Talk:Geologic time scale

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	Geologic time scale is a former featured article. Please see the links under Article milestones below for its original nomination page (for older articles, check the nomination archive) and why it was removed.
Article milestones Date Process Result December 1, 2004 Refreshing brilliant prose Not kept January 1, 2004 Featured article candidate Promoted March 8, 2004 Featured article review Demoted November 10, 2004 Peer review Reviewed Current Status: Former featured article

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This article has been reviewed by The Roanoke Times on July 1, 2005. Comments: Geologist Bob Bodnar of Virginia Tech found "the terminology and ages used [in the article] to be quite accurate and consistent with the most recent data." See the Wikipedia Signpost article. For more information about external reviews of Wikipedia articles and about this review in particular, see this page.

Archives
Archive 1 (2001—2008)

Contents 1 Interpolation 2 Earth clock 3 March 23, 2009 Vandalism 4 Time scale changes 5 Page size 6 Help requested 7 including the terminology "age" 8 Galactic Year

[edit] Interpolation

This commment is copied/pasted from above, and I started a new section to discuss it: Some rock layers are accurately dateable, most are not. Using stratigraphic principles, those layers that are not dateable can be dated approximately around the correct age. This would be a good topic to cover. Hardyplants (talk) 02:26, 10 February 2009 (UTC)

I agree that this would be useful. Does anyone have a suggestion as to where this would be useful to insert? Off the top of my head, the methods used for dating units that are not directly absolutely datable are:

• Interpolation of sedimentation rates
• Correlation with units which contain material that may be absolutely dated
• Correlation of fossils present with absolutely-dated sections with the same fossils
• Cross-cutting and erosional relationships to provide upper upper or lower bounds on when the units could be deposited.

Awickert (talk) 02:56, 10 February 2009 (UTC)

[edit] Earth clock

Mapping geological time units to 24 hours is a potentially useful educational tool, however the present graphic is erroneous. Rescaling the dates presented in the article to 24 hours would have the Archean ending at 10:52 (not approx. 18:40 as indicated) and the Proterozoic much longer. The 2 ma of the Quaternary represents 37.8 seconds (not 17). Some of the other boundaries look a little off too.

I don’t have the graphics skills or software to replace the clock image so for now shall simply remove it. If anyone cares to redo the graphic I’d be quite happy to contribute a full set of calculations. Shythylacine (talk) 07:06, 7 March 2009 (UTC)

Maybe a simple way to do it would be to use the ICS chart divided by 4.567 billion years, and make a pie chart in Excel, which we could then annotate. Anybody think this is too shoddy? Awickert (talk) 07:16, 7 March 2009 (UTC)

Another suggestion I have come across recently (documentary & book) is a 365 day calendar representing the timespan of the earth. Now I am not suggesting to replace that with the 24 hour day but a nice addition if someone wants to take up the gauntlet :-) -- Phoenix (talk) 08:38, 7 March 2009 (UTC)

That sounds like a cool idea - do you know how to make a succinct graphic out of it? (The nice thing about the clock was the circle.) Awickert (talk) 08:45, 7 March 2009 (UTC)

OK, here's an Excel pie chart clock, pretty shoddy compared to the original image, but accurate. Now, where to put it? I think the original was out of place in the history section so would suggest below the graphical time-line. It wouldn't need much text, eg:

"Another method of envisioning the geological time scale is to compress its vast length to 24 hours.

Once again, at 37.8 seconds the Quaternary is too short to display on a clock face."

So, is it too shoddy? Perhaps superfluous? Shythylacine (talk) 06:54, 8 March 2009 (UTC)

I'm glad I checked Wikipedia - I was just starting to make one of my own, so I'll stop. I actually really like it - I say it should definitely go in, and is a really good graphic! Awickert (talk) 08:45, 8 March 2009 (UTC)

Thanks for the image but could you add the Hadean? I found this image and since it is made by the US government I believe we can upload it or just use it as a reference (here's another one). Maybe a clock in a clock might be a good idea? Strike all that wikipedia already has a nice one... I'll change it right now.

