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1.
In 1982 and 1983 a surficial geology and overburden geochemistry survey was carried out on the Sisson Brook Mining Licence in York County, about 55 km northwest of Fredericton, New Brunswick, Canada.On the Sisson Brook Mining Licence three zones of W-Mo-Cu mineralization have been outlined; Zones I and II contain mainly wolframite with chalcopyrite and pyrrhotite, whereas Zone III has mainly scheelite and molybdenite.The glacial history of the area was studied during 1982 and 1983 to provide a framework for interpreting the geochemical results. Ice movement varied from 160° ± 10° towards the south during the Main Bantalor phase (maximum ≈ 13,500 y.B.P.) to 130° ± 10° toward the southeast during the Late Bantalor phase. Rapid changes in dominant pebble lithologies occur immediately upon crossing bedrock contacts. This suggests a very short distance of transport on the property. The glacier, butted against the Nashwaak Ridge, quickly sheared bedrock debris up into the body of the ice by compressive flow. Upon melting, some of this debris was deposited a short distance from source. Some debris appears to have been sheared up higher into the ice sheet, transported over the Nashwaak Ridge, and deposited approximately 8 km down-ice with no interconnecting dispersal train.In 1982, a geochemical orientation survey was carried out to determine which element(s) and sample medium could best and most economically be used in the search for W-Mo-Cu mineralization. Within the property area, both whole till <2000 μm (−10 mesh) samples and heavy mineral concentrates clearly defined the zones of mineralization (W, Mo, Cu) and associated geochemical dispersal trains (W, Mo, Cu, As, F). In later work, samples were not analyzed for As and F because this provided no additional information. The geochemical contrast between values in whole till samples derived from subcropping mineralization and those derived from barren bedrock is adequate to outline mineralization. Geochemical analysis of the whole till was used in later work because the sample preparation costs are considerably lower than those for heavy-mineral concentrates. Soils were not used because trace element patterns were diffuse, with the highest values occurring at variable distances down-ice from mineralization.In 1983, the objective was to better define glacial dispersal from the known mineralization and to explore for additional mineralization. Data from this program indicates a W dispersal train in whole till samples 300–400 m long. Tungsten values up to 1400 ppm and Mo values up to 260 ppm in whole till occur immediately down-ice from the main subcropping W-Mo mineralization. The element associations (i.e. W-Mo-Cu and W-Mo) in the till reflect the elemental composition of the source mineralization (i.e. Zones I and II and Zone III).Backhoe trenching is a useful and cost-effective technique to expose Quaternary sediments. Examination of the overburden sections provides an understanding of the glacial history which aids in tracing geochemical dispersal trains up-ice to bedrock source.  相似文献   

2.
Regional carbonate dispersal trains cross Melville Peninsula in the northeastern Canadian Arctic. These trains are 50-125 km across and 100-300 km long. The northern dispersal train crosses upland and lowland areas, while the Rae Isthmus train follows the lowlands. The distribution of carbonate in boulder, pebble and matrix till fractions indicates long-distance glacial transport of limestone, a low rate of dilution, and comminution from pebble to silt sizes. Dispersal patterns and geotechnical properties of the till suggest deforming bed and basal gliding mechanisms of ice flow associated with ice-streaming. Regional ice streams may have been 'normative' in carbonate terrain during the main Foxe (Wisconsin) Glaciation. Till plumes within regional dispersal trains, showing little dilution of carbonate down-ice from bedrock sources, are oriented towards lowlands. These features, sharp-edged and 300 mwide, mark zones of augmented flow. They are late-glacial features that formed after calving bays developed in Committee Bay. The dimensions of the dispersal trains, and ice-flow styles and mechanisms, are similar to those of modern Antarctic ice streams. The sharp edges of till plumes may delineate flow boundaries marked by lateral crevasse zones in the late-glacial ice sheet. Secondary streams-within-ice streams have not been reported previously in the literature.  相似文献   

