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1.
 Chemical data for 15 elements at depths at 10-cm intervals in 6 cores at two locations along the Yarmouk River as well as the heavy-metal enrichment factors (EFs) and anthropogenic factors (AFs) show that Cd and Ni for all the cores, and Mn, Zn, Cr, Co and Pb for core 3 at location A are anthropogenically enriched. The contents of these elements decrease clearly with depth in the sediment column. The sequence of element enrichment depends on whether the EF and the AF are used to calculate the elements which show no systematic decrease in enrichment with depth in all cores, especially for location A, probably due mainly to a higher sedimentation rate. The results of the present study show that the sediments of the Yarmouk River are uncontaminated with Fe, Cr, and Mn, whereas they are uncontaminated to moderately contaminated with Ni, Co, and Zn, moderately contaminated with Pb, and strongly to extremely contaminated with respect to Cd. Also, the study shows that the EF and AF values are higher than 1, which indicates that all the metals measured in the sediments of the Yarmouk River were enriched by various anthropogenic sources in the catchment area of this river. Heavy metal enrichment reflects the combined effects of agricultural activities, a treatment plant, a landfill site at El-Akader, and small industries in the region. Received: 16 March 2000 · Accepted: 12 August 2000  相似文献   

2.
 Surface sediments, suspended particulate matter and fluffy-layer material, collected in the Arkona Basin and the Pomeranian Bay during 1995–1997, as well as air particulate matter, collected on the island of Rügen during August 1995, were analysed for total organic carbon content, saturated and polycyclic aromatic hydrocarbons (PAH). The resulting concentrations and distributions of these compounds and molecular PAH ratios are discussed in terms of matrix, origin of the organic matter and seasonal variations. The data show that the Oder river can be identified as a major source for PAH transported into the southern part of the Arkona Basin. A strong atmospheric input of PAH is noted for the central and northern part of the basin. In general, anthropogenic and bacterially degraded hydrocarbons bound to organic carbon-rich and small particles are mainly deposited in the basin center, whereas their natural counterparts accumulate mainly on the basin flanks covered by coarser grained sediments. Received: 2 March 1999 · Accepted: 8 June 1999  相似文献   

3.
The Pomeranian Bay is a coastal region fed by the Oder River, one of the seven largest Baltic rivers, whose waters flow through a large and complex estuarine system before entering the bay. Nutrients (NO3 , NO2 , NH4 +, Ntot, PO4 3−, Ptot, DSi), chlorophylla concentrations, oxygen content, salinity, and temperature were measured in the Pomeranian Bay in nine seasonally distributed cruises during 1993–1997. Strong spatial and temporal patterns were observed and they were governed by: the seasonally variable riverine water-nutrient discharges, the seasonally variable uptake of nutrients and their cycling in the river estuary and the Bay, the character of water exchange between the Pomeranian Bay and the Szczecin Lagoon, and the water flow patterns in the Bay that are dominated by wind-driven circulation. Easterly winds resulted in water and nutrient transport along the German coastline, while westerly winds confined the nutrient rich riverine waters to the Polish coast and transported them eastward beyond the study area. Two water masses, coastal and open, characterized by different chemical and physical parameters and chla content were found in the Bay independently of the season. The role of the Oder estuary in nutrient transformation, as well as the role of temperature in transformation processes is stressed in the paper. The DIN:DIP:DSi ratio indicated that phosphorus most probably played a limiting role in phytoplankton production in the Bay in spring, while nitrogen did the same in summer. During the spring bloom, predominated by diatoms, the DSi:DIN ratio dropped to 0.1 in the coastal waters and to 0.6 in the open bay waters, pointing to silicon limitation of diatom growth, similar to what is being observed in other Baltic regions.  相似文献   

4.
Analysis of 59 surface sediment samples from the Polish exclusive economic zone (EEZ) shows that Szczecin Lagoon sediments are the most polluted by heavy metals and that the degree of heavy-metal pollution decreases substantially on passing from the Szczecin Lagoon to the Pomeranian Bay and the inner shelf area and then on passing to the Bornholm Deep and Słupsk Furrow. Heavy-metal pollution in the sediments of the western part of the Polish EEZ therefore appears to follow the dispersion of the Oder River. Fluffy material from the Oder estuary appears to be the main source of heavy metals in the muddy sediments of the Bornholm Deep. The formation of sulphides is therefore not the principal factor controlling the enrichment of heavy metals in the sediments of this anoxic basin, although it may be responsible for the uptake of Mo, Sb and As. Two main factors control the distribution of the rare earth elements (REE) in sediments of the Polish EEZ: the input of Fe-organic colloids from rivers and the presence of detrital material in the sediments.  相似文献   

