Talk:Late Devonian extinction
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Late Devonian extinction is part of WikiProject Geology, an attempt at creating a standardized, informative, comprehensive and easy-to-use geology resource. If you would like to participate, you can choose to edit this article, or visit the project page for more information. |
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[edit] 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:
- 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.
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)
- 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
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- 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)
[edit] 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)
