Talk:Impact crater

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Impact vs volcanic craters
The great majority of craters on the Earth are volcanic craters, rather than impact craters, even if impact craters tend to arouse the most interest. I added a disambig about volcanic craters at the top of this page, but I'm not sure that's enough. Maybe there should be a general crater page, with links to separate impact crater and and volcanic crater (or caldera) pages. After all, there is something to be said about craters in general, if anything because its often not easy to tell the origin of a specific crater.--Pharos 19:52, 20 Nov 2004 (UTC)


 * Hm... You're right, the current split is somewhat unsatisfactory. Calderas are a specific type of volcanic crater, so I don't think there's an article that addresses volcanic craters in general. I'm going to do some conservative tinkering to start with; I'm going to start a volcanic crater article and see what fits in there. Bryan 08:38, 9 Dec 2004 (UTC)

== Discussions that have been previously separated, (perhaps from 2005, and -- barely short of definitively -- until mid-2019), from "Impact vs volcanic craters" disc'n (The, a/o now, preceding talk section), by means a horizontal rule ... == ... which thus may or not have been intended to respond to that now distinct section; I'm retrofitting a title per contribution below, in what was the not-necessarily-adequately delimited section. (BTW, among possible but unannounced intentions may have been
 * starting a new section, without choosing its section title
 * creating a subsection for something perceived as a subordinate topic, without understanding the designed in feature addressing such situations,
 * not to mention scenarios that that may occur to me within le esprit d'scalier. --JerzyA (talk) 05:45, 29 June 2019 (UTC)When reasonably inconsequential, I don't do windows.

(Barringer)
Since Meteor crater redirects here, should the disambig statement at the top of the article mention the Barringer crater, as its most common name is simply "The Meteor Crater"? &mdash; Asbestos | Talk 09:32, 14 Jan 2005 (UTC)

Rename from "Crater" to "Impact crater"? & Dab'ate the former accordingly?
Surely the correct title here is Impact crater and Crater should be a disambiguation, including Caldera, and also Krater, BTW. Just logic. --Wetman 08:38, 3 Mar 2005 (UTC)
 * Krater? As in the Greek vases? &mdash; Asbestos | Talk  09:38, 3 Mar 2005 (UTC)

I think this Crater should be moved to Impact crater, then Meteor crater could be a disambiguation that includes Barringer Crater and Impact crater. Also this article currently includes Ramon crater which is formed from karst erosion and not impact nor other explosive event. Could Crater (disambiguation) be a dab for all possible kinds of craters (Impact crater, Caldera, electrical discharge, explosion, erosional)? -Wikibob | Talk 00:58, 2005 Mar 14 (UTC)

Commiment, and appropriately related followup
I have just done these moves and changes:
 * moved Crater to Impact crater
 * added this disambig to Meteor crater:
 * Meteor crater can refer to Impact crater, a pit-like landform created by a body impacting the topography, or Meteor Crater can refer to the common name for the Barringer Crater in Arizona.


 * added this disambig to Crater:
 * A crater is a landform resembling a pit or depression in the topography, and can be formed in several ways. For the constellation, see Crater (constellation).''


 * A meteorite impact with another body can cause an impact crater, an electrical discharge such as lightning may form a crater-like pit, volcanic activity may form a Volcanic crater or caldera, erosion may form depressions such as the karstic Ramon Crater, and a mine explosion or a bomb may form a crater.

-Wikibob | Talk 14:33, 2005 Mar 20 (UTC)
 * disambiguated some redirects to Impact crater


 * Tweaked formatting of the disambiguation pages. Gosh, lots of pages that link to meteor crater should point to impact crater. Anyone with a 'bot wish to clean this up? It's too daunting for me. --- hike395 15:48, 20 Mar 2005 (UTC)
 * Meteor Crater (with capitalized C) is a specific name and redirects to Barringer Crater, which is appropriate. "Meteor crater" (with lower-case c) is generic, so I've made it a redirect to Impact crater.--Pharos 17:34, 20 Mar 2005 (UTC)

