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1.
Extensive studies in the southern Canadian Cordillera have shown that using geological and geochemical techniques, it is possible to regionally map distinctive paleo-hydrogeological regimes. Since research programs in the Canadian Cordillera and elsewhere have shown that many types of mineralization are created by regional scale flow systems, it is possible to use the regional maps of paleo-hydrogeological regimes to define those areas likely to host particular styles of mineralization.An application of these concepts to exploration is documented using the example of mesothermal Au mineralization in the southern Canadian Cordillera. Approximately 75% of the 300,000 km2 study area can be eliminated from consideration for exploration due to the absence of the appropriate geological and geochemical indications of paleo-hydrogeological regimes capable of forming mesothermal Au deposits. Consequently, exploration efforts can be focussed on a much smaller, but more prospective region. 相似文献
2.
Henry F. STEGER 《Geostandards and Geoanalytical Research》1981,5(2):189-193
The Canadian Certified Reference Materials Project has amended its procedure in interla-boratory certification programs. The reasons for reducing to one from two the number of bottles of a candidate reference materials submitted to each participating laboratory are discussed. The effect of the smaller number of results of the one-bottle approach to be expected on the certified value and 95% confidence interval is shown to be minor. 相似文献
3.
《Geoforum》2017
Using the Canadian Arctic as a case study this paper explores how Internet-based research can be used to advance area studies in an era of rapid global change. Regions of the world are rapidly changing due to social, technological, and environmental processes, and traditionally marginalized groups are increasingly using digital tools to help shape new geographical imaginations of these regions. Digital research is uniquely capable of analyzing these political uses of digital technologies, to produce a better understanding of how many different stakeholders are shaping emerging geographical imaginations. The Canadian Arctic offers a particularly powerful case study to understand these processes both because it represents a geographic region that is complex, multi-scalar, and rapidly evolving, and also because it is a region in which traditionally marginalized indigenous groups are using the Internet to increase the visibility of their perspectives. This paper develops an innovative methodology, combining computational analysis of ‘big data’ along with traditional forms of qualitative analysis, to analyze representations of the Arctic across the websites of five different organizations. These organizational websites were chosen because each of the organizations has a different relationship to the Arctic, operates at a different geographic scale, has some relevance to areas of the Canadian Arctic in which Inuit live, and has a large website. The analysis successfully reveals how these different organizations use the web to shape different types of geographic imaginations of the Arctic, as well as the types of discursive politics being used by the organizations to push forward their own political goals. The result is a powerful form of area studies capable of highlighting the geographic imaginations and re-imaginations of a complex set of actors operating at many different scales. 相似文献
4.
Ernest S. GLADNEY 《Geostandards and Geoanalytical Research》1985,9(2):275-276
Uranium concentrations were determined in 30 reference materials from Japanese, French, and Canadian agencies using delayed neutron assay methods. Many of these materials are new and have few previously reported values for uranium. 相似文献
5.
Pierre Filion 《GeoJournal》2010,75(6):517-538
The Canadian urban system was first shaped by exogenous demand for staples and, subsequently, by the dichotomy between an
industrial heartland and a resource based hinterland. Presently, transformations affecting the economy, policy-making and
demography herald profound changes in the future configuration of the Canadian urban system. One possible scenario is a revival
of the staples economy as economic globalization raises demand for commodities. Another scenario would entail a concentration
of growth in large urban centres, by virtue of their attractiveness to specialized and high-order service occupations, two
rapidly expanding economic sectors, and their strong pull on immigrants. In the case of either scenario, we can expect further
polarization between growing and shrinking portions of the urban system (parts of the heartland in the first case and small
urban areas in the second) in a neo-liberal policy context that is unfavourable to regional economic development interventions.
The evolution of the Canadian urban system between 1971 and 2006 and present distributions of factors of growth and decline
point to the second scenario, a growing large city-small city dichotomy. The article closes by discussing likely consequences
of the resulting urban system configuration on labour market adjustments and public sector expenditure. 相似文献
6.
