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1.
M. Iggy Litaor 《地球表面变化过程与地形》1993,18(6):489-504
The influence of soil interstitial waters on the physicochemical characteristics of major, minor and trace metals in stream waters of an alpine watershed, Front Range, Colorado was assessed. Dissolution of Ca-aluminosilicate minerals, ion exchange reactions and the magnitude of solute flux within the alpine soil environment account for most of the observed concentrations of major, minor and trace metals in the alpine stream waters. The rate of mineral dissolution and magnitude of solute flux during the summer of 1989 was greatly affected by anthropogenic disturbance which resulted in large amounts of colloidal material and freshly exposed mineral surfaces. The alpine ecosystem responded very quickly to this disturbance. The magnitude of solute flux in the soil environment was also highly dependent on the duration and intensity of rain events, as well as the location of the site along the slope. Transport of most trace metals in the stream waters was achieved by adsorption onto colloidal surfaces of Al–Si hydroxides smaller than 0·45 μm. 相似文献
2.
The main objective of the present paper is to present an integrated approach to the study of faulting stages in coarse alluvial deposits. The study site is the alluvial fan of Nahal Shehoret, presently under an extremely arid regime. The exposure of fault scarps on the fan surfaces enables the identification of several geomorphic indicators employed in analysing and separating faulting events and periods of quiescence: (a) the nature of fault scarp topography; (b) soil catenary development on fault scarps; (c) buried paleosols in alluvial deposits; (d) colluvial bodies; (e) rotated clasts along fault planes. These indicators enable us to determine, at all sites studied, the total amount of displacement, to separate faulting events and the amount of their displacement per event, and to evaluate scarp stability and the duration of periods of tectonic quiescence. 相似文献
3.
Thomas C. Pierson 《地球表面变化过程与地形》1980,5(3):227-247
The grass-covered slopes on the southern flank of Mt Thomas, an upfaulted block of highly sheared sandstone and argillite 40 km NW of Christchurch, New Zealand, are presently undergoing severe erosion by a combination of mass-wasting processes. Gully erosion, soil slips, and debris flows have carved out a number of steep, deeply incised ravines, from which coarse debris is transported (primarily by debris flows) to alluvial fans below. Geologic and historical evidence indicates that debris flows have been episodically active here for at least the last 20,000 years and have been the dominant process in fan building. This demonstrates that catastrophic geomorphic processes, rather than processes acting at relatively uniform rates, can be dominant in humid-temperate areas as well as in arid and semi-arid regions. In April 1978, debris flows were triggered in one of two unstable ravines in the Bullock Creek catchment by a moderate intensity, long duration rainstorm with a return period in excess of 20 years. Surges of fluid debris, moving at velocities up to 5 m/s, transported a dense slurry of gravel, sand, and mud up to 3·5 km over a vertical fall of 600 m. Deposition on the alluvial fan occurred when the flows left the confines of an entrenched fan-head channel and spread out as a 0·16 km2 sheet averaging 1·2 m thick. In all, 195,000 m3 were deposited, roughly a third of that being reworked sediments from the head of the fan. Sediment yield from this one event would be equivalent to several thousand years worth of erosion at average sediment discharge rates for small South Island mountain catchments. Samples of viscous fluid debris during surges contained up to 84 per cent solids, composed of 70 per cent gravel, 20 per cent silt, and 4 per cent clay. Fluid density of the material ranged between 1·95 and 2·13 g/cm3, and it was extremely poorly sorted. Between surges the fluid was less viscous, less dense, and unable to carry gravel in suspension. Severe fan-head entrenchment of the stream channel (approximately 10 m in less than 24 hours) was accomplished by the erosive action of the surges. Tectonic uplift of the Mt Thomas block and the weak, crushed condition of the bedrock appear to be ultimately responsible for the catastropic erosion of slopes in the Bullock Creek catchment. However, forest clearing within the last few centuries appears to have greatly increased the rate of mass wasting and gully erosion on these slopes. 相似文献
4.
