Talk:Permian–Triassic extinction event
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- 1 Chart at the top of the article
- 2 Picture of supercontinent and areas marked
- 3 Copyright problem removed
- 4 impact event?
- 5 Using abbreviations without explanations.
- 6 Impact Origin of the Gulf of Mexico
- 7 Science News resource
- 8 Algeo et al.
- 9 Add?
- 10 New research.
- 11 Changes in marine ecosystems
- 12 Volcanism -reference does support
- 13 Possible relevant reference
- 14 Great Dying
- 15 "see map above"
- 16 Gibberish
- 17 Individuals
Chart at the top of the article
I think the caption for this chart might need a little more explanation. Can the vertical axis be labelled? I can infer the trend indicated in the chart, but I can't say I know exactly what it is saying. Regards, PDCook (talk) 17:26, 27 March 2010 (UTC)
Picture of supercontinent and areas marked
The supercontinent picture is a bit misleading because the text next to it says that the continents are labelled. However, Australia is missing. Also, India, which is a nation and not a continent, is labelled. Is there a way to fix this? —Preceding unsigned comment added by Montreux (talk • contribs) 05:03, 19 April 2010 (UTC)
- There is no problem with that picture, 1. Australia is there, 2. India is also a geological continent. Rursus dixit. (mbork3!) 20:01, 14 June 2010 (UTC)
Copyright problem removed
One or more portions of this article duplicated other source(s). The material was copied from: (see below). Infringing material has been rewritten or removed and must not be restored, unless it is duly released under a compatible license. (For more information, please see "using copyrighted works from others" if you are not the copyright holder of this material, or "donating copyrighted materials" if you are.) For legal reasons, we cannot accept copyrighted text or images borrowed from other web sites or published material; such additions will be deleted. Contributors may use copyrighted publications as a source of information, but not as a source of sentences or phrases. Accordingly, the material may be rewritten, but only if it does not infringe on the copyright of the original or plagiarize from that source. Please see our guideline on non-free text for how to properly implement limited quotations of copyrighted text. Wikipedia takes copyright violations very seriously, and persistent violators will be blocked from editing. While we appreciate contributions, we must require all contributors to understand and comply with these policies. Thank you. J. Spencer (talk) 00:08, 21 October 2010 (UTC)
While checking some rewording, I found that two chunks of text were copy-and-paste jobs, mostly from http://math.ucr.edu/home/baez/extinction/, but with some lines from http://www.santafe.edu/media/workingpapers/99-12-079.pdf woven in as well. What appears to have happened is the article The Big Five was merged to several extinction pages in September 2008 (in this page's case this edit) without it being known that the merged article was a copyvio.
After considering, I removed the chunks that were copyvios instead of rewriting as the first chunk was largely redundant with other text, and the second chunk had been slightly modified and was no longer accurate. J. Spencer (talk) 00:08, 21 October 2010 (UTC)
- How sure are you about this? I know the Baez site has borrowed significantly from Wikipedia in the past (and hence the copying might go in the other direction). In addition, someone who appears to have a vested interest in that site has on various occasions added material to Wikipedia, so it may have been added by the copyright owner. So I'd want to look closely before declaring an infringement. Of course, if it can be rewritten / replaced / removed without harming us then that is probably all for the best regardless. Dragons flight (talk) 00:21, 21 October 2010 (UTC)
- Here's a random pre-July 2008 (when "The Big Five" was started here) pull from Internet Archive; and here is the site today. The text for the Permian-Triassic, Late Devonian, and Ordovician extinctions are exactly the same as they are now, so the Baez site has to be the originator in this case. J. Spencer (talk) 00:31, 21 October 2010 (UTC)
What about the Hudson Bay impact? It is certainly large enough to have caused a mass extinction on a scale far exceeding the demise of the dinosaurs. Does anyone know when the Hudsom Bay impact occurred? —Preceding unsigned comment added by 126.96.36.199 (talk) 16:02, 23 October 2010 (UTC)
- If a person takes the time and effort to read through and look at the numerous detailed papers and geologic maps that has been published by geologists and other Earth scientists for the Hudson Bay shorelines and region, they would find that there is more than enough hard data to completely refute any ideas about the Nastapoka Arc being part of enormous extraterrestrial impact structure. The fact of the matter is that many geologists have looked long and hard for any evidence of impact deformed and brecciated rock, shocked quartz, shatter cones, high pressure mineral polymorphs, impact melt sheets and/or dikes, and impact-related pseudotachylytes associated with the Nastapoka Arc. Despite repeated efforts to find it by geologists and expectation that it would be found, such evidence has been found to be completely absent. Instead, they have found that local and regional structure, stratigraphy, and other aspects of the geology of the Nastapoka Arc soundly refute the theory that it was created by an extraterrestrial impact and solidly demonstrate the fictional and imaginary nature of a hypothesized "Hudson Bay Impact." The question about the age of the "Hudson Bay Impact" lacks any answer because the "Hudson Bay Impact" never occurred in the first place. When looking at Hudson Bay and Nastapoka Arc with Google Earth, a person has to understand that there are many other geological processes in addition to extraterrestrial impacts that are capable of producing arcuate geological structures and landforms. Go look at:
- 2. Eaton D. W. and F. Darbyshire, 2010, Lithospheric architecture and tectonic evolution of the Hudson Bay region. Tectonophysics. v. 480, pp. 1–22.Paul H. (talk) 05:28, 24 October 2010 (UTC)
Using abbreviations without explanations.
