Talk:Lake Agassiz

Lake size

bigger than all of the present-day Great Lakes combined

Wasn't it actually bigger than all modern lakes combined? I think I heard this somewhere, but don't have a source. —Michael Z.

The numbers don't add up

The article says the lake formed around 11,700 years ago & then drained about 11,000BC, which would be 13,000 years ago. I'm sure this is a typo on someone's part.

Rob 9 July 2005 00:23 (UTC)

-- Updated using info from the first external reference --

That struck me too, and the Science News paper quotes 13000 years ago as formation date.

Akhen3sir 16:41, 29 January 2006 (UTC)

Just FYI, the remaining lakes are not "relic" lakes but are RELICT lakes. A relic is a piece of broken pottery or the Holy Grail; a relict is something left over from a previous time. — Preceding unsigned comment added by 68.190.254.86 (talk) 18:44, 5 April 2014 (UTC)

Differences in dates

The article as now written (8 May 2007) uses dates apparently derived from an abstract of a piece by S. Perkins, which is now listed in the web sources as Lake Agassiz Overview. Being just an abstract, it does not have footnotes or cites. (Presumably the full article does). Those dates differ from the paper by Fisher listed under the printed media sources (but also available online) as River Warren boulders. The Fisher piece is richly sourced and may represent more recent research.

It may be appropriate to change the dates to conform with the Fisher article, give date ranges, or explain the matter in footnotes. I am inclined to do the former but wanted to raise it here first. Kablammo 20:20, 8 May 2007 (UTC)

Do employ your access to the most recent scholarly publications to improve the article in every way. --Wetman 22:22, 8 May 2007 (UTC)

Names

Might "Glacial Lake Agassiz" be a better name? -Ravedave 02:28, 16 August 2007 (UTC)

Google finds 124,000 hits for "Lake Agassiz" but only 41,700 hits for "Glacial Lake Agassiz", and most of those don't use the word "glacial" as part of its proper name. "Lake Agassiz" appears to be the most common name for the lake, so we should stick with it. Foobaz·o< 07:20, 16 August 2007 (UTC)

The existence of a named Wikipedia article itself greatly increases the mention of that name, so the "Google test" here means little. And every article which prefers Glacial Lake Agassiz will also yield a Google return for Lake Agassiz. Having said that, it does not much matter which form of the name is used here, as there are redirects, and there is no modern Lake Agassiz. Both Lake Agassiz and Glacial Lake Agassiz are in common and proper usage to refer to this glacial lake. Kablammo 13:41, 16 August 2007 (UTC)

New research

Whoever wants to incorporate that new piece of research into the article, which doubts that Lake Agassiz played any key role in the 8.2k event: http://sciencenow.sciencemag.org/cgi/content/full/2007/816/3?etoc Nils Simon 08:21, 19 August 2007 (UTC)

Map

A current map is needed. There are a number of maps available on the internet, but do not have a waiver of copyright. The present map is from 1895, and while it is consistent with modern maps of Agassiz' extent in the United States, does not show the full extent of the lake's various stages in Canada. Canadian maps are subject to Crown copyright; unlike works of employees or agencies of the United States, copyright is retained by the Candian federal government (and works of the provinces are also copyrighted). Has anyone found a free version of a more recent map? Kablammo 20:02, 23 August 2007 (UTC)

• Better map needed :) The current one, according to the description, is 'inaccurate'. Could we not have a correct one(s) showing the lake's boundaries as it changed? Malick78 (talk) 14:11, 15 November 2009 (UTC)

Carbon 14 years different than real years?

In a few places the article cites two different numbers of years before present -- one in "years" and the other in "carbon 14 years". I'm not aware of there being a standard "carbon 14 year" that's any different than a real one... just that there's often uncertainty associated with carbon dating. How do we reconcile these different numbers and use a different description than "carbon 14 years"? Jerde (talk) 13:56, 25 April 2008 (UTC)

It's not really just an uncertainty but actually a systematic difference – radiocarbon years (which is probably a better term than "carbon 14 years") assume the athmosphere C-14 level to be constant, whereas solar years, of course, do not. See Radiocarbon dating. -- Jao (talk) 14:53, 25 April 2008 (UTC)

See also Before Present - which indicates that "before present" means before 1950. This (usually, if not always, I think) applies to carbon 14 dates. Cheers Geologyguy (talk) 14:57, 25 April 2008 (UTC)

To the causal reader, the text implies that there is a set ratio between carbon-14 years and calendar years, which is not the case. Since carbon-14 years are simply a precalibration artifact, they should be left out of the article. Neitherday (talk) 20:47, 4 October 2008 (UTC)

The numbers still ain't no adding up

The article says, the lake formed about 13,000 cal. years BP, ok. Then later it says the lake drained 11,000 BC, which, of course, is about 13,000 years BP. Could be a simple typo (perhaps BP was meant) but how do you know? No exact reference is given for that date. --Jmk (talk) 08:06, 26 September 2009 (UTC)

