Talk:Cretaceous–Paleogene extinction event/Archive 3

Multiple impact event paragraph
This paragraph currently only relies on sources from Leslie Mullen that are all from website http://www.astrobio.net. This is a NASA-sponsored online popular science magazine, so it sounds to me a scientific reviewed source would be required. Actually in view of the latest Science article, I wonder if we should not just delete the paragraph. --Anneyh (talk) 11:32, 7 March 2010 (UTC)


 * I think: 1. we can rely on NASA-sponsored online popular science magazines, 2. "committee science" is a grave mistake, scientific debates shall not be shushed by committee decisions, so alternate view should be kept, even though they can be downplayed if the support diminishes. Rursus dixit. ( m bork3 !) 06:14, 8 March 2010 (UTC)


 * Sorry, but we have another 'All reputable scientists agree'. So saying "The climate was prone to violent natural changes even before man came along with his CO2...look what happened to the Dinosaurs", is now heresy.  Well done, your research grants will be renewed :-) 81.157.16.194 (talk) 18:39, 8 March 2010 (UTC)
 * Er, I don't think it would be heresy to say that there were extreme environmental excursions before humans (eg the glacial/interglacial cycles [E Vrba, Palaeoclimate and evolution], Dansgaard-Oeschger cycles, or the Palaeocene-Eocene thermal maximum, which is currently interpreted as a natural greenhouse-gas induced environmental catastrophe). But it would be considered odd to suggest that because the climate has undergone violent excursions naturally, the climate system is therefore safe from human interventions. Orbitalforam (talk) 15:06, 1 May 2010 (UTC)
 * Gerta Keller and Vincent Courtillot do not agree with Chicxulub as a single cause, they believe rather in multiple causes: global marine regression, Chicxulub hit, Shiva hit, Deccan flood basalts. Many extinction events are related to marine regressions and flood basalts. Researchers (leaded by David J. Archiblad) in the fields of terrestrial vertebrates, including dinossaurs, as well as freshwater vertebrates and invertebrates seem to not like the single cause idea as well. Shiva left an Ir deposit and had a diameter of 40 km, Chicxulub did not leave an Ir deposit and had a diameter of 10 km. If this group tells the truth, the single cause hypothesis does not have a chance. Schulte et al. is only a review of old literature, nothing new. --Chris.urs-o (talk) 14:27, 11 August 2010 (UTC)
 * In the article there is a paragraph about multiple impact events (that is different from multiple causes), referring for example to the Boltysh crater. The paragraph is only sourced by a serie of articles from Leslie Mullen in astrobio.net, one of these being . I saw you made extensive bibliography search and I wonder how often this hypothesis is proposed in publications. --Anneyh (talk) 15:01, 11 August 2010 (UTC)
 * It is not a search. They are mostly the 30 refs. of the 3 letters answering Schulte et al. (2010) Science article. I just wanted to help with an up to date overview of the literature. The summaries of the refs. do not discuss this multiple impact hypothesis. Shiva was deadly because it hit the potential seafloor spreading ridge, causing probably most of the Deccan traps. Triggering flood basalts was important, the impacts were not as bad. My personal feeling after some reading. --Chris.urs-o (talk) 16:24, 11 August 2010 (UTC)
 * Anneyh, I do not really know. If the multiple impacts come from a break up, they must have similar latitudes and hit times. If Shiva got a diameter of 40 km, the other asteroids must have similar diameters to be relevant. If Chicxulub is smaller, it can't be the main cause. The other asteroids to be K/T relevant must hit the Earth at similar times. Maybe is a seminal paper, and K/T is a flood basalt event too, triggered by an impact. The Shiva impact probably activated the ridge between Seychelles and the Indian Plate, inactivating the ridge between Madagascar and Seychelles . I'll add 2 refs, so the section gets a total of 2 refs. and Leslie Mullen ;) --Chris.urs-o (talk) 08:11, 13 August 2010 (UTC)
 * But Gerta Keller disagrees . --Chris.urs-o (talk) 10:00, 13 August 2010 (UTC)

Courtillot Believes Volcanism
Courtillot’s research has come to find various evidence supporting dinosaur extinction to of been caused by volcanism and gasses released into the Earth’s atmosphere. The Deccan Traps and Kilauea volcano of Hawaii were nonexplosive eruptions. Geophysical research papers suggest if a fissure eruption produces lava flows exceeding 100 SQ KM large quantities of sulfate aerosols are injected into the lower stratosphere which are known to lead to short-term atmospheric consequences such as darkening skies, acid rain, and even climate cooling. Hot air, gas, aerosols, and ash carried by these emissions continue to rise and expand over an even larger area of the atmosphere than just the lava fountains and fissures alone. Also, shocked minerals found in ash beds of the Deccan Traps which are usually only found at sites of violent eruptions indicate there had to of been explosive intervals. The remnants of two extremely large flood basalts solidify the idea of volcanism being a plausible cause for dinosaur extinction, one being the Deccan Traps and the other NATIP (North American Tertiary Igneous Province) – a plateau of basalts lining the coasts of Greenland and Scotland. Furthermore it is argued that meteorite impact resulted in all the iridium found in the K-T boundary layer in Earth’s crust, when in fact research has found high levels of iridium in tiny airborne particles from the Kilauea volcano eruption. The estimate is the Deccan eruptions were similar yet of vast abundance, thus 30,000 tons of iridium would have been emitted. NATIP erupted at a time Earth’s magnetic field was reversed pointing to the South Pole. NATIP erupted in the Northern Hemisphere and the Deccan Traps in the Southern Hemisphere – this means the distribution of volcanic material could easily be worldwide causing trauma to dinosaurs over a much larger range than meteorite impact alone. Pole reversal is caused by external affairs that directly disrupt the flow in the Earth's core seen in events such as plate tectonics or subduction causing rifting and fissure establishment. The geomagnetic field reverses approximately every 500,000 years, if the Earth is going through a “quiet state” meaning a longer than normal wait for a pole reversal, it can account for a lot of heat to be transferred from the core to the mantle due to the bottom layer of mantle material becoming so hot it is unstable. This can cause large plumes to escape and begin to rise allowing for eventual volcanic activity, often of excessive nature. In this case particularly, initiation of new mantle plumes from the core-mantle boundary was caused by a disturbance in mantle convection allowing for a magnetic pole reversal to occur as well as abundant volcanic activity caused by these plumes reaching the surface forming the Deccan Traps and the NATIP, large catastrophic events which are very likely to have caused a major wipe out in dinosaur life.(Weisburd, S. (1987). Volcanoes and extinctions: Round Two. Science News, 131(16), 248-250. http://www.jstor.org/stable/pdfplus/3971631.pdf)Bnixo006 (talk) 05:32, 4 April 2012 (UTC)

