|WikiProject Volcanoes||(Rated B-class, Mid-importance)|
|WikiProject Geology||(Rated B-class, High-importance)|
|To-do list for Mantle plume:|
Rate of ConvectionEdit
What is the speed of convection within a plume? With it being mainly solid matter under great pressure, pretty slow I imagine, but do the plumes rise at 1cm a year or 1 cm in 1000 years? Northfold 11:51, 7 September 2007 (UTC)
Could someone clean this up it seems pretty hard to understand for those of us that don't know much about the geography of the ocean floor.22.214.171.124 22:24, 20 June 2007 (UTC)
Definition of mantle plumeEdit
I have restored my former definition of a mantle plume as an upwelling of abnormally (or anomalously) hot mantle, because some time ago, someone only identified by an IP has reverted it to an upwelling of molten rock. It is important to understand that this is wrong: in most parts of the plume, the rock is not molten, and even in those uppermost parts where it may be partially molten, it is far from being a 100% melt. I hope the new formulation helps to avoid in the future the misunderstanding that the earth's mantle is a magma ocean.--TomR 20:22, 14 June 2006 (UTC)
Copyvio or mirroring?Edit
This page appears to have been copied from http://www.all-science-fair-projects.com/science_fair_projects_encyclopedia/Mantle_plumes (unless they copied it from here, who can say?)
They do -- credit is given at the bottom of their page to Wikipedia.--Vsmith 00:28, 9 Sep 2004 (UTC) OK - I hit save and got an edit conflict - StoatBringer got there before me and did essentially the same editing :-) --Vsmith 00:34, 9 Sep 2004 (UTC)
D'oh, I didn't spot that (still a Wiki Newbie) StoatBringer
Mantle Plume controversy?Edit
Current theories about mantle plumes are not fixed in stone (pardon the pun). In fact, many geologists maintain that there are no such things as mantle plumes, and that they need not be invoked to explain certain geological features.
http://www.mantleplumes.org/index.html is probably one of the best resources on this.
- I can add more on this "controversy", even though the mantleplume.org link is already on page (note: this page is maintained by anti-plume proponents). However, recent mantle tomography (e.g. Montelli et al 2005, and others) have imaged plume-like thermal anomalies that extend part way or all the way to the core mantle boundary. The non-plume arguments peaked in 2003 with the workshop in Iceland, but ALL of the evidence that has accrued since then documents the actual existence of these plumes. . Geodoc 23:06, 26 January 2007 (UTC)
- Feel free to jigger about with things as much as you need to. Especially helpful are references which are unbiased, or which at least balance things out. Cheers, Rolinator 00:32, 27 January 2007 (UTC)
- Just found an issue of journal Elements (published by American Min soc, Brit min soc) that deals entirely with mantle plumes and hotspots - bout half dozen articles. It is available free on web, and the writing is aimed at informed non-professionals, so anyone should be able to understand most of what is written. I will use that for refs and include pointer to page with journal issues listed (but not to that issue, which starts a 17 MB download!). I will keep the controversy, however: maybe there should be subsection devoted to it. Geodoc 02:13, 27 January 2007 (UTC)
- Very wise to teach the controversy :P Rolinator 09:34, 27 January 2007 (UTC)
Here is a conundrum: If a large basaltic body e.g. Hawaii, Iceland etc., rises above the ocean floor and then above the ocean itself attaining heights in excess of 4000 metres on Hawaii and whilst not so high - at about 1000 metres on Iceland. Basalt incidentally has a density of about 2800 kg per cubic metre and Mauna Loa on Hawaii has a volume of about 85 cubic kilometres - 8.5 x 1010 cubic metres which means it has a mass of about 2.4 x 1014 kilograms or 240000000000 tonnes. So what is keeping it up? If Folger et al's theory is correct that plumes don't exist and dense material sinks through less dense material how do those volcanic islands stay above sea level and why arethey not spread over the ocean floor? — Preceding unsigned comment added by 126.96.36.199 (talk) 15:51, 11 January 2014 (UTC)
I have been asked to contribute to this great discussion. The alternative hypothesis to plumes is the "plate hypothesis", which contends that tectonic plates are not rigid, undeforming entities, but have a certain amount of internal deformation. Where the lithosphere is in extension, volcanism is permitted that draws melt from relatively shallow depths (upper few hundred kilometres). Examples of this are the East African rift, the Basin & Range province, and the rift valleys of Europe. Many so-called "hot spots" are also on or very close to mid-ocean ridges, which are also zones of extension. This is summarised on the webpage http://www.mantleplumes.org/PTProcesses.html and described in detail in my book "Plates vs. Plumes: A Geological Controversy" published by Wiley http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1405161485.html .