Agassiz drained through the St. Lawrence just as Superior does today, but that does mean either was emptied by that outflow. The meltwater formed the lake, which at various times drained northwest, south, east, and finally north. Here the word "drained" does not mean "emptied", but it may be ambiguous. Kablammo (talk) 22:04, 26 September 2009 (UTC)

I see. Are you saying, then, that the 11,000 BC is correct? It looks very suspicious when it given as "BC", while all others are "BP". To avoid further confusion, perhaps someone can check it, fix it to BP scale like all the other dates, and provide a citation. --Jmk (talk) 12:04, 27 September 2009 (UTC)

I don't know if it is correct, and have no problem with the request for a cite. The timing of some of the events, especially the outburst floods and their relationship to climate changes, seems to be a matter of some disagreement, or at least differences. And consistency in date rendering would be a good idea. This article needs an editor, or group, who are willing to expand and improve it, rather than dabbling around the edges (as I and others have done). Kablammo (talk) 12:27, 27 September 2009 (UTC)

All right, we'll have to make do with the "citation needed" until someone checks it. I'm afraid I won't be of any help here, having virtually zero knowledge on glacial lakes. I just came here to verify the claim when somebody wrote in fi:Agassiz-jääjärvi that Lake Agassiz emptied 11000 years ago, citing "en-wiki says so". --Jmk (talk) 17:04, 27 September 2009 (UTC)

"...held more water than contained by all lakes in the world today"?

The article currently says: "...its area was larger than all of the modern Great Lakes combined, and it held more water than contained by all lakes in the world today." Okay -- the lake's surface area could be larger than all the modern Great Lakes... But The remaining rumps of the lake are very shallow. How much higher was the shoreline pre-drainage? If I am not mistaken Lake Baikal is so deep its volume is greater than all the modern great lakes. It seems to me that for this assertion to be correct Lake Agassiz would have to be not just larger than the modern Great Lakes, but many times deeper than current Lake Winnipeg and friends.

Okay, the article references a Canwest article for this assertion:

• "Noah's Ark flood spurred European farming". Canwest. 2007-11-19. Retrieved 2009-10-20.

I just checked that first reference. It contained many assertions wildly at odds with our article. It asserts that Lake Azassiz was "...larger than the combined areas of Saskatchewan and Manitoba."

Well, that is not what our map says. Geo Swan (talk) 00:57, 21 October 2009 (UTC)

The article says that at its large extent Lake Agassiz's area was 440,000 km^2. But Saskatchewan's area is 651,900 km^2, and Manitoba's area is 649,950 km^2. So the assertion it was larger than the two provinces combined is clearly incorrect... Geo Swan (talk) 01:14, 21 October 2009 (UTC)

Some thoughts:

• I agree that the Canwest article is not a reliable source for a science article. It would be best to obtain the underlying article.
• The relatively shallow depth of Agassiz' remnants are not indicators of its depth or volume ten millenia ago. Some of the sources listed sources contain more information.
• The map in the article, now well over a century old, is inadequate, as discussed above. But most maps show the lands covered, at one time or another, by the great lake, rather than the lesser areas covered at any particular stage.

Kablammo (talk) 21:49, 22 October 2009 (UTC)

Yup, the map is really old and seriously inadequate. As for the "more water than" statement, at the very least it should be emended to "all the freshwater lakes" - there is absolutely no way Lake Agassiz could have come close to the water volume of the Caspian alone, which is saltwater and much deeper. Even that way it's still a doubtful assessment, but at least not wildly impossible. 83.254.154.164 (talk) 18:13, 2 October 2014 (UTC)

Sea level rise

A back of the envelope calculation doesn't match up with the stated sea level rises resulting from its draining. If the area given is correct, it would require an average depth of about 800m to produce a 1m rise. This page says that most of the lake was under 200m deep, and also gives volume measurements far under that needed for a 1m sea level rise. Lavateraguy (talk) 16:22, 6 August 2010 (UTC)

Yes, I also cannot understand this. Fangorn-Y (talk) 19:28, 25 September 2012 (UTC)

This article confirms a 0.8-2.2 m rise in worldwide ocean depth resulting from the draining of Lake Agassiz. This is a peer-reviewed article published in a high impact journal. I don't know what else you could expect in terms of quality. SkepticalRaptor (talk) 19:35, 25 September 2012 (UTC)

The article documents a 0.8-2.2 m rise in sea level, but it does not claim the draining of Lake Agassiz was the only cause. It says the events are associated. Agassiz was a glacial lake, so it would have drained when the glaciers to its north melted. It sounds to me like the majority of the water came from the glaciers with a substantial minority coming from the lake. Foobaz·o< 09:49, 28 September 2012 (UTC)