A number of local, regional, state, and federal programs are in place that strive to protect and restore coastal waters and habitats, and which specifically address eutrophication and nutrient over-enrichment. There are, however, no easily implemented and reliable methods or sources of data and information for citizens, coastal managers, elected officials, and agency staff who are responsible for managing a coastal area to determine sources of nutrients and potential impacts to coastal waters. Coordination among federal and local agencies remains inadequate. In the few examples of successful coastal nutrient management programs, effective nutrient management strategies are often partnerships of national, regional, and local efforts. The recent National Research Council (2000) examination of issues and management options calls for development of a National Coastal Nutrient Management Strategy, coordinated between national, state and local programs, academia, and the private sector. The proposed National Coastal Nutrient Management Strategy includes recommendations for local programs to consider in developing an effective nutrient management strategy, such as setting goals for restoration, determining nutrient reductions needed to meet goals, and monitoring results. The proposed strategy also identifies priority actions which federal programs should consider, including identifying gaps and overlaps in existing and proposed national programs for all aspects of nutrient over-enrichment; increasing accessibility to data, information and expertise on nutrient over-enrichment causes, effects, and management options; and setting clear guidelines for nutrient loads. A nationally consistent monitoring program and targeted research, specifically for atmospheric deposition, seasonal variability of nitrogen and phosphorus enrichment effects, the role of specific nutrients in the occurrence of harmful algal blooms, and economic impacts of nutrient over-enrichment were also identified as priority needs. 相似文献
7.
Tree-ring-based mass-balance estimates for the past 300 years at Peyto Glacier, Alberta, Canada 总被引：1，自引：0，他引：1
Tree rings were used to reconstruct mass balance for Peyto Glacier in the Canadian Rocky Mountains from A.D. 1673 to 1994. Summer balance was reconstructed from tree-ring estimates of summer temperature and precipitation in the Canadian Rockies. Winter balance was derived from tree-ring data from sites bordering the Gulf of Alaska and in western British Columbia. The models for winter and summer balance each explain over 40% of the variance in the appropriate mass-balance series. Over the period 1966-1994 the correlation between the reconstructed and measured net balances is 0.71. Strong positive mass balances are reconstructed for 1695-1720 and 1810-1825, when higher winter precipitation coincided with reduced ablation. Periods of reconstructed positive mass balance precede construction of terminal moraines throughout the Canadian Rockies ca. 1700-1725 and 1825-1850. Positive mass balances in the period 1845-1880 also correspond to intervals of glacier readvance. Mass balances were generally negative between 1760 and 1805. From 1673 to 1883 the mean annual net balance was +70 mm water equivalent per year (w.e./yr.), but it averaged −317 mm w.e./yr from 1884 to 1994. This reconstructed mass balance history provides a continuous record of glacier change that appears regionally representative and consistent with moraine and other proxy climate records. 相似文献
8.
There is a large sociological literature on racial- class-, and economically- based segregation in the United States and there is some evidence that residential segregation by income may have deleterious health consequences for residents of large U.S. cities. The health consequences of segregation in Canadian metropolitan areas, however, remain unknown and the comparison with the U.S. is always compelling. In this paper, we investigate the hypothesis that residential segregation by income may be associated with mortality in Canadian and U.S. metropolitan areas. Given the strong relationship between individual level socioeconomic status and health, it follows that metropolitan areas which isolate individuals economically could produce conditions that severely limit the life chances and therefore the health chances of the most vulnerable. To investigate the association between residential segregation by income and population health, we examined the relationship between working-age mortality and Jargowsky's (1996) neighbourhood sorting index (NSI) for a large group of North American metropolitan areas. We found a relationship between increased segregation and increased mortality for U.S. metropolitan areas but no such relationship for Canadian metropolitan areas. We also determined that income segregation could not be considered in isolation from income inequality – that, in effect, income inequality provides the propensity for meaningful segregation to occur. We further demonstrated the importance of considering both income inequality and income segregation together, especially when the analysis is intended to compare metropolitan areas. We conclude with a discussion of the need for an improved measure of segregation to better reflect the theoretical arguments for the relationship between concentration of poverty and affluence and population health. 相似文献
9.
10.