I have added Ring dike to the See also section, but this article could do to mention ring dikes, in the context of disambiguating impact and volcanic craters. --Una Smith (talk) 15:08, 18 October 2008 (UTC)
 * Also Caldera, which has just been removed from the See also section. --Una Smith (talk) 17:41, 18 October 2008 (UTC)

Intro Paragraph
Since this article is about impact craters, isn't it out of place for the opening paragraph to discuss alternate causes of craters such as vulcanism and electrical discharge? I think if we mention them we should reference their pages. --zandperl 15:31, 1 Jun 2005 (UTC)


 * As there was no protest, I have removed the other types of craters from the intro paragraph since there's a link to the disambig page above it.
 * --zandperl 04:00, 23 Jun 2005 (UTC)
 * someone has removed the "link to the disambig page above it" Bejnar 22:22, 30 August 2006 (UTC)

crater lakes
I removed this sentence in the introduction: "In the center of craters on Earth a crater lake often accumulates, and a central island or peak (caused by rebounding crustal rock after the impact) is usually a prominent feature in the lake." It was misleading because impact crater lakes are not common at all (I know of one impact crater in Africa (Bosumtwi crater in Ghana) which is filled by a lake) --Cjackb 04:45, 28 January 2006 (UTC)

---
 * Current text: "Ancient craters whose relief has disappeared leaving only a "ghost" of a crater are known as palimpsests." This does not sufficiently introduce the specialized usage of "palimpsest" which means&mdash;I think&mdash; a crater that has been partially obliterated by subsequent impact events, not one that has simply "disappeared". --Wetman 07:20, 11 March 2006 (UTC)


 * A palimpsest (impact crater) is a crater that is obliterated by subsequent impact, erosion or isostasic activity -- it isn't limited to only subsequent impact events. -- hike395 07:45, 11 March 2006 (UTC)

Floor-fractured craters
This article could use a discussion of floor-fractured craters. I.e. impact craters that have been subsequently modified by a volcanic uplift of the interior, creating fracture lines. (Typically found on the Moon.) Anybody interested? :-) &mdash; RJH (talk) 21:05, 21 July 2006 (UTC)

Most simple craters are circular?
I have done a bit of research and am fairly confident so I added a note to the article saying that Simple craters are generally circular except for extremely low impact angles. However, I could not really find a good web-based link for this point so I added a link to "The Straight Dope" which is certainly not a very good source for this. The Straight Dope article references a 1992 article in The Journal of GeoPhysical Research, but unfortunately only back issues to 1994 are available on the web. If someone can come up with a better link, please update my link. (or, if necessary, refute it). Here's another (better?) ref: http://fgms.home.att.net/sudbury.htm Dzubint 23:08, 30 December 2006 (UTC)

Edit confusion?
I just did a tiny edit, but when I saved it a large amount of editing was attributed to me. I don't know where it came from so I reverted it all. Possibly someone else was editing at the same time and things got confused. I apologize if this wrecked someones edit. Please try again. Zamphuor 06:51, 24 March 2007 (UTC)
 * If someone else has confirmed that the other Z-editor either no harm was done, or it was repaired, it would be expedient for them or another presumed Samaritan to annotate accordingly (as I did in the currently preceding section). (If not... well, "... they say ev'ry distance is not near.") And i shan't repeat, from above, my prior sig-dec'n. --JerzyA (talk) 06:12, 29 June 2019 (UTC)

Location of Chesapeake impact crater
I changed the location of this crater from Maryland, US to Virginia, US. The corresponding WP page seems to indicate that the crater is in Virginia, and this USGS link http://woodshole.er.usgs.gov/epubs/bolide/ancient_cataclysm.html explicited states that the crater is centered under Charles City, VA. Xymmax 15:33, 20 April 2007 (UTC)

New user attempting a major expansion
I am new to Wikipedia - this is my first attempt to make a serious contribution. Guidance with the process and the etiquette of making major changes would therefore be welcome. It is my intention to try to lead the rewriting of this article so that it provides a significantly more comprehensive introduction to impact craters and impact cratering. Maybe sections something like the following: (1) History

(2) Crater formation and impact processes

(3) Structure, morphology and geology

(4) Ejecta

(5) Impact craters on earth

(6) Impact craters around the solar system

(7) Wider significance and everything that doesn't fit elsewhere

Under (5) there could be an introduction to about ten of the most significant terrestrial impact structures including Chicxulub, Sudbury, Vredefort, Meteor, Ries, Chesapeake, Manicouagan, Popigai maybe, plus a discussion of how impact craters are identified.

