Talk:Cambrian

The link to the Florian subsection of time is currently redirected to a certain St. Florian. Disambiguation and expansion with more information than I have is in order. 67.171.194.78 00:00, 12 January 2006 (UTC)

more info on what Fauna developed is needed Basalock 00:15, 4 March 2007 (UTC)

Confusing statement

Aside from a few enigmatic forms that may or may not represent animals, all modern animal phyla with any fossil record to speak of (except bryozoans) appear to have representatives in the Cambrian, and of these most except sponges seem to have originated just after or just before the start of the period. However, several modern phyla, primarily those with small and/or soft bodies, have no fossil record, in the Cambrian or otherwise.

What a mess those two sentences are. First it says that all modern phyla are represented, then it says some aren't. And are the "few enigmatic forms" from the Cambrian, or are they current (I'll take a guess at cambrian, but I shouldn't have to)? The structure of this part is very confusing, and should be sorted out. Totnesmartin 17:39, 4 March 2007 (UTC)

It's a very nice contradiction - that's what it is. It demonstrates bold attack followed by cowardly retreat. I'll take a look. Said: Rursus ☻ 12:18, 2 December 2007 (UTC)

Now reformulated. Said: Rursus ☻ 12:25, 2 December 2007 (UTC)

Ma vs mya

The article currently includes uses of both Ma and mya. My sense is that this should be standardized on one or the other, or is there a reason to use both forms? WilliamKF (talk) 19:14, 30 November 2008 (UTC)

Extinction events

It sounds like there is an extinction event at both the beginning and end of this period. However, I wasn't certain after reading. I feel some rework is needed around this concept to clarify it in the text. WilliamKF (talk) 19:37, 30 November 2008 (UTC)

• • Cambrian Characteristics**

The Cambrian era was known for all of its little creatures. Trilobites, opabinias, wiwaxias, anomalocarus and more. I am a lucky 11 year old girl who recieved a wonderful informational book for Christmas called Prehistoric Life. It was considered a reference book in the library. It has all the eras including Earth formation and evolution of humans. Say you flip over to the Cambrian era; it has pictures of fossils, what time in the Cambrian era it was from, and a short paragraph about it. Some of them even have a computer generated picture. —Preceding unsigned comment added by 76.95.19.243 (talk) 16:25, 22 January 2011 (UTC)

To-do list

GA review – see WP:WIAGA for criteria

{{subst:#if:This list may be handy for highlighting areas in need of completion before GA status is achieved. Feel free to edit it.|

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1. Is it reasonably well written?

   A. Prose quality:

   {{subst:#if:Improving; still sketchy in places|Improving; still sketchy in places|}}

   B. MoS compliance for lead, layout, words to watch, fiction, and lists:

   {{subst:#if:adequate|adequate|}}

2. Is it factually accurate and verifiable?

   A. References to sources:

   {{subst:#if:work in progress|work in progress|}}

   B. Citation of reliable sources where necessary:

   {{subst:#if:work in progress|work in progress|}}

   C. No original research:

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3. Is it broad in its coverage?

   A. Major aspects:

   {{subst:#if:*History

• Geography
• Geology
• Climate
• Events
• Palaeontology
• Geochemistry|*History
• Geography
• Geology
• Climate
• Events
• Palaeontology
• Geochemistry|}}

1. B. Focused:

   {{subst:#if:OK atm|OK atm|}}

2. Is it neutral?

   Fair representation without bias:

   {{subst:#if:Not really too many controversies here, I think|Not really too many controversies here, I think|}}

3. Is it stable?

   No edit wars, etc:

   {{subst:#if:Development in progress but no places of disagreement|Development in progress but no places of disagreement|}}

4. Does it contain images to illustrate the topic?

   A. Images are copyright tagged, and non-free images have fair use rationales:

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   B. Images are provided where possible and appropriate, with suitable captions:

   {{subst:#if:More images would be nice; especially for flora 'n' fauna|More images would be nice; especially for flora 'n' fauna|}}

5. Overall:

   Pass or Fail:

   {{subst:#if:Not yet ready for nomination|Not yet ready for nomination|}}

To the problem of the Lower Cambrian boundary and subdivision

Rozanov, A. Yu.; Maoyan Zhu, K. L. Pak and P. Yu. Parkhaev (2008). "The 2nd Sino-Russian Symposium on the Lower Cambrian Subdivision". Paleontological Journal 42: 441-446. doi:4. ISSN 10.1134/S0031030108040151. http://www.springerlink.com/content/l70876jn8q5412k0.  "The participants of the symposium pointed out the following: (1) The officially approved stratotype of the Lower Cambrian boundary for the base of the Cambrian at the Burin Peninsula, Newfoundland is inadmissible due to the insecure principle of using of ichnofossils for correlation, very poor faunal characteristics of the section, the absence of possibility to obtain detailed paleomagnetic and isotopic data. The problems of another possible principle for substantiation of this particular stratigraphic boundary and, consequently, another sections for the stratotype of the base of the Cambrian, were discussed. The "Dvortsy" Section on the Aldan River, Siberia was suggested as the most suitable candidate for the Lower Cambrian boundary stratotype (explanation: it is base of the Tommotian). ... (3) The major result of the symposium is the scheme proposed for the subdivision of the Lower Cambrian into stages, with a nomenclature, each stage stratotype and each lower boundary stratotype. It was reached a decision to send this scheme as the base of the nomenclature or a working model for the Lower Cambrian stages to the Subcommission of the Cambrian System. .... It was concluded that the most suitable level for GSSP of the Lower Cambrian boundary is the FAD of the mollusk Aldanella attleborensis, associated with the appearance of the first archaecyaths"

