Talk:Great Unconformity

Article name

When creating this article, I could not find the correct name for this feature. Is it Great Unconformity or The Great Unconformity? Vegaswikian 21:09, 15 Jun 2005 (UTC)

Essentially, just "Great Unconformity", although in running text a "the" is needed for grammar. Melchoir 15:16, 30 May 2006 (UTC)

Rewrite.

To put it simply: this article, and the references it is based on, are so poor that I am preparing to completely rewrite it.

- J. Johnson (JJ) (talk) 20:08, 3 October 2010 (UTC)

Done. I think there ought to be another section describing how "The Great Unconformity" is iconic for Young Earth creationists, but by WP:WEIGHT there should also be an explanation of why that view is totally rejected by the geology. And I don't have (yet?) sourcing for that. - J. Johnson (JJ) (talk) 22:13, 11 October 2010 (UTC)

Is this article right?

I'm not a geologist, but my impression is that this article is not consistent with modern usage, at least as it appears in this Nature paper. That paper describes the Great Unconformity as a global phenomenon associated with the end of Proterozoic Era, consistent with Powell's unconformity but worldwide in extent. Looie496 (talk) 21:54, 18 April 2012 (UTC)

That seems to be a very modern usage, with only that recent paper and some conference abstracts taking this global view - perhaps it's known as something else as well? I'll keep searching. Mikenorton (talk) 22:40, 18 April 2012 (UTC)

Cool. I encountered the term for the first time in that Nature paper, and came here looking for background, so I'm pretty much totally ignorant on the topic. Regards, Looie496 (talk) 22:50, 18 April 2012 (UTC)

As the article says, there are many unconformities (gaps in the stratigraphic record). Any sufficiently large and broad unconformity is likely to be deemed "Great" (usually associated with the supercontinent cycle). The article covers the two that seem most commonly mentioned in the popular press; I haven't surveyed the scientific literature for others. A quick Google Scholar search on "great unconformity" returns 33 hits, but only 18 with "-flood", so it isn't out of the question if someone wanted to survey those for other usages.

If the Nature article generates enough interest I might add a mention of Lipalian interval, but it will be several weeks before I get around to seeing the article myself. ~ J. Johnson (JJ) (talk) 00:48, 20 April 2012 (UTC)

I see some IP user already added a mention. That is fine, but please, per WP:CITEVAR, conform to the citation method already established in the article. I have reverted it; I suggest opening a new section here, and I will assist with the citation. I would also suggest that the new text really needs to clarify the time of this particular unconformity, and clarify its relation to the other two mentioned. ~ J. Johnson (JJ) (talk) 00:59, 20 April 2012 (UTC)

Section heading?

RM: Why do you think this article needs the section heading you added? It seems to me this is essentially a one-section article, so subdividing it into one section is, well, silly. (Unless, of course, someone wants to greatly expand the article, but that has not happened.) The TOC box also looks silly, so if you really want a section header the TOC needs to be suppressed with NTOC. ~ J. Johnson (JJ) (talk) 18:48, 6 June 2012 (UTC)

Please do not suppress the TOC it is correct here. If the heading is removed, then the article should be tagged with {{intro too long}}. Given that, the section heading actually makes sense. Vegaswikian (talk) 19:11, 6 June 2012 (UTC)

  The "intro" that (absent a header) you consider too long I consider the body of the article. If you consider that a long intro, then the obvious question is: where is the body? I think the real point of the header is to break out the lede from the rest of the article. But as I said, this is (so far) a one-section article, and I do not see why the lede has to be split out like that.

