Talk:Cretaceous/Archive 1

Archive 1

No Middle Cretaceous?

There are also the Middle Jurassic and Middle Triassic, so why no Middle Cretaceous? Jerkov 12:12, 13 July 2006 (UTC)

Basically, it just worked out that way. I think (not sure) that the stage subdivisions for the Cretaceous were worked out relatively early and accurately, especially in Europe; it is common in Europe to see reference almost exclusively to the stages such as Aptian, Campanian, etc. Americans have tended to be less familiar with those usages, though I think that is changing. In any case, as far as I know, there never was a Middle Cretaceous, so it is not a case of some later revisionists changing things. Strictly speaking, I guess one could refer to "middle Cretaceous" (not capitalized "M" because not a formal subdivision) to refer to, say, Albian and Cenomanian or the next earlier and later stages, but no one does that. Cheers --Geologyguy 13:22, 13 July 2006 (UTC)

Can we substitute for this parochial image a map of Cretaceous North America? (Wetman (talk) 00:35, 17 January 2008 (UTC))

I thought there was also some additional criteria (I think regarding herpetofauna) for dividing Cretaceous in just two parts. Not a geologist though... can anyone confirm radical changes between Albian and Cenomanian?--77.69.45.69 (talk) 23:54, 11 October 2009 (UTC)

AMK152's Geotimeboxes

AMK152 proposed in edits of 27 December 2006 a geotimebox for this article. I feel that the box information that is appropriate for the article is already contained in the footer, and that other information can be supplied where important, by links from the text. See discussion at Template talk:Geotimebox. --Bejnar 20:26, 29 December 2006 (UTC)

Demanding citations

I should like to say, before the aggressive demanding of citations gets out of hand at Wikipedia, that to require a citation for a commonplace derivation, one that is available in any dictionary, based simply on one's own ignorance and self-importance, is a discourtesy that interrupts the process of building an encyclopedia and serving Wikipedia readers. Let's nip this in the bud-- without singling out any individual. --Wetman 13:56, 24 May 2007 (UTC)

With respect, material was removed from Cretaceous-Tertiary extinction event by an editor citing the unreferenced portion of this article. Actually, on reflection I'm not sure the issue has been addressed. Cretaceous is K. "Creta" is latin, and that is what is used in English. However, it doesn't really address the issue of whether or not K was originally chosen from the German "Kreide" which is the claim underpinning this dispute. The choice of a K has been a very long running dispute and if possible I would like to see citations for that. Dragons flight 17:58, 24 May 2007 (UTC)

Extinction of plants

In the second paragraph of the Cretaceous-Tertiary extinction event article it states that many plants became extinct, whereas in the Cretaceous#Extinction section of this article it states that "Plants were nearly unscathed". I think these entries should be made more consistent by someone with specific expertise in the field. --Ben Best (talk) 13:10, 25 November 2007 (UTC)

Wikipedia doesn't require experts, just good research. Note the K-T event article is FA status, has been reviewed numerous times, and is well referenced. Note this articles is poorly written, unreferenced (specifically the section you're mentioning), and has not reached any particular review status. I'd take the information from the K-T article, and rewrite this one. OrangeMarlin ^{Talk• Contributions} 14:14, 25 November 2007 (UTC)

@@@@@@@

Tihs might be the one i do my project on —Preceding unsigned comment added by 68.18.158.155 (talk) 20:32, 11 October 2008 (UTC)

Why the errors in the Geology section?

To see those problems on this article kind of detracts from any value this page would have. It's incomplete and therefore shouldn't really be available until those problems are sorted out. How are we to know if there aren't other flaws in the article? —Preceding unsigned comment added by Kev1980 (talk • contribs) 07:12, 21 December 2008 (UTC)

Your specific concerns are...? J. Spencer (talk) 17:10, 21 December 2008 (UTC)

Was mich stoert ist der Begriff "Years" auf deutsch Jahr

Dieser Begriff erklaert sich nur aus dem GEDANKENGUT auf der Erde. Was ist mit der Sonne und dem Mond?

