Um. Yeah. Putting this up for FAC; article on one of the more important craters on earth. David Fuchs(talk) 11:38, 3 October 2007 (UTC)
Neutral. I think the article is much improved with the changes David Fuchs has incorporated, and now complies more carefully with the WP:MOS. I'm not familiar enough with the topic to have an opinion on its comprehensiveness, though, so I'll remain neutral. Karanacs 14:00, 5 October 2007 (UTC)
Oppose. There are several problems that need to be fixed. Karanacs 14:35, 3 October 2007 (UTC)
Some paragraphs are completely without sources. Please find sources for the facts included.
Extinction of the dinosaurs section starts with "This timing", but you have not discussed the timing in the body of the article yet.
The second paragraph of the extinction of the dinosaurs section does not read well.
I would reformat the article to begin with Discovery, then impact, then dinosaurs
There are a few instances where a specific measurement in kilometers is not translated into standard units.
Who issued the September 2007 report?
You don't have to separate your Notes and references here, since you are not citing specific page numbers. You could combine them into one section. With the additional sources, this looks much better as is :) Karanacs 17:35, 4 October 2007 (UTC)
You need a fair use rationale for the image of the quartz
I've added a slew of new sources; added the fair use rationale; moved around the article bits for added flow; changed/added km/mi conversions, reworded the awkward sentences. I think that it's easier just to leave the notes and references the way they are. David Fuchs(talk) 21:11, 3 October 2007 (UTC)
Oppose — Couldn't this wait more than a week for the Peer Review to finish? There are a number of suggestions there for improvement, but no reply. This article has nothing relating to the type of impactor, and some of the other PR comments have not been addressed. — RJH (talk) 22:38, 3 October 2007 (UTC)
Sorry, I didn't see the PR comments. Of all the peer review's I've submitted, this is the first one where I've gotten actual human feedback. David Fuchs(talk) 23:38, 3 October 2007 (UTC)
Sorry to be an obstacle, but I felt that those should be addressed for the article to meet the FA comprehensiveness requirement, &c. — RJH (talk) 16:54, 4 October 2007 (UTC)
Oppose for now The article is starting to look a little bit better. One thing I am looking for in an article like this is a more detailed description of the geology of the crater. Yes, there is some geology information included, but it is in a sort of narrative telling more the story of the discovery rather than a full, comprehensive review of the geology/stratigraphy of the region and the actual "structure." Checking Hildebrand's 1991 Geology paper, I found some things that probably should go in its own dedicated geology section:
They describe the crater as being in a thick carbonate sequence, and that shock-produced CO2 might have caused greenhouse warming.
They describe andesitic igneous rocks and glass interbedded with/by breccias that contain evidence of shock-metamorphism.
They describe the ejecta blanket, and isotope analysis of tektites is similar to those of tektites from other K/T boundry ejecta.
Could use one or more geology type digrams like the one from the Hildebrand paper.
A few general things:
"The crater was discovered by Glen Penfield, a geophysicist who had been working in the Yucatán while looking for oil..." it still doesn't say when. Even if you say it later, the intro still needs to have it.
The diagram does not actually mark the center of the impact.
Caption should say why the sinkholes are important, since the map labels them. Map has no scale, esp important because the map shows two different zoom levels. I do like the fact that it shows both a mapped and unmapped image.
"At the same time, Florentine Moras, a Haitan professor, discovered a unique geographic feature on Haiti, which at the time of the Cretaceous was underwater." What was the unique feature? A complete sentence should not be vague. Consider: "...Florentine Moras, a Haitan professor, discovered a (volcanic ridge? impact trough? series of disturbed strata?) on Haiti, which at the time of the Cretaceous..." BTW this is cited as Morás in the notes, but I don't see his name anywhere in the references section.
"Hildebrand and Boynton also reported their findings to an international petroleum geological conference in 1981" but history section starts off by saying that graduate student Hildebrand was working in the region in 1990. I think one reason I'm a little uncomfortable with this section (not just this sentence) is because it seems like the frame of reference of the narrative keeps switching back and forth. Instead of telling the story from the frame of reference of the Hildebrand team (which almost feels a bit like POV from the standpoint of Hildebrand) you could go strictly chronologically.
