Talk:Quaternary glaciation

Start

Hi. I want to make an article specifically about the Pleistocene glaciation. Then, I hope it can be summarized in the article about the Pleistocene epoch. ~ UBeR 16:40, 13 August 2007 (UTC)

Could please a real expert solve the contradictory times for the beginning of the pleistocene here versus that in the other special articles?? HJJHolm (talk) 10:07, 12 February 2009 (UTC) —Preceding unsigned comment added by HJJHolm (talk • contribs)

Doesn't take an expert. The Pleistocene period doesn't cover the Holocene period which is the interglacial that we are now in. --24.24.135.203 (talk) 21:37, 5 March 2012 (UTC)

Billions of Years

Don't you mean million, not billion? Vegasprof 00:49, 6 September 2007 (UTC)

Yes. Thank you. Feel free to change or delete anything you think is wrong. I hope to continue writing and expanding when I can, and eventually get it all referenced. ~ UBeR 23:52, 10 September 2007 (UTC)

Comments

Although the intro briefly mentions that there have been more than one cycle, the impression given overall is that there was one glaciation (These ice sheets started to disappear only between 15,000 and 20,000 years ago... suggests that they haven't disappeared before). One of the ice core, or ocean sediment pics, would help explain the cycles. As would mentioning that they have a 40k/100k cycle. The text at present reads strongly from a geologists perspective.

Also, we're still in the ice age - current ice is roughly at the same state as the last interglacial. So speaking of the ice age in the past tense is odd.

During the the glaciation, which began between two and three million years ago, the normal hydrologic system was completely interrupted... again makes it sound like one event. There was presumably no disruption during the various interglacials.

William M. Connolley 09:30, 11 September 2007 (UTC)

Sorry, I missed this comment in my watchlist. I can't help but to agree: we're still in an ice age, currently in an interglacial, which still has remnants of the massive ice sheets. Colloquially, however, most people will refer to the ice age as the last glacial. I would favor using language that implies we're still in a period of ice cover, i.e. still in an ice age. There might be a technical problem in that the Holocene began with the current interglacial, whilst this article specifically discusses the Pleistocene extent of the ice age. I'm not sure that this distinction is important though.

Any ambiguity should be fixed, of course. I think the sentence "Extensive evidence now shows that a number of periods of growth and retreat of continental glaciers occurred during the ice age" shows that there have been multiple glacials and interglacials within the Pleistocene ice age. If you know of any pictures that are currently on Wikipedia or could be uploaded on to Wikipedia, it would be great to include them. I think a big problem for encyclopedias is to clearly explain ideas and information to the general reader so that they get a clear image and understanding of the topic and general ideas surrounding the topic. Any help in this regard would be greatly appreciated. (Edit: see also User:UBeR/glaciation.)

Of course, it would also be great to broaden this article, including climatological and biological aspects of the glaciation, as well as giving historical perspective. The NA should be cut, for a separate article. (See below thread.) ~ UBeR (talk) 09:41, 12 December 2007 (UTC)

There is a big problem, because since the article talks about the P glaciation, its forced to start the P glac *was* and this is very confusing. The problem is that ehe Holocene is nothing special and shouldn't really exist; We're still in the P, really. Really the article should say the P glac *is*, and a bit lower down perhaps explain that the P is formally over. The P article itself pretty well admits that the "official" P timeperiod starts at the wrong time William M. Connolley (talk) 21:31, 14 December 2007 (UTC)

Alternatively, we could use Quaternary glaciation instead. What do you think? ~ UBeR (talk) 23:08, 14 December 2007 (UTC)

That would be an excellent idea, and appears to solve both problems William M. Connolley (talk) 21:58, 15 December 2007 (UTC)

A minor problem is that QG gets 9k google hits vs 23k for PG. But I can live with that easily William M. Connolley (talk) 22:01, 15 December 2007 (UTC)

Indeed. Without the quotation marks, Quaternary seems to be discussed just as much as the Pleistocene in the context of the ice age. It also seems to me that "Quaternary glaciation" is used more in contemporary sources. I don't think it shuold be a problem. ~ UBeR (talk) 00:08, 16 December 2007 (UTC)