  As to the TOC (with or without the section header): without the TOC the article pretty nearly fits on one screen, and there is little to be gained from such a navigational aid. Present, it impedes the flow from the opening pair of sentences to the rest of the article. ~ J. Johnson (JJ) (talk) 20:26, 6 June 2012 (UTC)

Well, if you consider the intro to be the body, then the article is missing an intro. The MoS says to have both. The TOC gets added based on the number of headings. There is no good reason for this article to be different and suppress it. Vegaswikian (talk) 21:14, 6 June 2012 (UTC)

  So is this a long intro with no body? Or a short article with no intro? Or should we make it a one-section article with an intro and (lest anyone get lost!) a TOC? I submit that the common characteristic of all of these is that, all in all, this is a short article. By actual count, 75 words in the first paragraph, and (counting markup) about 400 words in the rest. Please note that the MoS does not say an introduction is absolutely required. Specifically: "Where the article is a stub, a lead may not be necessary at all." Which is my position: here it is not necessary. Also: "Once an article has been sufficiently expanded, generally to around 400 or 500 words, editors should consider introducing section headings." (Emphasis added.) But not mandated. In this case the article is not long enough to warrant such a heavy superstructure. ~ J. Johnson (JJ) (talk) 20:36, 7 June 2012 (UTC)

The MoS also states Once an article has been sufficiently expanded, generally to around 400 or 500 words, editors should consider introducing section headings. Given that this article is not a stub and is close to 400 words, your argument does not really work for me. Is it possible to add 50 more words to the article? I think the answer is yes and doing that would be more productive then discussing the reasons to eliminate a heading and ToC. Vegaswikian (talk) 20:57, 7 June 2012 (UTC)

  Well, your apparent view that at some magical word counts headers are mandated doesn't work for me. Are getting just a little wrapped around an axle here?

  Your statement, that "The MoS says to have both", is incorrect. And the bit that we have both quoted says that around 400 or 500 words, editors should consider an introduction. Okay, fine, let us consider. The substantial content of this article barely constitutes a single section, and I say it's overkill to give it a header. Though if you insist on a header for the second and third paragraphs — which are not so much examples as the primary instances of where the term is applied — then that last paragraph, which is not "examples", needs its own header, and the first section is only two sentences. I say that the second and third paragraphs are really expansion of the first paragraph (currently the intro), and separating them, whether by a section header or TOC, impedes the narrative flow. (If you really insist on an introduction than it should preface the existing content. Which poses a bit of problem, because summarizing this very short article is tantamount to repeating it.) In short, I say that a section header (or headers) is not required, adds nothing, and actually detracts from the article. ~ J. Johnson (JJ) (talk) 22:27, 8 June 2012 (UTC)

Re recent edits

Vegaswikian: two points about your recent edits. First, you reinstated the TOC without discussion, which (as I have previously argued, above) is overkill for such a short article. Your previous argument was (please correct me if this paraphrase is inaccurate) "the MOS says so", which I find a bit of a stretch. If you have better reasons please let me know.

Second, the paragraph you added at the end ("At Frenchman Mountain ...") has multiple problems. First, is this a third instance of a Great Unconformity? Or another appearance of Powell's? This needs clarification. If the latter, then it should be worked into the proper paragraph. However, in that case there is a question of whether this appearance is notable for any reason other than being near your home town.

Which leads to the second problem, of the sources. The first is a television story about vandalization of the exhibit on the trail; it doesn't even get to the geology. The next reference is to a web page that actually says something about the geology, but identifies no reliable source, and is hardly better than a blog. (There certainly are better sources, by experts.) The last reference (about the trail) is from a travel brochure, which is a really flimsy source. There is also the matter of citation style: whatever sources you add need to conform to the rest of the article.

And there is the matter of whether your addition (which in a former version constituted half of the article) is simply a coatrack for mentioning this "Great Unconformity Interpretive Trail". There is no showing that this trail is notable anywhere outside of Nevada.