3.
 Abundant cinnabar (HgS) mineralization is associated with the Pinchi Fault in central British Columbia. Two formerly producing mercury mines have been developed on this fault: Pinchi and Bralorne Takla. The mercury content of till (a sediment type directly deposited by glaciers) in the area of this fault is primarily controlled by the occurrence of cinnabar mineralization in bedrock and the direction of ice flow. Cinnabar-bearing bedrock was eroded by glaciers, transported in the direction of ice flow, and deposited "down-ice" from its source. An example of such a dispersal train is documented for the Pinchi Mine area where mercury ore was transported over a distance of 12 km, as measured in the clay-sized fraction (< 0.002 mm) of till, and could have been transported over 24 km according to heavy mineral concentrates (specific gravity >3.3) of this same sediment. Antimony, chromium, and nickel dispersal trains were also detected in the region. These data indicate that natural glacial processes can result in the "mobilization" of metals in the surficial environment, a factor which has to be considered at mine sites in glaciated terrain, where mine reclamation and remediation measures are now required. Received: 31 October 1996 · Accepted: 27 May 1997  相似文献   

4.
The recovery of nickel, copper and cobalt from ocean manganese nodules by a segregation roasting technique was investigated under a wide range of conditions with several nodule samples all of which gave similar results. The best conditions for the segregation of the metals were achieved with CaCl2 as the chloride source at a batch retention time of approximately two hours; the highest recoveries were obtained at approximately 850°C for copper and at 1,050°C for nickel and cobalt. At 850°C, copper recovery was 75%, but nickel and cobalt recoveries were only about 25%. At 1,050°C, the nickel and cobalt recoveries were increased to about 60%, but the copper recovery dropped to only 35%. Electron-probe microanalysis showed the segregated metal to be an alloy, indicating that gaseous reactions play an important role in the reduction of chlorides to metal during the process.  相似文献   

5.
A small Cu---Co---Au occurrence was found by means of till geochemistry. The metal anomalies in the till are highly local and the fineness of the gold grains and their association with goethite suggest that Au may first have been dissolved and then reprecipitated. The till very probably contains remnants of an older preglacial weathering crust. There are also high concentrations of Cu, Co, As, Mo and Zn in the humus horizon. Only one humus sample had a Au content above the detection limit, 0.02 ppm. The heavy-mineral samples from the near-surface part of the till proved useful in the regional prospecting phase.  相似文献   

6.
A study was initiated to analyse metal flows from alum shale to the environment in an area in Öland, Sweden. The study was performed by elemental analysis and leaching experiments of alum shale together with analysis of groundwater and surface water samples.The metal concentrations in non-weathered alum shale were much higher than in weathered or burnt shale, especially for cadmium (Cd), nickel (Ni) and zinc (Zn), indicating a loss of metals during weathering or burning of the shale. The release of metals through weathering was clearly demonstrated by the leaching tests. A 36-week leaching period of non-weathered shale resulted in a drastic drop in pH and a significant increase in metal concentrations in the leachate. The metal concentrations in groundwater were inversely related to the pH. For surface waters, the concentrations of Cd, copper (Cu), Ni and Zn were generally increased compared to background values.In conclusion, metals are released through weathering or burning of alum shale, as well as from heaps of weathered or burnt shale. The release of metals is strongly related to low pH, especially for Cd, Ni and Zn.  相似文献   

7.
This paper summarizes advances since 1987 in the application of glacial sediment sampling to mineral exploration (drift prospecting) in areas affected by continental or alpine glaciation. In these exploration programs, clastic glacial sediments are tested by geochemical or mineralogical methods to detect dispersal trains of mineral deposit indicators that have been glacially transported from source by mechanical processes. In glaciated terrain the key sampling medium, till, is produced by abrasion, crushing and blending of rock debris and recycled sediment followed by down-ice dispersal ranging from a few metres to many kilometres. As a consequence of the mid-1980s boom in gold exploration, the majority of case studies and regional till geochemical surveys published in the past decade deal with this commodity. Approximately 30% of Canada and virtually all of Fennoscandia have been covered by regional till geochemical surveys that aid mineral exploration and provide baseline data for environmental, agricultural, and landuse planning. The most profound event in drift prospecting in the last decade, however, has been the early-1990s explosion in diamond exploration which has dramatically increased the profile of glacial geology and glacial sediment sampling and stimulated changes in sampling and analytical methods.  相似文献   

