Talk:Cambrian

Untitled

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

---

This list may be handy for highlighting areas in need of completion before GA status is achieved. Feel free to edit it.

1. Is it well written?

   A. The prose is clear and concise, and the spelling and grammar are correct:

   Improving; still sketchy in places

   B. It complies with the manual of style guidelines for lead sections, layout, words to watch, fiction, and list incorporation:

   adequate

2. Is it verifiable with no original research, as shown by a source spot-check?

   A. It contains a list of all references (sources of information), presented in accordance with the layout style guideline:

   work in progress

   B. Reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose):

   work in progress

   C. It contains no original research:

   D. It contains no copyright violations nor plagiarism:

3. Is it broad in its coverage?

   A. It addresses the main aspects of the topic:

• History
• Geography
• Geology
• Climate
• Events
• Palaeontology
• Geochemistry

1. B. It stays focused on the topic without going into unnecessary detail (see summary style):

   OK atm

2. Is it neutral?

   It represents viewpoints fairly and without editorial bias, giving due weight to each:

   Not really too many controversies here, I think

3. Is it stable?

   It does not change significantly from day to day because of an ongoing edit war or content dispute:

   Development in progress but no places of disagreement

4. Is it illustrated, if possible, by images?

   A. Images are tagged with their copyright status, and valid non-free use rationales are provided for non-free content:

   B. Images are relevant to the topic, and have suitable captions:

   More images would be nice; especially for flora 'n' fauna

5. Overall:

   Pass or Fail:

   Not yet ready for nomination

To the problem of the Lower Cambrian boundary and subdivision

Rozanov, A. Yu. (2008). "The 2nd Sino-Russian Symposium on the Lower Cambrian Subdivision". Paleontological Journal. 42 (4): 441–446. doi:10.1134/S0031030108040151. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help) "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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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)

The name comes from a combination of the Welsh word 'Cymru' - usually pronounced camm-ree in English - with the suffix also used in the name of places such as Northumbria and Cumbria. Hence Cam-bria

BTW, the terms are pronounced as Camm-bree-a and Camm-bree-ann, the first syllable rhyming with ram - not as in Cambridge. Cambrian and Cambria has nothing to do with the university city.

Other place names with the Roman 'ia' ending are Hibernia, Scotia, Caledonia and of course, Britannia, although whether Cambria was in fact the Roman name for what later became Wales, or whether it was a post-Roman name coined by the few literate monks and scribes of the early Anglo-Saxon period for the same area, I don't know.— Preceding unsigned comment added by 80.7.147.13 (talk) 15:58, 23 June 2012 (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. (2011). "Continuing progress on chronostratigraphic subdivision of the Cambrian System" (PDF). Bulletin of Geosciences. 86 (3): 391–396. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
Aleksey (Alnagov (talk) 11:44, 11 November 2011 (UTC))

LAST NEWS

By the rules of the International Commission on Stratigraphy, a GSSP may be revised after 10 years from the time of its ratification.

According to the order of the International Commission on Stratigraphy, the Subcommission on Cambrian Stratigraphy has created a new working group for revision of the GSSP of lower boundary of the Cambrian. Tasks of the Group:

1. Choosing a tool for identification of the lower Cambrian boundary (ichnofossils, chemostratigraphy or skeletal fossils).
2. Choosing a new locality and outcrops.
3. Choosing a level of the boundary in the outcrop (ie GSSP).

This information from oral report on the stratigraphic conference held 23-25 May 2013 in Moscow. Aleksey (Alnagov (talk) 22:10, 4 July 2013 (UTC))

Names of series and stages are derived from the name of the place where the GSSP is located. The name of Terreneuvian Series is derived from Terre Neuve, the modern French name for the island of Newfoundland. The name of Fortunian Stage is derived from Fortune Head, the headland on the Burin Peninsula, Newfoundland. If the new GSSP will be located in a other region of the world, then the Terreneuvian Series and Fortunian Stage will get new names. But it will not happen soon, because revision of the GSSP will take several years. Aleksey (Alnagov (talk) 07:34, 6 July 2013 (UTC))