for instance - what is "Ma"?
However, a study of uranium/lead ratios of zircons from rock sequences near Meishan, Changxing, Zhejiang Province, China date the extinction to 251.4 ±0.03 Ma, with
- Ma is "megaannum", or "million years". It's got a metric prefix, and is slightly more flexible than "million years ago" because the "ago" isn't explicitly part of the name (i.e., you can use it for comparisons, like "A was found in rocks 6 Ma older than B", which is clumsier when you've got to work around "ago"). J. Spencer (talk) 00:32, 18 November 2010 (UTC)
Impact Origin of the Gulf of Mexico
The AAPG essay / commentary, Stanton (2002), about the Gulf of Mexico being an impact crater is not only very speculative, but it is also very badly flawed and sloppy in terms of its scientific content and interpretations. It relies too heavily on very dated, if not antiquated, reference material, including a 1979 textbook. This essay simply ignores the overwhelming number of more recent peer-reviewed publications that contain geophysical and geological data and research that soundly refute specific interpretations made by it along with the idea Gulf of Mexico being an impact crater. For example, Viele et al. (1989) and Nichlas et al. (1989) summarizes decades of research that readily refutes the idea that either fold belts of the Ouachita orgeny or the metamorphism of their associated Paleozoic rocks could have possibly been created by an asteroid impact of any magnitude. They are the result of nonimpact tectonic processes that not only acted over tens of millions of years but also started hundreds of millions of years before the Permian–Triassic extinction event. In another case, there exists ample published geophysical and geological research, as summarized by Goldthwaite (1991) and Sawyer et al. (1991), that demonstrates that the central uplift, which Stanton (2002) claims to exist in the center of the Gulf of Mexico, is completely imaginary. The idea that the Gulf of Mexico is an impact basin and that there are seriously problems with a plate tectonic explanation of its origin is a dead issue among geologists in general as illustrated by the papers by Dickinson and Lawton (2001) and Galloway (2008). Stanton (2002) is so extremely badly researched and argued that it fails to provide a credible case for the Gulf of Mexico being an impact crater.
Dickinson, W. R., and T. F. Lawton, 2001, Carboniferous to Cretaceous assembly and fragmentation of Mexico. Geological Society of America Bulletin. v. 113, no. 9, pp. 1142–1160.
Goldthwaite, D., ed., 1991, Introduction to Central Gulf Coast Geology, New Orleans Geological Society, New Orleans, Louisiana.
Galloway, W. E., 2008, Depositional evolution of the Gulf of Mexico sedimentary basin, in K.J. Hsu, ed., pp. 505-549, The Sedimentary Basins of the United States and Canada, Sedimentary Basins of the World. v. 5, Elsevier, The Netherlands.
Nicholas, R. L., and D. E. Waddell, 1989, The Ouachita system in the subsurface of Texas, Arkansas, and Louisiana, in R. D. Hatcher, Jr., W. A. Thomas, and G. W. Viele, eds., pp. 661-672, The Appalachian-Ouachita Orogen in the United States: The Geology of North America, v. F-2. Geological Society of America, Boulder, Colorado.
Sawyer, D. S., R. T. Buffler, and R. H. Pilger, Jr., 1991, The crust under the Gulf of Mexico basin, in A. Salvador, ed., pp. 53-72, The Gulf of Mexico Basin: The Geology of North America, v. J., Geological Society of America, Boulder, Colorado.
Viele, G. W., and Thomas, W. A., 1989, Tectonic synthesis of the Ouachita orogenic belt, in R. D. Hatcher, Jr., W. A. Thomas, and G. W. Viele, eds., pp. 695-728, The Appalachian-Ouachita Orogen in the United States: The Geology of North America, v. F-2. Geological Society of America, Boulder, Colorado
Science News resource
Acidifying oceans helped fuel mass extinction; Great die-off 250 million years ago could trace in part to waters' change in pH by Alexandra Witze October 8th, 2011; Vol.180 #8 (p. 10) Science News 188.8.131.52 (talk) 00:55, 10 October 2011 (UTC)
- It would be better to consult the full paper instead a popular science article. The paper discussed in this article is:
- Montenegro, A., P. Spence, K. J. Meissner, M. Eby, M. J. Melchin, and S. T. Johnston (2011), Climate simulations of the Permian-Triassic boundary: Ocean acidification and the extinction event. Paleoceanography. vol. 26, no. PA3207, 19 pp. doi:10.1029/2010PA002058. Paul H. (talk) 11:59, 10 October 2011 (UTC)
Algeo et al.