OK, I see you've moved it: good. I've hacked the intro a bit. I *think* its important for people to realise the ice age periodicity and what everything means before talking too much about effects (this is probably a climatologist/core perspective; the geologists tend to see things a bit differently because they see geomorphology). I may have over stressed the meaning-of-ice-age but again, it can get very confusing unless we sure what we mean. I stuffed in the ice core pic; actually an ocean sediment core pic would be better, but I couldn't find one William M. Connolley (talk) 17:15, 16 December 2007 (UTC)

Yes, it looks good. I think people will get a better perspective now. I'll try to add some more stuff to the body now, other than effects. ~ UBeR (talk) 19:27, 16 December 2007 (UTC)

... 09.02.07 suspect in section 'Records of prior glaciation' the 'Phanerozoic Climate Change' chart may be in error (the X axis millions of years ago period abreviations, N, Pg, K, J, Tr, P, C, D, S, O, Cm).

Within the Phanerozoic eon the three eras Cenezoic (periods: Neogene, Paleogene) Mesozoic (periods: Cretaceous, Jurassic, Triassic) and Paleozoic (periods: Permian, Devonian, Cambrian) the period sequence thus should go N, Pa, Cr, J, T, Pe, D, Ca with each being about a 50Ma span... 0 to 542Ma. Bhug (talk) 17:21, 7 February 2009 (UTC)

Article organization

Already, the article is a getting long, and there's a lot more to be said. I don't think it should be overly-focused on the North American extent of the glaciation. For that reason, I would suggest a separate article, something like Pleistocene glaciation in North America, in which specific NA effects, perspectives, etc. could be discussed (Edit: I've removed the NA stuff). It could then be properly summarized here, per WP:SUMMARY.

A general outline that I have mind includes: (This is outdated See blow)

I. Intro
II. Historical perspective
III. Effects

A. Lakes

1. Pluvial lakes

B. Oceans

1. Sea level

C. Biological

D. Climate (or "Climatological")

E. Winds

(F. In NA)?

IV. Causes

Input and suggestions are appreciated! ~ UBeR (talk) 10:06, 12 December 2007 (UTC)

OK, this is outdated. So far, it should probably look something like this:

I. Intro

II. Causes

A. Astronomical cycles

B. Atmospheric composition

C. Plate tectonics and ocean circulation

III. Effects

A. Sea level / Oceans (not started)

B. Lakes

1. Pluvial lakes

C. Drainage systems (not started)

D. Isostatic adjustment

E. Winds

F. Flora and fauna (not started)

IV. Records of prior ice ages (or "prior glaciation")

V. The "next ice age"

VI. See also

VII. References

VIII. External links

Thoughts? ~ UBeR (talk) 01:28, 8 May 2008 (UTC)

Antarctica

The intro reads, "The Quaternary glaciation . . . refers to the period of the last few million years (2.58 Ma to present) in which a permanent ice sheet was established in Antarctica and probably Greenland . . ."

This might be somewhat confusing to the reader, however. Ice sheets on Antarctica weren't formed 3 Ma, per se (see geology of Antarctica). Glaciation there began some 20 Ma, long before the Quaternary. It simply has continued since then. I don't know whether this warrants a change in the wording for the intro. Thoughts? ~ UBeR (talk) 22:45, 7 May 2008 (UTC)

Conversely, this could be explained somewhere in the main body of the article. ~ UBeR (talk) 01:29, 8 May 2008 (UTC)

I am sorry but from what I have read on this subject the 3 million years ago there were forests on Antarctica here is a easy reference:

1. REDIRECT [[1]]
   

--OxAO (talk) 02:00, 19 May 2012 (UTC)

Vandalism

I noticed that this page was vandalized, by replacing small, subtle words in the page with ridiculous alternatives, including changing the "last 2.5 million years" to 2 days. I have undone the vandalism. Has this been a problem in the past? 67.11.3.168 (talk) 20:48, 22 July 2008 (UTC)

Southern Hemisphere Laurentide

Has evidence been found for Pleistocene glaciation on the scale of the Laurentide ice sheet in the Southern Hemisphere? I'm trying to understand why horses (Equus scotti) died out more or less simultaneously in N. America and S. America about 10,000 years ago. --Virgil H. Soule (talk) 02:16, 10 October 2009 (UTC)

It is very interesting to note that the rapid extinction of the megafauna of the Americas coincides with the arrival and spread of humans Quaternary_extinction_event#North_America at the end of the Pleistocene. — Preceding unsigned comment added by Mzzl (talk • contribs) 13:14, 2 December 2013 (UTC)

lengthening glaciations

If our glacial periods are caused by ocean access to the arctic ocean then they are caused by tectonic placement.