March 2010 Science article
I have strengthened the statements about the March 2010 Science article in two regards. First the panel did not just support "an asteroid impact" but specifically the Chicxulub impact and no other as the triggering event. Second, they did not conclude that this was the most likely hypothesis but were unequivocal that it was the cause. Being competent scientists they presumably would accept that all scientific conclusions are provisional, and I very much doubt that they expect proponents of alternative theories to throw in the towel just because of this report (which in fact makes no attempt to interpret the evidence from the point of view of any of the rival theories). Nevertheless they chose to report their results as being as close to a sure thing as one can get in science, and our summary of their work should reflect that. PaddyLeahy (talk) 19:09, 8 March 2010 (UTC)


 * That's what I mean too. It is a fact that the dinosaurs died out 'about' 65.5 mya, and it is a fact that a large asteroid struck the earth 'about' 65.5 mya.  But...'about' noon tomorrow means any time from 11:30 to 12:30.  How wide is 'about' from a range of 65.5 million years?.  How can we possibly know from so long ago that the dinosaurs had not been in terminal decline for hundreds of thousands of years before for other more subtle reasons, and the asteroid bumped-off the last few? 81.157.16.194 (talk) 19:25, 8 March 2010 (UTC)


 * As of the time that I'm leaving the comment, the wording indicates that the Chicxulub impact triggered the extinction. I think this is a fair wording, as triggered does not present the impact as the lone exterminating event, so much as the key event that kicked off a number of other events which together caused the mass extinction. This allows for the representation of a theory which cannot be proven or disproven with current evidence, while also presenting this theory as that which has the most evidence supporting it. Hiberniantears (talk) 16:01, 9 March 2010 (UTC)
 * Yes, for example it's always possible that JFK had a heart attack just before the assassin's bullets entered his body. But not probable. We never know for certain, that's true - but there is such a thing as reasonable certainty, with the proviso that new evidence could overturn it. Orbitalforam (talk) 16:29, 16 April 2010 (UTC)
 * The controversy is not over yet. The Economist, I am become Death, destroyer of worlds: The story of how the dinosaurs disappeared is getting more and more complicated -- From a note by User Legis about Sankar Chatterjee - 2 November 2009. --Chris.urs-o (talk) 08:56, 13 August 2010 (UTC)

Literature of the Controversy

 * Single Cause: Chicxulub hypothesis
 * A team of 41 scientists reviewed 20 years of scientific literature.
 * Multiple Causes: Chicxulub (diameter 10 km), Shiva crater (Iridium signal, diameter 40 km) and Deccan Traps
 * It seems that Schulte et al. overlooked some important papers. The quote of Archibald et al. is simply incredible. --Chris.urs-o (talk) 23:00, 10 August 2010 (UTC)
 * It seems that Schulte et al. overlooked some important papers. The quote of Archibald et al. is simply incredible. --Chris.urs-o (talk) 23:00, 10 August 2010 (UTC)
 * It seems that Schulte et al. overlooked some important papers. The quote of Archibald et al. is simply incredible. --Chris.urs-o (talk) 23:00, 10 August 2010 (UTC)
 * It seems that Schulte et al. overlooked some important papers. The quote of Archibald et al. is simply incredible. --Chris.urs-o (talk) 23:00, 10 August 2010 (UTC)
 * It seems that Schulte et al. overlooked some important papers. The quote of Archibald et al. is simply incredible. --Chris.urs-o (talk) 23:00, 10 August 2010 (UTC)

Single Cause

 * Schulte et al. (21 May 2010) literature for the sake of WP:NPOV.
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)
 * --Chris.urs-o (talk) 12:56, 12 August 2010 (UTC)

The Shiva hypothesis

 * The Shiva hypothesis
 * --Chris.urs-o (talk) 23:00, 10 August 2010 (UTC)
 * These are mostly the references given by the response letters to Schulte et al. Science article. Sankar Chatterjee and the Michael R. Rampino's Shiva hypothesis are given for the sake of completeness. Science and Nature articles are more review type articles than most articles. --Chris.urs-o (talk) 14:17, 11 August 2010 (UTC)/ --Chris.urs-o (talk) 09:15, 13 August 2010 (UTC)
 * --Chris.urs-o (talk) 23:00, 10 August 2010 (UTC)
 * These are mostly the references given by the response letters to Schulte et al. Science article. Sankar Chatterjee and the Michael R. Rampino's Shiva hypothesis are given for the sake of completeness. Science and Nature articles are more review type articles than most articles. --Chris.urs-o (talk) 14:17, 11 August 2010 (UTC)/ --Chris.urs-o (talk) 09:15, 13 August 2010 (UTC)
 * --Chris.urs-o (talk) 23:00, 10 August 2010 (UTC)
 * These are mostly the references given by the response letters to Schulte et al. Science article. Sankar Chatterjee and the Michael R. Rampino's Shiva hypothesis are given for the sake of completeness. Science and Nature articles are more review type articles than most articles. --Chris.urs-o (talk) 14:17, 11 August 2010 (UTC)/ --Chris.urs-o (talk) 09:15, 13 August 2010 (UTC)

Cephalopoda
"Except for nautiloids (represented by the modern order Nautilida) and coleoids (which had already diverged into modern octopodes, squids, and cuttlefish) all other species of the molluscan class Cephalopoda became extinct at the K–T boundary. These included the ecologically significant belemnoids, as well as the ammonoids, a group of highly diverse, numerous, and widely distributed shelled cephalopods."

