Talk:Pleistocene/Archive 1

Is it over?

General forum discussion about if/when it ended. No sources listed. Click show to read anyway

Why and how has the Pleistocene been determined to have ended? Is 12,000 years still too early to hit the coolest climate level? —Preceding unsigned comment added by 70.24.102.240 (talk) 18:49, 6 August 2009 (UTC) It isn't over. If it was, that would be the shortest known ice age by more than an order of magnitude. It's not at all clear that such a short ice age would even be possible. The Holocene is not all that much different from the Eocene which was the last interglacial warm period. 65.68.190.20 (talk) 10:14, 21 July 2017 (UTC) The Pleistocene ended 11,700 years before present. This was formally/officially determined by geologists who specialise in the study of the stratigraphy of the Pleistocene. The Pleistocene is only informally/unofficially/colloquially equated to "The Ice Age". GeoWriter (talk) 10:38, 21 July 2017 (UTC) I think there's a decent case to be made that the Pleistocene isn't over given the fact that we are likely in an interglacial period right now that will be followed by another glacial period, similar to interglacial and glacial periods in the Pleistocene. I don't think this should influence the content of the article, because the idea that we are no longer in the Pleistocene is the current consensus. But I think it's worth stating that marking a boundary between the Pleistocene and Holocene isn't the only reasonable interpretation of the changes in Earth's climate since the last glacial period. The article on the Holocene does state this, so I think there's a precedent for including such a statement in this article. I don't think this edit would make the article more "true", but I think it would make the point of view more neutral. Cretaceousa (talk) 16:43, 28 August 2019 (UTC) Please see WP:Original research NewsAndEventsGuy (talk) 19:42, 28 August 2019 (UTC)

Dates

The arithmetic for the length of the Pliocene in previous paragraph doesn't seem quite right. I think a 2000 year correction to the end of the period has morphed into a 200,000 year shift in the beginning, but maybe I'm missing something. ... And Radiocarbon dating in only good for about 100,000 years? Won't cover the whole Pleistocene, right? So 11,000 is a radiocarbon date, but 1.6 or 1.8 million isn't? Right? Butks I try not to rewrite things that might be correct. Is a clarification or correction needed?

The current versions of the dates are mine: but this was my "best guess" after examining several web sites, which were unclear and/or disagreed with each other. What you write about limits on radiocarbon dating had puzzled me at the time, I'd guessed some other kind radiometric dating was indended for the earlier dates, but then the 10% or so radiocarbon calibration is irrelevant. However I've seen the 1.6 million vs 1.8 million elsewhere. Please clarify and correct if you know any better, ideally with an authoritive reference if such a thing exists -- Hagedis

The start date depends on the dating of marine clays at the Global Stratotype Section and Point at Vrica in Italy. As best I can determine, the ambiguity in the date there is in fact about 200,000 years. Try a search on GSSP and Vrica. Maybe you can make more sense out of the papers on the subject than I could. They seem to me to be somewhat long on jargon and a bit short on content. DJK

If you're happy with 1.8-1.6 for the start of the Pleistocene, just delete this

I might have missed something, but the first para says the Pleistocene started 1,808,000 yrs ago, and the first section Pleistocene#Dating states 1,806,000. Isn't 1,806,000 correct?--PhilMacD (talk) 14:44, 7 April 2008 (UTC)

The date labeled for the end of the Pleistocene is simply ridiculous. We do not have accuracy to the ten-year mark. I am reminded of an anecdote concerning significant digits where a fourth-grader, being asked how old the earth is, responds: "four billion and three years," having been told the earth was four billion years old as a first-grader. It is misleading to give the impression that we have that kind of accuracy by attaching 50 years to the measurement. --Iamdalto (talk) 16:22, 4 May 2008 (UTC)

Excuse me for my poor English language. Radiocarbon only covers ages untill c. 40 Ka. Some people/institutes extend this to 50 or even 60 Ka, but this is incorrect. Even dates older than 30 Ka should not be trusted. So all dates older than c. 40 Ka are based upon quite different dating methods. The higher the age, the bigger the uncertainty. However based upon finetuning with the oxygen isotope record many ages within the Pleistocene can be at a level of 10 Ka. Some parts ages can even be certain at 1 Ka.