8.
Pine (Pinus Eldarica Medw.) needles as indicator for heavy metals pollution   总被引：1，自引：1，他引：0  
In this study, the pine tree (Pinus Eldarica Medw.) needles were evaluated as the biomonitors of heavy metal contamination in Tehran, Iran. The pine needle samples supplied from the old trees according to the main wind direction (highest wind speed) were obtained from each parts of tree and then were homogeneously mixed. The samples were taken from different locations with different degrees of metal pollution (urban, industrial, highway and control sites). Then, the concentrations of lead, zinc, copper, nickel and chromium were measured using a flame atomic absorption spectrophotometer. The result of this study showed that the highest and the lowest metal concentrations were found in the heavy traffic sites and the control site, respectively. However, samples taken from highway sites contained the high concentrations of nickel, copper and lead. Moreover, industrial areas were found to have high contents of zinc and chromium. The variation in heavy metal concentrations between the studied locations is due to changes in traffic density and anthropogenic activities. This research proved significant correlations between the heavy metal concentrations in pine needle samples. Finally, it is concluded that Pinus Eldarica Medw. needles can be applied to monitor polluted sites.  相似文献   

9.
Characterization of heavy metal contaminated soils in Northern Cyprus   总被引：5，自引：0，他引：5  
The Lefke region of Northern Cyprus was a site of intense copper mining and smelting activities until the 1970s, which produced large tailings. This study was initiated to characterize the heavy metal contamination of soils of the area and to assess the influence of this site on the surface seawater quality along the coastline. Soil and seawater samples were collected and analysed. Copper and arsenic concentrations exceeded the limits for 'extremely polluted' soils for some samples, which can be classified as 'polluted' by zinc, cadmium and lead. The results showed that seawater was seriously polluted by chromium, nickel and copper in the vicinity of the smelting facility. Copper and iron concentrations increased tenfold after rainfall (wet period), indicating the contribution of tailings to marine pollution. There is an urgent need for remediation treatment for the site.  相似文献   

10.
Since the late part of the 19th century prospecting for W in the western world has been based mainly on the mechanical concentration of heavy minerals in sediments (panning), followed by visual and chemical analyses of the heavy-mineral fraction. Since the early 1970's, W prospecting in Sweden has been based on the use of heavy-mineral concentrates from till.In tests performed in a scheelite-mineralized area in the Bergslagen area of central Sweden, samples from the A- and C-horizon of the podzolic profile have been collected along grid lines across the ore as well as down-ice along the direction of final glacial transport from the ore. The purpose of the study was to test which sample types should be used in geochemical prospecting for W in the region.The results show that all the sample types studied can be used in geochemical prospecting for W in southern central Sweden. The heavy-mineral concentrate of till is primarily recommended for use at a regional and local scale. Humus is given the lowest priority of the sample types studied because of the poor analytical reproducibility for some samples with high values of W.  相似文献   