Als Wissenschaftler (Physik) ist der Begriff Jahr aeusserst schwammig. Die Sonne scheint seit 4.7 Mrd Jahren auf die Erde und den Mond. Stellen sie sich die Erde mal vor wie den Mond heute, ohne Atmosphaere, Biosphaere, Lebewesen (Menschen Tiere), ohne Wasser Salzwasser Suesswasser. Dann haben sie zwei gleiche Planeten Kometen Meteoriten die im Tandem um die Sonne sich bewegen. Vielleicht sind sie auch in der einen oder anderen Weise aus dem Inneren aktiv.

• Spiegel 12 2009 Isle of Wight
• http://www.focus.de/wissen/wissenschaft/odenwalds_universum/frage-von-roswitha-kordt-welches-ende-wird-der-erde-beschieden-sein_aid_383263.html

Rechen sie mal, was ein Sonnenjahr Erdenjahr Mondjahr bedeutet. Da gibt es 2 Planeten, die drehen sich um die Sonne und die Erde dreht sich um sich selbst. Es wird noch veruekter, die ganze Astronomie Geologie ist auf diese physikalischen Groesse aufgebaut. Nun ist aber sichtbar, dass sich die Erde in einem Jahr sich 365/366 mal insgesamt 8760 Stunden aus dem Sonnenlicht und der daraus resultierenden Sonnenscheinflaeche dreht in 24 Stunden. Noch verrueckter wird es, wenn sichbar man die Minutenveraenderung der 180 taegigen WINTERZEIT und SOMMERZEIT beachtet. Das bedeutet, dass es erst alle 1 bis 2 Minuten pro Tag frueher hell und nach 180 Tagen verhaelt es sich genau umgedreht, dann wird es jeden Tag 1 bis 2 Minuten fueher dunkel. Das muss man sich vorstellen, wie eine Schraube mit einem 180igem Gewinde.

Sicher gibt es wissenschaftlich die C14 Jahranlyse so 6000 Jahre.

Aber was ist unter diesen Bedingungen mit Millionen und Milliarden Jahren? Wenn es nicht wissenschaftlicher Standard des 20 Jahrhunderts waere, wuerde jeder, der solche Jahreszahlen in die Welt setzt, als wissenschaftlicher Vollidiot bezeichnet.

78.151.242.80 (talk) 13:03, 28 March 2009 (UTC)

Sorry, but the German Wikipedia is thataway. J. Spencer (talk) 14:13, 28 March 2009 (UTC)

And it seems to be mainly about the changes in the length of the day through geological time, I can't see anything in here that relates to the Cretaceous at all (but then my German is pretty poor). Mikenorton (talk) 14:25, 28 March 2009 (UTC)

I understand German. This IP-user is probably a bit confused. He doesn't understand the use of "years" or "million/billions of years" in geochronology (calls anyone using those units a "Vollidiot" - a total idiot) and argues that "year" is not a sound physical unit for time since the length of a year differs on every planet, and even on Earth the length of a day was different in the past. The link he gave is an article about the end of the Solar System and friction slowing down the Earth's rotation when it is swallowed by the heliosphere.

What he doesn't understand is that with a "year", in geochronology a certain constant amount of seconds, the SI unit for time, is meant, equal to the average amount of seconds it currently takes the Earth to rotate around the Sun. Which makes the "year" of geochronology an exact unit. Woodwalker (talk) 15:39, 28 March 2009 (UTC)

Related article

There is a related article Cretaceous Thermal Maximum which doesn't seem to be linked from here. I don't know how valid it is; I only mention it because I left a talk message concerning the error messages that it shows. --Redrose64 (talk) 17:19, 26 January 2010 (UTC)

"Ma"?

This article says:

from circa 145.5 ± 4 to 65.5 ± 0.3 million years ago (Ma).

I had no idea what "Ma" means, so I entered it in the search box. Ma is a disambiguation page saying it's a Chinese surname and stands for "master of arts" and "mechanical advantage" and "medical assistant" and "Martin's axiom" and "Massachusetts" and lots of other things. Not one of them sheds the least bit of light on this. Someone is trying to be cryptic. Michael Hardy (talk) 12:50, 29 April 2010 (UTC)

...so I click on geologic timescale, thinking that may shed some light. Near the bottom of a long long article, I find this

may have evolved on earth around 4000 Ma during this era

and "Ma" is a clickable link. So that should explain it. So I click on it and I find the article titled year.