Fauna

Under the fauna section comes the flora section. This section only mentions the lack of land plants, other than algae, etc, and does not cover sea plants, which I'm pretty sure were present. Can anyone add this information? — Preceding unsigned comment added by 67.232.30.10 (talk) 15:03, 7 March 2012 (UTC)

Also... "Most animal life during the Cambrian was aquatic, with trilobites assumed to be the dominant life form,[30] which has since proven to be incorrect." If it has been proven to be incorrect, why is it included (without explanation as to why it is relevant)? — Preceding unsigned comment added by 82.36.164.132 (talk) 21:57, 12 August 2014 (UTC)

Geography? Map?

Hey guys, I noticed the map detailing different continents/etc during the Cambrian is missing, why? Also, I remember a better map being added a while back, why was it removed? I didn't bother reading the rest of the talk page. --76.226.76.64 (talk) 00:12, 27 March 2012 (UTC)

Seriously, why have the maps been removed? That is very annoying and makes the articles so much less useful. — Preceding unsigned comment added by 76.177.0.183 (talk) 23:47, 20 March 2015 (UTC) Copyright; that person doesn't want us to use their maps.Qwed117 (talk) 15:44, 10 August 2015 (UTC)

Stating the obvious

I mean this in the most supportive way possible. In a technical, scientific article, generalizations having no useful content can be distracting and annoying. This article has its share. I am moved to this view in particular having just read "Cambrian rocks are very old...." Well, yes, one could safely assume that to be the case. All things Cambrian are "very old" but so is the Tower of London. I don't want to copy-edit; I think perhaps the original writer intended some point but failed to express it well. Thanks to all who contribute.SteveO1951 (talk) 17:47, 1 April 2012 (UTC)

I've removed those sentences that weren't really saying anything specific to the Cambrian - thanks for pointing that out. Mikenorton (talk) 21:08, 1 April 2012 (UTC)

Key events timeline is messed up

It is not a browser issue either - I checked IE, Firefox and Chrome and they all show the same problem.

I tried my hand at editing it, but could not figure out how to get the blank lines between letters in the vertical "span" text to disappear. That is one of the things causing labels to spill over the boxes provided for them.

Commutator (talk) 06:03, 28 October 2012 (UTC)

Conflicting statements about Climate

The article does not give a reliable statement of prevailing climate during the Cambrian.

The lead states "The seas were relatively warm, and polar ice was absent for much of the period." The Palaeogeography section refers to "a lack of sea ice" "the sea level was high" "the continents being flooded in warm, shallow seas" "The sea levels fluctuated somewhat, suggesting that there were 'ice ages', associated with pulses of expansion and contraction of a south polar ice cap." - All apparently good cited stuff.

Then the Climate section paints a different, contradictory (and unsourced) picture: stating

"The Earth was generally cold during the early Cambrian, probably due to the ancient continent of Gondwana covering the South Pole and cutting off polar ocean currents. There were likely polar ice caps and a series of glaciations, as the planet was still recovering from an earlier Snowball Earth. It became warmer towards the end of the period; the glaciers receded and eventually disappeared, and sea levels rose dramatically. This trend would continue into the Ordovician period."

I don't have enough knowledge of the palaeoclimate evidence of this period to correct this - I came to the article for information on it - but is there another editor around who can put this right?? Plantsurfer (talk) 10:00, 19 April 2013 (UTC)

In the table for each Geological time period, Climate summary data references to footnote [6] point to a wikipedia page which doesn't exist, for the file TemperatureLevelsOverEarthHistory.png. Could this be a deletion from wikipedia commons? Is there a better source for this summary data than a chart? I will try to investigate. Suggestions are welcomed. 1 March 2017 Matt Lemmon (talk) 22:38, 1 March 2017 (UTC)

The appearance of terrestrial fungi in the Cambrian

...is probably an important element that needs to be added to the article. Anyone feeling up to the task? Belsavis (talk) 11:56, 3 November 2013 (UTC)

