, distribution and mobilization of As in the Mississippi River Valley alluvial aquifer. Application of surface complexation models (SCMs) to predict the sorption behavior of As and hydrous Fe oxides (HFO) in the laboratory has increased in the last decade. However, the application of SCMs to predict the sorption of As in natural sediments has not often been reported, and such applications are greatly constrained by the lack of site-specific model parameters. Attempts have been made to use SCMs considering a component additivity (CA) approach which accounts for relative abundances of pure phases in natural sediments, followed by the addition of SCM parameters individually for each phase. Although few reliable and internally consistent sorption databases related to HFO exist, the use of SCMs using laboratory-derived sorption databases to predict the mobility of As in natural sediments has increased. This study is an attempt to evaluate the ability of the SCMs using the geochemical code PHREEQC to predict solid phase As in the sediments of the Mississippi River Valley alluvial aquifer in Arkansas. The SCM option of the double-layer model (DLM) was simulated using ferrihydrite and goethite as sorbents quantified from chemical extractions, calculated surface-site densities, published surface properties, and published laboratory-derived sorption constants for the sorbents. The model results are satisfactory for shallow wells (10.6 m below ground surface), where the redox condition is relatively oxic or mildly suboxic. However, for the deep alluvial aquifer (21-36.6 m below ground surface) where the redox condition is suboxic to anoxic, the model results are unsatisfactory. 相似文献
17.
The changes in the lower Drava River water level, discharge and suspended sediment regime 总被引：1，自引：1，他引：0
Massive construction on the Drava River basin and on the river itself during the last centuries, as well as recent climate change and/or variability, has caused many different and possibly dangerous changes to its hydrological and ecological regime. Since 1975, numerous hydrotechnical works have been carried out on the 60-km long section of the Drava River from the Slovenian–Croatian border to the River Mura mouth. Three hydrotechnical power plants with three reservoirs and three long inlet and outlet canals have been built. Changes in water level, discharge and suspended sediment yield along the Drava River measured in Croatia, downstream of the three Croatian reservoirs, during the last 30–130 years are presented. The investigation focuses on changes that have occurred during the last thirty-odd years, caused by the anthropogenic influences on the Drava River watercourse and its catchment in Croatia and Hungary, and probably by climate change or variability. Methods of rescaled adjusted partial sums, statistical tests, as well as regression and correlation analyses are used to explain changes in water level, discharge and suspended sediment yield. There is evidence in the time series of decreases in the minimum, mean and maximum annual water levels, and minimum and mean discharges on the lower part of the Drava River. One of the main objectives of this study was to examine the effect of dams and reservoirs operation on the changes in the downstream suspended sediment regime. The amount of suspended sediment has been greatly reduced, which can cause serious consequences. 相似文献
18.
Byoung-Young Choi Hyeon-Jung Kim Kangjoo Kim Seok-Hwi Kim Hwa-Jin Jeong Eungyu Park Seong-Taek Yun 《Environmental Geology》2008,54(2):335-345
Vertical variations of redox chemistry and groundwater quality were investigated in an alluvial aquifer beneath an agricultural
area, in which deep groundwaters are free of NO3, Fe, and Mn problems that are frequently encountered during the development of alluvial groundwaters. This study was performed
to identify and evaluate vertical chemical processes attenuating these chemical species in the study area. For this study,
the processes affecting groundwater chemistry were identified by factor analysis (FA) and the groundwater samples collected
from six multilevel samplers were hierarchically classified into three different redox zones by cluster analysis (CA) based
on the similarity of geochemical features. FA results indicated three major factors affecting the overall water chemistry:
agricultural activities (factor 1), redox reactions (factor 2), and remnant seawater (factor 3). The groundwater quality in
the study area was revealed to be controlled by a series of different redox reactions, resulting in different redox zones
as a function of depth. It was also revealed that the low Fe and Mn levels in the groundwater of the deeper part are associated
with sulfate reduction, which led to precipitation of Fe as iron sulfide and adsorption of Mn on it. 相似文献
19.
冲积平原区生态地球化学调查方法技术研究中矿物鉴定和化学分析结果对比研究表明，土壤中化学元素的含量及其分布特征主要取决于土壤对成壤母质中各种矿物成分的继承，元素的区域地球化学背景差异和在不同深度的含量变化均可通过矿物和矿物组合特征较为直接地示踪显现，土壤中矿物组成对其化学元素含量的影响是直接的、决定性的。因此，利用土壤的矿物组成确定其常量和微量元素的初始值具有重要意义。据此可进一步解析土壤中元素地球化学异常成因，判别土壤的元素地球化学异常类型。 相似文献
20.
Geochemical properties of ore-bearing horizons composed of alluvial aluminosilicate terrigenous rocks have been compared at young and ancient hydrogenic uranium deposits. It has been shown that the lithological setting at the young deposit has an elevated neutralization capacity in relation to sulfuric acid of leaching solutions and, in addition, has a rather low reducing capacity. The redox differentiation of ore substance at the deposit is in progress. It ensures an elevated degree of uranium oxidation in ores. Both ore and nonore sandy rocks contain a sufficient amount of natural oxidizer U(IV) in the form of trivalent iron. Ancient deposits, unlike young ones, contain ore-bearing and ore-hosting rocks with a low neutralizing but high reducing capacity and with an elevated degree of uranium and iron reducing, as the reducing environment dominates in all epigenetic geochemical zones. It is suggested that, in this geochemical setting, the process of in situ leaching (ISL) is not effective without addition of artificial oxidizer to the working sulfuric acid solutions. 相似文献