For these reasons I am inclined towards removing the last paragraph entirely. ~ J. Johnson (JJ) (talk) 21:12, 20 September 2013 (UTC)

I just restored information that over time had been removed from the article. Now, if you want to rework the entire article to better list places where this geology is visible, that is clearly and option. I found it interesting that the Frenchman Mountain one shows up first on a Google search. As to this being different from the others, that would depend on how connected this feature is around the world. I'm not sure if we know the answer to that. However from what little I know, the various places where it is easily visible have a varying number of years visible. Given that, the best way would be to list the different sites in a table by location and the number of years missing. That would give readers more information and probably make for a better article. As to the TOC, yes it should be there. I'm glad you noticed that this was discussed a while ago, probably about 100,000 edits ago for me, so I find it interesting that my opinion of this has not changed over time. Vegaswikian (talk) 22:04, 20 September 2013 (UTC)

There is a recognized global connection or equivalent for Powell's Great Unconformity that is exposed in the Grand Canyon. This specific Great Unconformity, which is same unconformity exposed at Frenchman Mountain, is found across North America (Laurentia). Powell's Great Unconformity, is the craton-wide unconformity that forms the base of the Sauk Sequence (Megasequence) as discussed in detail by The Great American Carbonate Bank: The Geology and Economic Resources of the Cambrian-Ordovician Sauk Megasequence of Laurentia. Paul H. (talk) 04:29, 21 September 2013 (UTC)

I had thought from some scanning of sources that there might be the possibility of one. So my suggested table apparently needs to really list 'exposures' as you call them since these points are notable, but probably not sufficient for an article on their own. Vegaswikian (talk) 05:38, 21 September 2013 (UTC)

  Thank you, Paul. That's rather how I thought it was: craton broad, with multiple exposures. That certainly should be explained in the article, and that the Grand Canyon is not the only exposure (But possibly the first known?) I seem to recall another interpretive site in Pennsylvania, and I wonder how many others exist across North America. A quick Google search suggests: Missouri, Ohio, Wisconsin (?), North Dakota. This might warrant further study. Unfortunately, I don't have that book.

  VW: Showing up first in Google is significant only in that a Google algorithm calculates that a lot of people are interested in that site. It says nothing about notability. While it might be useful to mention some of the places where people can see the GU, the text you have added is gives WP:UNDUE weight to a single exposure, does not fit the structure of the article, and has extremely poor references not consistent with the other references. Sorry, but I am taking this out. If you have a better formulation please propose it here. ~ J. Johnson (JJ) (talk) 20:56, 21 September 2013 (UTC)

I have and you have chosen to ignore it. Vegaswikian (talk) 22:43, 21 September 2013 (UTC)

Your original formulation is faulty on multiple grounds. You have not proposed a better formulation, there is nothing to ignore. However, this point is rapidly becoming moot, as Paul has prepared a better formulation which covers what you wanted included. ~ J. Johnson (JJ) (talk) 21:54, 22 September 2013 (UTC)

Two comments. First, there are so many exposures that it will be impractical to list and calculate the age of missing time for all of them. Finally, that being said, the Grand Canyon and Frenchman Canyon exposures of the Great Unconformity are both regarded as being quite exceptional, if not unique, by geologists relative to all other exposures in the extent to which this unconformity is exposed and detail in which it can be studied. The Grand Canyon exposures are also notable in being the type section for the Great Unconformity. The Frenchman Mountains are regarded as both notable and unique by geologists in they expose the Great Unconformity and essentially a section of overlying Phanerozoic sedimentary rocks equivalent to the section found in Grand Canyon and, completely unlike the Grand Canyon, both the unconformity and section of underlying Phanerozoic sedimentary rocks are readily accessibility to both researchers and the lay public. Paul H. (talk) 23:43, 21 September 2013 (UTC)

  An excellent, most impressive rewrite! You do seem familiar with "Ga" geology, and I am pleased that I don't have to dive into it. Thanks.

  A number of comments. First, a strong objection to changing the reference style (i.e., short cites pointing an alphabetized list of references collected in a separate section). Hopefully there will be no objection to returning to that style?

  Other matters: the lead paragraph should be essentially a summary. I think the second paragraph should be in its own section. ("Unconformities in general"? "Introduction"? "Background"?)