[sarcasm] Great. [end of sarcasm]

Could it be that somewhere in the article titled year that strange glyph is explained? I go to the edit menu and click on "find", and enter "ma".

marked

marked

climatic

markers

approximation

Martian

Mars

anomalistic

Summary

information

Germanic

.... March, estimated, many, main, normally, lots of others ........

...and finally:

The SI multiplier prefixes may be applied to it to form ka (kiloannum), Ma (megaannum) etc.

Now let's remember what the article said:

from circa 145.5 ± 4 to 65.5 ± 0.3 million years ago (Ma).

[sarcasm] Great. [end of sarcasm]

It appears to say that it's 65.5 million years ago on the "Ma" scale or something like that, and when the geologic timescale article says "4406±8 Ma", it doesn't say "4406±8 million Ma", nor should it say that. But this article includes the words "million" and "Ma" in the same breath. One wild guess is that someone intended "million years ago (Ma)" to be understood as meaning "Ma" means a million years. That might have a little bit of merit if it had said "million years (Ma) ago". That's only a wild guess. It is very generous of me to think whoever wrote this was that deranged and no more.

As I said, someone wants to be cryptic. Michael Hardy (talk) 13:23, 29 April 2010 (UTC)

Ma, or Megaannum is a common way of saying millions of years ago. Abyssal (talk) 14:02, 29 April 2010 (UTC)

....which makes the particular way it occurs in this article inappropriate because it is, among other things, cryptic. Michael Hardy (talk) 23:04, 29 April 2010 (UTC)

For crying out loud! It means millions of years! Doesn't anyone read the "year" article! — Preceding unsigned comment added by 24.36.148.242 (talk) 06:49, 26 August 2011 (UTC)

I don't have or want a wikipedia account, so this will be an unsigned post. I don't know wikipedia's official policy. But I have seen this kind of thing a lot, and I am just going to leave an opinion here on how to handle it. I think when users go through the trouble of posting about confusion they had while reading, it is actually meant to be as feedback to help others improve the article, if possible. It's not a cry for help to clear up the confusion that they had initially, nor is it intended to provoke a blame game war. I wish more wikipedeans would see that these things are feedback and consider them on that basis. The question is never "would I have been confused by this?" It is always "Is there a way this article can be made more clear to _everyone_ reading?" To my mind, it's highly doubtful that the users are lying about their initial confusion, and each one who posts is statistically likely to represent some contingent of the readership. Unfortunately, the user's frustration can sometimes come through, in this kind of feedback, in unproductive ways. I think we all just have to try our best to see the value in each other's contribution. These people are usually trying to learn something and are frustrated. So the way I see it, more points for compassion in this instance than for expertise. My 2 cents. — Preceding unsigned comment added by 97.68.160.138 (talk) 14:44, 9 March 2018 (UTC)

Vandalism Detected

Vandalism detected in "Extinction" section. I'm not expert enough to correct this. Help, please? —Preceding unsigned comment added by DMGualtieri (talk • contribs) 02:50, 1 June 2010 (UTC)

Actually, there was one missed edit, but it should all be gone now if you reload your page or purge the cache. J. Spencer (talk) 03:34, 1 June 2010 (UTC)

Tylosaurus largest known Mosasaurus?

There is a section in the article with these exact words. It could be confusing to folks who aren't major dino-nerds. What I expect they mean is that Tylosaurus is the largest known mosasaur. It can't be two genera at once. Someone please fix this! — Preceding unsigned comment added by 24.36.148.242 (talk) 06:43, 26 August 2011 (UTC)

Largest mosasaur found in North America. Mosasaurus itself is larger, and a European genus. 98.67.1.188 (talk) 01:45, 29 October 2015 (UTC)

{{Period end error}}

The lead has given the end of the Cretaceous as "66 ± 0.3 million years (Ma) ago". The GSSP table of the International Commission on Stratigraphy, which I think is the official body deciding such matters, gives 66.0 with no ±, though it does give a range for other boundaries. How to correct the lead? The wikitext uses {{period end error}}, so Template:Period end error/doc should tell me how to edit this, but the so-called documentation refers me to Template:Period start error/doc, which tells me nothing at all. For want of a better approach, I am deleting {{period end error|Cretaceous}}. Is there a better way? Peter Brown (talk) 15:50, 26 March 2013 (UTC)