11.
The analysis of the glacial landscape of southern Saskatchewan (Canada) through multiple data sets (e.g. digital elevation model, till compositional data) has revealed previously unrecognized subglacial sediment–landform assemblages. A southwest-trending corridor of mega-scale till lineations (Maskwa corridor) bounded on each side by hummocky terrain extends from the Canadian Shield to southwestern Saskatchewan. This landform assemblage is clearly cross-cut by a broad south to southeast trending corridor (Buffalo corridor) consisting of subparallel curvilinear till ridges. The carbonate content of the surface till is spatially consistent within these assemblages, suggesting a strong sediment–landform relationship. The two corridors are interpreted as the product of palaeo-ice streams. The Maskwa palaeo-ice stream flowed up the regional slope and across preglacial valleys, indicating it was thick and stable. Narrow dispersal trains extending across as well as down-glacier from the Athabasca Basin suggest that the Maskwa palaeo-ice stream extended far into the ice sheet across contrasting shield and platform terrains. In comparison, the Buffalo palaeo-ice stream was thinner and largely controlled by subglacial geology and topography. Its catchments were located at the Canadian Shield boundary and the system was oriented along-slope. It experienced lateral shifts and it was fed by a network of tributaries. The glacial dynamics shift from the Maskwa to the Buffalo system occurred at about 13.5 14C kyr BP. The Buffalo system later evolved into thin outlet lobes until final deglaciation of the area. The proposed model has implications for ice-sheet reconstruction and the assessment of till properties in the prairies and in similar terrains.  相似文献   

12.
In some glaciated regions, weathered mantles, formed under previous climatic regimes, were not always eroded bare by glacial activity, but instead lie buried beneath the glacial overburden. It is obviously important that geochemical exploration programs in such terrain should take into account some of the known regolith features seen in deeply weathered regions. The effects of glacial action upon deeply weathered terrain are considered in three conceptual models. The critical factor in each is the depth of truncation of the preglacial weathering profile. All three proposed models are dynamic systems and a wide range of intermediate situations must be expected.In Model 1 a complete, largely undisturbed, weathering profile is preserved beneath till. The key characteristic is preservation of a lateritic duricrust which may contain areally large (up to 200 km2) geochemical anomalies. It would be critical, firstly, that the duricrust be sufficiently continuous to allow a reasonable success rate in its being sampled, and secondly that the duricrust be recognizable in drill spoil. The most efficient geochemical exploration could be based upon wide-spaced overburden drilling directed at sampling the duricrust. For reconnaissance, holes could be based upon a 1-km grid where stratabound massive polymetallic sulphide or stratabound gold deposits are sought. Even wider spacing could be tried where larger-sized ore deposits are expected.Model 2 is characterized by a weathered profile that was partly stripped prior to glaciation. The essential feature is a vertically zoned weathering profile in the basement rock in which the upper levels of the weathering profile have undergone leaching of certain elements and lower levels contain enrichments of these elements. Any gossans present would show strong vertical zonation. Relatively strong sources for dispersion in till are likely to be enriched gossans where erosion has cut deep into the profile, zones of supergene enrichment of ore deposits, and supergene ore deposits themselves. In many situations, saprolite under glacial drift would be too soft to provide boulders so important in conventional till prospecting.The essential ingredient in hypothetical Model 3 involves progressive planing away of the weathering profile by glacial action. Thus any halo in duricrust is initially dispersed, followed by dispersion of progressively deeper levels of saprolite. If taken deep enough the supergene enriched zone of a mineral deposit could add to the glacial dispersion. A broadly zoned anomaly would be expected; a till anomaly would be characterized distally by elements from the former duricrust anomaly, with elements more characteristic of supergene zones closer to the source.  相似文献   

13.
Water and sediment samples were collected from 20 location of the Buriganga river of Bangladesh during Summer and Winter 2009 to determine the spatial distribution, seasonal and temporal variation of different heavy metal contents. Sequential extraction procedure was employed in sediment samples for the geochemical partitioning of the metals. Total trace metal content in water and sediment samples were analyzed and compared with different standard and reference values. Concentration of total chromium, lead, cadmium, zinc, copper, nickel, cobalt and arsenic in water samples were greatly exceeded the toxicity reference values in both season. Concentration of chromium, lead, copper and nickel in sediment samples were mostly higher than that of severe effect level values, at which the sediment is considered heavily polluted. On average 72 % chromium, 92 % lead, 88 % zinc, 73 % copper, 63 % nickel and 68 % of total cobalt were associated with the first three labile sequential extraction phases, which portion is readily bioavailable and might be associated with frequent negative biological effects. Enrichment factor values demonstrated that the lead, cadmium, zinc, chromium and copper in most of the sediment samples were enriched sever to very severely. The pollution load index value for the total area was as high as 21.1 in Summer and 24.6 in Winter season; while values above one indicates progressive deterioration of the sites and estuarine quality. The extent of heavy metals pollution in the Buriganga river system implies that the condition is much frightening and may severely affect the aquatic ecology of the river.  相似文献   