Apart from these dating item, the definitions of what is Pleistocene, Quaternary, Neogene etc. are incorrect on this page. The Pleistocene is part of the Quaternary, and not of the Neogene. The latter is a proposal published as the 'new' geological timescale by Gradstein et al. However as this proposal is not yet ratified by the board of IUGS, this Gradstein timescale still is a proposal and not the official geological timescale. The valid timescale is that before this and this means that the Neogene ends before the Quaternary, both in fact are at the same hierarchiological level. Another problem is the base of the Pleistocene and/or the Quaternary. The majority of geologists (which are in fact the Quaternary geologists!) is strongly in favor of a lower boundary at c. 2.5 Ma. This is common use in most places in the world, including England. The fact that the English wikipedia uses the Gradstein timescale instead of the last but one is a serious mistake.--Tom Meijer (talk) 11:00, 5 July 2008 (UTC)

The current (2008) GSSP date from the ICS for the beginning of the Holocene appears to be 11784 years ago. - Parsa (talk) 23:27, 5 May 2009 (UTC)

Great Basin anomaly

It is ironic that the American Southwest, now an arid-to-semiarid region, was much moister, with giant lakes, even though almost all of the rest of the unglaciated world was then much drier. Could this have been the result of the topography of the region, with the deep, large valleys becoming their own hydrological systems?

Here's what I figure happened: the high peaks got snow during the winter and it of course melted during the summer, but the meltwater filled the lower levels of the basins as lakes. Cooler temperatures reduced the evaporation, but such little water that evaporated from the lakes tended to remain within the valley, being deposited on the upper walls of the valleys as rain or snow. The basins thus became closed water systems.

In any event, it is worth noting that many of the conceptions of the climatic conditions of the Pleistocene era, that climatic belts simply shifted equatorward as ice sheets advanced and advanced poleward with the retreat of the ice sheets, as might be suggested by the record in the Great Basin, were wrong. The Great Basin is a geologist's paradise because it is accessible, has generally good weather, and has little human influence in the form of farming or other settlement, so it is an easy area for geological exploration -- but it is apparently uncharacteristic of the rest of the world. --66.231.41.57 06:45, 20 November 2005 (UTC)

What if...

Ever thought about what would happen had the Pleistocene megafauna (e.g. the giant ground sloths, mammoths, and the such) never became extinct, so the next 10,000 years involved us alongside these giant animals? What could come from this alternative history?

• We would have different facts in our artiAAARRRGGGH!

(SEWilco 04:11, 7 August 2005 (UTC))

• Well, I figured that much. I was contemplating actually more realistic impacts, like on human societies and the such.

The impact would be that it would be "totally cool". 76.64.156.168 (talk) 12:03, 27 July 2008 (UTC)

Well, we still have a fair amount of giant mammals living today, most of them live in Africa (or in the sea, but I suppose that doesn't count).

Maybe a link to proposals about bringing them (North American) back for a theorized positive effect on the environment such as importing cheatas and lions to large game reserves as well as possibly elephants. Theory goes (with my guesses) Mammoth's would have de-haired here in N.A. as well but succumbed to greater environmental pressures such as increased reliance on them for food by Humans, and the dominant role of cattle on the land and wolves/possibly the last of the big cats (Mountain Lions) as predators has made an imbalance in the environment in terms of Deer etc... —Preceding unsigned comment added by 70.24.102.240 (talk) 18:46, 6 August 2009 (UTC)

End date

"The Pleistocene has been dated in 2005 by the International Commission on Stratigraphy (a body of the International Union of Geological Sciences) from 1.806 million (±5,000 years) to 11,550 years before present, with the end date expressed in radiocarbon years. It covers most of the latest period of repeated glaciation, up to and including the Younger Dryas cold spell. The end of the Younger Dryas has been dated to about 9600 BC (11550 calendar years BP)."

Problem: 11,550 years before present in radiocarbon years does not equal 11550 calendar years BP. The correct date seems to be exactly 10,000 radiocarbon years BP or 11,430 ±130 calendar years (BP?), acc to GeoWhen[1]. Do I have this right?

You are correct. It is 10,000 radiocarbon years BP. Bejnar 20:00, 5 November 2006 (UTC)

Query: How can a 2004 publication be the reference for an event that took place in 2005?