Under (7), impacts and extinctions, early life, transport of life between planets, impact hazard, economic significance, early earth, the moon-forming impact, shock waves in solids, and the effect of atmospheres on meteoroids, are possible topics.

Comments and suggestions?... Mrwarn 16:41, 16 June 2007 (UTC)


 * Sounds like a good idea--do it!Rppeabody (talk) 15:07, 26 June 2011 (UTC)
 * Yes, please continue. I personally find that inline academic citations are crucial for ensuring the quality of the article. If you suggest major changes to existing content it is polite to post them here first to get comments, but this is not strictly necessary. --Thorseth (talk) 06:31, 27 June 2011 (UTC)

Crater types?
Should there be a section describing the various types of craters? Eroica (talk) 14:53, 23 February 2008 (UTC)
 * Microcrater
 * Simple crater
 * Complex crater
 * Elongate crater
 * Peak-ring crater
 * Multi-ring basin
 * Impact basin

Science facts?
Check out my username. Um there is not enough scientific evidence for Sout Pole Basin to be even classified as an impact crater.--Murriemir (talk) 18:26, 12 June 2008 (UTC)

Cratering rate in Introduction
The introduction has this curious sentence: "Earth experiences from one to three impacts large enough to produce a 20 km diameter crater about once every million years on average." How many? Was that one to three impacts every million years, or just one? If somebody has a source, that would help. —MiguelMunoz (talk) 09:47, 24 January 2009 (UTC)

Grieve and Shoemaker (1994) estimate that present-day formation rate for craters 20 km in diameter or greater is 5.6 x 10-15 per km2 per year. Multiplying that by the surface area of the Earth (5.1 x 108 km2) gives 2.86 craters (>20 km) per million years. The numbers given in the article are fine, but I might have replaced 1-3 per million years with "a few" or "several" per million years. Reference is Carr, M.H. (2006) The surface of Mars; Cambridge University Press: Cambridge, UK, p. 23, citing Grieve R.A.; Shoemaker, E.M. (1994). The Record of Past Impacts on Earth in Hazards due to Comets and Asteroids, T. Gehrels, Ed.; University of Arizona Press, Tucson, AZ, pp. 417-464. Of course, most of the Earth's surface area is covered by ocean, so the number of such craters on land would be a little less than 1 per million years on average. Schaffman (talk) 14:34, 4 October 2010 (UTC)

Added referenced to text. Schaffman (talk) 14:55, 25 October 2010 (UTC)

FYI - proposed renaming for Category:Craters hierarchy of 76 impact crater-related categories
FYI - see the CFR renaming discussion. 76 categories with "craters" in their names, all part of the Category:Craters hierarchy, have been proposed to be renamed to use "impact craters" in their names. All the higher-level categories in the hierarchy have text instructions that they are for impact craters, not craters of volcanic or explosives origins. The renaming is intended to make their purposes more obvious and lead to less confusion. Ikluft (talk) 09:29, 22 August 2009 (UTC)

Trimmed list and renamed section "Impact craters on Earth"
I renamed the section "Notable impact craters on Earth" to "Impact craters on Earth", since editors were apparently taking "notable" to mean it's OK to add anything that has an article on Wikipedia.

The section is intended as an abridged intro which refers readers to List of impact craters on Earth for the full list. So I removed articles which do not meet the criteria listed below. The idea is to make an introductory list for newcomers to the subject, which are good reading for those discovering the subject matter.
 * The crater must be scientifically confirmed, as indicated by the Earth Impact Database.
 * Generally we want the list to include all the largest craters, and the best-documented examples of smaller ones.
 * The article must have good imagery. For craters smaller than 20km, it must be a good photo, not just a graphic rendering.
 * The article should not be just a stub - some are still assessed as stub class but have useful intro text.