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An updated list of earthquakes and earthquake parameters (location, homogenized magnitude, macroseismic data) for the southern Baltic Sea area reveals activity north of the sea, whereas there are very few epicentres in the sea itself and in the region south of it. This is the first study to combine seismological data for the whole region to cover also the sea. Macroseismic data for the 1930 earthquake were reinvestigated leading to an intensity of V–VI (MM or MSK scale), a radius of perceptibility of 135 km and an unusually big focal depth of about 40 km. It is difficult to correlate individual earthquakes with specific faults, but some seismotectonic relations are suggested, e.g. for the Tornquist zone, the predominant structure of the region. Only few reliable focal-mechanism solutions exist. Possible seismogenic processes (ridge push, isostasy, etc) are discussed.  相似文献   

7.
The Samborombon Bay wetland is located on the west margin of the Rio de la Plata estuary, in the Province of Buenos Aires, Argentina. This paper analyses the geological, geomorphologic, soil and vegetation characteristics of the southernmost sector of this wetland and their influence on surface water and groundwater. The study area presents three hydrologic units: coastal dunes, sand sheets and coastal plain. Coastal dunes and sand sheets are recharge zones of high permeability with well-drained, non-saline soils, and a few surface water flows. Changes in the water table are related to rainfall. Groundwater in coastal dunes is Ca–Mg–HCO3 to Na–HCO3, and of low salinity (590 mg/l). Groundwater in sand sheets is mainly Na–HCO3 with a salinity of about 1,020 mg/l. The coastal plain exhibits medium to low permeability sediments, with submerged saline soils poorly drained. Groundwater is Na–Cl with a mean salinity of 16,502 mg/l. A surface hydrological network develops in the coastal plain. Surface water levels near the shoreline are affected by tidal fluctuations; far from the shoreline water accumulates because of poor drainage. Both sectors have Na–Cl water, but the former is more saline. Human intervention and sea level rise may affect the wetland severely.  相似文献   

8.
The Oligocene Balleny Group of Chalky Island, southwestern Fiordland, comprises a typical continental margin sequence 900 m in thickness. Thin nearshore traction deposited sediments at the base are overlain by submarine canyon and fan lithofacies that were deposited by the full range of subaqueous mass-transport processes. A steep-walled channel within Balleny Group is interpreted as a fossil proximal fan-channel. The sedimentary fill of the channel is texturally similar to sediments moving by slump-creep in Recent submarine canyons and fan-valleys. The field data presented indicate (1) that a small canyon complex at Sealers Bay was initially cut by subaqueous debris-flows derived from an adjacent cliffed continental coast; (2) that transport within the upper parts of the canyon and fanchannel complex was primarily by inertia-flow and slump-creep; and (3) that these more proximal types of mass-transport gave way gradationally and successively to fluxoturbidity and turbidity currents at locations further down-slope, with consequent deposition of sediment in more distal fan-channel and fan-surface environments as fluxoturbidites and turbidites, with lesser contributions from inertia-flows.  相似文献   

9.
A dense grid of multichannel high-resolution seismic sections from the Bay of Kiel in the western Baltic Sea has been interpreted in order to reveal the Mesozoic and Cenozoic geological evolution of the northern part of the North German Basin. The overall geological evolution of the study area can be separated into four distinct periods. During the Triassic and the Early Jurassic, E–W extension and the deposition of clastic sediments initiated the movement of the underlying Zechstein evaporites. The deposition ceased during the Middle Jurassic, when the entire area was uplifted as a result of the Mid North Sea Doming. The uplift resulted in a pronounced erosion of Upper Triassic and Lower Jurassic strata. This event is marked by a clear angular unconformity on all the seismic sections. The region remained an area of non-deposition until the end of the Early Cretaceous, when the sedimentation resumed in the area. Throughout the Late Cretaceous the sedimentation took place under tectonic quiescence. Reactivated salt movement is observed at the Cretaceous Cenozoic transition as a result of the change from an extensional to compressional regional stress field. The vertical salt movement influenced the Cenozoic sedimentation and resulted in thin-skinned faulting.  相似文献   