14.
Authorities have been applying very strict regulations for the treatment of industrial wastewater recently because of the threatening level of the environmental pollution faced. Industrial wastewater containing heavy metals is a threat to the public health because of the accumulation of the heavy metals in the aquatic life which is transferred to human bodies through the food chain. Therefore, recently, researchers have been oriented toward the practical use of adsorbents for the treatment of wastewater polluted by heavy metals. The aim of this research was to determine the retention capacity of compost for copper, zinc, nickel and chromium. For this purpose, experiments in batch-mixing reactors with initial metal concentrations ranging from 100 to 1,000 mg/l were carried. It was also observed that compost could repeatedly be used in metal sorption processes. The experiments conducted indicated that compost has high retention capacities for copper, zinc and nickel, but not for chromium. Thus, compost has been approved as a potential sorbent for copper, zinc and nickel and may find place in industrial applications. Thus, solid waste which is another source of significant environmental pollution will be reduced by being converted into a beneficial product compost.  相似文献   

15.
氨基膨润土对铜镍镉污染土壤的钝化修复研究   总被引：1，自引：0，他引：1  
采集土壤,加入铜、镍和镉制成重金属污染土壤。以四乙烯五胺改性膨润土和膨润土原土作为修复剂,通过模拟酸雨和混合提取剂提取有效态重金属,评价膨润土和氨基膨润土对土壤中铜、镍、镉的钝化效果。结果表明:p H=3. 5的模拟酸雨对各污染土壤中重金属离子的提取率均在0. 1%以下。混合提取剂对污染土壤中有效态金属的提取能力比模拟酸雨强很多。添加膨润土原土和氨基膨润土均能钝化土壤中的铜、镍和镉,氨基膨润土上嫁接的氨基对金属有络合作用,因而比膨润土原土对铜、镍和镉具有更强的钝化能力。综合评价表明氨基膨润土是一种对铜、镍和镉污染土壤具有应用前景的钝化修复材料。  相似文献   

16.
以江西省武宁县石门寺钨铜矿区燕山期和晋宁期岩体风化作用过程中W、Cu等元素的表生地球化学行为为研究对象,通过反映风化程度的化学风化指数CIA、风化作用过程中组分得失的估算、不同介质中W、Cu等成矿元素的含量变化及大离子亲石元素表生地球化学行为等方法的研究表明,石门寺钨铜矿区2个时期岩体元素淋失与风化强度有关,土壤剖面中碱金属、碱土金属元素大量淋失,而W、Cu等成矿元素在土壤B层中显著富集;从岩石到土壤、再到水系沉积物风化过程中,W、Cu等成矿元素含量逐渐升高,为此,一级水系沉积物和B层土壤是赣北九岭W、Sn、Cu、Mo多金属矿集区地球化学找矿的绝佳采样介质,是矿集区内找矿新突破的有效手段。  相似文献   

17.
胡小梅  龚鹏  李娟  闭向阳 《地质通报》2014,33(5):741-750
以江西省武宁县石门寺钨铜矿区燕山期和晋宁期岩体风化作用过程中W、Cu等元素的表生地球化学行为为研究对象,通过反映风化程度的化学风化指数CIA、风化作用过程中组分得失的估算、不同介质中W、Cu等成矿元素的含量变化及大离子亲石元素表生地球化学行为等方法的研究表明,石门寺钨铜矿区2个时期岩体元素淋失与风化强度有关,土壤剖面中碱金属、碱土金属元素大量淋失,而W、Cu等成矿元素在土壤B层中显著富集;从岩石到土壤、再到水系沉积物风化过程中,W、Cu等成矿元素含量逐渐升高,为此,一级水系沉积物和B层土壤是赣北九岭W、Sn、Cu、Mo多金属矿集区地球化学找矿的绝佳采样介质,是矿集区内找矿新突破的有效手段。  相似文献   