Nurg 02:12, 5 November 2006 (UTC)

The data that the ICS confirmed is in the publication. Bejnar 20:00, 5 November 2006 (UTC)

The current (2008) GSSP date from the ICS for the end of the Pleistocene and the beginning of the Holocene appears to be 11784 years ago. - Parsa (talk) 01:42, 6 May 2009 (UTC)

Pleistocene ≠ Paleolithic

Recent additions to the bloated infobox include cultural levels presented as if they were faunal stages. Shouldn't Paleolithic human cultures be included as a subsection here instead, with a Main article... heading? --Wetman 21:59, 25 February 2007 (UTC)

I'd support that. At a minimum, the things in the infoboxes need to be made consistent with the facts as written in the corresponding articles - e.g., the Mesolithic (and both Kebaran and Natufian) is described as part of the Pleistocene but is in Holocene in the box; until I changed it just now, Paleolithic was listed in the box as Holocene, when it is actually Pleistocene and maybe partly Pliocene. Lots of inconsistencies. Cheers Geologyguy 22:12, 25 February 2007 (UTC)

Glacial Ice Picture

I was a bit unsure at first, but then I checked a recent atlas and determined that the Union of Soviet Socialist Republics did indeed dissolve in late 1991. Does anyone, parchance, have a more recent picture displaying the maximum extent of glacial ice in the north polar area during Pleistocene time? It is no big deal, but you have to admit, it's a tad absurd to continue having that picture up. Aufs klo 23:28, 16 May 2007 (UTC)

This may sound like splitting hairs, but the nomenclature is confusing enough with Eras, Periods and Epochs, in that hierarchy. Should not the Pleistocene and Holocene be consistently described as the most recent two Epochs of the Neogene Period? I have noticed sometimes a relaxed categorization such as Pleistocene Period, which I believe is incorrect. Sandy Lawrence —Preceding unsigned comment added by 71.112.53.107 (talk) 00:18, 9 February 2011 (UTC)

Incorrect stratigraphy

The Pleistocene is NOT part of the Neogene. The Pleistocene constitutes with the Holocene the Quaternary that follows the Neogene. The last publication of the Geological timescale is only a proposal and is erroneously cited by many people (as is the case on this page). This proposal is not ratified by IUGS and, therefore, not valid yet. The Geological Timescale before this proposal is still valid, so the Cenozoic Era is composed of the Paleogene, Neogene and Quaternary! --Tom Meijer (talk) 11:14, 21 February 2008 (UTC)

I am rather astonished, embarrassed, about the mistakes and incorrect information on this page. I'm not very at home in this wikipedia but in the Dutch wikipedia we should place a message in big lettering that this page contains incorrect information!!! I'm afraid this page needs to be rewritten, at least parts of it.--Tom Meijer (talk) 11:24, 21 February 2008 (UTC)

Actually, the point for the beginning of the Pleistocene, and the extent or even existence of a Quaternary Period is currently under debate. The main issue is whether the Gelasian stage is in the Pliocene or the Pleistocene. You can follow the debate at the ICS forum here. - Parsa (talk) 23:01, 5 May 2009 (UTC)

We are still in the Pleistocene!

It seems ridiculous, not to mention showing the usual civilized hubris, to create a special "geologic" age to accommodate us the civilized humans, roughly speaking. Is anyone working on fixing this embarassment? The Holocene is the latest interglacial. There will be another glacial in a few thousand years. Nothing changed 10,000 years ago. I have seen scholars tapdance around this, gradually distancing themselves from the idea, and using Holocene as the interglacial name. About time someone took this one up, no? —Preceding unsigned comment added by V.B. (talk • contribs) 16:05, 26 May 2008 (UTC)

From a non-homocentric viewpoint it may be ridiculous, but that what humans did. The Wikipedia is not prescriptive, it is descriptive of what happened. --Bejnar (talk) 02:42, 7 July 2009 (UTC)

That's why I'd argue that this article NOT including a statement that the Holocene may be a Pleistocene interglacial period, similar to the statement on the introduction of the Holocene article, is an NPOV issue. Cretaceousa (talk) 17:01, 28 August 2019 (UTC)

I was surprised by this statement in the article "... suggests that the next glacial will begin in about 3,000 years." echoed a few paragraphs above. (Somehow it's not in the original Milankovitch article.) Is this true? or should it be more like 30k years? According to the graph, interglacials seem to be about 40ka to 80ka long. We only get 15ka or 20ka this time? I'll have to get a new parka or something :-). OsamaBinLogin (talk) 10:18, 8 November 2011 (UTC)