Symbol

Why does the lead of the this article contain detailed information on making the symbol for the Cambrian? Much less, why is it even necessary? Is it so important that the symbol "Є" be covered at all? I've commented it out, but only on the grounds that this is baffling. If it must be kept, surely it can be moved out of the introduction. Or even footnoted if it is given to be so important that means of its insertion need be discussed. 209.255.230.32 (talk) 12:57, 6 November 2013 (UTC)

A single sentence is not exactly putting too much weight on it. It is discussed because it is widely used. The information is factual and can be reliably sourced. Wikipedia itself uses it. See the fossil range bar in the infobox on the right. I wouldn't object to moving it elsewhere though. But as of now, I can't really see any subsection where it would fit.-- OBSIDIAN†SOUL 18:26, 7 November 2013 (UTC)

Precambrian

The second paragraph of the lede says, "The Cambrian marked a profound change in life on Earth; prior to the Cambrian, the majority of living organisms on the whole were small, unicellular and simple; the Precambrian Charnia being exceptional." First, the majority of organisms today are on the whole small, unicellular and simple. Secondly, our own article on Ediacaran biota describes a variety of complex life forms, indicating that Charnia was not exceptional. Zyxwv99 (talk) 17:52, 6 September 2016 (UTC)

"Phylogenetic analysis has supported the view that during the Cambrian radiation, metazoa (animals) evolved monophyletically from a single common ancestor: flagellated colonial protists similar to modern choanoflagellates."

Just reading a book by Richard Dawkins called "the ancestors tale" in it he states the last common ancestor of all animals, including choanoflagellates, was about a billion years ago. Nearly twice as long as stated here.

Why the massive discrepancy? Surely someone has got this catastrophically wrong? — Preceding unsigned comment added by 2A02:C7D:5EB8:8C00:6110:6EE4:A213:1A5 (talk) 15:15, 22 February 2017 (UTC)

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Montezuman

The relationship between the "Montezuman" North American stage and the ICS scale as depicted in the table doesn't match the numbers I'm getting from other sources (~530-525 Ma). What gives? Abyssal (talk) 08:44, 20 November 2017 (UTC)

Which symbol?

Is the correct symbol for this period Є or Ꞓ? This article uses Є; Є redirects to Ukrainian Ye. There, at Ukrainian Ye#Related letters and other similar characters, we find Ꞓ, described as a Latin letter—but the description, "Latin letter Ꞓ", links to Ꞓ—which links back here, to Cambrian, rather than to an article about that letter. So it's unclear to me which of the two glyphs is actually the symbol for the Cambrian period. Largoplazo (talk) 17:32, 5 December 2017 (UTC)

The symbol Є is not correct. Cambrian period marked by the Latin symbol Ꞓ. Geologic Age Symbol Font. But Ꞓ not always correctly displayed in Internet browsers. Aleksey (Alnagov (talk) 10:33, 6 December 2017 (UTC))

Ah, I see. Because now I'm on browser at home (Windows 7) and can't see the Ꞓ, whereas it displayed properly on my office computer (Windows 10) yesterday. Thanks. Largoplazo (talk) 12:23, 6 December 2017 (UTC)

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Subdivisions

The table lists the ICS series, but only various regional stages, not the ICS ones where they exist. Is there a reason for this? Orcoteuthis (talk) 13:24, 18 January 2021 (UTC)

ICS link

Please update the link in ref [1] after "Subdivision of the Cambrian according to the ICS, as of 2021.[1]" to point to its new address https://stratigraphy.org/timescale/

Martin (Smith609 – Talk) 11:00, 28 June 2022 (UTC)

 Done Thanks for reporting this. The fix required a change to Template:Cambrian graphical timeline, which I have done. GeoWriter (talk) 18:40, 28 June 2022 (UTC)

"Was" or "Is"

The introduction says "Cambrian WAS the first geological period of Paleozoic...", while other periods have this verb in the form IS. Which one is correct then? Jack Jackie Pomi (talk) 14:22, 15 August 2022 (UTC)