18.
Sedimentological, structural and chemical characteristics of till and weathering crust are studied in the Kittila area of western Finnish Lapland. Four separate till beds and a weathering crust are discovered at three study sites - Pulju, Jerisjarvi and Mantovuoma. An upper grey till bed and a brown till bed are found at each site, the former being interpreted as a melt-out till, the latter as a lodgement till. A yellowish brown till bed occurs only in the Pulju area and is interpreted as a local saprolite till of a lodgement facies, while a lower grey till bed, seen only in the Jerisjärvi area, is a melt-out type till. The weathering crust (saprolite) is a product of chemical weathering of long duration and must be preglacial in age. In the earlier stages of glaciation the ice divide was located near the Scandinavian mountain range, ice movement took place from the northwest, and a lower grey till bed was deposited in the study area. In the later stages of deglaciation the ice divide was located south of the area, so the ice flowed from the south, depositing a brown till bed and locally also a yellowish brown till bed. In the latest stages the ice flowed from the southwest, depositing an upper grey till bed.  相似文献   

19.
Interpretation of indicator dispersal trains preserved in till sheets is widely used to investigate past glacial processes and to explore for buried bedrock mineralization. We present a conceptual model of erosion and entrainment and transport of indicator material in a glacial system. Indicator concentration in an individual size fraction of till is controlled by dilution and comminution. Dilution is the result of incorporation of additional material to the glacier's debris load down-ice of the indicator source, and is described in terms of erosivity and erosion length scale. Erosivity describes the amount of bed material eroded along a flowline, and is a function of both bed properties and the erosive power of the glacier. Erosion length scale describes the persistence of an indicator dispersal signal during transport, and controls both the maximum total indicator concentration and the eventual length of apparent dispersal. We adapt a modified batch grinding particle comminution model to describe breakdown of indicator material during transport and modification of the indicator particle size distribution. Indicator dispersal concentrations are the product of dilution and comminution processes.  相似文献   

20.
Organic materials dissolved in surface waters have long been implicated in metal binding and transport. In particular, fulvic and humic acids are considered to have a significant impact on speciation, total metal levels in solution and on the persistence of those metals. This work emphasizes the role played by dissolved organic matter (DOM) on the complexation of nickel, copper and cobalt and on its application to interpretation of surface water hydrogeochemical survey data. Waters from a number of well-known mining districts in Canada have been studied; in particular from Cobalt (Ontario), Sackville (New Brunswick) and Thetford Mines (Quebec). The diafiltration binding technique was used and shows that nickel, copper and cobalt are complexed significantly by DOM in natural waters. The tendency towards complexation was found to be Cu > Ni > Co. The binding functions determined were observed to be highly sensitive to pH and ligand:metal ratios; a gradation of binding site strength is evident.Data from some hydrogeochemical surveys conducted in the Kenora, Algoma and Ottawa districts of Ontario have been reinterpreted in the light of available data on the complexation behaviour of nickel, copper and cobalt. Occurrence of large water-borne anomalies unsupported by lake sediment loadings is most likely for cobalt and nickel and least likely for copper according to both field observations and experimental data. These studies provide good evidence for the formation of strong solution stable metal-organic species; the principal differences in persistence and migration behaviour are probably due to rates of coagulation and adsorption-precipitation processes which preferentially remove copper from solution. It is fair to conclude that these metals can be of use in mineral exploxation surveys using surface waters provided caution is exercised in interpretation of anomalies, especially in the absence of supporting sediment anomalies. Dissolved organic matter concentrations should always be determined when nickel, copper and cobalt are to be employed.  相似文献   

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