Isn't this sentence a bit too complicated ? Moreover, it's false because belemnites are coleoids. Nautiloids, except for being paraphyletic, were also represented only by Nautilida, which are extant. So, major extinctions at the K-T boundary affected only Ammonoids and Belemnites. It would be more simple to say that, if you agree.N@ldo (talk) 15:13, 18 February 2011 (UTC)

Edit reverted, please double-check
I made an edit to improve readability of the first few sentences. It was quickly reverted, with the comment that the edit was "huge" and "some of it not clear", disagreeing with my comment that it was "some minor copy-editing".

I then reviewed my edit and found that it changed the following:
 * "large-scale" to "large"
 * "K is the abbreviation for" to "K stands for" (2x)
 * "Non-avian dinosaur fossils" to "Fossils from non-bird dinosaurs (non-avian dinosaurs)"
 * sentence order ("aaa bbb" -> "bbb aaa")
 * punctuation such as splitting "aaa, bbb" -> "aaa. Bbb"
 * inserted a linebreak

I would maintain that these changes are indeed small, not "huge". It may seem bigger because linebreaks get shown as a big red splotch followed by a big green splotch, but that's something well-known which the diff display has done forever. Also, I don't see how the edit in question made things less clear.

Having checked, I can't see what is so problematic about the edit, so I think the reverting was not justified. Please review the edit and re-apply it. Thank you. --84.130.44.73 (talk) 03:31, 13 April 2011 (UTC)
 * I made the reversion. Non-avian dinosaur fossils is so much clearer.  Revert stands unless you've got some compelling reasons that are more convincing than what you state.   Orange Marlin  Talk• Contributions 03:53, 13 April 2011 (UTC)
 * I'm of the opinion that the change did not improve the readability of the article. Some of the changes probably have merit, but "non-bird dinosaurs (non-avian dinosaurs)" is awkward, and "stands for" is both informal and ambiguous. "Is the abbreviation for" really is much better here. I'm not opposed to a reworking of some of the wording in the lede, but some of the changes made don't improve the article. Firsfron of Ronchester  06:18, 13 April 2011 (UTC)
 * Sometimes it's best to makes edits one at a time so that the "good" doesn't get reverted with the "bad". J IM ptalk·cont 02:38, 27 April 2011 (UTC)

K-Pg
The Cretaceous is a geologic period - the period following it is the Paleogene. To call the extinction that occurs at this boundary the "Cretaceous-Tertiary" (K-T) extinction is like calling it the "Maastrichtian-Cenozoic" extinction, or calling the "Permian-Triassic" extinction the "Permian-Mesozoic" extinction; it's identifying the event as the transition from one unit of geologic time to another unit that's of a totally different scale.

I'm fine with the article keeping the K/T title, because that's what most people call it and if it's changed then people might conceivably think they're looking at the wrong subject, but in the body of the article I think it should be written as K/Pg. To do otherwise would be to promote scientific imprecision and perpetuate the misapprehension that the Cretaceous and the Tertiary are geologic equivalents. As the article states, there is a push in geologic circles to try to move away from use of the word Tertiary, and I think the article would be best served by adopting this philosophy. Troodon311 (talk) 22:54, 25 April 2011 (UTC)
 * Tertiary is no longer used in geologic nomenclature and most (all?) recent technical sources use K-Pg. It hasn't really filtered into popular secondary sources yet, but it would make sense to switch. MMartyniuk (talk) 00:54, 26 April 2011 (UTC)
 * Not true in North America, at least; K-T is still technical here. There is major no push that I know of (as a geologist) to get rid of the use of "Tertiary". Awickert (talk) 02:24, 27 April 2011 (UTC)

Ago
It has been suggested that "Ma, assumes BP". The "M" is for "mega" i.e. "million". The "a" is for "annum" i.e. "year". "Ma" means "million years". Where is the implication of "ago"? Sure readers can guess that we mean "65 million years ago" but "65 Ma" doesn't mean "65 million years ago", it means "65 million years". If I wrote "Many species went extinct 65 million years.", I'm sure you'd be able to guess what I mean but you'd want to finish my sentence off. It has been suggested that adding this clarification would confuse the reader. I'd like to suggest that removing it might be even more confusing. J IM ptalk·cont 02:14, 27 April 2011 (UTC)


 * "Ma" in terms of "ago" is standard geological usage. It's come up across many articles on Wikipedia that this is confusing to those who aren't used to it. Suggestions are (1) defining its first occurrence, (2) changing things to "Myr BP" or "Myr ago", or (3) writing out "million years ago". "Ma ago" looks really weird to geologists. Awickert (talk) 02:22, 27 April 2011 (UTC)


 * Fair enough. I'm no geologist.  Things aren't always logicical, even in science ... but if you're using "Ma" for a specific past time, what do you use for a duration (or a future time)? J IM ptalk·cont 02:34, 27 April 2011 (UTC)


 * I use "Myr" for duration personally, though I'm honestly not sure if geologists are consistent about this. I also use Myr as future. I think it's that the "ago" got appended so "ka/Ma/Ga" could be a convenient shorthand, so I use "Xyr" for anything else... but I honestly haven't looked into this too much. Awickert (talk) 03:26, 27 April 2011 (UTC)