The distributions of dissolved and of particulate iron in the Dead Sea during the period which preceeded its overturn and thereafter (1977–1980) are reported. During 1977–1978, the vertical profiles of the iron phases revealed facets of the mixing pattern: the progressive deepening of the pycnocline, restricted mixing within the upper water mass and penetration of surface waters into the deepest layer. The inventories of particulate iron suggest resuspension of bottom sediments in November 1978 and after the overturn the gradual disappearance from the water column of iron sulfides and iron oxy-hydroxides. Fluxes of iron from and to the lake in the undisturbed meromictic Dead Sea have been estimated: it appears that diffusion of divalent iron from bottom sediments was the major source for the standing crop of iron in the lower water mass. Low settling velocities of solid particles in the dense and viscous Dead Sea is one of the causes for the relatively large concentrations of particulate iron. The rate constant for oxidation of divalent iron in Dead Sea sediment interstitial waters is larger by two orders of magnitude than in other natural waters. 相似文献
5.
6.
The paper describes a sequence of Pliocene(? ) to Quaternary age calcretes developed within alluvial fan and fluvial gravels in the Tabernas Basin, Almería Province, southeast Spain. Calcrete profiles are described from sites adjacent to major tributaries of the Rambla de Tabernas. Six distinct calcrete units are identified within the basin. These have variable distributions but have developed in an identifiable evolutionary sequence. Two pairs of calcrete units are widely present across the basin preserving two former land surfaces. Each of the former land surfaces has been planated and subsequently buried by alluvial fan or fluvial gravels. A massive calcrete unit is present at the base of each gravel sequence, immediately in contact with the underlying bedrock, with a less well developed calcrete unit situated at the top of the gravel sequence. The lowest two calcrete units within the basin are more spatially restricted and are confined to the floors and flanks of incised drainage lines. The geochemistry, macro- and micromorphological properties and geomorphological positions of the calcrete units are outlined and, on the basis of this information, their mode of origin identified. Two main modes of calcrete genesis appear to be present: massive calcretes situated in direct contact with bedrock are suggested to have formed by groundwater processes, whilst calcretes situated at the top of gravel sequences are likely to have developed by pedogenic processes. Calcrete genesis is subsequently considered in the context of the reconstruction of the early phases of landscape development, and is suggested to have been controlled by phases of uplift and stability within the Tabernas Basin. © 1998 John Wiley & Sons, Ltd. 相似文献
7.
Ian C. Grieve 《地球表面变化过程与地形》1984,9(1):35-41
Dissolved organic matter (DOM) and iron in a moorland stream were determined at 8-hour intervals over a 6-month period to examine relationships with streamflow. Regression of both solutes on discharge were positive and explained 50–70 per cent of the variance in the solute data, but better predictions were obtained in both cases when a covariate reflecting temporal variation in the relationships was introduced (explained variance 80–90 per cent). Variations in the regression of Fe on DOM were also identified, indicating differences in the complexing power of DOM for Fe and possible variations in the chemical composition of the DOM. 相似文献
8.
B. G. Katz 《水文研究》1989,3(2):185-202
During 1983 and 1984, wet precipitation was primarily a solution of dilute sulphuric acid, whereas calcium and bicarbonate were the major ions in springs and ground water in two small watersheds with a deciduous forest cover in central Maryland. Dominant ions in soil water were calcium, magnesium, and sulphate. The relative importance of mineral weathering reactions on the chemical composition of these subsurface waters was compared to the contribution from wet precipitation, biological processes, and road deicing salts. Mineral reaction models, developed from geochemical mass-balance relationships, involved reactions of primary and secondary minerals in metabasalt and metarhyolite with hydrogen ion. Geochemical weathering reactions account for the majority of total ion equivalents in soil water (46 per cent), springs (51 per cent), and ground water (68 to 77 per cent). The net contribution of total ion equivalents from biological processes was 20 and 16 per cent for soil water and springs, respectively, but less than 10 per cent for ground water. The contribution of total ion equivalents from deicing salts (10 to 20 per cent) was related to proximity to roads. Strong acids in precipitation contributed 44 per cent of the total amount of hydrogen ions involved in mineral-weathering reactions for ground water in contact with metarhyolite compared to 25 per cent for ground water in contact with metabasalt, a less resistant rock type to weathering. 相似文献
9.
