Wikipedia talk:WikiProject Geology

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Adopting a policy concerning the relative abundance of less common elements?

A few weeks ago we revamped the table in Abundance of elements in Earth's crust. In discussing those changes, the related problem of the relative abundance of elements in individual or group pages on elements was raised.

As you may know, a determined IP user has been adding unsourced lines like:

• It is the 45th most abundant element in the crust.

to elements like Hafnium, Europium, Erbium ‎and so on and on. These have been reverted. I removed a bunch more over the weekend.

A few pages, eg Lead have sources for relative abundance. The two sources that do give explicit relative abundance are Elmsley "Nature's building blocks : an A-Z guide to the elements" 2011 and Greenwood and Earnshaw (1997). Chemistry of the Elements (2nd ed.) There may be more. I don't know if the numbers in Elmsley vs Greenwood and Earnshaw agree.

I have not found any scientific or textbook discussion of relative abundance, but all of the primary and secondary sources on abundance make the point that the concentrations vary widely. The CRC handbook reports "median" values across multiple sources, saying something like "values of the less abundant elements may vary with location by several orders of magnitude."

In my opinion ranking the less abundant elements is not "knowledge" because the numerical value reported creates an illusion of solidity contrary to the evidence. Unfortunately our options are limited by the sources. For example we can't say "Hafnium is the around the 45th most abundant element in the crust" because that is not what the source says.

Some options for discussion:

1. Status quo. The referenced ranking stay; the unreferenced ones are reverted.
2. Agree that ranking are not notable. Remove the few existing ones. Revert additions.
3. Add Elmsley values with ref but without comment.
4. Add Elmsley values by name, eg "Elmsley reports Hafnium is the 45th most abundant element in the crust.(ref)"

(I picked Elmsley because its available online). While I would prefer to omit this "factoid" and in option 2, I lean to option 4 though I suppose our determined editor will just find some other way to "contribute".

Thoughts? Johnjbarton (talk) 16:22, 15 April 2024 (UTC)

Not being a geologist, I do have the book by Greenwood & Earnshaw, and I don't have any by Elmsley. On the iodine example I can say it does not agree to the other sources that I can consult online. This is what they say about the iodine abundance:

Iodine is considerably less abundant than the lighter halogens both in the earth's crust and in the hydrosphere. It comprises 0.46 ppm of the crustal rocks and is sixtieth in order of abundance (cf. Tl 0.7, Tm 0.5, In 0.24, Sb 0.2).

Wikipedia, on these days, says iodine is the 64th, while having mentioned the Greenwood-&-Earnshaw 0.46 ppm (strange).

On the other hand, a study of 300 various rocks' samples found that the iodine abundance is even lower 0.119 ppm (in continental earth's crust, the surface of which is "contaminated" by constantly cycling iodine from the richer oceanic crust and seawater).

I'm being inclined to the option #2, but not that strict. I would avoid indicating the direct rank, shift focus to the distribution peculiarities, absolute concentrations or relative abundance if possible. To find the optimal path in the complex reference landscape, so to speak.

Tosha Langue (talk) 18:32, 15 April 2024 (UTC)

By the way, I found a source that ranks an element roughly. "[...] lutetium, the scarcest REE (rate earth element), is about the 60th most abundant. But I don't know if it is that reliable.

Yet another thought: an element's abundance rank may provide more sense when viewed along with another metric, characterizing the element's dissemination extent, right? But I don't know if such a measure exists.

Tosha Langue (talk) 08:45, 16 April 2024 (UTC)

There's the Goldschmidt classification, but it's not quantitative. — hike395 (talk) 14:43, 16 April 2024 (UTC)

Yes, thanks, we applied that across the table in Abundance of elements in Earth's crust. Johnjbarton (talk) 16:09, 16 April 2024 (UTC)

All of the comments similar to: "lutetium, the scarcest REE (rate earth element), is about the 60th most abundant" are bogus in my opinion. The scarcity of an element is unrelated to its average concentration in the crust. Many elements are concentrated as pure metals in veins or in ores. Their average concentration may be very low but they can easily be mined and thus are not scarce.

