Canadian Shield

Canada s most productive district is in the Canadian shield at Cobalt, Ontario. Nearly 97% of the silver values in this pre-Cambrian age ore were found as great slabs of nearly pure silver. One slab was 474 kg. The huge open-pit Kidd Creek Mine has had an aimual output of over 80 t of silver. 

Glaciers are powerful agents of physical erosion. In a detailed geomorphological study of the glaciated Canadian Shield, Sugden (1978) concluded that erosional style was related primarily to the basal thermal regime of the ice. From the center of divergence on an ice cap. 

Bodaly RA, Rudd JWM, Fudge RJP, Kelly CA. 1993. Mercury concentrations in fish related to size of remote Canadian shield lakes. Can J Fish Aquat Sci 50 980-987. 

Vast undulating till plains occur in North America, between the Canadian shield area and the loess belt. This area is either covered with thick tills or with deglaciation sediments, lacustrine sediments in particular. The lake areas are level as such but the till landscape has a typical hummocky relief. The main characteristic of hummocky tills (40% of the total area) is the predominance of very local drainage patterns (mainly in depressions). Tills and loess have in common that they are internally uniform and that they all date back to deglaciation periods. 

Millot R, Gaillardet J, Dupre B, Allegre CJ (2002) The global control of silicate weathering rates and the coupling with physical erosion new insights from rivers of the Canadian Shield. Earth Planet Sci Lett 196 83-98... 

The NICO deposit is located at the south end of the GBMZ in the Proterozoic Bear Structural Province of the Canadian Shield, about 160 km northwest of Yellowknife, Northwest Territories (Fig. 1). It represents an economically significant source of Co-Au-Bi-Cu-Fe with calculated reserves of 21.8 Mt with 1.08g/t Au, 0.13%Co and 0.16% Bi (Fortune Minerals 2008). Mineralization at NICO consists of a number of mineral showings predominantly hosted in brecciated and altered siltstone and wacke of the 1.88 Ga... 

The Cretaceous sedimentary rocks of the Western Canada Sedimentary Basin (WCSB), renowned for their hydrocarbon resources, are seldom considered to have potential to host base metal sulphide mineralization. These sedimentary rocks have also discouraged those who presumed that the Precambrian rocks of the Canadian Shield to the east and north are more favourable hosts of base metal mineralization (ctMacqueen 1997). 

The regional-based survey pattern of the GSC-determined Hg concentrations (ppb) in stream sediments across Canada is shown in Fig.1. Of particular interest are (i) the high Hg concentration cluster near the central north-eastern border of the Yukon Territory (Survey Zone 3), (ii) the somewhat elevated background levels in the southern portions of the Canadian Shield along the Great Lakes, (iii) the scattered pattern of similar values throughout British Columbia, Labrador and... 

Individual samples of isotopically heavier granitic rocks have also been reported from the Canadian Shield (5T i = +7.3 to +11.3 new and updated data from Bottomley et al. 2003) and from the Isle of Skye, Scotland (8 Li = +8.1 Pistiner and Henderson 2003). These are all rocks with long near-surface histories and modal chlorite or epidote, suggesting their isotopic... 

Figure 19. Plot of Li isotopic composition vs. inverse Li concentration for lakes and basinal/oilfield brines. Lakes open circle = major global lakes (Chan and Edmond 1988 Falkner et al. 1997) semi-open circle = western U.S. closed basin lakes (Tomascak et al. 2003). Oilfield brines inverted triangle = Williston basin, Saskatchewan (Bottomley et al. 2003) diamond = Israeli oilfields (Chan et al. 2002d). Mine waters (Canadian Shield basinal brines) square = Yellowknife, NWT (Bottomley et al. 1999) triangle = Sudbury, Ontario, area (Bottomley et al. 2003) star = Thompson, Manitoba, area (Bottomley et al. 2003). Average composition of seawater is included for reference.

Kaufmaim RS (1989) Equilibrium exchange models for chlorine stable isotope fractionation in high temperature environments. In Proc 6 Int S>mp Water-Rock Interaction. Miles DL (ed) p 365-368 Kaufmann RS, Frape SK, Fritz P, Bentley H (1987) Chlorine stable isotope composition of Canadian Shield brines. In Saline Water and Gases in Crystalline Rocks, Fritz P, Frq)e SK (eds) Geological Association of Canada Special Paper 33 89-93... 