Rebecca Bartlett Simon H. Bottrell Karen Sinclair Steve Thornton Ian D. Fielding Dave Hatfield 《水文研究》2010,24(6):726-735
Depth profiles of solute chemistry and sulfate isotopic compositions are presented for groundwater and pore water in a sequence of Quaternary glacial outwash sediments. Sand units show evidence for hydraulic connection to the surface and thus modern sources of solutes. Finer‐grained sediments show a general pattern of increasing solute concentrations with depth, with sulfate derived from ancient rainwater and pyrite oxidation in the soil/drift. In these sediments sulfate has undergone bacterial sulfate reduction (BSR) to produce biogenic sulfide. In clay sediments, with d10 ≤ 1·6 µm, high concentrations of sulfate and acetate now co‐exist, implying that BSR is inhibited. The correlation with smaller sediment grain size indicates that this is due to pore size exclusion of the sulfate reducing bacteria. Mechanical restriction of microbial function thus provides a fundamental limitation on microbial respiration in buried clay‐rich sediments, which acts as a control on the chemical evolution of their pore waters. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
10.
土壤是母岩、气候、生物、地形和时间等综合作用的产物,在其它因素相同的条件下,显示土壤特性的物理化学参数均随着风化时间的增长而有规律的变化。本文初步建立了河源断裂山前地带三级冲积扇中Bms层土壤的pH值、容重、有机质、次生粘土和三水铝石等与冲积扇形成年龄的关系,并依据次生粘土与三水铝石的增长速率对第Ⅲ级冲积扇的形成年龄进行了计算,初步确定了三级冲积扇形成的年代序列 相似文献
11.
黑藻对沉积物及土壤中不同形态磷的利用与转化 总被引：3，自引：0，他引：3
利用同一区域湖泊和河流沉积物及土壤培养黑藻,运用化学连续提取法对底质中磷的不同形态进行分离,同时分析黑藻生物量及底质中上覆水和间隙水中磷浓度的变化,并对底质中生物可利用磷进行了估算,揭示沉水植物对底质中不同形态磷的利用与转化规律。结果表明,底质中弱吸附态磷、可还原性磷（RSP）是黑藻利用的主要磷形态;土壤与沉积物相比不利于黑藻生长,营养水平高的河流沉积物有利于黑藻初期生长,但容易使其早衰;沉积物作底质上覆水和间隙水磷浓度主要受底质中RSP含量的控制;土壤作底质上覆水和间隙水磷浓度主要受弱吸附态磷控制;黑藻能促进底质中磷向可利用态转化;黑藻对土壤中生物可利用磷的利用率比沉积物低。 相似文献
12.
Interstitial water samples from the Guatemala Basin and the coast of Baja California have been analyzed for manganese, iron, copper, nickel and nitrate. The data provide a systematic look at changes in trace metal diagenesis proceeding from red clay to highly reducing nearshore sediments.In red clay sediments, the nitrate concentrations suggest that only aerobic respiration is occurring. Manganese and iron are below detection. Nickel concentrations remain the same as in bottom seawater but copper shows a pronounced maximum just at the sediment/water interface. Proceeding to hemipelagic sediments, denitrification becomes increasingly important and manganese and iron remobilization occur in the sediments.The linear manganese and nitrate profiles suggest regions of production or consumption separated by zones of diffusion. This differs from the conventional picture of a continuous series of reactions within the sediments. Manganese reduction always occurs before iron reduction. The pore water nickel correlates well with manganese in these sediments, suggesting that nickel is associated with MnO2 in the solid phase. The pore water flux ratio of manganese and nickel agrees well with the ratio in solid phase authigenic oxides. Copper still displays a core top concentration maximum as well as a second maximum associated with the remobilized manganese. The calculated ratio of the Cu/C flux ratios support the argument for copper remobilization during organic carbon oxidation. Comparison of the upward and downward diffusive fluxes with the rate of copper buried by sedimentation shows that at least half of the copper buried must be of diagenetic origin and less than 25% of the copper reaching the sediments is buried. 相似文献
13.
