Talk:Canadian Shield

region map

i was looking for a region map trusting wikipidia to have one i was a little shocked to be unable to find on that highlight the region wich i needed for a project

Sounds like you should find and add one then. This isn't a commercial product, it's an open-source dictionary. Halogenated (talk) 17:27, 14 January 2019 (UTC)

Map?

A map would be nice —The preceding unsigned comment was added by 82.9.173.226 (talk • contribs) 20:38, 22 March 2005 (UTC)

Good idea. There is one now. Thanks, User:Tomf688! (SEWilco 19:27, 11 October 2005 (UTC))

The introductory paragraph states that the shield "also includes most of Greenland and extends into the United States as the Adirondack Mountains", but neither are indicated on the map. How is this ? —Preceding unsigned comment added by 24.17.110.63 (talk) 18:03, 14 December 2007 (UTC)

Because the map is generalized, and because some would define the shield geographically (Canada), whereas the statement that it includes Greenland and the Adirondacks is a reference to the fact that similar rocks underlie those areas. Cheers Geologyguy (talk) 18:08, 14 December 2007 (UTC)

IP users version

User_talk:64.25.167.132 uploaded a new version of the page, I am not sure if any of this is worth incorporating. There was no source provided. -Ravedave 04:51, 14 April 2006 (UTC)

The Canadian Shield is the geographic foundation of Canada. The Shield underlies not only much of Canada but also parts of the United States. More than half of Canada is covered by the Shield. Some of the world's oldest rocks (3.96 billion years old) are located in the Shield near Great Slave Lake. Today, most of the Shield is relatively flat with rounded hills of rock which are actually the roots of ancient mountains. Two types of rock, igneous and metamorphic, form most of the Shield. They contain valuable minerals in great quantities. Because of the vast deposits of lead,gold,nickel,copper,zinc,and other important metals, the Canadian Shield is often called the stonehouse of Canada's Metallic minerals. In addition, diamonds have recently been found where ancient volcanoes once existed. How were mineral deposits formed in the rock of the Shield? Minerals were present in magma (molten rock) beneath the earth's crust. As magma rose toward the surface, it forced it's way into cracks and cavities in the shield rock. This process of magma slowly rising toward the surface took thousands or millions of years. As it cooled, some minerals were deposited in the magma itself. Other deposits were formed when minerals, dissolved in very hot water, were forced deep into cracks in the surrounding rock. This process allowed minerals to be deposited in high concentrations which makes mining worthwhile.

As the minerals slowly cooled, they separated into layers according to their density. The lighter ones floated on top of the heavier ones. Those that had similar density floated to the same level. Nickel and copper are often found together because they have similar densities. Mining companies are attracted to the Shield because of the presence of metallic minerals. Many cities and towns, such as Sudbury in Ontaffsahyhyshrio, Thompson in Manitoba, and Yellowknife in the Northwest Territories, rely on the mining industry for jobs. The mineral ores are smelted to remove waste materials. The concentrated minerals are shipped to factories in Canada and other parts of the world where they are used to manufacture products we use every day. While the Shield is well-suited to mining,it's ill-suited to farming because it has very thin soils. However, it's ideal for recreation because of it's scenic rivers, waters, lakes, rock outcrops, and vast forests. The action of the glaciers affected the drainage of the Shield. The scraping and gouging action of the ice created depressions in the bedrock. These depressions filled with water to form the hundreds of thousands of lakes that now dot the Shield. Because the bedrock is impervious, which dammed rivers or forced them to flow in different directions. The result is a very disorganized pattern of winding rivers, lakes, and swamps. These rivers and swamps are the breeding ground for the many blackflies and mosquitoes found in the Shield. People visit the Shield to canoe, fish, hunt, and "get back to nature." The tourist industry is very important to the towns and cities in the southern parts of the Shield. The Shield's plentiful water flows have made it an excellent surce of water-generated energy, and the pattern of drainage has affected where hydro-electrical plants are located. The centre of the Shield is much lower than it's outer portion. This gives it the appearance of a saucer, with Hudson Bay occupying the low-lying centre. As a result, most of the rivers of the Shield flow toward it's centre and into Hunson Bay. Hydroelectric generating stations have been built where the rivers tumble from the Shield onto the Hudson Bay Lowlands. The energy produced by these stations is transmitted by power lines to cities and towns both on and off the Shield.