The remark that "ALL of the evidence that has accrued since" 2003 documents plumes is nonsense. Plumes are an assumption, not a proven fact. The papers in the Elements volume mostly assume plumes exist without question or seeking to test the hypothesis. The plume hypothesis is so flexible that essentially any volcanic phenomenon can be explained by some contrived variant of it, so many workers see no point in not assuming it (see http://www.mantleplumes.org/DefinitionOfAPlume.html ).
Regarding what holds Hawaii up, the answer is the ca. 100-km-thick Cretaceous lithosphere on which it sits. Get two people to hold a bed sheet between them and stretch it out and dump a sack of potatoes on it. This will give you a picture of what happens at Hawaii. The ongoing volcanism there constantly dumps more material on the top, and the island itself constantly subsides with time, which is why the older islands are lower and eventually sink below the ocean to become seamounts. It is not the subaerial position of the islands that needs to be explained, but the volcanism. And despite studies like Montelli's (which is discredited, along with a number of other seismic studies that claim to image plumes, since their approach was flawed (see http://www.mantleplumes.org/BananaDoughnuts.html ), no seismological experiment has ever reliably imaged a mantle plume. – Gillian R. Foulger (note spelling). — Preceding unsigned comment added by 188.8.131.52 (talk • contribs) 11:45, 6 June 2015
Sorry but you are WRONG! Hawaii is moving roughly northwest and the older islands sit on cold dense lithosphere which is not buoyed up by something which is pushing the Big Island up. Even allowing for the deformation of the lithosphere due to the loading when the island moves too far away the moat remains but the island sinks - even allowing for erosion. On several studies carried out at supposedly non-hot spot locations xenoliths that are known to have originated at the core-mantle boundary (CMB) have been recovered. They didn't arrive at the surface courtesy of some magical process or little green men. Ms Foulger is known to be controversial and her ideas are the only ones that matter and if you disagree then "god help you!" she will make sure that you don't work in academia in "My University!" I happen to know of several very promising students who had their work ridiculed by her and her cohorts. Oh and the first person to postulate the existence of plumes was actually Tuzo Wilson in 1963. As regards no seismic experiment has reliably imaged a mantle plume - oh yes they have! Do your research. — Preceding unsigned comment added by 184.108.40.206 (talk) 14:38, 13 August 2015 (UTC)
"[...] several studies carried out at supposedly non-hot spot locations xenoliths that are known to have originated at the core-mantle boundary (CMB) have been recovered." Can you please cite these studies? — Preceding unsigned comment added by 220.127.116.11 (talk) 10:15, 7 September 2015 (UTC)
For a B category article, there is a rather notciable lack of images/diagrams. Jason McConnell-Leech 10:43, 28 October 2007 (UTC)
Incomplete identification of sourcesEdit
A large number of footnotes refer to an author's surname and a year, period. The list of more complete sources attached at the bottom of the article does not include many of these sources: for example, a search for Morgan turns up no source. This means the incomplete sources in the footnotes are useless. Brews ohare (talk) 17:21, 20 February 2010 (UTC)
- Can you provide a few details? RockMagnetist (talk) 04:55, 19 January 2014 (UTC)
- Foulger is also the name of the Coauthor of this quite plume critical book http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1405161485.html which content could be subscribed with this phase "Another hypothesis for unusual volcanic regions is the "Plate model". This attributes volcanoes to passive leakage of magma from the mantle onto the Earth's surface where extension of the lithosphere permits it. This model attributes essentially all volcanism to plate tectonic processes, with volcanoes far from plate boundaries resulting from intraplate extension." sentences like "The hypothesis of mantle plumes is not universally accepted because many of its predictions have not been confirmed by geophysical or petrological observation.. As a result, it has become less popular with many groups in the geological sciences." seam to me just to represent the opinion of the author. But there is quite good evidence of very deep sources, take a look here http://eprints.gla.ac.uk/125/1/Harris,J_1997pdf.pdf. --Christian b219 (talk) 12:12, 19 January 2014 (UTC)
- Both of the external links are to organizations affiliated with Foulger. Zyxwv99 (talk) 03:19, 19 June 2014 (UTC)
Is NPOV the right tag?Edit
I notice that nobody's addressed the NPOV tag for several months. It seems like the criticism raised on the talk page might also fall under the lines of Fringe and Reliable Source issues. Can we get an expert to address this article? 18.104.22.168 (talk) 13:22, 31 May 2014 (UTC)
The "plate hypothesis" section seems to present the "plume vs. plate" debate as either/or. For instance "The Plate hypothesis embodies the concept that deep mantle plumes causing surface, time-progressive volcanism do not exist" and "The Plate hypothesis thus attributes all of Earth's volcanism to a single process".
Is this either/or presentation correct? Is anyone really suggesting that ALL occurrences must conform either to plume theory or ALL to plate hypothesis? Isn't it more like "some hot-spots and volcanism seem best explained by plume theory while others seem better explained by the plate hypothesis"? (My wording is probably quite inaccurate, but I hope you get the idea.)