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In the Baltic Sea south of Skåne county in southern Sweden, an over- consolidated marine clay succession on the northeastern slope of Kriegers Flak was observed in shallow seismic data as a unit overlain by younger Weichselian sediments. Two cores were taken from the clay succession. The Foraminifera present were predominantly of two species, Elphidium excavatum and Elphidium albiumbilicatum, reflecting deposition under arctic– boreal conditions. Stable oxygen isotope analyses were performed on foraminiferal tests, and the results show extremely light δ18O values ranging between −11‰ and −12‰. The cause of these extreme values is uncertain but may result from the high influence of meltwater. Brackish conditions are also indicated by the tolerance for low salinity shown by the Foraminifera. Radiocarbon dating shows an infinite age >40000 yr BP. The pollen flora seems mainly to have been redeposited, which makes interpretation difficult. The sea may have entered the Baltic basin during periods with high eustatic levels, an isostatic downloading of the crust, or a combination of both. It is suggested that the deposition of the overconsolidated marine clay succession occurred in the Late Saalian, Early Eemian or Early Weichselian. © 1998 John Wiley & Sons, Ltd.  相似文献   

13.
精细岩相模式是油气藏研究的重要基础,为储层预测和评价提供合理的约束。目前火山岩还缺少微相尺度的相模式。参照的5相15亚相分类方案,在莱州湾凹陷南斜坡中生界火山地层中建立了相—亚相—微相划分方案,识别出3相4亚相10微相。具体为爆发相的热碎屑流亚相和热基浪亚相,细分为火山口- 近火山口、近源和远源微相。喷溢相熔岩流亚相,细分为简单熔岩流和碎屑堆积微相。火山- 沉积相崩塌再搬运堆积亚相,细分为再搬运块状堆积和基质堆积微相。钻井揭示研究区的亚相占比从高到低的顺序为爆发相热基浪亚相、喷溢相熔岩流亚相、爆发相热碎屑流亚相和火山- 沉积相崩塌再搬运堆积亚相。火山地层具有复杂岩相叠置关系,亚相单元横向延伸范围有限、对比难度大。储层孔渗条件由好到差的顺序为热基浪亚相、热碎屑流亚相、熔岩流亚相和崩塌再搬运堆积亚相。热基浪亚相近源微相、热碎屑流亚相近源微相、熔岩流亚相简单熔岩流微相上部、崩塌再搬运亚相块状堆积微相的储层较好;其中,热基浪亚相近源微相储层条件为最优。本研究可为火山岩储层预测和评价提供地质依据。  相似文献   

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Anthropogenic pollutants were determined in a dated sediment core, collected from a riparian wetland of the Lippe River (Ruhr district, Germany). The historical trend in heavy metals, polycyclic aromatic hydrocarbons, organochlorines, polychlorinated biphenyls and linear alkylbenzenes as well as more recent contaminants such as industrial additives, organotins, synthetic musks, methyltriclosan and some other compounds were determined for the time period between 1930 and 1986. Emission sources, information on technical production and usage, as well as on the individual pollution pathways, with appropriate environmental stability, were considered in the interpretation of the sediment contamination over the past 50 years.Contaminants were analysed and interpreted according to two different criteria: (a) the origin of the main contaminants as related to mining and industrial activities as well as municipal sewage and agricultural effluents and (b) the pollution history. Due to a significant appearance of formerly missing contaminants in sediments deposited since 1970, we suggest classifying contaminants as either common (predating 1970) or modern (postdating 1970).In summary, the study provided a comprehensive reconstruction of the pollution history of the Lippe River system.  相似文献   