- Life in the Sea Found Its Fate in a Paroxysm of Extinction April 30, 2012 New York Times 184.108.40.206 (talk) 23:51, 8 July 2012 (UTC)
- That's no doubt important work. But it would be better not to rely on a New York Times summary for it, even trustworthy as the Times generally is. Looie496 (talk) 16:14, 9 July 2012 (UTC)
I came across this new research into why life took so long to recover from the extinction. According to this much of the planet was simply too hot for life to survive for millions of years.
- Science Daily is essentially a newspaper, and therefore not a good source for Wikipedia science article, but the Science paper that the story is based on would be usable (http://www.sciencemag.org/content/338/6105/366.abstract), or http://www.sciencemag.org/content/338/6105/336.summary, which is a perspective piece about it. Looie496 (talk) 14:43, 19 October 2012 (UTC)
- In 2003, Dr. Peter Ward observed, that global atmospheric oxygen levels plummeted, from Carboniferous / early Permian levels near 30%, to a third of that, from the later Permian, through the Triassic, and into the Jurassic. Those oxygen levels are plotted in figure two, of the following article:
- By c.300Ma, Pangea had assembled. Major mountain ranges eroded through the Permian. Then, Pangea began to break apart. Massive rifting, with immense flood basalts, occurred c.260Ma in China (Emeishan traps), c.250Ma in Siberia (Siberian traps), and c.200Ma with the opening of the Atlantic (Central Atlantic Magmatic Province). Those repeated rifting events coincide with repeated mass extinctions, and repeated falls in global atmospheric oxygen levels. Global temperatures rose, much of Pangea desertified, flora evidently died back. The global ecosystem did not begin to recover, until the Jurassic, after 200Ma, and after the last major episode of rifting. Dinosaurs, evolved with bird-like air sac respiratory systems, could cope with lower levels of oxygen, and began to dominate. Meanwhile, mammals, with less efficient lungs, were required to remain small. A prolonged period of rifting, breaking apart Pangea, with immense flood basalt eruptions; and resulting low levels of oxygen; and dinosaurs having better bird-like lungs; can explain the prolonged period of mass extinctions from c.260-200Ma, the rise of dinosaurs, and the relegation of mammals to small sizes & secondary niches. Mainstream citable sources could include Nature:
- as well as the documentary series Miracle Planet (episode 4). 220.127.116.11 (talk) 15:32, 24 October 2012 (UTC)
- Evidence for accelerating global extinctions from 270-250Ma, repeating 200Ma; and for Parareptiles struggling to survive, through that entire epoch, until vanishing 200Ma. Ipso facto, the period 270-200Ma may have been a single prolonged epoch of massive magmatism amidst the rifting apart of Pangea. The massive volcanisms repeatedly plunging the planet into greenhouse conditions, de-oxyifying the oceans, and atmosphere, without sustained recovery, until the Jurassic. 18.104.22.168 (talk) 17:29, 24 October 2012 (UTC)
Changes in marine ecosystems
Prior to the extinction, approximately 67% of marine animals were sessile and attached to the sea floor, but during the Mesozoic only about half of the marine animals were sessile while the rest were free living.
- Can't access the reference, but I was wondering if it really said 67% and not two-thirds, which seems a more likely approximation. Ssscienccce (talk) 08:51, 5 November 2012 (UTC)
- You can often find access to a paper by searching in Google Scholar even if it is paywalled by the publisher. I looked at the cited source and I don't believe it actually gives numbers for this at all -- I think the actual source for the numbers is probably this PNAS paper, which is publicly accessible -- see figure 1. Looie496 (talk) 23:00, 5 November 2012 (UTC)
Volcanism -reference does support
Recent climate models suggest such a rise in CO2 would have raised global temperatures by 1.5 to 4.5°C (2.7 to 8.1°F), which is unlikely to cause a catastrophe as great as the P–Tr extinction.