As for the calendar idea it was shown as a full year calendar with all the days coloured to represent the geological times. So you see all 365 days at once and the amount of time each eon/period/etc took up. -- Phoenix (talk) 09:46, 8 March 2009 (UTC)

Cool! But now I like both; the bottom one looks nicer, and the top one has all of the geological periods in 2 circles. I wonder if it would look bad to use both, or if we can get away with it. Awickert (talk) 10:25, 8 March 2009 (UTC)

Problem is you can't read the text on the lower image - even at the 600 pixel scale it's a challenge for my bleary eyes (maybe I need more coffee to clear the morning fog). Point being, do we need the second, unreadable image just 'cause it's "prettier" - seems redundant to me. Vsmith (talk) 13:03, 8 March 2009 (UTC)

Personally it showed up just fine on my PC at 600px. Well since the newly created one was re-inserted I placed the File:Geologic clock.jpg image I found on wikipedia higher since the articles title is Geologic time scale. But can anyone edit the File:Earth Clock 2.gif image to include Hadean? If not it should just show the pre-cambrian. -- Phoenix (talk) 03:04, 9 March 2009 (UTC)

I omitted the Hadean on account of its informal status, but have since seen that ICS use it (informally) on their 2008 [[1]]. So yep, agree that Hadean needs to be in. The term is such evocative counterpoint to all those -zoics too ;) Shythylacine (talk) 10:39, 9 March 2009 (UTC)

This article does not need two clocks. Of the alternatives I prefer the one with the black background for its greater information density, so shall delete mine. I also prefer its aesthetics - the round clock of earth in the black of space-time. It's not perfect, but it's not boring either. The present layout with the clock next to the introduction leaves space to add some caveats and disclaimers in an expanded caption. Will have a go at that now. Shythylacine (talk) 10:52, 9 March 2009 (UTC)

OK - but please leave it on Commons: I like it, and have some friends who teach intro geology who would find something like that useful. Awickert (talk) 00:05, 10 March 2009 (UTC)

Well if you do keep the image can you either edit or upload a version that has the Hadean in it? Either that or make it pre-cambrian :-) -- Phoenix (talk) 08:49, 10 March 2009 (UTC)

[edit] March 23, 2009 Vandalism

64.187.47.18 made a series of changes on March 23, 2009. Most were silly vandalism such as adding the everett to several random locations.

Two were more substantial. This person apparently removed the much of the "History of the Time Scale" section. This revision could not be easily undone, and restoring the section is beyond my wiki-abilities. This person also made a revision deleting several lines from the "Graphical Time Scale" section. Also could not be "undone". Could someone else fix these? —Preceding unsigned comment added by Ukemike (talk • contribs) 21:22, 25 March 2009 (UTC)

[edit] Time scale changes

I suggest that the eras in the Hadean Eon be removed. They do not reflect either the International Commission on Stratigraphy International Stratigraphic Chart 2008, the Commission for the Geological Map of the World Geologic Time Scale 2008 color coding, or USGS time scales (see below).

Also, the text states the colors are from the ICS standard, but this is not the case. They more closely resemble USGS time scale and geologic map colors.

-Parsa (talk) 02:31, 29 March 2009 (UTC)

I personally like having the Hadean subdivisions because, although not official, they are used in the literature.

The color issue has been brought up before; if there's a consensus to change the timescale templates to use the ICS colors, I'd say it would be a decent thing to do, and would help. Awickert (talk) 04:22, 29 March 2009 (UTC)

[edit] Page size

As of this posting, the page is 3.4MB in total! 59.167.39.47 (talk) 12:01, 28 April 2009 (UTC)

[edit] Help requested

In watching recent changes I came across this edit: [2]. Seeing this was a revert of a ClueBot reversion and noting a less than gentle appraisal of the redirect as it was, I reverted. The editor has taken issue with my reversion. With my limited experience in the technical details of the subject I am hesitant to take issue with the editor (even though I think the ClueBot version was correct). If the editors here could look into the matter I would appreciate it. If I'm making mountains out of mole hills, I will offer my apology in advance. Thanks. Tiderolls 15:33, 29 April 2009 (UTC)

[edit] including the terminology "age"

I was wondering in the Geologic time scale#Terminology the table of "Units in geochronology and stratigraphy" should include the classification systems of Age and The Great Year as footnotes.

In the Origin of Religion (part 2) it mentions that in the Ancient Science (Astronomy and Astrology), each 25,765 years is called The Great Year according to the 12 Celestial sphere Constellation, that is viewable from Earth. There hasn't been any new map/grid (proposals, theories, concepts...etc) published to the any research organization or to the general public and I think this infromation if perfectly valid, since current science still related information like Equinox, Solstices, Star navigation...etc. There is also scientific evidence that this time measuring system is based on the Earth's axial precession and each 2150 years is called an Age. --75.154.186.241 (talk) 22:59, 26 September 2009 (UTC)

[edit] Galactic Year

I've never seen the 'galactic year' used for purposes of geology other than on the linked page (which calls it a suggestion, not an accepted convention) and derivative Wikipedia entry. Moreover, the abbreviation "GY" is highly unfortunate as it may easily be interpreted as "gigayear" (properly "Ga"). I propose the section be deleted as non-notable. Orcoteuthis (talk) 21:30, 19 November 2009 (UTC)