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The southern coast of Lake Michigan is the most urbanized and most densely populated area in the Great Lakes region. Development of steel mills, harbors, and municipalities in NW Indiana and in NE Illinois in the last century and a half altered the nearshore environment so much that native beach gravel (>8 mm) now exist only in the exhumed paleo-beach remnants from the Nipissing Phase (~4,500 years ago) of Lake Michigan. Native gravel, collected from paleo-beach remnants at Mount Baldy Dune and Beach House Blowout, contain predominantly beach shingle, very platy siltstones (71–78 %), with secondary crystalline pebbles (18 %) in the east, and carbonate pebbles (12 %) in the west. A large amount of anthropogenic fill (steel industry waste, waste from power generating plants, construction debris, railroad, and road fill) has been added since the late 1800s to fill Lake Michigan and expand industrial land. Four areas of major coastal structures—Michigan City Pier and Breakwater, Burns Harbor Pier and Breakwater, Gary Works Pier, and Indiana Harbor Peninsula—altered the natural littoral drift and created four independent sectors on Indiana’s coast—Northeastern, Eastern, Central, and Western—between which no natural transfers of coarse sediments occur. Downdrift from the coastal structures, severe beach erosion has prompted extensive beach nourishment with non-native sandy gravel. Four distinct populations of modern beach gravel now exist along Indiana’s coast of Lake Michigan: (1) native gravel with diluted beach nourishment influence, (2) native gravel with a minor industrial influence, (3) compact gravel of nourished origin, and (4) anthropogenic gravel of industrial origin. Native gravel with diluted nourishment influence is found in the western, downdrift areas of the Northeastern (from Long Beach to Washington Park Beach) and Eastern Sectors (from eastern Indiana Dunes State Park to western Dune Acres) and contains up to 40 % compact carbonate and crystalline pebbles in addition to native beach shingle. Native gravel with minor industrial influence is found in the Central Sector of Indiana’s coast (from central Ogden Dunes to Marquette Beach) and contains predominantly beach shingle, platy clastic lithology, but also up to 30 % of chert and other pebbles released by industry. Compact gravel of nourished origin contains 60–90 % of carbonate and crystalline pebbles, and is found in the eastern, updrift areas of the Northeastern (Michiana Beach and Duneland Beach) and Eastern Sectors (from Crescent Beach to the western Beverly Shores). Anthropogenic gravel of industrial origin contains 70–90 % compact chert and slag and is found in every beach of the Western Sector and in the westernmost beach of the Central Sector. Streams draining into southern Lake Michigan generally contain little coarse sediment except in their channels near the roads and railroads, where angular to subangular anthropogenic pebbles predominate (70–90 %). However, streams have very little influence on gravel lithology along the coast because they seldom discharge anthropogenic gravel into Lake Michigan. Recent changes in gravel lithology along the southern Lake Michigan coast may affect changes in nearshore benthic flora and fauna as well as algal and bacterial blooms during warm summer months.  相似文献   

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钦州湾-杭州湾结合带是位于扬子与华夏两大古陆块中间的巨型构造结合带。根据内部结构不均一性和演化历史的差异,钦-杭结合带可划分为3段:北(东)段、中段和南(西)段,分界线大致为北纬24°和北纬27°。中段与南岭带大体一致;北段指南岭以北地区,即绍兴-江山-萍乡一带;南段位于南岭以南区域,大致与云开-十万大山带相当。钦-杭结合带南段是华南大陆壳再造和矿产资源寻找的重要研究课题。它的地质演化与钦-杭结合带具有整体一致性,特别是具有一致的开-合历史。震旦系底部的粤西云浮大降坪块状硫化物矿床是海底喷流沉积的产物,它与信宜和陆川新元古代蛇绿岩等是南段洋壳存在的重要证据。在进一步的矿床勘查中,要重视斑岩型铜(钼)矿床的寻找。中酸性斑岩体来自于元古宙岛弧底部玄武质岩石(下地壳)在中生代时期的部分熔融,本质上该类矿床带有岛弧俯冲环境的基因。  相似文献   

20.
钦州湾-杭州湾构造结合带(南段)地质演化和找矿方向   总被引:14,自引:0,他引:14  
钦州湾-杭州湾结合带是位于扬子与华夏两大古陆块中间的巨型构造结合带。根据内部结构不均一性和演化历史的差异,钦-杭结合带可划分为3段:北(东)段、中段和南(西)段,分界线大致为北纬24°和北纬27°。中段与南岭带大体一致;北段指南岭以北地区,即绍兴-江山-萍乡一带;南段位于南岭以南区域,大致与云开-十万大山带相当。钦-杭结合带南段是华南大陆壳再造和矿产资源寻找的重要研究课题。它的地质演化与钦-杭结合带具有整体一致性,特别是具有一致的开-合历史。震旦系底部的粤西云浮大降坪块状硫化物矿床是海底喷流沉积的产物,它与信宜和陆川新元古代蛇绿岩等是南段洋壳存在的重要证据。在进一步的矿床勘查中,要重视斑岩型铜(钼)矿床的寻找。中酸性斑岩体来自于元古宙岛弧底部玄武质岩石(下地壳)在中生代时期的部分熔融,本质上该类矿床带有岛弧俯冲环境的基因。  相似文献   

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