The reference cited does back up the non italic part of this sentence, but not the rest. Is this just the author's opinion, original research, or has a second citation, which does support the last part, been mistakenly left out? Common sense isn't enough, please add a source which does back up the claim that a 1.5 to 4.5°C rise "is unlikely to cause a catastrophe as great as the P-Tr extinction". 22.214.171.124 (talk) 22:46, 24 February 2013 (UTC)
- I agree. It is as if the CO2 link is artificially inserted. The Permian extinction was mostly a sulfur poisoning event. As we know volcanoes produce lots of sulfur, especially when they are huge and go on for almost a million years. So why create an artificial global working/bacteria reason for sulfur? Marcperkel (talk) 02:49, 18 March 2014 (UTC)
- If the second part of the assertion is not supported by the authority cited, the sentence violates WP:SYNTH and should be modified or removed. I don't know enough to edit it intelligently, but perhaps 126.96.36.199 or @Marcperkel: would kindly do it? J. D. Crutchfield | Talk 20:13, 9 June 2014 (UTC)
Possible relevant reference
I came across this http://www.readcube.com/articles/10.1038/ngeo154?locale=en which casts doubt on the theory that hydrogen sulphide emmissions could have caused the mass extinction. Maybe this could be included in the article? But unfortunately you can only see part of it without a subscription. G-13114 (talk) 18:24, 6 October 2013 (UTC)
- Interesting, but this is a study from 2008 which suggest the ozone layer stayed intact. But since 2008 studies have shown that methane potential is higher with implications for stratospheric ozone. Prokaryotes (talk) 18:31, 6 October 2013 (UTC)
This has been the common name for as long as I can remember. We have multiple WP:RS sources, ranging from National Geographic to COSMOS. Why would anyone revert such a perfectly reasonable and accessibility-improving addition to the intro? I was quite shocked to see such a speedy revert. — Preceding unsigned comment added by 188.8.131.52 (talk) 13:11, 1 April 2014 (UTC)
"see map above"
"The continents of the end-Permian and early Triassic were more clustered in the tropics than they are now (see map above),"
This sentence, in the "Methane hydrate gasification", says "see map above", but there is no map above. There is one map on the page, lower down, but doesn't seem to be the one this is referring to. Was the map removed? Was this text copied from elsewhere?
- Removed the (see map above) bit - don't know the explanation ... but there is no map above. Thanks for noting that. Vsmith (talk) 03:22, 10 April 2014 (UTC)
- I suspect "See map above" was referring to the map of Pangaea, which appears below the former reference. The present map, however, does not show the location of tropics. We can speculate that the equator is supposed to be across the middle of the map, and that the tropics would lie some distance above and below that; but the map as it stands doesn't contain enough information to support the statement. It would be useful, if somebody wanted to take the trouble, to substitute a map that indicates the equator and the tropics, and then to restore the reference to it in the text. J. D. Crutchfield | Talk 19:49, 9 June 2014 (UTC)
The sub-section "Impact event" contains the following:
- One attraction of large impact theories is that theoretically they could trigger other cause-considered extinction-paralleling phenomena . . . .
What on earth are "cause-considered extinction-paralleling phenomena"? Would somebody who knows what this sentence is trying to say translate it into English, please?
I'll also point out that, as it now stands, the sentence attributes the power of causing such phenomena to large theories, rather than to large impacts. J. D. Crutchfield | Talk 19:40, 9 June 2014 (UTC)
- Ha ha. The trouble is, I think it's supposed to mean something legitimate: that large-impact theories are attractive because large impacts could trigger other phenomena that are considered potential contributors to the mass-extinction, so that large-impact theories can wrap up multiple potential causes in one package. I just don't know enough about the subject to be confident that that is true, or that it's what the original writer meant to say, so I don't want to put my interpretation into the article. J. D. Crutchfield | Talk 19:08, 10 June 2014 (UTC)
I'd like to know what Ma is an abbreviation for? I've never seen it before and can't find a reference on the internet; one site lists 750 different things it could be. — Preceding unsigned comment added by 184.108.40.206 (talk) 15:26, 17 October 2014 (UTC)
Ma is the standard abbreviation that Earth scientists use for megaannum, which is a unit of time equal to one million years. For a discussion of its usage go see Discussion of GSA Time Unit Conventions. Paul H. (talk) 21:15, 17 October 2014 (UTC)
Trying to bring this into perspective for people. When you say that 57% of 'families' went extinct, either it's very abstract for them, or they think of 'family' like a mother and father and kids, and they all died. I hear people say 96% of species went extinct, but apparently that's only marine species. And so they tend to think only 96% of the individual animals died. Which is a bad thing to happen, but not nearly accurate.
So, how many individuals died? If 96% of all species went extinct, that means 100% of the individuals in 96% of the species died. Probably a lot of individuals in the surviving 4% of species also died, but less than 100% for each of these species. So I'm guessing, something like 99.9% of all individuals died, but that's just a guess. That number would really bring the PT extinction into perspective. — Preceding unsigned comment added by 220.127.116.11 (talk) 21:57, 4 October 2014 (UTC)