I hope that helps make the list more consistent and useful as an introduction for readers. Ikluft (talk) 09:11, 10 January 2010 (UTC)

History
I don't think Comet Shoemaker-Levy 9 was named after Gene, but his wife Carolyn. I'll check this. Schaffman (talk) 14:46, 4 October 2010 (UTC)

Okay, JPL/NASA site listed both as co-discovers. My bad. Schaffman (talk) 14:51, 4 October 2010 (UTC)

Shouldn't G.K. Gilbert and Ralph Balwin be included in history? The study of lunar craters was important in developing ideas of impact cratering process.Schaffman (talk) 20:01, 25 October 2010 (UTC)

Objection to use of term pit crater
The first paragraph of the article implies that pit crater is the generic term for all craters not caused by impact. I don't think this is correct. Pit crater is just one type of volcanic crater (calderas and maars being other examples). Other natural depressions formed by collapse (e.g. sinkholes) are not generally refered to as pit craters either. I'd change: "This is in contrast to the pit crater which results from an internal collapse." to "...in contrast to volcanic craters or other craters formed by internal collapse."Schaffman (talk) 13:37, 9 October 2010 (UTC)

I'm going to make change to read: "This is in contrast to volcanic craters, which result from explosion or internal collapse. My reference is Basaltic Volcanism Study Project (1981). Basaltic Volcanism on the Terrestrial Planets; Pergamon Press, Inc: New York, p. 746. http://articles.adsabs.harvard.edu//full/book/bvtp./1981//0000746.000.html.Schaffman (talk) 13:03, 25 October 2010 (UTC)

Proposed addition to 1st Paragraph
I think were should also state that impact craters are also distinquished from volcanic craters by having floors that are below the level of the surrounding terrain. (For example volcanic craters often lie atop volcanic peaks.) Schaffman (talk) 13:13, 25 October 2010 (UTC)

Inline References
I am adding inline references as I come across them. This is ongoing effort.Schaffman (talk) 15:22, 25 October 2010 (UTC)

Is the Wood and Anderson 1978 classification scheme relevant?
I'm a little unsure how relevant the uncited Wood and Anderson (1978) lunar crater classification scheme is to this article. This classification scheme is rarely used, and including it here takes away from the actual classification scheme of simple, complex, peak-ring, and multiring. I will remove this section unless there are serious objections.Rppeabody (talk) 17:43, 24 January 2011 (UTC)

Merger Proposal
I am proposing to merge Thalassoid into this article, as it is an uncommon term which does not merit a full article. However, it has been suggested it would be best merged into this article instead of simply being deleted, as it has interesting history and relevance. Primefac (talk) 21:54, 15 October 2014 (UTC)
 * If so, it would be appropriate to merge into Lunar craters, not Impact crater. Stas (talk) 00:09, 16 October 2014 (UTC)
 * Good point, I'll switch it over. Primefac (talk) 15:54, 20 October 2014 (UTC)

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Barringer Crater
"Meteor crater" (small c in crater) redirects here and "Meteor Crater" (capital C) redirects to Barringer Crater in Arizona, but the page name there is "Meteor Crater". These two pages should have a consistent way to tell them apart due to the ambiguity in searching. — Preceding unsigned comment added by 98.163.105.227 (talk) 15:41, 19 January 2018 (UTC)
 * Ambiguity is a fact of life. The "see also" links on each of the Meteor Crater (a.k.a. Barringer Crater in Arizona) and Meteor crater (generic name for an impact crater) pages are probably the best way to handle it considering the meanings of each term. Do you have a suggestion for how it could be improved? As it is, when someone lands on one page, even if they didn't know about both, they're still one prominent link away from the other, which is good enough. Ikluft (talk) 06:21, 29 June 2019 (UTC)

subsurface craters?
Is there a special term for impact craters not visible on the surface, such as Logoisk crater? - Altenmann >talk 00:11, 23 June 2024 (UTC)


 * The more generic term "impact structure" can be used; I've seen authors use it as a catch-all for any structure created by an impact event regardless of the extent of degradation. Otherwise, I don't recall any specific terms, probably because we can only identify buried impact structures reliably on Earth. ArkHyena (talk) 00:35, 23 June 2024 (UTC)