PRECAMBRIAN CANADIAN SHIELD

The earth was formed about 4,600,000,000 years ago. The Precambrian era began at this time and lasted for about 4,000,000,000 years, approximately 87% of the earth's history. Many cycles of Mountain Building and erosion took place during this era. During the Precambrian Era, the only part of Canada that existed was the Canadian Shield. At times, the peakes of the Canadian Shield were as high as 12,000 metres above sea level. These enormous mountains were taller than any that exist today!!!!!! The uplifting was accomplished as enormous pressure caused the earth to buckle in a process called folding. Other processes such as volcanic action and faulting, in which the earth cracks open, also contributed to the formation of these mountain. Over millions of years, these mountains were gradually eroded only to be replaced by new mountains. Areas of land and ocean developed and then disappeared many times. The rest of Canada, as we know it, did not even form until hundreds of millions of years later. The Canadian Shield is the largest landform region in Canada and the other regions have formed around it. The Shield consists mainly of igneous and metamorphic rock and some sedimentary rock. Igneous rock is created when hot, melted magma rises from deep under the earth's crust, then cools and hardens. Igneous rock can either be changed directly into metamorphic rock or break down into particles or sediments that harden into sedimentary rock. When pressure and heat melt the sedimentary rock, the result is also metamorphic rock. There are fossils in the Shield dating back to the Precambrian era. These are the remains of material deposited by algae, the first single-celled organisms. By the end of this era, more complex organisms had developed.

ASSERT EXPERT && GEOLOGY-STUB TEMPLATE

• I just made this series of edits to 'unconfuse' the sense between the shield and a craton... which was the sense before I fiddled.
• These distinctions should be checked by a geology expert.
• If the 'CS' is part of Laurentia, then logic dictates that the 'shield' should not be confused with it's 'foundation', the craton.

• From the context(s) it seems to be the shield is defined as that part of the craton that was glaciated, not the rock itself, the subject of the craton. Or so I surmise, as a poor humble engineer who's never taken a geology course.

Thanks, FrankB 19:20, 5 May 2006 (UTC)</nowiki>

Just a note

Just a note, the templates above have absolutely nothing to do with Canada or the Shield. The Person Who Is Strange 15:06, 20 June 2006 (UTC)

The Canadian Shield extends into the United States. --tomf688 (talk - email) 15:09, 20 June 2006 (UTC)

Reference 1 is cited wrongly: Corrigan, D., Galley, A.G., and Pehrsson, S., 2007, Tectonic evolution and metallogeny of the southwestern Trans-Hudson Orogen, in Goodfellow, W.D., ed., Mineral Deposits of Canada: A Synthesis of Major Deposittypes, District Metallogeny, the Evolution of Geological Provinces, and Exploration Methods: Geological Association of Canada, Mineral Deposits Division, Special Publication 5, p. 881-902. —Preceding unsigned comment added by 130.92.9.58 (talk) 13:17, 15 December 2008 (UTC)

Proposed Merger

I have proposed merging Ancient Mountains Of The Canadian Shield into this page because it appears to me attempting to be a page about, well, the Canadian Shield as a whole. It might be better if it were re-written to be about the mountains - but I know nothing about the subject so have no idea how plausible this is. I'd appreciate opinions from people more in the know! --JennyRad 17:06, 6 July 2006 (UTC)

If it was up to me, I would just delete Ancient Mountains of the Canadian Shield - there is no useful specific content other than the idea of 12,000 m mountains (no idea how they were able to quantify that) and perhaps the fact that there are diamonds in the Precambrian rocks of the Canadian Shield, which is already mentioned. The rest is just generic stuff in my opinion. --Geologyguy 18:01, 6 July 2006 (UTC)

Looks like someone's school essay to me. Nothing new there - a simple redirect seems the logical temporary solution. I'll do that now. Also note that this page could use some serious editing ... maybe someday :-) Vsmith 18:10, 6 July 2006 (UTC)

Typical Canadian Shield photo

The caption Typical Canadian Shield: pines, lakes, bogs, and rock is maybe a little misleading. For one thing, the trees in the foreground may be members of the Pinaceae, but they aren't actually pines. (I do see some pines in the background of the picture.) For another thing, coniferous forests are typical only of the southern half of the Canadian Shield--the northern half(more or less) is mostly rock and tundra. Granted, the landscape in the image is typical of landscape in the portion of the Shield that's most familiar to the largest number of people. I'd prefer a caption like "A typical landscape of the southern Canadian Shield." 65.213.77.129 (talk) 20:21, 23 June 2009 (UTC)

Canadian Shield Landform photo

I don't understand what the photo "Canadian Shield Landform[1]," prominently located at the top of the infobox, is supposed to represent. The word landform, as I understand it, and as it's defined in Wikipedia and elsewhere, is a generic term for any conspicuous topographic feature of the earth's surface, like a mountain, plateau, valley, etc. This photograph looks to me like a place where a few feet of land has been cut away to build a road, and as such it could have been taken at any of a nearly infinite number of locations in the world.