T.F. Pedersen 《Marine pollution bulletin》1983,14(7):249-254
Dissolved Zn, Cu and Cd concentrations in interstitial waters collected from a lacustrine mine tailings deposit indicate that the tailings are not releasing heavy metals to the overlying lake water at present, and there is no evidence to suggest that significant oxidation is occurring in the deposit. The lake waters are enriched in metals from surface drainage, however, while pore waters in natural sediments are heavy-metal-depleted. Diffusion into the natural sediments therefore tends to buffer the lacustrine metal load, but only to a very limited extent. 相似文献
14.
滇池福保湾间隙水氮磷分布及其与底泥微生物和磷酸酶相互关系 总被引：9，自引：0，他引：9
在滇池福保湾不同区域应用Peeper(渗析膜式)技术,分析了底泥间隙水NH4 -N、Po43--p的垂向分布特征和近表层10cm内底泥的微生物活性(FDA)、碱性磷酸酶活性(APA),并对它们之间的相互关系进行了统计分析.结果表明,NH4 -N和Po43--p浓度自上覆水向下层间隙水呈先升后降趋势,反映它们有自间隙水向上覆水扩散的潜在危害;底泥有机质(Loss-on-Ignion,LOI)、APA和FDA活性也有从表层底泥向下层逐步降低的趋势.在空问分布上,Po43--p浓度变化为河口区>湾心区>西部沿岸区>东部沿岸区,与沉积物中LOI、APA和FDA活性的大小顺序基本相同.间隙水NH4 6-N浓度与表层10cm内底泥的APA和FDA活性具有显著正相关性(α＝0.01).Po43--p浓度与底泥APA和FDA活性具有负相关性.但相关系数很低. 相似文献
15.
The toxicity of sediments in the Gulf of Gdansk is analyzed in relation to the chemical composition of interstitial and near‐bottom waters, and sediment properties. The toxicity of sediments, pore waters and saline elutriates is determined by using the Microtox® test based on changes in light production of the luminescent bacteria Vibrio fischeri. The results indicate considerable toxicity in the majority of examined sediments. Since the sediment elutriates and pore waters are toxic in some cases, the total toxicity of the sediments is likely to be due to both sediment‐bound and water soluble substances. The sediment toxicity is related to the percentage contribution of the fine fraction of sediments. A significant correlation between the toxicity of the sediments and the black carbon content implies anthropogenic contamination. The toxicity of the sediments is seen to increase with the increase of hydrogen sulfide concentration in pore waters. The ammonia in pore waters was found not to be responsible for the toxicity of the sediments. 相似文献
16.
Alluvial fan development in Alpine areas is often affected by catastrophic sedimentary processes associated with extreme ?oods events, causing serious risks for people living on the fans. Hazard assessment in these areas depends on proper identi?cation of the dominant sedimentary processes on the fans. Data from a set of 209 alluvial fans from the central Alps of Italy are presented in this paper and analysed with the help of various statistical techniques (linear regression, principal components analysis, cluster analysis, discriminant analysis and logistic regression). First, we used modern sedimentary facies and historical records (?ood events since 15th century), to distinguish between the two dominant sedimentary processes on alluvial fans: debris ?ows and stream?ows. Then, in order to analyse the main controls on past and present fan processes, 36 morphological, geological and land‐use variables were analysed. As with observations for arid‐environment fans, catchment morphology is the most in?uential factor in the study area, whereas geology and land use are minor controls. The role of climatic change and landsliding within the catchments also seems to be very important and is discussed. Statistical techniques also help in differentiating groups of alluvial fans by sets of controlling factors, including stage and type of evolution. Finally, by using discriminant analysis and logistic regression, we classi?ed alluvial fans according to the dominant sedimentary process, with a success rate ranging between 75 and 92 per cent. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
17.