 * It seems that geologists are not yet unanimous on adopting  the usage of Ma, but until recently the AGU editorial guidelines used Ma to denote millions of years  Before Present (before the epoch January 1, 1950), while using Myr for elapsed times between two events. ,  , ,  pertain.LeadSongDog  come howl!  03:42, 27 April 2011 (UTC)
 * All one has to do is click on the Ma wikilink in the article. It clearly states everything.  Million years ago is also stated first.  Ma ago and Ma BP does look really stupid.  It's been Ma for 3 years, gone through an FA and an FAR, been on the main page, and never once has this been brought up.  Just because one editor is confused does not mean all are.  Can we discuss something relevant or useful?  Orange Marlin  Talk• Contributions 04:47, 27 April 2011 (UTC)
 * Here's what it says when you click on the wikilink: Ma (for megaannum), is a unit of time equal to one million (106) years. It is commonly used in scientific disciplines such as geology, paleontology, and celestial mechanics to signify very long time periods into the past or future. For example, the dinosaur species Tyrannosaurus rex was abundant approximately 65 Ma (65 million years) ago (ago may not always be mentioned; if the quantity is specified while not explicitly discussing a duration, one can assume that "ago" is implied; the alternative but deprecated "mya" unit includes "ago" explicitly.). In astronomical applications, the year used is the Julian year of precisely 365.25 days. In geology and paleontology, the year is not so precise and varies depending on the author. Orange Marlin  Talk• Contributions 04:50, 27 April 2011 (UTC)
 * One reason why geologists and Palaeontologists have to be a bit more relaxed about the term is that the number of days in the Earth's orbit around the sun has changed somewhat over geological time. cf for example: S J Mazzullo: Length of the year during the Silurian and Devonian periods: new values. Geological Society of America Bulletin 1971, 82, no 4 1085-1086 and Wells, J. W. Coral growth and geochronometry, Nature 1963 187, 948–950 . So the use of an absolute duration for the year (which is not an SI unit) in terms of days could lead to differences between elapsed time and number of orbits, which would be unhelpful. re the K/T acronym: it may be technically inappropriate, but it is widely used, so we may as well accept it for now. Orbitalforam (talk) 09:06, 26 September 2011 (UTC)

Objection:
The first paragraphs imply that the Dinosaur went extinct at the KT event. This from: "Non-avian dinosaur fossils are found only below the K–T boundary, indicating that non-avian dinosaurs became extinct during the boundary event.[3] A very small number of dinosaur fossils have been found above the K–T boundary, but they have been explained as reworked fossils, that is, fossils that have been eroded from their original locations then preserved in later sedimentary layers.[4][5][6]." This appears to be a paradigm issue. In the later section Evidence the North American Fossils indicate a different pardigm of decline across the Maastrichtian Stage. Any positive extinction evidence is significant and should trump geriatric Chicxulub impact dinosaur extinction rhetoric. This particulary in light of warm blooded Dinosaur prognosis albeit Nova Arctic Dinosaur documentary.

Morbas (talk) 12:38, 30 October 2011 (UTC)


 * The nature of your objection is unclear. Are you against (non-avian) dinosaurs going extinct at the K-T, because they may have declined beforehand? These two statements are not necessarily exclusive. If you've got a problem with the literature, you should be aware that Wikipedia is not the place for introducing your own theories. J. Spencer (talk) 00:10, 31 October 2011 (UTC)

Jim, you clearly represented the paradigm. I quote the article: "non avian dinosaurs became extinct during the boundary event" but this is not supported by any fossil record. The only evidence is a decline going into and across the lower-mid Maastrichtian Stage. The upper Maastrichtian is void of dinosaur fossil witnessed by the fact that KT is the most researched extinction of the Phanerozoic. No fossils at the KT event threshold, no evidence of non-avian dinosaurs going into the KT event.

The existence of the Arctic Dinosaur coupled with a warm blooded bone growth structure, is the prognosis of the NOVA Arctic Dinosaur supported by a leaf structure indicating a deep seasonal climate above the artic circle. The dinosaur were not dependent on warm climate. The Wiki article presents an unsupported view and this is not the place for introducing your own theories. Morbas (talk) 20:36, 31 October 2011 (UTC)(UTC) .


 * There seems to be more than one issue going on here, but dinosaurs were certainly not absent from the late Maastrichtian. Well-established genera more or less limited to the late Maastrichtian include Tyrannosaurus, Ankylosaurus, Pachycephalosaurus, Triceratops, Thescelosaurus, and Edmontosaurus annectens. Are you perhaps thinking of the "3 meter gap" at the top of the Hell Creek Formation? Dinosaur bones are historically absent from the 3 meter gap, but there is evidence that additional study will close this gap, and at any rate the Hell Creek Formation is significantly thicker than 3 m. There's a good, relatively recent summary on the Hell Creek Formation here. (Incidentally, my name is not Jim, but one name's as good as another). J. Spencer (talk) 22:23, 31 October 2011 (UTC)

Honorable J.Spencer then it is...

The 2011 abstract there is evidence indicates the 3m gap is not closed (yet), so we can or cannot use that inference?.

Tyrannosaurus, Ankylosaurus, Pachycephalosaurus, Triceratops, Thescelosaurus, and Edmontosaurus annectens were present late Maastrichtian? Should be some record of that (can you help)? I do not see any dinosaur Stratigraphic position in the Hell Creek Formation  article, and once for middle Bakker et al. (2006). Is it not premature to make the statement "non avian dinosaurs became extinct during the boundary event" ? Morbas (talk) 02:37, 1 November 2011 (UTC)