I don't understand, first of all, why it is referred to as a landform (If so, what type of landform is it, part of a very low hill?), and, second, how it provides a distinctive and meaningful representation of the Canadian Shield, which it should do if it's going to be placed at the head of the infobox.

The only relevance I can think of is that it shows a very thin soil layer over the bedrock where it's been cut away for the road, which I understand is typical of the Canadian Shield. But if that is this photograph's only significance, it would be much more useful elsewhere in the article, with a more explicit caption calling attention to the thin soil. It might work well in the Ecology section as an illustration of the lead sentence:

The current surface expression of the Shield is one of very thin soil lying on top of the bedrock, with many bare outcrops.

However, it does not illustrate bare outcrops, since the bedrock here was pretty obviously exposed by a road-building crew, not a glacier.

If this photograph does represent the Canadian Shield in some comprehensive way that I just can't see, somebody please explain it to me, and try to improve the caption so the photo's significance will be clearer to people like me.--Jim10701 (talk) 08:02, 22 October 2009 (UTC)

Geology but not climate

I think that the Shield article is sort of being used as a catchall article as an "area of Canada." I don't think this is accurate. It underlies some US states as well. It is a massive geologic structure with ores, but inserting modern climate and modern ecology seems inappropriate to this article. These subsections should be moved. In the case of modern climate and historical climate, how it shaped the shield might be useful. Can't see how ecology is useful here at all. Student7 (talk) 16:04, 24 November 2010 (UTC)

The Canadian shield is very distinct at the surface and the underlying geology governs the hydrology, vegetation, and animal life and is appropriate here. The Ecology section should remain in place. The current section is a concise summary and covers a variety of topics, all of which have articles of much greater detail elsewhere. Some of the links could be more specific (e.g. link to Laurentide ice sheet instead of the more generic glacier).Hilmar (talk) 02:02, 27 November 2010 (UTC)

Thanks for your answer. I agree that the shield has on it, distinctive ecology. But this ecology is germane to the area (almost polar to temperate). It is not generated by the shield itself. The subsection is well-written and IMO should be moved to an "x area of Canada article" (or several articles) but is not germane to the shield itself. The shield has a long existence. The ecology only deals with today's lifeforms anyway. This, to me, seems like a giveaway that this subsection should not be here. Okay for the shield to be linked from this (hypothetical) other article(s).

Ecology tends to be more of a function of latitude (geography) than underlying geology, particularly with the progression of time.

We have some articles on huge geologic formations. For example Chazy Formation (also ancient), Lake Hitchcock (end of last ice age and smaller). Anyway, the point is that these formations are beyond ecology. Just not the same realm. It should be moved. Student7 (talk) 20:36, 28 November 2010 (UTC)

Historical information

Is there any information available about when geologists identified it as a geological shield and perhaps when the name "Canadian Shield" started being used? Dr. Lobotomy (talk) 03:56, 24 August 2011 (UTC)

This might have nothing to do with anything but I've heard Canucks say the U.S. could never invade them because of the "Canadian shield"...is there some other use and reason for such a use of this term by Canadians? Or are they just being their odd, head flapping selves? 67.1.78.91 (talk) 05:44, 5 September 2012 (UTC)

East Antarctica?

Quote: The Canadian Shield is part of an ancient continent called Arctica, which was formed about 2.5 billion years ago during the Neoarchean era. It was split into Greenland, Laurentia, Scotland, Siberia, East Antarctica and is now roughly situated in the Arctic around the current North Pole.

I'm no expert, but that seems to be a bit unlikely, Canada, Greenland, Scotland, Siberia, and East Antarctica forming an ancient continent? Is it documented or a mistype? 70.74.191.229 (talk) 04:51, 17 November 2013 (UTC)

See Nena (supercontinent) and also figure 1f in this paper which shows East Antarctica adjacent to Nena (1800 to 1100 Ma). Vsmith (talk) 15:12, 17 November 2013 (UTC)

External links modified

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I am adding a reference where a citation is needed in the general information on the Canadian Shield. The Canadian Shield article [2] seems reliable.Jrradney (talk) 00:08, 24 January 2018 (UTC)

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Ecology section, taiga, you may know it as boreal forest

This is rather incoherent. We have "The boreal forest area gives way to the Eastern Canadian Shield taiga that covers northern Quebec and most of Labrador"; but for "boreal forest", the wiki entry reads "Taiga (/ˈtaɪɡə/; Russian: тайга́, IPA: [tɐjˈɡa]; relates to Mongolic[1] and Turkic[2] languages), generally referred to in North America as a boreal forest or snow forest..." (yes, it is redirected to "taiga"). So, going east, boreal forest gives way to taiga, or equivalently, taiga gives way to boreal forest. And a little later we have "boreal forests that give way to taiga in the most northerly parts". This way lies madness, eh? 2001:56A:F0E9:9B00:154F:E1BC:6203:D915 (talk) 03:25, 3 November 2021 (UTC)JustSomeWikiReader

