Talk:Late Devonian extinction

Reorganisation
Some good content here, but it needs to be rephrased for the general (non-academic) reader and reorganised. Possible sections for a reorganised version: It may be necessary to adjust the order of the sections when we can see how it all reads, and to balance the content depending on how much of it is covered by more specific articles.Philcha 14:00, 14 January 2007 (UTC)
 * Introduction = first para in current version, including "marine biodiversity" image.
 * Brief description of late Devonian geography. Few non-specialists will have any idea that the world looked completely different then. Probably not including a map, as this would have to be large and there is a lot of disagreement about the details.
 * Difficulties of Devonian stratigraphy (confuses duration and timing). Needs to be pretty non-technical, but link to an article on stratigraphy for those who want to go further.
 * Duration and timing.
 * What died and what survived, plus any patterns if generally agreed by researchers, plus impact on ecosystems if generally agreed by researchers.
 * Possible causes. May have to be split into "major changes during this time" and "possible causes", as there was a lot going on which non-specialist readers would be unaware of - increase in size, extent and diversity of land plants (may have been a contributory factor!), increase in numbers and diversity of jawed fish, emergence of tetrapods.
 * References and links.


 * Yes, I'm unclear about a few things... but I'll just mention this: "Anoxic conditions in the sea-bed of late Devonian ocean basins produced some oil shales." How and why? Sorry if that's a stupid question but I'm honestly curious. 16:39, 6 February 2007 (UTC)Gerhard Bohm


 * I don't know specifics about this, but in general anoxic conditions allow for the preservation of organic material in fine sediments (mud that turns to shale) because the organic material is not oxidized and thereby lost. The absence of oxygen results in a cesspool-like situation that preserves organic material, ending up with (often) some very rich oil source rocks.  Hope this helps. Cheers Geologyguy 16:51, 6 February 2007 (UTC)


 * I've re-written much of the article to Philcha's scheme, but have reached the limit of my knowledge of the topic. I'd be very grateful if anyone able could expand upon what I've written, especially with regards to Devonian stratigraphy.  Thanks, Verisimilus  T  16:43, 14 February 2008 (UTC)

Bolids here
Has anyone tried to connect the Siljan bolide with the The Kellwasser event and the late Devonian extinction?  Said: Rursus   ☻   21:56, 26 February 2008 (UTC)


 * Yes. Found a google books something: "The Cretaceous-Tertiary Event and Other Catastrophes in Earth History" by Graham Ryder, David E. Fastovsky, Stefan Gartner. The craters possibly related would be: Charlevoix/Quebec/Canada 54 km Ø 357±15Ma and Siljan Ring/Dalarna/Sweden 55 km Ø 368±1.1Ma. According to the link from the article to the Earth Impact database, the Siljan ring is instead 376.8±1.7Ma, which may be due to different datings of the surrounding stratigraphicl layers.  Said:  Rursus   ☻   21:56, 26 February 2008 (UTC)

Graph
Can anyone wrap the text round the opening graph in the usual fashion?--Wetman (talk) 20:17, 12 December 2009 (UTC)

Copyright problem removed
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"Age of Fish" at cost of others ?
Beak-toothed placoderms (Ptyctodontida), like Materpiscis, preyed upon hard-shelled invertebrates. According to the documentary Animal Armageddon:


 * This lack of heavy armor was typical of its order, Ptyctodontida, which means "beak-teeth." Materpiscis was thought to live near the sea bottom, where it preyed on hard-shelled invertebrates like clams or corals. After snatching its food with its beak-like mouth, Materpiscis would grind up its prey with powerful crushing tooth plates.
 * http://animal.discovery.com/prehistoric/materpiscis/

