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Geology B‑class High‑importance

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Philcha's notes (for use in article)

• - Dorritie's very comprehensive account; explains poor fossil record; lots of refs.
• - Benton
• - "How to kill almost all life"
• - links
• - C13 oscillations: good if it had date estimates
• - Ward & co argue for press/pulse model
• - plants!
• - late P dry, early Tr wetter; Lystrosaurs' tolerance for low O2 and high CO2
• - coal gap, correlated to wetter climate.
• - insects!
• - fungal spike eases correlation problems
• - White (Leeds) covers a lot of ground.
• - dating of final extinction and Siberian Traps
• - more volcanism (non-basaltic) in China!
• - Isozaki on non-basaltic volcanism's contribution to double whammy and superanoxia
• - Wignall examines linkage (not 100%) between FBs/LIPs and extinction
• temporal link bet Emeishan and Guadalpian extinction.
• useful links and analysis.
• - Siberian Traps extended into sea.
• Hypercapnia and hypoxia: , , , ,

Philcha Philcha (talk) 14:52, 18 January 2008 (UTC)

Nature article

This recent article also provides a good review that could usefully be incorporated into this article. Verisimilus T 07:57, 12 July 2007 (UTC)

Nature articles are only available to subscribers - if you have access, I suggest you add a summary.Philcha 19:00, 13 July 2007 (UTC)

Marine losses

It also strikes me that the article's review of extinct organisms is very much oriented to the ones that went catastrophically extinct. It doesn't seem to provide a very rounded view of the extinction as a whole, making it look even more severe than it actually was. Could this be addressed? In fact, the table itself isn't thoroughly encyclopaedic and I'm not sure it's in its best position in the text of the article - perhaps it would be more appropriate to float it? Verisimilus T 08:06, 12 July 2007 (UTC)

Everything I've ever read about the P-Tr extinction suggests or states that the slaughter was appalling and the survivors may just have been extremely lucky. Michael Benton even wrote a book "When Life Nearly Died". Other sources I've seen suggest this extinction was the only one which showed evidence of severe losses among land plants and insects (they say this but without giving details, alas - can you help?).

Re the percentage level of extinction, I've seen articles which say that the widely-quoted estimate of marine species lost was calculated from the empirically-supported figures for marine families lost, but that this calculation made some dubious "business as usual" assumptions about the intermediate ratios needed to estimate species-level extinctions from family-level extinctions - that's on my "to do" list.

What do you mean by the table itself isn't "thoroughly encyclopaedic"? If you mean not detailed enough, I suggest adding much more detail would require it to be moved to a separate "List of victims" article. But then the P-Tr extinction article would still have to have some sort of summary.

I'm not sure about floating the "victims" table. The problems are: it makes the text very narrow and therefore harder to read (web usability studies suggest that about 60 characters per line is optimum); and as the table gets longer unrelated paragraphs / sections get caught up in the float, which makes it appear that the table is relevant to them as well (unless you add BR tags as I did for the ankle images in Archosaur, but that has disadvantages too). Philcha 19:16, 13 July 2007 (UTC)

In the "Marine Extinctions" table, placoderms are listed as having gone extinct. But other sources--both within and outside of Misplaced Pages--date the extinction of the placoderms to the late Devonian (example: the Late Devonian extinction article, http://en.wikipedia.org/Late_Devonian_extinction; I think they should be removed from the table, unless perhaps there's some debate about the time of their extinction I'm unaware of.

I do like the tables, however, and it would be great to make one for terrestrial extinctions, and also to add them to add them to all the other mass extinction articles and standardize their format. Glyptodon 08:52, 13 November 2007 (UTC)

Dubious

When are you counting as the start of the history of the oceans? The oceans were almost enitrely anoxic until around 2,700 million years ago... This could use a little re-wording.

