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I'm not an expert on this subject, but hotspot theory, once seemingly unassailable, is newly controversial. See the Geological Society debate and http://www.mantleplumes.org/ . I think it would be good if the article reflected this discussion. --Rodii 23:09, 26 Dec 2004 (UTC)
mantle plumes have now been imaged all the way to core-mantle boundary. The www.mantleplume.org site is a tract against plumes by small group of dissidents; it does not represent current consensus. But it is important to distinguish between observed fact (hotspots) and presumed origin (mantle plumes, or not). In the 2 years since previous comment, plumes have become well established. Geodoc 21:24, 21 January 2007 (UTC)
Possible expansion and ammendment
It is some time now since I finished studying geology, but I believe there is some distinction made between hotpots occuring in the middle of tectonic plates (for example Hawaii), and those occuring at plate boundaries (eg. geothermal activity over the Mid-oceanic ridge in the Atlantic - Iceland being a good example)
Certainly explanations as to the cause of the former are more controversial and open to debate than those in the latter, where the cause is fairly self evident.
I am new to Wikipedia, so am still unclear on the etiquette of amending articles. Is there somewhere an article could be submitted for peer review before being made live?
- Hi Zx9rsteve, jump right in :-) Of course, conside what has been done previously (not a lot here) and see the references given in the article and above. Probably best to start with a relatively small addition, see what the reaction is, and then move on to bigger edits. If you make a mistake, no problem, it can be easily undone. Go for it - I'll be watching to see what you do. This does need expansion. Also, sign your posts on talk pages with ~~~~ that's four tildes, this puts your sig and a date stamp on it. That's not for article edits though. Have fun, -Vsmith 02:06, 2 Mar 2005 (UTC)
It seems that someone's been confusing St. Helena with Mount St. Helens. It should be noted that Mt. St. Helens is obviously not a hotspot-generated volcano. I'm aware that St. Helena is an island of volcanic origin in the South Atlantic Ocean which, although extinct, may have a hotspot associated with it. St. Helena is best known as the island where Napoleon Bonaparte was exiled to after being captured by the British. -NorthernFire 16:27, 24 October 2005 (UTC)
I would recommend making hotspot volcano page part of mantle hotspot page -- essentially same thing. The Geological Society Debate was conjured up by people who contest hotspots, but as evidence accumulates - especially new seismic tomography of mantle plumes - their arguments are becoming weaker (were never that strong to begin with). Geodoc 06:38, 21 January 2007 (UTC)
Do hotspots always make volcanoes, or do they also make pockets of magma many of kilometers under the earth's surface that do not form volcanoes? Because I know some rock formations that appear related to a hotspot about 125 million years ago, but I dont know if these are ancient volcanoes that are now vastly eroded, or they were formed when lava didn't reach the surface because they are made of gabbro and other types of rocks. Black Tusk 04:43, 05 Augest 2007 (UTC)
- It seems that in the edge of Brazil and Australia the hotspot could not burn an hole through :). Quote: "We agree with Burke (1996) that hotspots are more readily seen in Africa because the exceptionally slow velocity of the African plate allows them to 'burn' through." (W. Jason Morgan and Jason Phipps Morgan. Plate velocities in hotspot reference frame: electronic supplement. p. 111. Retrieved 2010-04-23.), (Burke, K., 1996, The African plate: South African Journal of Geology, v. 99, p. 341-409.) --Chris.urs-o (talk) 23:01, 24 April 2010 (UTC)
Plate Tectonic Processes
I removed the section about Plate Tectonic Processes theory because it was poorly written and poorly sourced to an about.com answer page. This is controversial because it's new, maybe, but it's mainstream geologists debating the issue and belongs in an article about hotspot geology. However, it should be written up in a neutral and accurate manner, not as it was. --18.104.22.168 (talk) 06:25, 2 July 2009 (UTC)
List of Hotspots
Your edit summary: "the New England hotspot lies at the African Plate not the North American Plate"
Quote: "The New England seamounts mark the most striking and best dated track in the North Atlantic. Their ages range in a linear fashion from ~100 Ma near the coast and to ~80 Ma farthest from the coast. The on-land early-extension of this track crosses the White Mountains of New Hampshire, the volcanics of the Monteregian Hills, and northwestward into the Canadian Shield west of Hudson Bay. Seaward, a less-clear continuation goes to Corner Rise. East of that, the projected age of the track is younger than the age of the seafloor on the North American side – the track then appears on the African side of the mid-ocean rift as the Great Meteor track (present-day center at 29.4°N, 29.2°W)" --Chris.urs-o (talk) 22:01, 24 April 2010 (UTC)