It is not all certain that there will be another glacial cycle at the rate that carbon dioxide gases are accumulating. At current rates, the Earth is heading to mid-Cretaceous climates. a good paper about this is:

Hay, W. W., 2011, Can humans force a return to a ‘Cretaceous’ climate? (PDF version) Sedimentary Geology. v. 235, no. 1-2, pp. 5-26. Paul H. (talk) 12:50, 8 November 2011 (UTC)

Obsolete, abandoned, and discarded terminology used in tables

The tables under "Four of the better known regions with the names of the glacials" and "The interglacials corresponding to prior glacials" need to be completely revised or removed. The problem is that many of the North American stages, i.e. Nebraskan, Aftonian, Kansan, and Yarmouthian stages are no longer used. This is discussed in:

Aber, J.S., 1991, Glaciations of Kansas. Boreas. vol. 20, no. 4, pp. 297-314. - (Note this references contains an excellent summary of how and why the Nebraskan, Aftonian, Kansan, and Yarmouthian stages were abandoned.) and

Roy, M., P.U. Clark, R.W. Barendregt, J.R., Glasmann, and R.J. Enkin, 2004, Glacial stratigraphy and paleomagnetism of late Cenozoic deposits of the north-central United States, PDF version, 1.2 MB. Geological Society of America Bulletin. vol. 116, no. 1-2; pp. 30-41; DOI: 10.1130/B25325.1

Another problem is that these table falsely indicates a one to one correlation between certain stages and individual glacial or interglacial periods. It is now known, as many of these stages were defined, that they, i.e. the Beestonian, Wolstonian, consist of multiple glacial-interglacial periods. Finally, the Alpine nomenclature has been largely abandoned as being too poorly defined to be of any real use. These tables should just be removed as there no way of revising them to accurately reflect current stratigraphic usage (and in many cases non-usage) of the nomenclature present by them. Paul H. (talk) 18:16, 17 November 2008 (UTC)

I agree. These tables and the Timeline of glaciation article have errors. For instance, more recent literature uses the term "Independence glaciation" for the glacial period in northeast Kansas 600-700 kA (Aber, 1991 cited above). See this site for more. - Parsa (talk) 22:54, 5 May 2009 (UTC)

Something needs fixing here

The statement "Four major glacial events have been identified, as well as many minor intervening events. " appears to be wrong. The diagram right next to it seems to show at least seven glacial stages in the Pleistocene. Checking the link to "timeline of glaciation", also seems to claim 4 glacial events, but that is refering to 4 over the whole history of the earth ( counting the whole Pleistocene as one) and not to 4 in the Pleistocene. Some expert needs to check this. If 4 events in the Pleistocene is indeed what is intended, there needs to be some explanation of why there is clearly seven or more in the diagram.Eregli bob (talk) 14:44, 20 November 2008 (UTC)

Commas

Commas should be avoided in these dates. SI and the ISO 31-0 standard says a period (full stop) and a comma are both decimals, not separators. Use nothing, or use a thin space, but not a comma. That's why official organizations use ka and Ma.- Parsa (talk) 23:26, 5 May 2009 (UTC)

Pleistocene start date

Woodwalker jumped the gun a bit and failed to provide citation in the edit to the Pleistocene article of 13:09, 24 May 2009, Edit summary ICS voted overwelmingly in favour of the INQUA proposal, only formal rectification of the IUGS is now needed. Gelasian is now with 99% certainty part of the Pleistocene and Quaternary. The ICS has not reported the vote yet on their webpage (as of 1 July 2009), and as Woodwalker pointed out it still requires IUGS approval. See "Letter by ICS to INQUA Executive Committee" 2007 for the current actual status. A description of the problem occurs on page 8 of Oldroyd & Grapes History of Geomorphology and Quaternary Geology. Also the text as provided by Woodwalker no longer fits the citations to footnotes #1 (Gibbard, P. and van Kolfschoten, T. (2004) "The Pleistocene and Holocene Epochs" Chapter 22PDF (2.96 MiB) In Gradstein, F. M., Ogg, James G., and Smith, A. Gilbert (eds.), A Geologic Time Scale 2004 Cambridge University Press, Cambridge, ISBN 0521781426) nor footnote #2 (For the top of the series, see: Lourens, L., Hilgen, F., Shackleton, N.J., Laskar, J., Wilson, D., (2004) “The Neogene Period”. In: Gradstein, F., Ogg, J., Smith, A.G. (Eds.), A Geologic Time Scale 2004. Cambridge: Cambridge University Press.) When we get citations to reliable published sources, then we can change the article, not before. --Bejnar (talk) 17:52, 1 July 2009 (UTC)

• When we change the article to reflect the decision of the IUGS, when it is made, we should be careful to adequately cover the issue that publications before 2009 will reflect the start of the Pleistocene as 1.8 million years ago, and will place Gelasian events in the Pliocene. --Bejnar (talk) 18:06, 1 July 2009 (UTC)

CO2 chart?