A.Yu. Rozanov, V.V. Khomentovsky, Yu.Ya. Shabanov, G.A. Karlova, A.I. Varlamov, V.A. Luchinina, T.V. Pegel’, Yu.E. Demidenko, P.Yu. Parkhaev, I.V. Korovnikov, N.A. Skorlotova (2008). "To the problem of stage subdivision of the Lower Cambrian". Stratigraphy and Geological Correlation 16 (1): 1–19. doi:10.1007/s11506-008-1001-3. http://www.springerlink.com/content/v6785v3x25263l85/. 
Free text: http://vendian.net76.net/Lower_Cambrian.pdf

Remember though that at present, the Tommotian stage is only regionally used, in Siberia. Where Russian stratigraphers establish the base of their Tommotian division has no meaning to the rest of the world, which uses the Fortunian ICS stage. There seems to be a dispute between Russian and American stratigraphers going on, which is probably more political than scientific in nature. Therefore I doubt this information is important enough to be included in the article. What seems important to me is: A the information that the Cambrian is officially subdivided into four series and twelve stages, most of which haven't been named yet; B the names of the internationally recognized stages and series; C that local subdivisions are widely used too, of which the Siberian is an important one; D the name Tommotian (and other Siberian names) can be used in this article, but not in the current predominant way (the Siberian stratigraphic subdivision is given unequal weight -this is a POV!). Best regards, Woodwalker (talk) 12:32, 17 August 2009 (UTC)

Where ignorance, there negation and emptiness. Aleksey (Alnagov (talk) 11:54, 18 August 2009 (UTC))

So okay, what part of that was ignorant? Or are you opposed to using the ICS timescale as a reference at Wikipedia? Please give a constructive reaction instead of being cryptic. Woodwalker (talk) 12:42, 18 August 2009 (UTC)

Symbol

Do we really want the Cambrian and Precambrian represented in the geological period template by an "E"? I can see that we want to avoid ambiguity with the Cretaceous and Carboniferous, but can't we do that by just choosing different colours and retaining "C"? And how do we edit the geological period template? --Michael C. Price ^talk 12:04, 15 December 2009 (UTC)

The standard symbol for the Cambrian in geologic maps is a capital C with a horizontal bar through it. It may look like an E. Woodwalker (talk) 18:24, 15 December 2009 (UTC)

Thanks. --Michael C. Price ^talk 20:24, 15 December 2009 (UTC)

Reference to broken DOI

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Є?

Why is Є representative of Cambrian? The symbol appears only in the color-coded bar in the upper right, with no explanation in the article. Spril4 (talk) 02:34, 27 July 2010 (UTC)

To avoid confusion with the Carboniferous? (I asked the same question [1]) --Michael C. Price ^talk 04:07, 27 July 2010 (UTC)

Millions and millions

Hi there. In the Subdivisions section the article reads, (499 ± 2 million years ago to 488.3 million years ago million years ago ; also known as Late Cambrian, Merioneth or Croixan). There's an extra "million years ago" in there, but there's some period span code used and I don't know how to fix it. Any takers? --Smoggyrob | Talk 05:59, 2 September 2010 (UTC)

Origin of the name of the period

The name 'Cambrian' is stated to be the Latin name for Wales. In the article on the Precambrian it is said to be the Roman name for Wales. The article Cambria refers to the name (Cambria) as being the 'classical name of Wales', a 'Latinised form' of the native Welsh word 'Cymru'. The question is this: was 'Cambria' the name used by the Romans of the country they invaded 2000 years ago (and hence 'Roman' and indeed 'Latin') or is it a later coinage as is asserted elsewhere on the web (and hence not Roman but simply 'Latinised')? There is interesting discussion in the etymology section at Wales. I'll make further enquiries myself. It would be good to get this right. cheers Geopersona (talk) 07:28, 12 December 2010 (UTC)

What mark the base of Tommotian?

What mark the base of Tommotian? For example, FAD of Treptichnus pedum in the Fortune Head, Newfoundland mark the base of the Cambrian. Mikelemot (talk) 21:09, 30 October 2011 (UTC)

Future of the GSSP of the base of the Cambrian System

At last it happens! The leading members of the International Subcommission on Cambrian Stratigraphy recognized the failure of the GSSP of the base of the Cambrian System in the Fortune Head section, Newfoundland, and Treptichnus pedum as its marker.

"In the future, when most Cambrian GSSPs are established, it will be necessary to restudy the definition of the GSSP at the base of the Cambrian System. A problem has arisen with the ichnofossil whose FAD has been defined as coinciding with the base of the Cambrian. Subsequent to ratification of the GSSP in the Fortune Head section, Newfoundland, Trichophycus pedum has been found at horizons 3.11 m and 4.41 m below the GSSP point in the stratotype section (Gehling et al. 2001). Zigzag traces of Trichophycus sp. have been found even farther below the GSSP level in the stratotype. After re-examination of the occurrences of trace fossils in the Fortune Head section, Gehling et al. (2001) recommended a re-evaluation of the stratigraphic ranges and taxonomic assignments of ichnotaxa there. In addition to the issue of identifying the horizon containing the Cambrian GSSP on trace fossil evidence, there are no stratigraphic tools other than trace fossil assemblages that can be used to constrain the GSSP in the stratotype, nor to correlate the horizon outside its place of definition. This means that the GSSP level, or the T. pedum FAD level, has never been confidently recognized in any section in the world apart from Fortune Head. This casts doubt on the international correlation utility of this GSSP."

PENG, S.C.; BABCOCK, L.E. (2011). "Continuing progress on chronostratigraphic subdivision of the Cambrian System". Bulletin of Geosciences 86 (3): 391-396. http://www.geology.cz/bulletin/fulltext/1273_Peng.pdf. 
Aleksey (Alnagov (talk) 11:44, 11 November 2011 (UTC))