- The New England and Great Meteor hotspots are the same thing. They are just different names that come from different features within its track. Check this out. It states: In the Atlantic, one of the longest hot spot tracks is the Great Meteor, or New England hot spot, located at 28ºW, 33ºN. BT (talk) 22:08, 24 April 2010 (UTC)
Exactly, The hotspot is on the Mid-Atlantic Ridge, and there is one chain East (New England) and one chain West (Great Meteor), as in Iceland hotspot, and Azores hotspot. See: New England Seamount chain, image:NE seamounts.jpg, image:Portion of the New England hotspot.png --Chris.urs-o (talk) 22:18, 24 April 2010 (UTC)
- Yes. It has created the magma intrusions of the White Mountains in New Hampshire, the New England seamounts and seamounts in the Great Meteor seamount chain. More from here: Finally, between 100 and 80 million years ago, the hot spot formed the New England seamount chain. Bear Seamount—the oldest—formed about 100 to 103 million years ago. Moving southeasterly along the chain, the seamounts get progressively younger, with the Nashville Seamount being about 83 million years old. During the formation of the New England Seamount chain, the oceanic crust (itself only 120 to 80 million years old) pushes over the hot spot at a rate of about 4.7 cm per year. Finally, 80 million years ago, the mid-Atlantic Ridge migrated to the west over the plume. The track of this hot spot then continues on the African Plate and is found today at the Great Meteor Seamount. So what do you disagree with? There is no reason to have separate articles on the same hotspot with two different names. It can easily be New England/Great Meteor hotspot. BT (talk) 22:33, 24 April 2010 (UTC)
- The Great Meteor track is NOT just on the African Plate if that is what your disagreeing with. The entire hotspot track has different names. It can be Great Meteor hotspot track or New England hotspot track. From here, it states "The 115-140 Ma Great Meteor hotspot track in eastern North America is delineated by mantle-derived igneous intrusions of various compositions. The western Quebec seismic zone (WQSZ), a 150-km wide band of mid- crustal seismicity that extends from the Adirondack Highlands into Laurentian uplands of Quebec, is located along a segment of the inferred hotspot track that lacks contemporaneous igneous intrusions. Here, it is proposed that the seismicity in western Quebec is primarily controlled by mafic intrusions that were trapped in the middle crust during the passage of North America over the hotspot. In particular, present-day seismicity may be controlled by focusing of crustal stresses due to large strength contrasts under mid-crustal conditions between mafic intrusive rocks and more felsic host rocks. In addition, the surface expression of the hotspot track is offset to the east of its predicted location, as inferred from plate reconstruction models and seismic tomographic images of the lithospheric mantle. The misalignment is anti-parallel to the direction of North American plate motion and increases with age along the track. We propose that the misalignment reflects lithospheric strain arising from traction at the base of the North American plate. If this hypothesis is correct, basal traction associated with plate motion could exert a significant role in the crustal stress field." It is clear from that paragraph that the term "Great Meteor hotspot track" is also used for the North American portion of the hotspot track. BT (talk) 23:44, 24 April 2010 (UTC)
Hello !!! Calm down. This list was a stable text from (Steinberger, Bernhard (2000). "Plumes in a convecting mantle: Models and observations for individual hotspots". Journal of Geophysical Research 105 (11): 11127–11152. doi:10.1029/1999JB900398. Retrieved 2008-06-15.). I just tried to add some rates, azimuths, and locations from the electronic suplement (W. Jason Morgan and Jason Phipps Morgan. Plate velocities in hotspot reference frame: electronic supplement. p. 111. Retrieved 2010-04-23.). This is a better text than (oceanexplorer.noaa.gov - Geology). W. Jason Morgan and Jason Phipps Morgan (after 2005) named New England/Great Meteor hotspot differently, but they are the same, agree. The azimuths are always of the movement of the tectonic plates over the hotspots. This list seems ok for me now, I'll check for typos later. --Chris.urs-o (talk) 07:58, 25 April 2010 (UTC)
The hotspot concept seems immature. As a plate gets underneath in the subduction zone it changes its phase, as the volume of the Earth is constant, there is a pressure to get magma on the surface. Many hotspots are in one of there categories:
- Almost static plate and the hotspot has time to burn a hole through, e.g.: African Plate.