I'm struggling to see the reason we have a chart of CO2 and not estimated temperature? is it only so we can point out that C02 is higher now than its has been in 650 million years? I really don't care about CO2, i was interested in Ice Ages. If the temperature can be estimated, then show that, if its there I can't see it.danielmyles1 (talk) 05:11, 20 January 2010 (UTC)

650 million years? Hardly. Back on the Jurassic CO2 levels were over five times current levels. —Preceding unsigned comment added by 201.47.52.207 (talk) 22:25, 2 March 2010 (UTC)

More about dates

I looked up the article to refresh my memory about the presently accepted timeline of the Pleistocene. The first sentence expresses start and end times in BC. Under section 1 Dating, there are dates given as before present, and radiocarbon years before present. Upon what basis is the former BP dating category based? In summary, the BC dates clearly need to be corrected but I am hesistant to just change the C to P because of the aforementioned ambiguities. Can someone with the necessary expertise fix the date error and ambiguities. 90.19.38.75 (talk) 13:38, 12 December 2010 (UTC)

Human single-origin theory still current?

In view of recent findings that all non-African Homo sapiens share some neanderthalensis DNA, is the single-origin theory still current, as represented in the article? Anyone competent to update this? Wegesrand (talk) 12:06, 3 January 2011 (UTC)

I've reworded the appropriate section to reflect current knowledge. Warren Dew (talk) 06:43, 3 September 2011 (UTC)

Image doesn't seem to belong here?

In the Fauna section is an image labeled "Pleistocene fauna of North America".

However, the image depicts Synthetoceras, Amebelodon, Teleoceras, Epigaulus and Cranioceras. This is a scene depicting Miocene fauna--and I've seen the same image or portions of the same scene identified as such in other sources.

Perhaps it was mislabeled in the book it was sourced from, or the original mural contains Pleistocene animals in a different portion? 74.243.14.32 (talk) 17:43, 4 November 2011 (UTC)

So it seems; I'll take it out. Johnbod (talk) 17:57, 4 November 2011 (UTC)

Yikes, I misread it, the book actually says Pliocene... FunkMonk (talk) 19:04, 4 November 2011 (UTC)

I changed the commons file to "Miocene" (not the category I think) & then forgot to remove it here. Can I leave that with you? Johnbod (talk) 19:08, 4 November 2011 (UTC)

Already done, heheh. FunkMonk (talk) 19:09, 4 November 2011 (UTC)

Permanent El Nino?

It is my understanding that the permanent El Nino scenario occurred up to 3Mya during the Pliocene. Federov et al. (2006) suggests that recent proxy data indicates the absence of cold surface waters off the coast of Africa and the Americas until about three million years ago. Federov reached this conclusion from examining Mg/Ca ratios between the east and west equatorial Pacific. Alongside the Mg/Ca ratios, Federov uses alkenones from the east equatorial Pacific which support the Mg/Ca ratios. Federov suggests that prior to three million years ago the oceanic heat gain at low latitudes and heat loss and high latitudes were minimal. The ocean’s thermocline was deeper than today’s due to high latitude processes. Gradual atmospheric cooling during the Cenozoic and the decrease of temperature in the deep ocean caused the gradual shoaling of the thermocline. Federov suggests that this gradual shoaling reached a point, 3 Mya, where the thermocline was shallow enough for the winds to initiate the upwelling of the cooler deep waters.

Fedorov A.V.,P.S. Dekens,M. McCarthy,A.C. Ravelo,P.B. deMenocal,M. Barreiro,R.C. Pacanowski,S.G. Philander, (2006),The Pliocene Paradox(Mechanisms for a Permanent El Nino), Science,Vol:312. — Preceding unsigned comment added by Coriolisat25N (talk • contribs) 18:38, 18 December 2011 (UTC)