Also, excuse me meddling with your prose as you write it... I'm always being told off for writing sentences that are too long and an aversion to them has become ingrained... Verisimilus T 20:47, 13 July 2007 (UTC)

WP:CITET

OK, this is just my interpretation, and mostly it's what's done in articles. If its a newspaper or magazine, you use the exact date of year-month-day. If it's a science journal, only the year is required, because if you cite correctly, everyone searches by volume and/or issue number, so the exact date of publication isn't useful. Furthermore, you do not have to wikilink the date, the template does it automatically. Orangemarlin 15:13, 14 July 2007 (UTC)

linkage and foil

This is a very good article with excellent links. Very interesting. I have however a few remarks on the science, firstly, sorry i say it becus i said it before, i remember from the book first posing impact as the cause of the jurassic extinction it said for many if not every major extinction an iridium anomaly is there. It is a bit strange to see it so consistently denied.(esp. since the theory has been denied herself. My guess would be he sampled greenland) Next, the low sea levels preceding the extinction are significant. Generally spoken water does not generate on a planet our size, does it? It will actually more often evaporate from a planet. (any subsequent sealevel rise suggests a high concentration of water in the then atmosphere) A sudden reversal in such a trend is hard to understand, wich makes me interested in radioisotopes of water from around the boundary(i would guess arid places being the best to start looking). Then i wonder why noone notices the possibillity of several impacts of eg. cometary fragments, or even seperate objects. It is also impossible that there are 2 huge craters dating to aprox. the boundary and there would be no Ir- anomaly at all . Have there been attempts to date impacts through the late permian in that way? Lastly i don't quitte well see how the cometary impact theory can be easily discarded, especially that the majority of extinctions was seabased, suggest something to have to do with water. Another reason to look for several impacts is the anoxian phase in the record since it supposedly stems from continued heating of the environs. Perhaps this is weird, but as long at is is not researched how will we know if not several impacts in a row (some of them near simultaneous, and probably in sea) caused the heating. Possibly the confusion is due to the siberic ashlayers. But elsewhere the option that geologic events caused such widespread extinction is made rather improbable. Although there is no clear relation between impacts and vulcanism, there is also no reason why a present pressurized magma chamber would not coincedentually interact, perhaps it is as obscure as that.(has there been an impact in the vulcanous region (siberia) of that period) 77.251.179.188 23:40, 18 October 2007 (UTC)

The evidence is generally against impact(s) being the primary cause, the best records recording plant pollen and spores show that the extinctions occurred over many years, not as one or a few major catastrophes. Also keep in mind that the oceans had been around for a long time before this event occurred and sea level relates more to the placement of the land masses resulting from effects caused by continental drift and how much water is "tied up" in poler ice or glaciers. If you want to look for correlations between impacts and volcanism, look for magma intrusions and/or volcanoes on the opposite side of the plant from were you thick the impact zone is. 00:14, 19 October 2007 (UTC) —Preceding unsigned comment added by Hardyplants (talk • contribs)

GA Review

I am troubled that an editor with hardly any experience with this article nominated it for WP:GAC. I think the article is close, but a long ways from GA status. Here are a few concerns:

1. The article is about the extinction event (which is biological). It is not about the geological causes of that event. Similar to the two articles, Cretaceous–Tertiary extinction event, an Featured article that focuses solely on the biological extinction, and K–T_boundary, which focuses on the geological event. They are separate, become one did not necessarily lead to the other.
2. The references, though cleaned up, are still a mess. I continue to find errors, use of unreliable sources and websites. Moreover, there are still a few references that have not been standardized to WP:CITET.
3. Several sections need substantial copyediting. Bullet-pointed sections just aren't acceptable.
4. There are a bunch of wiki-links that aren't pointing to real articles.

I am concerned that an uninvolved editor decided to to move to GA status without discussing it with the editing group. I hope any GA reviewer will take this under consideration. OrangeMarlin 02:52, 9 January 2008 (UTC)

Actually, the extinction event and the boundary itself are inextricably linked. Geological boundaries- particularly major ones like the PT and KT - are traditionally discriminated on the basis of faunal and floral change - between Palaeozoic and Mesozoic communities, and Mesozoic and Cainozoic respectively, in these cases. It's not by chance that extinctions are coincident with chronostratigraphic boundaries, and such a boundary is not really an "event" (except in so far as it may be taken to be an arbitrary point in time). As for the rest of your points - I'm surprised. From a brief glance, I think it might pass as a GA. Badgerpatrol (talk) 21:34, 9 January 2008 (UTC)

I know that they are linked, but IMHO, shouldn't we keep the geological stuff separated from biological. Both together, like at K-T made for a HUGE article that was hard to handle. I agree they are linked, but for the purpose of GA, tighter articles go further. Moreover, it is well-understood that GA is not as critical as FA. I think with K-T, I just skipped GA and went straight to FA. This article requires a lot more copy-editing, which I'm trying to do, in between putting up with personal attacks from Creationists. OrangeMarlin 06:27, 14 January 2008 (UTC)