  Although I think "unique" gets over-used, and incorrectly, I am inclined to accept your statement that the Frenchman Mountain exposure is notable, even exceptional, for the reasons provided. Granting that this is documented somewhere, yet it is unclear: where? This is a problem with collecting all of the citations at the end of a paragraph: it disconnects them from specific points, making verification unnecessarily harder. I strongly suggest that supporting references should be per sentence.

  As to VW's suggestion of listing exposures: I would suggest not exposures as such, but interpretive sites. Surely there are not that many. And I think it would be an excellent bit of geological education if the article could guide people to such sites in their region. ~ J. Johnson (JJ) (talk)

Thanks for your comments. Yes, I object to changing the reference style back. I find the fill-in-the-blank-column format to be an utterly useless, hopelessly inflexible, and utterly pain-in-the-rear end way of formatting citations. As far as I am concerned, it is also quite pointless and cumbersome to have separate "Notes" and "references."

That being said, I will review the use of "unique" and your other comments. Paul H. (talk) 00:22, 23 September 2013 (UTC)

  Well, I object that you changed it in the first place. I would also cite WP:CITEVAR. But let's break out that discussion into its own section.

I think "unusual" works. I was a little surprised that you took out "completeness and accessibility", as those go straight to why that exposure is notable. And not all redundant. ~ J. Johnson (JJ) (talk) 21:52, 23 September 2013 (UTC)

Does Hutton's Unconformity fit in here?

Although I'm aware that Hutton's Unconformity is sometimes referred to as the "Great Unconformity", it doesn't seem to fit in with the rest of the article. Sections 3,4 & 5 are all about the "Base Cambrian" unconformity, which Hutton's Siccar Point example is not. Would it be better to just mention it in a hatnote? Mikenorton (talk) 23:44, 11 January 2023 (UTC)

@Mikenorton: Agreed. The two "great unconformities" are hundreds of millions of years apart and totally unrelated to each other (except for simply being unconformities, of which there are innumerable instances worldwide and both sometimes being referred to as "GU"). Both GUs warrant their own article. I suggest that:

• this article be renamed to "Great Uncomformity (Grand Canyon)"
• its Hutton section be removed
• both articles have cross-refencing "For X see Y" hatnotes

If there is no major objection to this in the next week or so, I will implement the above suggestion.

Further, the "Background" section doesn't belong here; it is simply describing the principle of "unconformity" which already has its own article. Similarly the section "As a widespread phenomenon" doesn't belong. Perhaps we need a DAB page with a much stripped-down sentence or two from the "as a..." section.

Feline Hymnic (talk) 10:59, 21 November 2024 (UTC)

Thanks for looking at this. I'm not sure that your suggested title of "Great Uncomformity (Grand Canyon)" will work as it is also present elsewhere in Laurentia, such as in the Needle Mountains in Colorado, but otherwise this seems like the best approach. Agree about ditching the "background" section, that's what internal links are for. Mikenorton (talk) 22:26, 22 November 2024 (UTC)

@Mikenorton: Thanks. Yes, I'm tending to back away from my proposed "Great Uncomformity (Grand Canyon)" thought, and simply let the existing title stand. Then this little sprint can focus on content, without being distracted by titles. Feline Hymnic (talk) 11:45, 23 November 2024 (UTC)

I don't recall Hutton's Unconformity ever being labelled as a 'Great Unconformity' but it has perhaps been referred to as 'great' (lower case 'g') with reference to its significant role in the development of the science of geology; that is very much its claim to fame. Geopersona (talk) 14:14, 23 November 2024 (UTC)

@Geopersona: Yes, I'm struggling to find a WP:RS that attaches the label "Great Unconformity" to Hutton's Unconformity. So I think for the purposes of this exercise, which is about the content of the North American G.U., we can, for the moment, not worry about the label G.U. being significantly applicable elsewhere. Feline Hymnic (talk) 15:08, 23 November 2024 (UTC)