Ho KT Burgess RM Pelletier MC Serbst JR Ryba SA Cantwell MG Kuhn A Raczelowski P 《Marine pollution bulletin》2002,44(4):286-293
The identification of toxicants affecting aquatic benthic systems is critical to sound assessment and management of our nation's waterways. Identification of toxicants can be useful in designing effective sediment remediation plans and reasonable options for sediment disposal. Knowledge of which contaminants affect benthic systems allows managers to link pollution to specific dischargers and prevent further release of toxicant(s). In addition, identification of major causes of toxicity in sediments may guide programs such as those developing environmental sediment guidelines and registering pesticides, while knowledge of the causes of toxicity which drive ecological changes such as shifts in benthic community structure would be useful in performing ecological risk assessments. To this end, the US Environmental Protection Agency has developed tools (toxicity identification and evaluation (TIE) methods) that allow investigators to characterize and identify chemicals causing acute toxicity in sediments and dredged materials. To date, most sediment TIEs have been performed on interstitial waters. Preliminary evidence from the use of interstitial water TIEs reveals certain patterns in causes of sediment toxicity. First, among all sediments tested, there is no one predominant cause of toxicity; metals, organics, and ammonia play approximately equal roles in causing toxicity. Second, within a single sediment there are multiple causes of toxicity detected; not just one chemical class is active. Third, the role of ammonia is very prominent in these interstitial waters. Finally, if sediments are divided into marine or freshwater, TIEs perforMed on interstitial waters from freshwater sediments indicate a variety of toxicants in fairly equal proportions, while TIEs performed on interstitial waters from marine sediments have identified only ammonia and organics as toxicants, with metals playing a minor role. Preliminary evidence from whole sediment TIEs indicates that organic compounds play a major role in the toxicity of marine sediments, with almost no evidence for either metal or ammonia toxicity. However, interpretation of these results may be skewed because only a small number of interstitial water (n = 13) and whole sediment (n = 5) TIEs have been completed. These trends may change as more data are collected. 相似文献
18.
Composition and origin of a lithalsa related to lake‐level recession and Holocene terrestrial emergence,Northwest Territories,Canada 
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下载免费PDF全文 Lithalsas of the Great Slave Lowland, Northwest Territories, occur within fine‐grained glaciolacustrine, lacustrine, and alluvial deposits. Detailed investigations of a lithalsa revealed that it is composed of ice‐rich sediments with ice lenses up to 0.2 m thick below 4 m depth. The observed ice accounted for about 2 m of the 4 m between the top of the lithalsa and adjacent terrain. The ice is isotopically similar to modern surface water, but enriched in δ18O relative to local precipitation. Total soluble cation concentrations are low in the basal, Shield‐derived and unweathered glaciolacustrine sediments of the lithalsa. Higher concentrations in the overlying Holocene‐aged lacustrine and alluvial deposits may be due to greater ion availability in Holocene surface waters. Increasing Cl‐ and Na+ concentrations in clays at depth likely relate to exclusion and migration of these dissolved ions in pore water during ice lens formation though total soluble cations remain comparatively low. The lithalsa developed 700 to 300 cal yr BP. A conceptual model of lithalsa formation and landscape evolution illustrates that this feature and more than 1800 other lithalsas in the region have developed in association with Holocene terrestrial emergence following lake‐level recession. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
19.
