Talk:Atoll

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[edit] Bikini Atoll

is the famous bikini atoll a coral atoll? If it is, perhaps mention it


This page has a great deal of text that appears to be extensively (if not entirely) plagerized from some old textbook (the style is very olde English). Beyond the section describing (in some places incorrectly) the relationship between volcanoes and atolls, the next two sections on volcanoes and diatoms bear NO relationship to the subject of atolls. I suggest complete removal of the page (owing to lack of attribution), returning to the earliest, single line definition to refleshed from there. Marshman 02:25 26 Jul 2003 (UTC)

I've since replaced the old plagerized stuff with new content to cover the subject Marshman 17:41 28 Jul 2003 (UTC)

Marshman, you have done good job on the article, it is certainly an improvement over what was orginally here. I just have a query about the statement that atolls are limited to the oceanic basins of the Pacific and Indian oceans. I thought they could also be found in the Atlantic ocean such as Rocas Atoll of the coast of Brazil. -- Popsracer 00:08 29 Jul 2003 (UTC)

I am starting a new paragraph on atoll distribution and admit to being a bit out on a limb there. I woulld want to know more about Rocas Atoll and perhaps a few others associated with the Great Barrier Reef before proceeding down the interesting road of the relationship between atolls and oceanic hot-spots. Any help appreciated. Your catches on my contribution have been right on. Marshman 00:49, 29 Jul 2003 (UTC) I found some papers on Rocas Atoll and others in the Atlantic. These are not without controversy about whether or not true atolls, but a good case can be made. I'll work something up 24.94.86.252 02:58, 29 Jul 2003 (UTC)...That's me, my log-in timed-out I guess Marshman 03:00, 29 Jul 2003 (UTC)

Some contributors are wandering off the subject, or are not aware of the definition of an atoll. The amount of land area is not pertinent. Indeed, Christmas Atoll has the largest land area of any atoll, and that fact makes it less of a true atoll than atolls with very little land above sea level. There are no or perhaps only one or two true atolls in the Atlantic. This fact is widely debated. A few islands appear close to being atolls, and some scientists accept them as such. Bermuda is not one of these. Submerged banks are somewhat of a problem because they deviate from the ideal form, but if their mode of formation is correct as per Darwin, then these are either atolls or submerged atolls. - Marshman 04:54, 28 Apr 2005 (UTC)

The confusion about largest this and largest that results because someone missed a critical point in the definitions: the size of an atoll is the sum of its reef and lagoon areas (not lagoon and "land" areas). Land on atolls is material thrown by waves onto the reef, and therefore typically counted as part of reef area. Knowing land area (important obviously to human inhabitants) is of no value in these calculations. However a large lagoon, because it is typically surrounded by a reef, does indicate a large atoll. - Marshman 18:05, 28 Apr 2005 (UTC)

[edit] Coral island

What is the difference between coral island and atoll? -Indolences 18:01, 27 March 2007 (UTC)

[edit] Northernmost atoll & strict definitions

Several authorities on the Florida Keys claim that Marquesas Key between Key West and the Dry Tortugas is the Northernmost atoll. See, for example, http://www.nwrc.usgs.gov/factshts/047-02.pdf ("Marquesas Atoll") Verify?

Also, do prehistoric meteor strikes ever qualify as atolls, or is an atoll strictly a volcanic/erosion formation? —The preceding unsigned comment was added by 65.216.235.42 (talk) 17:18, 5 April 2007 (UTC).

[edit] Largest Atolls by total size

I tried to list the largest atolls by total area, including the submerged ones (their inclusion may be a matter of dispute, though). Most of the size information is from [1], and I tried to complete the list of the largest atolls from other sources. From [2], I did not use the Amirantes Bank (3951 km²), which is obviously not an atoll, but has atolls on it. I am not certain about the atoll status of all entries in the list. If you are certain that one or another is not an atoll in the geomorphological sense at any stage of development, please explain (if possible with sources) and delete the entry.--Ratzer 09:02, 18 May 2007 (UTC)

[edit] Caicos Islands?

Are the Caicos Island an atoll by any chance? The spatial arrangement of the islands would suggest it (large islands along the northern rim, and smaller islets and reefs in the south). It would be the largest atoll of the world, measured by land size, and among the 10 largest by total size.--Ratzer 13:34, 18 May 2007 (UTC)

What do you mean by "measured by land size, and among the 10 largest by total size"? I just checked and Kiritimati is bigger than these islands. -Indolences 13:56, 18 May 2007 (UTC)
I also checked. About Kiritimati, widely differing land area figures are in circulation, one of about 388 km², and another of 642 km², as I found out just now. Judging from satellite images, the lower figure seems more plausible. For the Caicos Islands, I put a well researched land area figure of 589.5 km² in the article.--Ratzer 19:54, 18 May 2007 (UTC)
Source? -Indolences 20:15, 18 May 2007 (UTC)
Source: [3] (I should have put this one as a reference in the article, and I shall still do it), plus some searching on maps and in gazetteers (among them [4]) which islands belong to the Turks Islands and which ones to the Caicos Islands.--Ratzer 21:41, 18 May 2007 (UTC)
Wait this isn't just one big island? Otherwise it doesn't count. -Indolences 18:00, 24 May 2007 (UTC)
Aldabra is also not just one big island, but four big islands. Nevertheless, it is generally accepted that Aldabra is an atoll.--Ratzer 10:04, 15 August 2007 (UTC)

The first picture on the article is not a good example of an atoll. To someone not familiar with reefs they may get it confused with a fringing reef and not portion of an atoll.Why not just put a picture of a full view of an atoll. The biddler 22:14, 12 September 2007 (UTC)ThebiddlerThe biddler 22:14, 12 September 2007 (UTC)