Much improved, I now find the prose in Discovery section a lot more engaging! Jeff Dahl 17:30, 5 October 2007 (UTC)
"Geological tests show that this impact structure..." In the intro, should probably mention what specific tests were used. For example, something along the lines of: "Presence of shocked quartz in the impact crater, isotope analysis of impact-related tektites, and magnetic and gravity field anomalies in the region show that this impact structure..."
How does their presence date the crater? Presence of tektites and shocked quartz indicate that there was impact, but how about the date? I think this would be done by isotope analysis, stratigraphy etc. and probably should mention in intro. Intro should still be a little more comprehensive, such as mentioning the size of the meteor. Intro doesn't mention anything in the origins section either.Jeff Dahl 17:30, 5 October 2007 (UTC) Looking much better, maybe someone from Wikiproject Geology can also have a look through. Jeff Dahl 23:48, 6 October 2007 (UTC)
Anyway, it is a good start, but I think it still needs to be more thorough. A really good geological drawing (showing those things that geology people are interested in, but readable by non-specialists) would help immensely. Jeff Dahl 19:17, 4 October 2007 (UTC)
Ok, I'll get cracking. As for the image questions, I'll probably have to make my own to effect the changes you want, so that'll take some time. David Fuchs(talk) 19:35, 4 October 2007 (UTC)
Further comment: Is there a free copy of the Hildebrand paper online? The source was added by someone else, and the site given requires a subscription. David Fuchs(talk) 22:01, 4 October 2007 (UTC)
I doubt that there is a free copy of this article available online. This journal is available for download for subscribers, so I suppose I could email you a copy. If you have access to a University library, or sometimes even a public library will have subscriptions to a lot of journals. There is probably at least one review article out there too, which might be worth checking.Jeff Dahl 03:19, 5 October 2007 (UTC)
Another thing that would help immensely would be a picture of the iridium layer. I know I have seen these floating around out there; in core samples the iridium layer is a pretty distinct layer that looks good in a photo. Not essential, but would help a lot and should be available somewhere. I know the geology map is a tough one, but essential in an article about a geological formation. Jeff Dahl 17:30, 5 October 2007 (UTC)
Actually, I'm a neophyte when it comes to image stuff. Could you take a look at the NASA one and see if I can modify that version? It would make adding the changes much simpler than doing it from scratch. David Fuchs(talk) 20:03, 5 October 2007 (UTC)
Adding a scale bar and dot to the NASA map to indicate the town of Chicxulub/the center of the crater would help. If you check out the Hildebrand paper (if you request I can send you a copy by email) you can see what I mean about the geological diagrams. Though these specific diagrams are copyrighted, they could be used as an example from which to draw new, free diagrams using information from this and other sources. I know this is difficult, and if it is too hard to put up a geo map, at least a more complete summary needs to be in the article of the information about the geology of the region. Jeff Dahl 18:11, 6 October 2007 (UTC)
Ok, I'm going to assume I can modify the NASA map if I still attribute. If you send me the Hildebrand paper, I'll get cracking on Geology. :) David Fuchs(talk) 18:14, 6 October 2007 (UTC)
↔Ok, I've added in my new image. David Fuchs(talk) 21:21, 10 October 2007 (UTC)
The main image is much better. But I am still not convinced that the coverage is thorough. Checking this website I felt I got a better treatment of the impact site, especially with their diagrams and an animation. But here's an idea: there is an email address listed at the very bottom of that page to get permission to use the images. It is possible that these folks, who are associated in some way with the NASA space imagery center, may be willing to give one or more of these images a suitable license so we can use them here. Especially valuable would be the image "Chicxulub structure" and the animation. One thing I learned from that website not covered here is how the sinkholes were actually formed. I just think it needs more. Jeff Dahl 20:36, 11 October 2007 (UTC)
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