 * Regarding the 3 m gap: I'd say the reader is free to accept the gap, on the grounds that one fossil is not enough, or to consider the gap closed/in the process of being closed. Alternately, the reader may find the 3 m gap to be, overall, a "red herring;" the Hell Creek Formation is several tens of meters thick altogether, so fossils missing from 3 meters may not be significant.
 * On the issue of dinosaur fossil distribution in the Hell Creek Formation: I've linked here to a detailed study of the Hell Creek Formation and overlying Fort Union Formation of southwestern North Dakota. The citation is:
 * Pearson, Dean A.; Schaefer, Terry; Johnson, Kirk R.; Nichols, Douglas J.; and Hunter, John P. (2002). "Vertebrate biostratigraphy of the Hell Creek Formation in southwestern North Dakota and northwestern South Dakota". In Hartman, Joseph H.; Johnson, Kirk R.; and Nichols, Douglas J. (eds.). The Hell Creek Formation and the Cretaceous-Tertiary Boundary in the Northern Great Plains: An Integrated Continental Record of the End of the Cretaceous. Geological Society of America Special Paper, 361. Boulder, Colorado: Geological Society of America. pp. 145–167. ISBN 0-8137-2361-2.
 * All of the figures were available in this online version, which is very useful. The Google Books link is subject to linkrot, but searching for the title of the article should find it quickly.
 * A small bit of background: the Hell Creek Formation of southwestern North Dakota ends just before the K-T. This is because its age varies slightly from location to location: the Hell Creek Formation represents a depositional environment that appears at slightly different times over a wide area. In this area, the K-T is found low in the Fort Union Formation, which is the next formation up.
 * Table 4 (p. 154) of this article is a compilation of all vertebrate species and genera in the Hell Creek Formation of this part of North Dakota and neighboring South Dakota. The assemblage includes rays, sharks, bony fish, frogs, salamanders, turtles, the aquatic reptile Champsosaurus, crocodilians, pterosaurs, theropods, birds, horned dinosaurs, hypsilophodonts, duckbilled dinosaurs, and early mammals. The authors found (Figure 4, p. 155) practically no vertebrate fossils within about the upper two meters of the Hell Creek Formation and lowest meter of the Fort Union Formation. This is not the only fossil gap in the two formations; for example, there is about 20 m without fossils between 60 and 40 m. Figure 5 on p. 157 shows the uppermost slice of these results, calibrated to the K-T boundary. This figure also shows a gap at the top, greater than two meters. Only one fossil was found in this gap: a specimen of a horned dinosaur, at 1.8 m below the boundary.
 * My reading of these charts is that there are a number of fossils, including dinosaur fossils, almost to the boundary; but the absence of practically any kinds of vertebrate fossils at the very top, and the presence of other sizable fossil gaps lower in the Hell Creek Formation, make it difficult to draw any conclusions about what was specifically happening to dinosaurs during that final gap. The dinosaurs are certainly present very close to the end of the Late Maastrichtian, and they don't show up again in the Paleocene part of the Fort Union beds. J. Spencer (talk) 01:23, 2 November 2011 (UTC)

This discussion is rather pointless. This is Wikipedia: cite or it didn't happen. Your argument that the absence of dino fossils at the exact KT boundary indicated that they may have been extinct before then is your own interpretation of published data, otherwise known as original research. If there is a source that explicitly proposes the same hypothesis it can be included if it's made clear that this is an extreme minority viewpoint. MMartyniuk (talk) 12:46, 2 November 2011 (UTC) The statement "non avian dinosaurs became extinct during the boundary event" is a citation objection. No dinosaur fossil have ever been located at the event layer...to my knowledge. Thus the statement is factually wrong. You may close this section at your leasure Morbas (talk) 08:43, 7 November 2011 (UTC)

Time for a name change
"Tertiary" is no longer a formal period in the geologic time scale. The formal name is now "Cretaceous-Paleogene extinction event" and although that is clearly referred to in the article I think the title should reflect this. The name "Cretaceous-Tertiary will still be referred to in the intro so as not to confuse people who aren't familiar with the name change. I attempted to change the title using the DISPLAYTITLE word but it didn't work so I'm not sure if anyone could do this for me. Cadiomals (talk) 00:35, 8 November 2011 (UTC)
 * Well, then we need to do a name change to the article. It makes no sense now.   Orange Marlin  Talk• Contributions 22:23, 29 November 2011 (UTC)
 * I would appreciate it if someone who actually knows how to change the title would do this for us Cadiomals (talk) 22:58, 1 December 2011 (UTC)
 * I know that Tertiary is no longer a formal name but KT is pretty commonly used and widely understood. I'd need to see some evidence before supporting a move. I shall consult my personal geologist, who favours preciseness over folk understanding though. Anyone who can be prompted to explode upon the simple reference to pterosaurs as "dinosaurs" can be relied upon to provide a good opinion. Sabine's Sunbird  talk  20:42, 27 January 2012 (UTC)
 * My expert says that although KP may be more technically correct, geologists tend to favour the old usage. Sabine's Sunbird  talk  00:18, 29 January 2012 (UTC)
 * You know how the saying goes: "Old habits die hard." I also have a habit of saying KT just because its easier to say, even though I'm well aware the official name is K-Pg Cadiomals (talk) 00:27, 29 January 2012 (UTC)
 * Not just an old habit, I've been told it was an unpopular decision that hasn't won universal acceptance amongst geologists. Let alone achieved any recognition outside of geology, literally the first I heard of it was a few days ago on the talk page of bird, and I don't like to think I'm not paying attention. That said, if it what geologists insist upon I guess it is what the article should be called. Sabine's Sunbird  talk  03:40, 30 January 2012 (UTC)
 * Remember that they didn't just change the name of the Tertiary period, they split it in two. I read that this was done for two reasons: 1) to keep it more aligned with the other eras which have more than two periods and 2) The Cenozoic era was one of rapid diversification by mammals so it was necessary to split it into three periods because of the more rapid evolutionary events. Cadiomals (talk) 05:36, 30 January 2012 (UTC)

Self published speculations removed
I've removed the following as the website summary and the new Kindle book via Amazon (pub 7 March 2012) are rather obviously self-published material by L. Granier.
 * The Multi -One Theory developed by the theoretician Laurent Granier explains by environmental changes under "Domino effect", the extinction of "super species", among them, dinosaurs. His double theory gives the evidence of an increase of gravity explained by an increase of Earth speed rotation after the impact of a part of the meteorite in Caribbean Sea, in addition to the one in Yucatan.

Vsmith (talk) 12:16, 11 March 2012 (UTC)

Requested move

 * The following discussion is an archived discussion of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section. 

The result of the proposal was move. RockMagnetist's comment at the bottom of this discussion is the clearest rationale for the move. WP:COMMON isn't a one-size-fits-all tool: it gives more weight to scientific and reliable sources. In this case, those sources have been using the requested page title for several years.