If the evolution of jaws, by 410Ma, gradually gave rise to the Devonian "Age of Fishes", the perhaps the success of fish represents their consumption of other parts of the food web? 66.235.38.214 (talk) 11:22, 21 October 2012 (UTC)
 * From the marine extinction graph in the article, an the background rate of extinction rose c.400Ma, about the time of the evolution of jaws, and the dawn of the "Age of Fishes".66.235.38.214 (talk) 11:25, 21 October 2012 (UTC)
 * Relevantly, the ensuing Carboniferous period was the "Golden Age of Sharks"; aside from Coelacanths, all marine sarcoptergyian "lobe-finned fish" vanished with their placoderm "bony armor fish" cousins; Romer's Gap can be construed (from the article) to have been the ensuing "recovery period".66.235.38.214 (talk) 11:41, 21 October 2012 (UTC)
 * Inexpertly, given the extended duration of the decline, the entire episode can be construed as attributable to the "Age of Fishes", and the "Golden Age of Sharks", i.e. as a global fish feeding frenzy after their evolution of jaws. First, more primitive invertebrates were hunted out; then Sharks outcompeted (almost) all other fish, perhaps by being lighter, faster, and smarter.  Jaws, and the resulting explosion of fish, generated the biodiversity required for a few to evolve into tetrapods.66.235.38.214 (talk) 11:45, 21 October 2012 (UTC)
 * Repetitiously, lobe-finned fish did not emerge onto land "fleeing Mass Extinction"; instead they plausibly emerged onto land as part of the "fish feeding frenzy", brought about by jaws, and their ensuing genetic explosion. Worldwide, fish populations were booming, in the seas; so much so, that some even swam ashore.66.235.38.214 (talk) 12:33, 21 October 2012 (UTC)

The late Devonian extinction events coincides with the Variscan orogeny. 66.235.38.214 (talk) 15:02, 22 October 2012 (UTC)

Confusing References
Could someone explain references 1, 2, 4, and 5?

Currently they look like:
 * 1) Racki, 2005
 * 2) McGhee, 1996
 * 3) (a link to a source)
 * 4) Caplan and Bustin, 1999
 * 5) Stigall, 2011

I assume the names are authors, and they published something relevant in the years listed. Anyone know what? I'm doing some research. It's would be nice to know exactly what books or papers I'm looking for. Also if I not getting a Wikipedia policy or something, please provide a link explaining it. Thanks. 70.74.191.229 (talk) 08:43, 25 January 2015 (UTC)

This also applies to 18, 21, and 22. I assume that #4 is "Devonian-Carboniferous Hangenberg mass extinction event, widespread organic-rich mudrock and anoxia: causes and consequences" but don't what to change a reference without having read it yet. 70.74.191.229 (talk) 08:53, 25 January 2015 (UTC)


 * Seems those were added in Jan. 2010 by a Univ. of Chicago ip with the edit summary "Will add full references later" -- but "later" never came. Any help clarifying/completing those would be welcome. Vsmith (talk) 12:42, 25 January 2015 (UTC)


 * - #2 is George McGhee, The Late Devonian Mass Extinction: The Frasnian/Famennian Crisis. #1 is Toward understanding Late Devonian global events: few answers, many questions. #4 is Devonian–Carboniferous Hangenberg mass extinction event, widespread organic-rich mudrock and anoxia: causes and consequences as stated above. #5 may be Speciation collapse and invasive species dynamics during the Late Devonian “Mass Extinction”, although it has a 2012 date. I have access to full text versions of 1,4 & 5, if anyone needs copies. Mikenorton (talk) 16:47, 25 January 2015 (UTC)


 * Vsmith and Mikenorton: Thanks for the quick response. Any idea about 18, 21, and 22? If no one has any objections (or does it first) I will update the references in the article in the next couple of days with the information Mikenorton provided. 70.74.191.229 (talk) 22:26, 27 January 2015 (UTC)


 * Brezinski et al. 2009 is Evidence for long-term climate change in Upper Devonian strata of the central Appalachians. I'll search for others later. Mikenorton (talk) 07:31, 28 January 2015 (UTC)
 * Korn 2004 is probably Korn et al 2004 The youngest African clymeniids (Ammonoidea, Late Devonian) ± failed survivors of the Hangenberg Event. Mikenorton (talk) 20:21, 28 January 2015 (UTC)
 * Foote 2005 - which of Michael Foote's many papers this is I can't work out, 2005 seems to be the only year that he didn't publish one. Mikenorton (talk) 20:30, 28 January 2015 (UTC)

Viluy traps
In recent years the Viluy traps have been getting more attention. If you just go to Google Scholar and search on "Late Devonian extinction" and "Viluy," then filter for recent papers (last few years) you'll see what I mean. It looks like the underlying cause may have been Laurussia crashing into Gondwana, then spinning around, possibly disrupting mantle convection currents. The result was several mantle plumes breaking the surface at about the same time. book link Zyxwv99 (talk) 23:15, 29 April 2015 (UTC)

Article needs focus
When the Late Devonian extinction was classified as one of the big five by Raup and Sepkoski in 1982, it was based on elevated extinction levels for three successive stages: the Givetian, Frasnian, and Fammenian. Since then scholars have obtained more fine-grained data. There were extinction events at the end of each of these three stages. There were also highly elevated levels of background extinctions throughout the Devonian, with fluctuations that are not sharp enough to be called "events" but rather "biodiversity crises."