Population

Quel est la population du Bouclier Canadien ? 65.94.199.239 (talk) 23:09, 16 November 2021 (UTC)

Greenland

Two related issues. 1. Precambrian Shield redirects here, but strangely is not mentioned - yet seems to be a synonym. It, PS, seems to deserve an "also known as". 2. This article claims that most of Greenland is part of the Canadian Shield. Hmmm. The one map I found on-line (and I found only 1 with Greenland) showed only a small part of Greenland was included (western coast). Yet Greenland's geology article claims Greenland is underlain by the Precambrian Shield. This probably needs a subject expert to disentangle - or perhaps someone can find a valid authoritative reference to the nomenclature. It could be that one term is older/obsolete or it could be that various schools or disciplines prefer one or the other, IDK. Could someone straighten this out? (And also if Greenland IS part of the "Canadian Shield" then find a map showing that. ... OBVIOUSLY the article's current map is significantly flawed if that be the case. I should also mention that the Greenland wikipedia article claims that Greenland's "eastern core" is part of the Greenland Shield. So, seems likely that two different nomenclatures are in conflict.207.155.85.22 (talk) 18:28, 1 May 2022 (UTC)

Thanks for reporting this. "Precambrian shield" should not redirect to "Canadian Shield" because the Canadian Shield is only one example of Precambrian shields. I have already changed "Precambrian shield" to redirect more appropriately to the general Shield (geology) article. GeoWriter (talk) 19:57, 1 May 2022 (UTC)

Precambrian Shield is a strange thing to redirect here. Precambrian shields are present on all continents.Unless someone can point to a reliable source for this term being specifically the Canadian Shield, the redirect should probably be to Continental shield.

Greenland is part of the North American craton. This is not precisely the same as saying it is underlain by the Canadian Shield; that seems to refer to portions where the Precambrian rock is exposed as the surface which,a s you say, is only the west coast. Will look for a reliable source. Kent G. Budge (talk) 20:00, 1 May 2022 (UTC)

Redirects for "Precambrian shield" and "Precambrian Shield" going to different target articles is a problem - the difference could probably be too subtle for most readers. If "Precambrian Shield" turns out to be a synonym for the Canadian Shield (and for only that shield, which I very much doubt), then I suggest the redirect "Precambrian Shield" should be renamed to "Precambrian Shield (North America)". If it is a not an exclusive synonym, I think that "Precambrian Shield" should redirect to "Shield (geology)" i.e. redirect to the same article to which "Precambrian shield" redirects. By the way, "Continental Shield" redirects to "Shield (geology)", so perhaps "Continental Shield" should be renamed to Continental shield. Such are the joys of article name case sensitivity. GeoWriter (talk) 14:38, 2 May 2022 (UTC)

I agree with moving "Continental Shield" to "Continental shield". It's a redirect to a general topic so it's not appropriate to capitalize it like a proper noun.

I Googled around a bit, and found somewhat to my surprise (and, frankly, annoyance) that there are a fair number of scholarly articles that use "Precambrian Shield", without other qualifiers, in their titles and which are specific to the Canadian Precambrian Shield. I would favor "Precambrian Shield (North America)" since anyone entering "Precambrian Shield" will see it pop up as a completion and its scope will be immediately obvious.

But, yeah, article name case sensitivity ... Kent G. Budge (talk) 15:24, 2 May 2022 (UTC)

Grading Rocks

The intro describes the shield as containing "high-grade metamorphic rocks". What does it even mean to grade a rock? Are rocks graded on a curve? 8-) — Preceding unsigned comment added by 2601:1C0:5E81:31B0:A2E1:1881:ED40:2B38 (talk) 16:30, 14 January 2023 (UTC)

I've added a link. --Fama Clamosa (talk) 17:13, 14 January 2023 (UTC)

Davis and James

The first sentence after the lede includes, ...four smaller physiographic provinces: the Laurentian Upland, Kazan Region, Davis and James. The Davis and James... what? Are the uplands, lowlands, regions, fields...? It seems unlikely that geologists just say, "Davis has a lot of tonalite," or, "James is rather flat" (well, unless a colleague named Jim is a boor at parties). I can't seem to find a reference due to signal-to-noise when including either term, since there are a lot of papers by people with one name or the other. Cheers, Last1in (talk) 12:17, 10 July 2024 (UTC)