Cretaceous–Tertiary extinction event → Cretaceous–Paleogene extinction event – This is the proper name according to the International Commission on Stratigraphy, and Tertiary, although still commonly used, is now officially defunct. As an encyclopedia we need to be as accurate and up-to-date as possible, and using "Tertiary" is no longer accurate or up-to-date. The former Tertiary period has since been split into the Paleogene and Neogene periods to better align with the other eras. Please see this website. - Cadiomals (talk) 15:57, 12 March 2012 (UTC)
 * Yikes. "Cretaceous–Tertiary extinction", "K–T boundary", etc. are so ingrained in the consciousness of non-scientists who know a little bit about science that I'm a little surprised this was "officially" changed. I'm not sure that officially changing this is enough to cause the name in a general encyclopedia to change, given WP:UCN and all that. I wonder if this is something where we are going to have to wait and see how usage develops. Good Ol’factory (talk) 23:26, 12 March 2012 (UTC)
 * No - wait a while for usage to follow official decree. A note regarding the official name in the lead with an explanation of the official name change in the body of the article should suffice. Keep the common name until usage passes it by :) What's the rush? Vsmith (talk) 00:30, 13 March 2012 (UTC)
 * Question, was the K-T event "officially" changed or just the Tertiary? The end Cretaceous event has an established name and should remain until (and if) usage in published literature switches to K-P. Vsmith (talk) 00:44, 13 March 2012 (UTC)
 * I reverted your change to a long-standing portion of the lead because it is necessary to clearly indicate that this is the official name according to the ICS, which is ultimately the master of these matters. Your use of "perhaps" is very weasel-ly, also. We cannot expect people to warm up to K-Pg if we don't assert it. Cadiomals (talk) 01:40, 13 March 2012 (UTC)
 * Heh, noted that. And yes I do recall seeing the wording change last fall, but just let it slide then. Now, it makes it look as if someone wants to pre-empt the discussion or something. As that was brought to my attention by the current request - I sez to myself, we keep the lead consistent with the article title until that move/rename is done. And yeah "perhaps" was perhaps a bit weasely. Did the ICS "masters" rename the K-T? or just "officially" redefine "Tertiary" as dead and gone? I see the reference for Cretaceous-Paleogene usage is to Ogg's 2004 book - does the book discuss the K-T/K-Pg usage? Vsmith (talk) 02:06, 13 March 2012 (UTC)
 * Whatever the name of the article results at, it would be most appropriate to refer to that particular name first in the article. If it is to remain at the current name, it would probably be better to say something like, "The Cretaceous–Tertiary extinction event, formally referred to as the Cretaceous–Paleogene extinction event, ...". Otherwise it becomes confusing to readers to have the lead first use a name that does not conform to the article title. Good Ol’factory (talk) 02:17, 13 March 2012 (UTC)


 * No view except if moved, Cretaceous–Paleogene needs the "&amp;ndash;". -- Ohconfucius  ¡digame! 02:58, 13 March 2012 (UTC)
 * Oppose WP:COMMONNAME is the current name, and the new name is still WP:JARGON. WP:AT says we should use a generally recognizable name, and the new name certainly isn't. 70.24.251.71 (talk) 04:21, 13 March 2012 (UTC)
 * Comment revised to rename to "K-T Extinction Event" per Dinoguy2, as the abbreviation is more common than the expanded form (so override abbreviation expansion). 70.24.251.71 (talk) 15:52, 13 March 2012 (UTC)
 * Support That's the new name. Retaining the old name because it's more familiar would be like retaining Brontosaurus well after it was changed to Apatosaurus. The former is still well-known today but if Wiki had existed in the 1910s, maybe it would have been squashed faster in favor of the correct name. We're here to educate people bout the current state of the science, not help outdated information persist because it's familiar. Or... MMartyniuk (talk) 15:45, 13 March 2012 (UTC)
 * Alternative As a compromise, maybe we could change the name to K-T Extinction event (arguably the abbreviation is more familiar to the general public anyway). Then explain in the lede that K-T stands for "Cretaceous-Tertiary, Tertiary being an historical name for the Paleogene and Neogene periods." Remove all further instances of the word "Tertiary" but retain the abbreviation K-T. All set. MMartyniuk (talk) 15:48, 13 March 2012 (UTC)
 * Comment that works for me ("K-T Extinction Event"). 70.24.251.71 (talk) 15:52, 13 March 2012 (UTC)
 * I totally agree with the Brontosaurus-Apatosaurus example. There are still many laymen today who use the world Brontosaurus instead of Apatosaurus. WP:COMMONNAME does not apply to this situation. That guideline applies to things such as formal species names, celebrity stage names, etc. but not here. Once again, Brontosaurus is still a common name mistakenly used in place of Apatosaurus, that doesn't mean the defunct term should be immortalized. The best thing to do is change the title to Cretaceous-Paleogene extinction event but make sure that Cretaceous-Tertiary is referred to in the lead and make sure readers understand that this is the new formal name and why it was changed. That way, we can revert the lead back to this: "The Cretaceous–Paleogene extinction event, formerly named and still commonly referred to as the Cretaceous-Tertiary extinction event..." which perfectly clarifies things for the reader. Cadiomals (talk) 23:44, 13 March 2012 (UTC)
 * Why would WP:UCN apply to formal species names but not a formal scientific name in this context? What is the justification for distinguishing the two situations? Good Ol’factory (talk) 23:57, 13 March 2012 (UTC)
 * I can see a significant difference. For a species, there is the common name, and the formal name. For example, the formal name of lions is Panthera leo. The formal name is rarely used even by zoologists and strictly for classification purposes. K-T and K-Pg are different. One is no longer used; the latter has replaced the former. They are not interchangeable. The same goes for Brontosaurus and Apatosaurus. One is outdated and has replaced the other. For the nth time, there are still ignorant laymen out there who mistakenly use Brontosaurus, that doesn't mean they're right. Cadiomals (talk) 15:51, 14 March 2012 (UTC)
 * What does "for the nth time" mean in your comment? I hope it's not an expression of frustration, as in "I've told you a million times", as my comment was sincere, not baiting, and I believe I have a legitimate disagreement on the merits of this proposal. Good Ol’factory (talk) 20:53, 14 March 2012 (UTC)
 * Sorry, I wasn't m ad, I just don't like repeating the same things to different people. Extinction events are normally named after the two periods they border (Permian-Triassic, Triassic-Jurassic, etc.) and Tertiary simple isn't a period anymore, Paleogene is. Its a scientifically deprecated name the same way Brontosaurus is scientifically deprecated. Once again, we don't need to encourage it. Cadiomals (talk) 22:36, 14 March 2012 (UTC)
 * I do understand what you are saying and I had read of the brontosaurus example in your previous comment, I just don't believe it's WP's job to be a leader in establishing or encouraging "proper" usage. I'm more of the opinion that it should reflect the common usage. If "brontosaurus" was the overwhelmingly common name that is used, I would support using it. But I don't think it is anymore. Good Ol’factory (talk) 23:14, 14 March 2012 (UTC)
 * But bronto and apato are two different skeletons, one with a different skull from the other, so the bronto is a (nonexistent) animal with a different head from the apato. This is the same under both names. 65.94.76.38 (talk) 03:48, 15 March 2012 (UTC)
 * Actually this is a widely believed myth. The fact that the skull as initially reconstructed didn't resemble the real skull as eventually discovered has nothing to do with the name change. Brontosaurus did certainly exist, and happened to have been the same as Apatosaurus. It was not, and never was, a chimera. The Apatosaurus article explains this in detail. MMartyniuk (talk) 19:40, 15 March 2012 (UTC)
 * Yeah; so it's not a great parallel. "Brontosaurus" as such never existed, so it's a bit of a different kettle of fish. Good Ol’factory (talk) 05:11, 15 March 2012 (UTC)
 * Oppose on the basis of the en dash–hyphen error alone. No opinion on the other part.  Dicklyon (talk) 03:33, 14 March 2012 (UTC)
 * Fixed. Cadiomals (talk) 15:43, 14 March 2012 (UTC)