Paleomagnetic data and rock magnetic results suggest that a widespread orogenic remagnetization caused a pervasive chemical remanent magnetization (CRM) that resides in magnetite in the Mississippian Madison Group in the Sawtooth Range, Montana, during the Late Cretaceous to Early Tertiary. The CRM is similar to a CRM reported by workers from equivalent units in the southern Canadian Cordillera. The CRM is interpreted to be related to alteration by fluids, and there are two likely fluids: hydrocarbons which migrated into the unit and externally derived radiogenic fluids. 相似文献
11.
Geochronology of carbonatites from the Canadian and Baltic Shields, and the Canadian Cordillera: clues to mantle evolution 总被引：2，自引：0，他引：2
Carbonatites are known to range in age from the Archean through to the Recent, with an increasing abundance towards more recent times. Of the known 500 or so carbonatites, however, few have been precisely dated. In this paper, some new, precise U/Pb, Th/Pb as well as Pb/Pb dates from several carbonatite complexes from Europe and North America are presented and used to establish important reference points in defining mantle perturbations. Events at 2617, 1964, 583 and 382 Ma are now firmly established for the Fennoscandian Shield, while several distinct events of 2680 Ma, and between 1897–1881 and 1164–1083 Ma are documented for the Canadian Shield. Other, less well-defined, events in Canada include magmatism at 1770 Ma from Argor, 570 Ma from Manitou Islands, and an event at 360 Ma from the Canadian Cordillera. One carbonatite from the Ukrainian Shield (Chernigovka) has been precisely dated at 2074 Ma. Events from the Fennoscandian Shield also include carbonatitic magmatism at 1792 Ma from Halpanen, and between 386 and 377 Ma from Kola. Most of these events from quite distinct Archean cratons can be correlated with LIPs and associated mafic magmatism, such as flood basalts and regional dyke swarms, generally considered to be the result of plume magmatism and associated continental fragmentation. Few mafic events are associated with the post-orogenic shoshonitic magmatism at ca. 1800 Ma for the Fennoscandian Shield and the Devonian continental margin extension in the Canadian Cordillera. 相似文献
12.
Evaluation of the vanadium, chromium, cobalt, nickel, and copper contents of five biotites, chloritized to varying degrees,
from a magmatic granitic series of the 2700-million-year-old Giants Range Batholith of Northeastern Minnesota, USA, on the
southern margin of the Canadian Shield, determined by wavelength-dispersive x-ray fluorescence spectrometry, shows that, during
progressive chloritization of biotites in granites, the content of vanadium decreases and the contents of chromium, cobalt,
nickel, and copper increase. The results emphasise the need for great caution when interpreting whole-rock trace-element data
in petrological research. 相似文献
13.
A basement-interacted fluid in the N81 deposit, Pine Point Pb-Zn District, Canada: Sr isotopic analyses of single dolomite crystals 总被引：1，自引：0，他引：1
The Mississippi Valley-type Pb-Zn deposits of the Pine Point district (Northwest Territories, Canada) are located close to the eastern edge of the present day Western Canadian Sedimentary Basin. The deposits are thought to have formed as the result of basin-wide fluid flow in the Presqu’ile Barrier, the host to the ore deposits. A laser ablation multi-collector inductively coupled plasma mass spectrometric study of 87Sr/86Sr ratios of ore-related dolomites from the N81 deposit at Pine Point indicates that at least two sources of Sr were present in the mineralizing system. One fluid has a range in Sr isotopic values from 0.07073 to 0.71200 and is interpreted to be derived from Middle Devonian seawater that interacted with clastic units in the basin. The second fluid has higher Sr isotopic values (up to 0.71520), similar to those found in some Canadian Shield brines, and is interpreted to represent an evaporated seawater-derived brine which has interacted with crystalline basement rocks. Reactivation of old structures in the basement may have provided a pathway for cross-formation fluid flow to the site of mineralization. The data suggest that the stratigraphic location of the Pine Point District, near the interface between the Western Canadian Sedimentary Basin and its basement, may have exerted a fundamental control on the formation of these deposits. 相似文献
14.