Perhaps {{period end error}} is not the problem. {{ma|Paleocene|error=show}} yields 66 million years ago. This does not accord with the GSSP table. In any case, I have no idea how to address the matter. Peter Brown (talk) 20:40, 26 March 2013 (UTC)

Oxygen levels

I think we should change the citation for this value in this article and in that of the Jurassic and Triassic. It seems that the graph sourced is based on old knowledge, according to Sander et al. 2011. Biology of the sauropod dinosaurs: the evolution of gigantism. The current understanding is that the oxygen levels were either significantly lower in the Jurassic and Cretaceous than today, citing 5 papers (Gans et al., 1999; Dudley, 1998; Berner, 2006; Berner et al., 2007; Ward, 2006) or at about the same level, citing 2 papers (Bergman, Lenton & Watson, 2004; Belcher & McElwain, 2008).

This figure from the paper shows the levels in line with current understanding. Mike.BRZ (talk) 05:43, 12 July 2013 (UTC)

Opening is quite unclear for a new reader.

I've been spending a few minutes of quality time each day with a secondhand textbook on Earth's geology and life. Having been through it a couple times, I thought Wikipedia might have more up-to-date information, more clearly stated. Instead, I found the opposite in the opening paragraphs. For a new reader the second and third sentences are more like the Guinness Book of Records than any useful or comprehensible information: "In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the Cenozoic era. It is the last period of the Mesozoic Era, and, spanning 79 million years, the longest period of the Phanerozoic Eon." This sentence is unclear "These oceans and seas were populated with now extinct marine reptiles, ammonites and rudists, while dinosaurs continued to dominate on land." With knowledge from my textbook, I see what is being said is that the dominant groups of this period, the marine reptiles, ammonites, rudists, and dinosaurs all went completely extinct, while other existing groups, which Wikipedia doesn't mention in the opening, squeaked through. For someone who doesn't already know this, the statement is unclear. Leptus Froggi (talk) 12:28, 17 February 2014 (UTC)

Large vs. narrow

The caption to section Cretaceous#Terrestrial_fauna pictures says:

The mammal Eomaia, with a large pelvic opening, could give birth to well-developed offspring.

But in article Eomaia it says:

Eomaia, like other early mammals and living marsupials, had a narrow pelvic outlet suggesting small undeveloped neonates requiring extensive nurturing.

Can someone figure out what was intended as a caption, or perhaps which other early mammal was intended as the example? Shenme (talk) 22:39, 20 August 2015 (UTC)

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Cool or warm tropics?

The link given in the climate section "see also" describes how a gentle temperature gradient would result in cooler tropical temperature despite warmer average temperature, and the final paragraph of the Climate section starts off with this. However, it then proceeds to describe how the tropics were significantly hotter than today's tropics. Either the tropics were warmer or cooler than today's tropics. Can't have it both ways at the same time. Ingebot (talk) 07:54, 9 June 2016 (UTC)

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66 million years ago

The Cretaceous Period ends in 65.5 million years ago, why ending 66 million years ago. Nicholasstaffiere (talk) 4:33, 25 November 2016 (UTC)

New data and recallibrations show that the Cretaceous Period ended 66 million years ago, not 65.5 million years ago.--Mr Fink (talk) 21:55, 25 November 2016 (UTC)

Dinosaur documentarys like Walking with Dinosaurs and Dinosaur Revolution, and the Pixar film The Good Dinosaur never lies. Nicholasstaffiere (talk) 6:49, 1 December 2016 (UTC)

Wow, in relation to the above (ridiculous) comment, I have to point out that the wording in this section is confusing: "These oceans and seas were populated with now-extinct marine reptiles, ammonites and rudists, while dinosaurs continued to dominate on land. During this time, new groups of mammals and birds, as well as flowering plants, appeared." This seems to say that dinosaurs and mammals were existing together on the planet -- I am pretty sure this is incorrect. Can an expert in the field clarify and reword? Thanks! 148.177.1.217 (talk) —Preceding undated comment added 16:43, 13 February 2017 (UTC)

Um, you are aware that the earliest mammals were contemporaries of the earliest dinosaurs during the Triassic Period, right?--Mr Fink (talk) 18:11, 13 February 2017 (UTC)

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