 * Support A closer look at WP:COMMON reveals that "more weight should be given to the name used in reliable sources published after the name change than in those before the change." Note the word "reliable". A quick search of articles since 2004 on Google Scholar strongly supports C-Pg. Alternative names like "K-T extinction" can be redirected, so a name change is not likely to cause confusion, especially if the former name is mentioned in the first paragraph. RockMagnetist (talk) 19:11, 15 March 2012 (UTC)
 * Thank you, RockMagnetist. Yes, most reliable scientific sources for the past five or so years have been using Cretaceous-Paleogene. Wikipedia relies on reliable sources. Also, this name change does not violate the common name guidelines upon closer reading. Cadiomals (talk) 20:44, 15 March 2012 (UTC)
 * The above discussion is preserved as an archive of the proposal. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Recent edits
I'm not sure that "K-Pg Extinction event" is very readable considering how many times it's repeated through the article. Just for efficiency sake, I think that K-Pg event is more than adequate, even for the non-scientific reader (like me). Or we can say K-Pg extinction event (or K-Pg event) right in the lead, then everyone knows what it means. I'm all for efficiency of writing. Of course, I miss K-T event which is much easier to write, but I won't fight that battle! SkepticalRaptor (talk) 21:05, 21 April 2012 (UTC)

Name change at Talk:K–T boundary
I'm trying to make the name of K–T boundary consistent with this article, using K–Pg boundary layer instead. The articles are intertwined, as the boundary layer article describes the geological layer which represents the date of the extinction event. Similar to the discussion here on the name change, we're seeing the same arguments there. I think WP:COMMON supports the change since almost all reliable sources now use K–Pg, since Tertiary was deprecated. Tertiary, of course, was a name invented far before our current understand of both evolution and geology. Someone needs to help out there. I have no patience with dumb arguments, but I don't think the other article is carefully watched. SkepticalRaptor (talk) 23:10, 11 May 2012 (UTC)

Alvarez hypothesis
Shouldn't the Alvarez hypothesis be mentioned in the lede? its highly significant in the development of our understanding of this phenomenon.Mercurywoodrose (talk) 04:11, 26 November 2012 (UTC)
 * You were right, and I added it. You can wordsmith it if you think it's not enough. SkepticalRaptor (talk) 02:14, 29 November 2012 (UTC)

"Pterosaurs did not decline" support references
Richard Butler, Paul Barrett, Steven Nowbath & Paul Upchurch: "Estimating the effects of the rock record on pterosaur diversity patterns: implications forhypotheses of bird/pterosaur competitive replacement, SVP meeting abstracts2008, 59A" is considered non-peer reviewed, yet it pretty much reflects most opinions on Maastrichtian pterosaur faunas, to the point that no contesting papers have been written on the subject. ''Witton, M. P. and Naish, D. 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS ONE, 3, e2271.'' pretty much reflects the current statements on Ptersaur.net in regards to azhdarchoid ecology: while not mentioning it directly, it seems to imply azhdarchids replaced similar pterosaur clades like Chaoyangopteridae. — Preceding unsigned comment added by 89.154.214.153 (talk) 22:59, 28 November 2012 (UTC)


 * Waiting 10 minutes for replies is "immature" to quote your rather rude edit summary. You need to review WP:RS. You are providing an abstract, which is definitely not peer reviewed, and a primary source, which has marginal value. And pterosaur.net is absolutely not a reliable source. Also, this is a Featured Article, and as such your citations would need cleaning up. I would suggest relaxing, and let a full discussion happen here. It might take a few days, because there are a limited number of editors that are experts on this topic. SkepticalRaptor (talk) 02:17, 29 November 2012 (UTC)
 * 1- Considering abstracts have previously been used before on featured articles (see Turtle), that stance is ostensibly hypocrital
 * 2- Pterosaur.net is currently the most consistently up-dated site in regards to pterosaur palaeobiology. Saying it's "absolutely not reliable" is like saying J.K. Rowling's statements bear no relevance to Harry Potter. (talk)
 * See WP:RS. Thank you. SkepticalRaptor (talk) 06:23, 29 November 2012 (UTC)