Today, "Late Devonian extinction" generally refers to the end-Frasnian extinction at 374.5 mya (also known as the Frasnian/Fammenian extinction). This was a pulsed event with five pulses, two of them notably larger and known as the Lower Kellwasser (LKW) and Upper Kellwaser (UKW) events.

"Late Devonian extinctions" (plural) includes the end-Frasnian and end-Famennian extinctions (but not the end-Givetian) as well as the "biodiversity crises" of the Frasnian and Fammenian.

Even though these are not the only possible definitions of these terms, these definitions are in widespread use. Conflating definitions goes against WP:DICT. Furthermore, we don't need to delete material in this article relating to the extinctions (plural) so long as we clearly identify it as a subsidiary or related topic. The main effect of my proposed revision would be on the organization of the lead. Zyxwv99 (talk) 00:57, 31 July 2015 (UTC)


 * You're are right, but the age of Kellwasser event is wrong, the event was placed at 374.5 ± 2.6 Ma (Geologic Time Scale 2012 by Gradstein). In the new ecological-severity ranking of biodiversity crises (McGhee et al,2013), the Kellwasser event raise to fourth-most severe in the Phanerozoic traditional biodiversity crises. Therefore, Kellwasser event is Late Devonian extinction, not other, and Hangenberg event is end-Devonian extinction.Aleral Wei (talk) 05:11, 6 January 2016 (UTC)

Incomplete sources, revisited
As mentioned above, there are a number of incomplete sources added by an editor in 2010. I don't have access to these materials; can anyone complete them?


 * Racki, 2005
 * Caplan and Bustin, 1999
 * Stigall, 2011
 * Sallan and Coates, 2010
 * Brezinski et al. 2009
 * Korn, 2004
 * Foote, 2005
 * Algeo et al., 2008
 * Digby McLaren, 1969
 * Archaeopterids, see Beck (1981) in Algeo 1998
 * (Caputo 1985; Berner 1992, 1994) in Algeo 1998

I'll post about this at the relevant wikiProjects as well.

Leschnei (talk) 12:53, 24 January 2017 (UTC)


 * OK, I provided links to several of these in the section above and will send you copies of the full text versions by e-mail if you like - I'll try to work out what the remaining ones are as well. Foote 2005 is a mystery - probably the wrong year quoted, as is the case for Stigall (2012 not 2011). Mikenorton (talk) 21:52, 2 February 2017 (UTC)
 * The first is in "Understanding Late Devonian and Permian-Triassic Biotic and Climatic Events: Towards an Integrated Approach" edited by D.J. Over, J.R. Morrow and P.B. Wignall, entitled "Toward understanding Late Devonian global events: few answers, many questions" by Racki G. in 2005. link to full text pdf. I'll spell out some of the others if I get time. Mikenorton (talk) 21:58, 2 February 2017 (UTC)
 * It's great that you're finding these sources but it would probably be better if you just add them yourself when you have time. I really have no knowledge of late devonian - I just stopped by to try to fix incomplete references. I doubt that I could slog my way through the sources and confirm that they are appropriate. Leschnei (talk) 02:54, 4 February 2017 (UTC)

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Another possible cause
I and many others believe that the galactic bow shock is responsible for many to all of the mass extinctions. Can you possibly list that as a cause? ThePRoGaMErGD (talk) 22:05, 1 May 2019 (UTC)
 * Got sources? — JFG talk 10:04, 26 May 2019 (UTC)

Loss of ozone
This article discusses the loss of ozone during this extinction event, but doesn't mention a supernova as a cause. Source: https://www.southampton.ac.uk/news/2020/05/ozone-extinction-event.page 98.123.38.211 (talk) 03:33, 10 May 2024 (UTC)

Is it possible that there was a coronal mass ejection (CME) during this period, which wiped out stratospheric ozone? 98.123.38.211 (talk) 10:47, 10 May 2024 (UTC)

Temperature
Shouldn't we mention what the average temperature was during the late Devonian extinction event? Isn't this a basic piece of information that people reading this article would expect to find here? 98.123.38.211 (talk) 03:35, 10 May 2024 (UTC)