The paper says, "The total inferred eustatic sea-level rise associated with the very final stage of LAO drainage at 8.2 ka ranges from 0.8 to 2.2 m, considerably higher than previous estimates." I don't know, but that sounds like they are associating it with the LAO drainage. Unless you're saying it was just correlated with the time period of the LAO drainage, which isn't very clear from the author's writing, which would be original research on our part. SkepticalRaptor (talk) 15:11, 28 September 2012 (UTC)

Unless I read it incorrectly, the paper acknowledges that the Antarctic and Laurentide ice sheets could have contributed, and calls for more research. Perhaps we should change "This final drainage of Lake Agassiz contributed an estimated 0.8 to 2.8 m (2.6 to 9.2 ft) to total post-glacial global sea level rise" to "This final drainage of Lake Agassiz is associated with an estimated 0.8 to 2.8 m (2.6 to 9.2 ft) rise in global sea levels." Kablammo (talk) 16:38, 28 September 2012 (UTC)

I'm fine with that. SkepticalRaptor (talk) 17:26, 28 September 2012 (UTC)

Move

An editor moved this page to "Glacial Lake Agassiz" on the strength of the title of Upham's work. While the move was in good faith, I have reversed it, as such a move should first be discussed here. There is a previous section further up on the name issue, and it appears that at least one other editor likes the shorter name.

A review of the sources used for the article shows that "Lake Agassiz" is the more common name. Even Upham's work used "Lake Agassiz" in the text. The title information for the monograph, where not all in caps, captitalizes it as "The glacial lake Agassiz", which shows that "glacial" is being used as a modifier and not a formal title.

In any event "Lake Agassiz" seems to be the more common name, and has the added virtue of being shorter. Kablammo (talk) 16:38, 28 December 2010 (UTC)

Effects on early human civilization

There seems to be a difference of opinion as to whether or not the article should link to Pre-Columbian era when discussing the lasting effects the draining of the lake may have had. Since the article makes references to effects beyond the Americas, I believe that narrowing the scope of "civilization" in this manner would be imprecise. Regards, Orange Suede Sofa (talk) 23:44, 28 May 2011 (UTC)

BP vice BC or BCE

By this edit the dates were changed from BP to BC, and a request was made to discuss here before reverting. The edits text was changed back to the prior compututation without such discussion,[1] an action I agree with. The source use "Before Present" or an equivalent. It is not for us to change what the sources say. Kablammo (talk) 02:08, 11 June 2012 (UTC)

I think that the current page, not using BCE or BP is a sufficient compromise. Thanks Kablammo. Ph8l (talk) 13:06, 11 June 2012 (UTC)

Yes, I see that some of the online source use "ago" or something similar, which the present language follows. I have a couple of the print sources which I will check also. Kablammo (talk) 13:35, 11 June 2012 (UTC)

That sounds great. I agree that we shouldn't "change what the sources say," but I think it's important to communicate their content in a readily accessible way. As it was written, it would have necessitated clicking on the BP hyperlink for most readers to get a full understanding. Once again, nice work. Ph8l (talk) 03:45, 12 June 2012 (UTC)

Actually SkepticalRaptor did the work, but thanks to your interest his work now follows the sources more exactly. Regards, Kablammo (talk) 18:30, 12 June 2012 (UTC)

Actually there is a problem, radiocarbon dates (and other such dates) are all somewhat uncertain. Radiocarbon dates generally BP (meaning before 1950) and needs correction for uneven C14 generation. The corrections are varying because they get better and better data, the better data make it problematic to set a correct date since in a few cases you have a choice of two dates with an impossible period in between (possibly caused by release of fossil carbon due to natural gas leaks or decomposition of peat) which is making for some disorientation! I go for sticking to the published dates OR a complete recomputation of all dates which would be a major project! (Needed but we will have to wait until better data on historical C14 levels (and modify for different absorbtion of C12 and C14!).)Seniorsag (talk) 15:24, 10 August 2015 (UTC)

Location overview

Could an overview map including the coasts of North America be placed showing where it was and how it flowed out? This is largely described with the names of states, but that doesn't help if one doesn't know where those are. DirkvdM (talk) 05:56, 15 June 2018 (UTC)

location issue

This article says that this lake existed in "Manitoba, Ontario, and Saskatchewan in Canada; Minnesota and North Dakota in the U.S." none of which existed at the same time as the lake. can this be corrected? Kikila mai Tawhiti (talk) 19:59, 15 June 2024 (UTC)

maybe replace it with the traditional territories of the Indigenous folx who lived there until white settlers came and genocided them? might be more appropriate. Kikila mai Tawhiti (talk) 20:00, 15 June 2024 (UTC)

I disagree. The sources don't do that. Masterhatch (talk) 20:47, 15 June 2024 (UTC)

The text says that the ice sheet was located in central North America, and when it melted the "lake came to cover much of what are now southeastern Manitoba, northwestern Ontario, northern Minnesota, eastern North Dakota, and Saskatchewan". It does not state that that those provinces and states existed during the ice ages. Kablammo (talk) 01:21, 16 June 2024 (UTC)