A simple Google scholar search for papers published between 2008-2012 will show a consensus opinion that pterosaurs were in severe decline during the Cretaceous but, not necessarily due to competition with birds. Most preliminary report of LK pterosaur diversity beyond the azhdarchinae have been considered spurious at best and debunked at worst (e.g. Gwawinapterus. No reason to qualify the statement that pterosaurs were in decline before the K-Pg, but possibly good reason not to mention birds as a mechanism for this which is controversial and/or only weakly supported, if at all, by modern studies. MMartyniuk (talk) 18:44, 29 November 2012 (UTC)
 * This article currently states that "possibly" declined because of archaic birds, but fully states that birds radiated because of empty niches. Seems like the current section is in line with modern studies. This is why I don't like cherry-picked articles, especially non-peer-reviewed ones. SkepticalRaptor (talk) 21:25, 29 November 2012 (UTC)
 * Err, no. Azhdarchidae is pretty much consistently noted as being diverse, if not morphologically-wise as species-wise. It's like saying sauropods were in decline only because titanosaurs survived until the Maastrichtian. — Preceding unsigned comment added by Chaoyangopterus (talk • contribs) 17:15, 30 November 2012 (UTC)
 * Err, we are only concerned with WP:RS that support a point of view. Original research is deprecated. SkepticalRaptor (talk) 01:17, 1 December 2012 (UTC)

Ösi et al. 2011 as well as Mark Witton's and Naish's paper do state azhdarchids were thriving and not declining... — Preceding unsigned comment added by Chaoyangopterus (talk • contribs) 17:08, 2 December 2012 (UTC)
 * This article is about the K-Pg event. If you want to edit about Pterosaurs, go there. If your cite is accurate, and so far you're cherry picking, it's hardly notable with respect to this article. Also, learn how to make proper citations for an article of the quality of this one. See WP:CITET. And also sign your comments here. SkepticalRaptor (talk) 20:00, 2 December 2012 (UTC)
 * Just because one family among the whole group was doing ok at the K-Pg does not mean the group as a whole was not in decline. In the early-mid K a diverse array of azhdarchid species exited at the same time as ornithocheirids, tapejarids, pteranodontids, and other pterosaur groups. By the Maastrichtian all but the azhdarchids were extinct. The fact that the azhdarchids themselves did not decline in diversity doesn't change the fact that pterosaurs as a whole had due to the loss of all those other clades. I suspect the people commenting here might simply have different definitions of the word 'diversity'. In most published studies on this topic, diversity = species count, which also declined sharply during the course of the Cretaceous. MMartyniuk (talk) 12:35, 4 December 2012 (UTC)

" Only One family of pterosaurs, Azhdarchidae, was definitely present in the Maastrichtian, and it became extinct at the K–T boundary. It is hypothesized that another family of pterosaurs, Nyctosauridae, also became extinct during this event. " - Sidelight 12 Talk 07:38, 3 December 2012 (UTC)
 * Let's give the new editor some slack, while keeping this article in good form. Something like:


 * If the citation is not in English, that creates an excessive obstacle for the Wikipedia community to verify it. In this case, work your potential contribution out on this talk page before inserting it. For original research, or first hand sources try Wikiversity, Wikisource or Wikibooks. and possibly Spanish Wiki's for Spanish related citations. From this post thread, assumptions (ie. associating the decline with another species) muddy information. Sidelight 12 Talk 02:12, 4 December 2012 (UTC)


 * PLoS is peer reviewed, and it contains the full text. Sidelight 12 Talk 04:48, 6 December 2012 (UTC)


 * Piksi is a post-Turonian ornithocheirid from North America — Preceding unsigned comment added by Chaoyangopterus (talk • contribs) 13:27, 29 December 2012 (UTC)


 * Also a very relevant quote from the essay:

"However, Campanian-Maastrichtian beds of Europe yielded isolated remains referable to Ornithocheirus (Ornithocheiroidea; see Wellnhofer 1991) and other non-azhdarchid taxa (Jianu et al. 1997; Barrett et al. 2008), and Campanian- Maastrichtian beds of USA and Brazil yielded fragmentary specimens of pteranodontid-like taxa and Nyctosauridae, respectively (see Company et al. 1999). Additionally, a nearly complete rostrum from the Maastrichtian of USA was recently assigned to the Tapejaridae (Kellner 2004). To these reports, here we add the non-azhdarchid Piksi barbarulna, also from USA. In conclusion, the current record of the Pterosauria is suggestive of a large diversity of Late Cretaceous pterosaurs, probably comparable to that of Early Cretaceous times and contrasting with previous claims of poor diversity for this time." — Preceding unsigned comment added by Chaoyangopterus (talk • contribs) 14:32, 29 December 2012 (UTC)

This is the written out reference. My consensus is to keep the first inserted paragraph, ("Recently, several new pterosaur..."). It needs to be shown that other pterosaur were around during the Maastrichtian time, and it is inaccurate to leave that part out. I have no opinion on the second inserted part, ("however, pterosaur competition..."). - Sidelight 12 Talk 12:31, 31 December 2012 (UTC)"


 * Could you clean up? Its hard to understand the point with the codes in between. At any rate, it fits the require requisites; the information you seemingly have not noticed has an excerpt above. - Chaoyangopterus, 31 December 2012


 * Between the tags is what I was giving you the chance to paste into the text for the reference webpage you provided, not just the link. There is even a wiki gadget that can do it for you. Click on the word reference before " ", and it will make sense. I noticed the museum pdf, and the page number of that information is in the ref tag. My point was, I agreed with the first edit, and the reference. I don't think the first edit should have been reverted. PrimeBOT (talk) 23:09, 6 July 2017 (UTC)