Really the only significance of relative abundance is in relation to cosmology or geochemical cycle. And in those applications we are only interested in orders of magnitude. Johnjbarton (talk) 16:17, 16 April 2024 (UTC)

Bogus. Agree with the estimate! The best I managed to find is Clarke number. Tosha Langue (talk) 18:59, 16 April 2024 (UTC)

References

Late Glacial Interstadial and Bølling–Allerød warming

Are these two articles the same topic? The article on the Bølling–Allerød warming currently begins The Bølling–Allerød interstadial (Danish: [ˈpøle̝ŋ ˈæləˌʁœðˀ]), also called the Late Glacial Interstadial... which implies that it is exactly the same topic as the Late Glacial Interstadial article. If this is the case, then these two articles are clearly duplicates and should be merged. However, reading the academic literature, the term "Bølling–Allerød warming" seems to apply specifically to the sharp warming episode at the begnning of the interstadial, though I am not sure that would warrant a standalone article from the interstadial itself. Hemiauchenia (talk) 20:48, 21 April 2024 (UTC)

I've opened a merge discussion at Talk:Bølling–Allerød_warming. Participate if interested. Thanks. Hemiauchenia (talk) 21:01, 21 April 2024 (UTC)

Monzogranite not in great shape

I found the Monzogranite article filled with too many details and too much jargon. Attempted to clean it up, but it's still missing the "big picture" of what monzogranite is and why it's interesting (if it is interesting). Having an expert in petrology look at it could be helpful. Thanks! — hike395 (talk) 05:59, 9 June 2024 (UTC)

The lead section seems to be based almost entirely on a particular field example, which is not representative. Still trying to find a reliable source for this but apparently 70% of granites are monzogranites. I've opened a discussion on the talk page. Mikenorton (talk) 14:42, 9 June 2024 (UTC)

Thinking more on this, and after looking at the syenogranite article, I would suggest that both of these are simply redirected to granite, which already contains all you need to know about the terms - they're both essentially dictionary definitions with examples. Mikenorton (talk) 17:16, 11 June 2024 (UTC)

Wobbly maths in Template:Infobox geologic timespan?

I applied this template to Bølling–Allerød Interstadial today, after first spotting it at the Allerød oscillation stub (now merged to the Interstadial article.) It's a neat template, but I am not quite sure how it does some unit conversions. I.e. based on Figure 2 of this Nature study, I set the mean CO₂ concentration for 235 ppm - and the infobox automatically wrote that this was 1 times pre-industrial - even though the actual preindustrial CO₂ level was at ~280 ppm.

On the other hand, I tried work backwards for Mean surface temperature parameter. The same figure in the same paper stated that the temperature was ~1.5C lower than the early Holocene mean (which appears practically the same as the preindustrial based on Figure 6 here, so I wanted to set a value that would be described as "2.5 below modern" or thereabouts. Yet, somehow, it didn't work - setting the temperature at 12C results in "2 C below modern", yet 11.5 somehow results in "3 below modern". How does that work?

Lastly, it's probably not a good idea that CO₂ concentration is described relative to preindustrial, yet temperature relative to "modern". It would obviously need regular updates for the foreseeable future to avoid becoming misleading, yet even if those updates are being done, there is no way to tell at a glance whether the temperature value the infobox considers "modern" in fact matches the present-day temperature value (which, lest we forget, continues to rise). InformationToKnowledge (talk) 16:34, 9 June 2024 (UTC)

I fixed the rounding of |CO2= in the infobox --- it will supply one additional significant figure if the concentration is less then 560ppm.

As to temperature, IIUC, the paleoclimate estimates are not accurate to 0.1C, so rounding to the nearest 1C seems wise. I believe by "modern", the infobox means "compared to the global mean of 1961-1990" The term "modern" is ambiguous, but I think making the infobox more wordy would not serve the users. We could add a reference to that paper (although we would then depend on an article having a References section). Pre-industrial mean temperature is probably 13.5C, so it would most likely not make a difference in any infobox, unless the paleotemperature was supplied with 0.1C precision. I would recommend just leaving it alone, but if other Geology editors think it should be changed, will go along with consensus. — hike395 (talk) 17:49, 9 June 2024 (UTC)

Later -- I changed the temperature baseline to 13.5C and displayed the difference to the nearest 0.5C. I'm not convinced that we know paleotemperature averages to 0.5C, so I worry this is WP:OVERPRECISE. Thoughts? — hike395 (talk) 02:17, 10 June 2024 (UTC)

This is much better, thanks! I have added this to Younger Dryas as well now, in addition to B-A Interstadial. Please check if there are any errors (i.e. I just copied the links for Chronological unit and Stratigraphic unit from what Allerød oscillation used to have, but I am not sure if that is accurate?)

I should also say that at least for those two periods, these are temperatures from the geologically recent past, <15,000 years ago, where five different methods of estimating temperature are available. If Nature does not consider their temperature graphs overprecise, who are we to say otherwise?