Responding to a need created by voluminous collections of fish life history, catch and angler effort information, a computerized information management system was developed at the National Marine Fisheries Service laboratory in Beaufort, N.C. for use on an IBM Model 360/65 Computing System. The management system incorporates sequential data storage on disks, analytic programs written in IBM FORTRAN IV, and editing/updating programs written in American National Standard COBOL. The file creation procedure utilizes single or multiple card entry records to generate a single master record. Analytic programs generate arrays displaying fish weights and simple statistics, length-frequency distributions, catch curves, back-calculated fish lengths per annulus, back-calculated length frequency distributions, percentages sexually mature, reproductive condition, age at sexual maturity (using gonad index), occurrence and abundance. 相似文献
15.
Grant M Young 《Precambrian Research》1974,1(1):13-41
The Hadrynian (Upper Precambrian) rocks of Victoria Island in the western part of the Canadian Arctic Archipelago comprise a sedimentary sequence some 12,000 ft. (4,000 m) thick, capped by a 1,000 ft. (330 m)-thick basic volcanic and pyroclastic unit. These rocks outcrop in an elongate, topographic high called the Minto Arch, and in smaller inliers in Lower Paleozoic rocks in the south part of the island (Duke of York and Wellington highs).Stratigraphic and sedimentological investigation of these rocks in the southern part of the Wellington high near Cambridge Bay suggest that they were deposited by rivers flowing from a land mass that lay to the east. Clasts in the Hadrynian sedimentary rocks attest to the existence of at least two earlier periods of sedimentation and one phase of tectonic compression in the basement rocks.Study of the lower part of the Hadrynian succession (Glenelg and Reynolds Point Formations) in the northeastern part of the Minto Arch reveals a general thickening to the west. Rock types present include dolomite, limestone, siltstone, sandstone and shale deposited in a dominantly shallow marine environment together with some marine deltaic units and possibly distal fluvial deposits. Cross bedding and ripple-mark orientations suggest a paleoslope to the northwest. However, the pattern of cross-bedding distribution is complex with modes not only in the northwest quadrant, but also in the northeast and southwest quadrants, the latter possibly reflecting longshore currents in a generally shallow marine environment.Stromatolites are abundant in both formations studied. They are almost exclusively laterally linked shallow-dipping domes in the cherty dolomites of the Glenelg Formation. However the capping stromatolitic dolomite of this formation is composed of columnar stromatolites, as also are the abundant stromatolitic banks and reefs of the overlying Reynolds Point Formation. Elongate domes in the lower part of the Glenelg Formation have a preferred orientation in a northwest-southeast direction, perhaps reflecting tidal currents. The topmost stromatolitic unit of the Glenelg Formation in more easterly areas has large elongate mounds on its upper surface. Elongation of these mounds has a preferred orientation in a northeast-southwest direction. Possibly this orientation is related to longshore currents flowing along the depositional strike.The Hadrynian sediments of Victoria Island and areas to the south and west may have been deposited in a shallow embayment of the Upper Precambrian Sea, open to the northwest and in continuity with a wedge of sediment that thickened westward and extended along the length of the North American continent. There is some evidence to support the existence of three such embayments in the southern part of the Canadian Arctic Archipelago, separated and defined by northerly salients of older rocks of the Canadian Shield. These salients reflect an east-west tectonic stress on a very large scale. 相似文献
16.
锂是重要的能源金属,分布高度集中。目前可开发利用的锂矿床主要有盐湖卤水型、伟晶岩型、黏土型、锂沸石型、其他卤水型（包括油气田卤水亚类和地热卤水亚类）和离子吸附型6种类型。除伟晶岩型锂矿的时代呈幕式分布,其他类型的锂矿主要集中形成于新生代。新生代锂矿占全球已查明资源量的75%,主要分布于显生宙造山带如安第斯锂三角地区、中国川藏地区、北美科迪勒拉等地区,其余锂矿则主要分布在前寒武纪克拉通如西澳克拉通、刚果克拉通、西非克拉通和加拿大地盾等区域。盐湖卤水型和伟晶岩型锂矿找矿潜力大,是目前勘探开发的主要类型。 相似文献
17.