&#x;ukasz Stachnik Jacob C. Yde Adam Nawrot &#x;ukasz Uzarowicz Elbieta &#x;epkowska Katarzyna Kozak 《水文研究》2019,33(12):1638-1657
The aluminium (Al) cycle in glacierised basins has not received a great deal of attention in studies of biogeochemical cycles. As Al may be toxic for biota, it is important to investigate the processes leading to its release into the environment. It has not yet been ascertained whether filterable Al (passing through a pore size of 0.45 μm) is incorporated into biogeochemical cycles in glacierised basins. Our study aims to determine the relationship between the processes bringing filterable Al and glacier‐derived filterable nutrients (particularly Fe and Si) into glacierised basins. We investigated the Werenskiöldbreen basin (44.1 km2, 60% glacierised) situated in SW Spitsbergen, Svalbard. In 2011, we collected meltwater from a subglacial portal at the glacier front and at a downstream hydrometric station throughout the ablation season. The Al concentration, unchanged between the subglacial system and proglacial zone, reveals that aluminosilicate weathering is a dominant source of filterable Al under subglacial conditions. By examining the Al:Fe ratio compared with pH and the sulphate mass fraction index, we found that the proton source for subglacial aluminosilicate weathering is mainly associated with sulphide oxidation and, to a lesser degree, with hydrolysis and carbonation. In subglacial outflows and in the glacial river, Al and Fe are primarily in the forms of Al(OH)4‐ and Fe(OH)3. The annual filterable Al yield (2.7 mmol m‐2) was of a magnitude similar to that of nutrients such as filterable Fe (3.0 mmol m‐2) and lower than that of dissolved Si (18.5 mmol m‐2). Our results show that filterable Al concentrations in meltwater are significantly correlated to filterable and dissolved glacier‐derived nutrients (Fe and Si, respectively) concentrations in glaciers worldwide. We conclude that a potential bioavailable Al pool derived from glacierised basins may be incorporated in biogeochemical cycles, as it is strongly related to the concentrations and yields of glacier‐derived nutrients. 相似文献
20.
Contaminated sediments deposited within urban water bodies commonly exert a significant negative effect on overlying water quality. However, our understanding of the processes operating within such anthropogenic sediments is currently poor. This paper describes the nature of the sediment and early diagenetic reactions in a highly polluted major urban water body (the Salford Quays of the Manchester Ship Canal) that has undergone remediation focused on the water column. The style of sedimentation within Salford Quays has been significantly changed as a result of remediation of the water column. Pre‐remediation sediments are composed of a range of natural detrital grains, predominantly quartz and clay, and anthropogenic detrital material dominated by industrial furnace‐derived metal‐rich slag grains. Post‐remediation sediments are composed of predominantly autochthonous material, including siliceous algal remains and clays. At the top of the pre‐remediation sediments and immediately beneath the post‐remediation sediments is a layer significantly enriched in furnace‐derived slag grains, input into the basin as a result of site clearance prior to water‐column remediation. These grains contain a high level of metals, resulting in a significantly enhanced metal concentration in the sediments at this depth. Porewater analysis reveals the importance of both bacterial organic matter oxidation reactions and the dissolution of industrial grains upon the mobility of nutrient and chemical species within Salford Quays. Minor release of iron and manganese at shallow depths is likely to be taking place as a result of bacterial Fe(III) and Mn(IV) reduction. Petrographic analysis reveals that the abundant authigenic mineral within the sediment is manganese‐rich vivianite, and thus Fe(II) and Mn(II) released by bacterial reactions may be being taken up through the precipitation of this mineral. Significant porewater peaks in iron, manganese and silicon deeper in the sediment column are most probably the result of dissolution of furnace‐derived grains in the sediments. These species have subsequently diffused into porewater above and below the metal‐enriched layer. This study illustrates that the remediation of water quality in anthropogenic water bodies can significantly impact upon the physical and chemical nature of sedimentation. Additionally, it also highlights how diagenetic processes in sediments derived from anthropogenic grains can be markedly different from those in sediments derived from natural detrital material. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献