Yes, I was thinking of temperatures much further in the past. I think 0.5C precision may be a good compromise for all of the different time periods. — hike395 (talk) 22:16, 14 June 2024 (UTC)

At the same time, I have a question about how the "sea level" parameter is coded. You can see it in Figure 3 of the paper I linked earlier, but when I actually tried applying it with "-70" it didn't auto-convert to meters, as I thought it would, nor to any other unit, and instead just kept "-70" next to the Sea level above present day caption. Can we both account for units/negative values and change this line in the template to something more neutral, as we presumably want this infobox to be usable for glacial periods when the sea level was well below the present (or preindustrial, for consistency with the temperature/CO₂ lines?) and not just for the hothouse periods? InformationToKnowledge (talk) 14:50, 11 June 2024 (UTC)

@InformationToKnowledge: |sea_level= may accept non-numeric values (e.g., a call to {{convert}}). In parallel to other infoboxes, I created a new parameter, |sea_level_m=, which accepts only a numeric value and does what you've asked for, above. Feel free to use it. — hike395 (talk) 22:16, 14 June 2024 (UTC)

References

Cambrian page

I've added sections and edited others on the Cambrian page and I've 2 requests: One, can someone with more coding nous than me add a ICS (global) subdivisions table cf. Ordovician or Carboniferous please. Gives the info nice and concisely; and two, there are at least two other Cambrian pages that are now obsolete Stratigraphy of the Cambrian and Early Cambrian geochemical fluctuations. Again, could someone with more knowledge of Wikipedian ways delete them. Just to tidy things up. Thx Silica Cat (talk) 15:06, 14 June 2024 (UTC)

The process for obsolete pages is called Wikipedia:Merging and the page gives detailed step by step instructions. It is essentially a review process, so a bit more involved than just tidying up. Johnjbarton (talk) 16:55, 14 June 2024 (UTC)

I've already found that page but I'm not sufficiently familiar with code to follow the process. I prefer to focus my efforts on content creation. The tidying up referred to having potentially obsolete pages on Wikipedia rather than a comment on the process involved. Silica Cat (talk) 17:35, 14 June 2024 (UTC)

Changing the standard order for Geological periods

In reverting my change @Silica Cat claimed:

• The Geological Period pages have a standard structure

I assume that means Category:Geological_periods. I also infer (because I don't know where the standard policy is) that the "standard structure" puts "Geology" first, but only includes a single section "Stratigraphy", the content actually being chronostratigraphy in a very dry and detailed presentation.

Placing stratigraphy early makes all of the articles dull for normal readers. I'm sure geologists are very excited about stratigraphy, but we should try to make the articles approachable for non-experts. The early parts of the article should be about the most interesting and least technical aspects of a given period. Johnjbarton (talk) 18:18, 14 June 2024 (UTC)

@Johnjbarton @Silica Cat I agree with Silica Cat. First, we have no idea as to whether nongeologists find stratigraphy more boring than paleogeography or vica versa. The best that I can tell this is a personal opinion, which as far as I know, is neither supported nor unsupported by any reliable source. Second, it is "standard structure" / policy in geology as looking at any geological report will show. Third, this "standard structure" is standard because in geology, as in many sciences, the field observations (data), i.e. lithology, fossils, and stratigraphy, are presented before how they are interpreted, i.e age and paleogeography, in a progression from what is directly observed to what is inferred from these observations. Finally, whether it boring or not, putting paleogeography before chronology will confuse people because provides the time frame in which the paleogeography changes over time during the Cambrian. Paul H. (talk) 03:10, 15 June 2024 (UTC)

@Paul H. These are all fine reasons, but completely unknown and unknowable to readers and editors who are not geologist. If the order of presentation is part of the "lesson" of these pages, then include that information in the pages. For example, label the first section "Field observations". Use "Chronology" or "Chronostratigraphy" rather than "Stratigraphy". State early in the article that its organization follows "any geological report". I don't think readers come to Wikipedia to read geological reports, they come to learn about geology. Johnjbarton (talk) 16:05, 15 June 2024 (UTC)

FAC notification

Volcanism of the Mount Edziza volcanic complex is at FAC if anyone is interested in participating. Volcanoguy 15:48, 16 June 2024 (UTC)

Requested move at Talk:Slate Islands#Requested move 14 July 2024

There is a requested move discussion at Talk:Slate Islands#Requested move 14 July 2024 that may be of interest to members of this WikiProject. 98𝚃𝙸𝙶𝙴𝚁𝙸𝚄𝚂 • [𝚃𝙰𝙻𝙺] 22:42, 14 July 2024 (UTC)