- The hotspot is isolated in the middle of a plate, e.g.: Hawaii hotspot on the Pacific Plate
- The plate is not thick, e.g.: South Pacific Ocean.
- The trail and many geologic features have the orientation of the plate motion, implying deep faults underneath, e.g.: Isla Guadalupe and the Raton hotspot trail alignment on the North American Plate, Basin and Range Province; parallel to a section of the Colorado River flowing through a fault.
- The Saint Helena hotspot is suspicious too: St. Helena Seamount Chain - Cameroon Volcanic Line. The volcanoes get younger Westwards, but so does the seafloor East of the Mid-Atlantic Ridge.
- Don L. Anderson and Gillian Foulger are adversaries of the Mantle plume theory.
- Quote: "In his [Anderson's] view, all non-plate boundary volcanism can be explained by shallow, plate-related stresses that fracture the lithosphere and cause volcanism along these cracks, promoted for instance by secondary, edge-driven convection in the upper-mantle." (D.L. Anderson (1998), The edges of the mantle, in: M. Gurnis et al. (eds.) The Core-Mantle Boundary Region, American geophysical Union, Washington, DC, pp. 255-271. D.L. Anderson (2000), The thermal state of the upper mantle: no role for mantle plumes, Geophys. Res. Lett. 27:3623-3626.)
- The primary hotspots seem ok.
- The secondary hotspots seem ok too. Superplume (Plume tectonics) determination over French Polynesia and Western Africa by Dziewonski & Woodhouse (1987) (Dziewonski, A.M.; Woodhouse, J.H. (3 April 1987). "Global images of the Earth’s interior". Science 236 (4797): 37-48)
- A good and recent review about hotspots and this page would look better. --Chris.urs-o (talk) 13:33, 4 September 2010 (UTC)
Both Anderson and Foulger are unable to explain how if the hotspots don't exist, large masses of basalt density between 2.8 and 3.2 x 10^3 m^3 can remain, for example Iceland, Hawaii, Reunion etc; above sea level. Indeed Anderson claims that the track of the Hawaiian islands is along a fracture, but he is unable to explain why the islands are above sea level.The Geologist (talk) 16:22, 10 April 2012 (UTC)
CAMP c.200Mya --> Iceland (N) + Tristan (S) ?
Inexpertly, the major mantle plume producing the CAMP c.200 Mya, which sundered Africa & Eurasia from the Americas, has rifted both northwards, towards Iceland; and southwards, towards Tristan hotspot. Perhaps both hotspots are the northern & southern "ripples" of the ancient mantle plume head, which melted through to earth's surface, 200 Mya ? 22.214.171.124 (talk) 06:44, 1 October 2012 (UTC)
Origin of Tuamotu–Line Island chain: Easter hotspot? Not from hotspot?
In the section on postulated hotspot volcano chains, instead of the name of the hotspot of the Tuamotu–Line Island chain there was this:
- Could it be a Crough hotspot, it is probably not a hotspot trail
I restored what I think was the name of the hotspot–-Easter hotspot–-based on this from the article on the Easter hotspot:
- The hotspot may also be responsible for the formation of the Tuamotu Archipelago, Line Islands, and the chain of seamounts lying in between.
A footnote to that cites the same authority cited in the footnote to the item on the Tuamotu–Line Island chain in the list of postulated hotspot volcano chains in this article.
It says in the opening paragraph " They may be unanimously hot, and provide a great deal of molten magma." Is that accurate phraseology? Seems wrong to me, but I don't know geology much. Still seems like "uniformly" or some something would be more appropriate, but I'm not sure, because I can't even figure out for sure what the sentence is saying. How IS something "unanimously hot", if that is the correct word?.45Colt 10:11, 14 January 2015 (UTC)