First, Badgerpatrol is right - many scientists treat the fungal spike as the boundary between the Permian and Triassic (yes, I know it's not the international standard definition, see GSSP for the Permian-Triassic Boundary; but that's no good for terrestraila sediments, see PALEOSOL AND VERTEBRATE EXTINCTION ACROSS THE PERMIAN-TRIASSIC BOUNDARY IN THE KAROO BASIN, SOUTH AFRICA; so for practical purposes the fungal spike and the C13/C12 anomaly are treated as markers, see for exmaple An accurately delineated Permian-Triassic Boundary in continental successions).

Second, it would be ridiculous not to discuss the causes of the "mother of all mass extinctions"; and a thorough, balanced dicussion cannot exclude any type of cause just because it is the subject of the "wrong" scientific discipline. You've implicitly conceded that yourself, in I think with K-T (Cretaceous–Tertiary extinction event), I just skipped GA and went straight to FA", as the two most likely causes of that are astronomical and geological. In fact the K-T article (FA!) shows that the whole of objection 1 above ("It is not about the geological causes of that event") is nonsense. Also K–T boundary is not a good example of anything -it's a poorly-scoped mess at present.

Objection 2 above is little better. "I continue to find errors, use of unreliable sources and websites" contains no examples and therefore is: (a) unhelpful; (b) an attempt to avoid scrutiny of the criticism.

Objection 3 above is not based on Misplaced Pages's stated rules (Misplaced Pages:Embedded list).

In fact I've just checked Misplaced Pages:Good article criteria and Misplaced Pages:Scientific citation guidelines, and the only objection supported by these is objection 2, but that has no value if not supported by examples of each of the alleged faults. Philcha (talk) 13:46, 18 January 2008 (UTC)

Not inconsistent

Someone flagged

It was the Earth's most severe extinction event, with up to 96 percent of all marine species and 70 percent of terrestrial vertebrate species becoming extinct. Because approximately 25 percent of species survived the event,

as being inconsistent. Sorry to blockquote here but,

Misplaced Pages said (in its species page)"

* 287,655 plants, including:

o 15,000 mosses, o 13,025 ferns, o 980 gymnosperms, o 199,350 dicotyledons, o 59,300 monocotyledons; * 74,000-120,000 fungi; * 10,000 lichens; * 1,250,000 animals, including: o 1,190,200 invertebrates: + 950,000 insects, + 70,000 mollusks, + 40,000 crustaceans, + 130,200 others; o 58,808 vertebrates: + 29,300 fish, + 5,743 amphibians, + 8,240 reptiles, + 10,234 birds, (9799 extant as of 2006) + 5,416 mammals.

"

This demonstrates the 25% can't be worked out from the data in the first sentence and is thus not based said data. I see nothing else for it to be inconsistent with. Hence, the flag was removed. Menswear (talk) 10:42, 15 January 2008 (UTC)

I may have missed the point here, but surely the actual reason it's not inconsistent is because it is mixing environments. It is possible for 96% of marine species and 70% of terrestrial vertebrate species to be extinguished and still retain 25% of overall species-level biodiversity. That may be what you are trying to say, in which case I apologise for restating it.(In any case, if the 96% is taken from the Sepkoski curve or some variant thereof, it is a bit misleading. That curve specifically refers to marine shelly organisms. There's no direct evidence (for obvious reasons) for a reduction in diversity of e.g. picoplankton, which are extremely small and have no preservable hard parts.) Badgerpatrol (talk) 12:41, 15 January 2008 (UTC)

Recovery

According to Sahney, Sarda and Benton, Michael "Recovering from a mass extinction" 2008-01-18 the full ecological recovery (measured by the presence of highly specialized niche species) took 30 Ma. LeadSongDog (talk) 16:26, 18 January 2008 (UTC)

1 extinction or 2? Other timing considerations

In a long-ago version

Undue weight issues. Most articles do not give much credence to the view. Moreover, the fungal spike has been largely discredited too. It's not our job to represent every single theory. OrangeMarlin 18:43, 18 January 2008 (UTC)

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