Card, K.D. Ciesielski, A. 1986. Subdivisions of the Superior Province of the Canadian Shield. Geoscience Canada, 13, 5-13. 

The Athabasca Basin occurs within the southwestern part of the Churchill Structural Province of the Canadian Shield. The 100,000 km basin is filled by an unmetamorphosed clastic sequence of the Mesoproterozoic (Helikian) Athabasca Group. The basin is underlain by an Archean/Paleoproterozoic basement complex that was strongly deformed and metamorphosed during the Hudsonian... 

The Cage district is located to the North-East of the Canadian Shield, along the eastern side of the Ungava Bay (Fig.1). 

Geological Setting The Grenville Province is a major structural province included within the Canadian Shield. The first two units of this Province are semi continuous, stacked belts the Parautochtonous belt (PB) and the structurally overlying Allochtonous Polycyclic belt (APB) (Fig. 1). The Allochtonous Polycyclic belt and the Allochtonous Monocyclic belt (AMB) are two allochtonous units. After Carr et al. (2000) and Tollo et al. (2004), the Allochtonous Monocyclic belt is divided into three separate units the Wakeham... 

The McArthur River Uranium Deposit lies in the eastern portion of the Athabasca Basin and within the Churchill Structural Province of the Canadian Shield. The deposit straddles the unconformity between the quartz arenite - rich Late Paleoproterozoic Athabasca Group and... 

Rempel RS, Harrison AD (1987) Structural and functional composition of the community of Chironomidae (Diptera) in a Canadian shield stream. Can J Zool 65 2545... 

Frape SK, Fritz P (1987) Geochemical trends from groundwaters from the Canadian Shield, In P, Fritz, SK Frape (eds,) Saline water and gases in crystalline rocks, Geol Ass Canada Spec Paper 33 19-38... 

Frape SK, Fritz P, McNutt RH (1984) Water-rock interaction and chemistry of groundwaters from the Canadian Shield, Geochim Cosmochim Acta 48 1617-1627 Freeman KH (2001) Isotopic biogeochemistry of marine organic carbon. Rev Miner Geochem 43 579-605... 

Kettles, I.M. and Shilts, W.W. (1994) Composition of glacial sediments in Canadian shield terrane, southeastern Ontario and southwestern Quebec applications to acid rain research and mineral exploration. Geological Survey of Canada Bulletin, 463, Report, 58 pp. 

Auclair, J. C. 1995. Implications of increased UV-B induced photoreduction Iron(II) enrichment stimulated picocyanobacterial growth and the microbial food web in clear-water acidic Canadian Shield lakes. Canadian Journal of Fisheries and Aquatic Sciences 52 1782—1788. Auclair, J. C., P. Brassard, and P. Couture. 1985. Total dissolved phosphorus Effects of two molecular weight fractions on phosphorus cycling in natural phytoplankton communities. Water Research 19 1447—1453. 

Standard Canadian Shield saline solution (SCSSS), with a composition approximately that of saline solutions obtained from various sources in the Canadian Shield. 

The presence of saline solutions at depth in plutons in the Canadian Shield (11) should not be detrimental to retaining technetium in the valut since the experiments showed that technetium removal occurs from highly saline solutions. 

In these studies a dynamic testing method (the mixing-cell) has been used to measure the sorption kinetics of 4 different radionuclides on Lac du Bonnet granite from the Archean Superior Province of the Canadian Shield. This method has been used previously (2) for measurement of sorption kinetics without the interference of hydraulic dispersion common in many other dynamic techniques. 

Static sorption studies with drill core material from two rock formations in Canadian Shield have shown a positive correlation between Ce sorption and mafic mineral concentration and transition metal oxide concentration in the rock (5). 

The water was doubly distilled and deionized before use. Granite groundwater (G.G.W.) and standard Canadian Shield saline solutions (SCSSS) were prepared according to the method of Vandergraaf (3). 

Servos, M.R., Muir, D.C.G. (1989a) Effect of dissolved organic matter from Canadian shield lakes on the bioavailability of 1,3,6,8-tetrachlorodibenzo-p-dioxin to the amphipod Crangonyx laurentianus. Environ. Toxicol. Chem. 8, 141-150. 

Sections of eastern North America are being adversely affected by deposition of acidic precipitation and aerosols, generally termed acid rain. Most severely affected are ecosystems which overlie the Canadian Shield, a silicate bedrock with low Mg and Ca... 

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