For the past five years the Millsaps Sorbent Laboratory has been actively engaged in developing standards for initial and long-term oil spill remedial technologies. As a voting member of the American Society of Testing Materials (ASTM) F-20 Committee, Canadian General Standards Board, and the US Coast Guard Sorbents Task Force, the laboratory has been engaged in developing useful, pragmatic protocols for various chemical and physical sorbent and filtration technologies driven by the deadlines imposed by the Oil Pollution Act of 1990 (OPA 90). The open border approach to certification of technologies and products promulgated by the US/Canadian Free Trade Agreement has placed the US users and producers of such products and systems in a unique and tenuous position. Canadian standards and goals are grandfathered into the United States under this agreement and products have official US government certification based on Canadian regulations. This situation is unfavorable to the US domestic environment and economy for several specific scenarios. Included in these scenarios are: abundant warmwater zones and inland waters of the US versus Canada, the basic chemical variation between Canadian and US crude oils, the different generally accepted remediation technologies in the US versus Canadian, and the technology validation procedures prior to purchase inherent to both countries. 相似文献
18.
Upper Cretaceous sediments of the Kanguk Formation exposed in Eidsbotn and Viks Fiord grabens on Devon Island, Nunavut, Canadian High Arctic, yielded 91 fossil marine diatom species and varieties (including indeterminate taxa), representing 41 genera. Excellent preservation of the assemblages was aided by shallow burial, protection in downfaulted linear grabens, and the presence of abundant volcanic material. Planktonic species and resting spores comprise nearly 70% of the diatom assemblage, and provided abundant food resources for the Late Cretaceous Arctic ecosystem. Deposition of the approximately 225 m-thick stratigraphic sequence was predominantly in a shallow marine neritic setting, with an upward progression to interbedded terrestrial deposits of the Expedition Fiord Formation, reflecting a regression and eventual persistence of terrestrial facies into the Early Cenozoic. The Kanguk Formation is widespread across the Canadian Arctic, and diatom biostratigraphy indicates a Santonian–Campanian age for the sequences reported herein, based on the presence of Gladius antiquus in the lowermost strata and occurrence of Costopyxis antiqua throughout the succession. However, Amblypyrgus sp. A and Archepyrgus sp. aff. A. melosiroides, encountered in the lower part of the succession, are known exclusively from the Lower Cretaceous. This may suggest a slightly older age. New information on shallow shelf diatom assemblages from this study is compared to reports on two other Late Cretacous Arctic diatom assemblages. These three sites represent an environmental transect from shallow to distal shelf settings and into the oceanic realm. 相似文献
19.
Ronald Doig J. Brendan Murphy Georgia Pe-Piper David J.W. Piper 《Geological Journal》1996,31(2):179-188
The Cobequid Highlands in the Canadian Appalachian orogen lie within Avalonia adjacent to the Meguma Terrane. U-Pb (zircon) data show that the age range of voluminous bimodal plutonism in the highlands is from 358 to 363 Ma (late Devonian). This age range is much narrower than that previously suggested by Rb/Sr geochronology and confirms that the Cobequid Highlands preserve the youngest large-scale plutonic event in the Canadian Appalachians. Late Palaeozoic tectonic history of the Appalachian orogen is profoundly influenced by predominantly dextral motion on the Avalon-Meguma terrane boundary. This age of plutonism is coeval with previously published 40Ar/39Ar (muscovite) plateau ages derived from shear zones in the Meguma terrane adjacent to the terrane boundary, which is defined by the Minas fault zone. The NNE trending structural grain of the Appalachian orogen is disturbed in this area by the E-W Minas fault zone and pluton emplacement may have been associated with motion along this terrane boundary. 相似文献
20.
H.F. STEGER G.H. FAYE W.S. BOWMAN R. SUTARNO 《Geostandards and Geoanalytical Research》1979,3(2):173-175
Under the Canadian Certified Reference Mate-vials Project (CCRMP), four new ore reference materials, one uranium ore BL-5 and three sulphide concentrates (CCV-1, CPB-1 and CZN-1) have been recently issued. The preparation, characterization and certification of these samples are briefly presented. 相似文献