Our lengthening glacial periods could be caused by the solar system exiting its cool period of orbit.

Then it becomes harder and harder for the oceans to pile enough ice on land masses to lower their depth enough to halt the circulation of the arctic which causes the glacial period.

Our current increase in ocean circulation is cooling the oceans, causing desertification similar to that in glacial periods.

b. mcintyre —Preceding unsigned comment added by 24.65.176.221 (talk) 14:02, 9 December 2009 (UTC)

Fact vs. Theory

Why is this in here: Global warming has exacerbated the retreat of these glaciers ? This is a theory, not a fact... even if it is cited with a source. If this sentence is going to be in the introduction, I think it should say something like The theory of global warming has exacerbated the retreat of these glaciers. —Preceding unsigned comment added by Nvog86 (talk • contribs) 19:22, 21 December 2009 (UTC)

If it's not warmer temperature, then what is it? With regards to your last sentence, theories do not cause ice retreat. ~ UBeR (talk) 18:45, 24 June 2012 (UTC)

1. Recent studies show that albedo changes alone can increase melt. Soot from multiple sources (coal, nuclear test fallout from 900 above ground tests in the Russian north) has increased melting. 2. Mechanical action increases melt, similar to the effect of crushed ice vs cubed ice. Storms and icebreakers increase mechanical melt effect in the seas. Earthquakes and volcanic action under glaciers. 3. An increase in the transport of Arctic ice through the Fram strait into warmer waters has increased the melt rate of Arctic ice. 4. Finally the glacial detritus turnover rate lowers albedo of certain glaciers. — Preceding unsigned comment added by 192.73.31.49 (talk) 22:12, 8 August 2013 (UTC)

Ocean currents

I added the following to the "effects" section:

• Ocean currents
  • Thick glaciers were heavy enough to reach the sea bottom in several important areas, thus blocking the passage of ocean water and thereby affecting ocean currents. In addition to direct effects, this caused feedback effects as ocean currents contribute to global heat transfer.

Hey, I know it's true, and the effect is alluded to in several places in the article, but I am not an expert and I do not not have any refernces. Can an expert please refine this and add references? -Arch dude (talk) 01:22, 4 January 2013 (UTC)

Time scale

Why is there no clearly expressed time scale for this glacial period? When did it begin and when did it end? Kortoso (talk) 19:20, 4 September 2013 (UTC)

Removed graph from "Atmospheric composition" section

I removed the "Co2 glacial cycles 800k" graph from "Atmospheric composition" section because the stratigraphic terminology used in it is grossly antiquated, obsolete, and now known to be quite meaningless as I discuss in the talk section for that figure. Before it can be used, this graph needs to be revised to remove the discredited terminology and have it replaced with the correct terminology. Paul H. (talk) 15:43, 17 November 2013 (UTC)

Next glacial period

In the section about the next glacial period, very specific time frames are listed for the onset of the next glacial period: 50ka if if CO2 levels increase to 750 parts per million, 15ka if CO2 drops to 210 ppm. What are the sources for these figures? I added the citation needed tag because figures this specific are probably based on a paper, but not mentioned in the references in this section. Both figures would break the trend of the past 1 million years, and it seems to me they would cause the next glaciation to be out of sync with the Milankovic cycles, so I'm very interested in the source. Mzzl (talk) 12:08, 2 December 2013 (UTC)

General improvements

There hasn't been any changes to this article for a year and a half. I hope to make a number of changes - some may be large scale changes. If any contributors from the past have concerns let me know. Mark Buchanan (talk) 23:00, 24 July 2014 (UTC)

Maximum thickness of the ice

What is the maximum thickness of the ice sheets during the Quaternary? Regardless of extent the ice sheets never seam to have grown thicker than four kilometres (2½ miles). Anyone who can verify this?

2015-01-10 Lena Synnerholm, Märsta, Sweden.