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Dear WM, You may be interested in the following thought-provoking passage commenting on the collegiality of some eminent historical scientists–Bruce Julian

"Unlike Fermat, Descartes gave the impression that he was often uninformed of what others had done before him; at least he only rarely mentioned the work of anybody else in his writings. And when he did, it was often in the most unpleasant manner one could imagine: at various times in his life he called his critics "two or three flies," "less than a rational animal," "a little dog," and "extremely contemptible." The actual works of others were often rejected in incredibly offensive language, e.g., as being fit only for use as "toilet paper" or, in the case of Fermat, as being "shit."–Paul J. Nahin"

Dear WM, I send you two working papers (Paper 1, Paper 2) that describe new types of information on poorly known trace elements and their variations along the Iceland-Reykjanes Ridge region. The interpretations have been challenging. The data are available on the EarthChem Library and PeTDB for anyone to use and/or further interpret. Please solicit comments on our papers on your Mantle Plume website.–Jean-Guy Schilling

Dear WM, The number of plume types has now reached 70! Congratulations for this new milestone, and looking forward to the next ten!

Thermal (1); Fossil (2); Channelled (3); Toroidal (4); Tabular (5); Depleted Residual (6); Finger-like (7); Recycled (8); Edge (9); Cold (10); Cacto- (11); Super (12); Asthenospheric (13); Dying (14); Not very energetic (15); Spaghetti (16); Baby (17); Head-free (18); Splash (19); Pulsating (20); Subduction fluid-fluxed Refractory (21); Hydrogen (22); Heterogeneous (23); Flattened Onion (24); Subduction-driving (25); Subduction-triggered (26); Washboard (27); Bent-shaped (28); Failing (29); Delamination-triggering (30); Concentrically-zoned (31); Mushroom (32); Laminar (33); Advected (34); Extinct (35); Bilateral (36); Bifurcated (37); Geriatric (38); Primary and Secondary (39); Accreted (40); Diverted (41); Deformed (42); Golden (43); Veined (44); Hidden (45); Weak (46); Pulsing (47); Young (48); Blob-like (49); Cavity (50); Starting (51); Passive (52); Stealth (53); Tilted (54); Asymmetric (55); Mega (56); Mini (57); Not-hot (58); Killer (59); Deflected (60); Stripy (61) ; Diamondiferous (62) ; Transient (63) ; Dehydrating (64); Doughnut (65); Rear(66); Side (67); Volatile-bearing (68); Incipient (69) ; Migrating (70).

1 (Griffiths & Campbell, 1990); 2 (Stein & Hofmann, 1992); 3 (Camp & Roobol, 1992); 4 (Mahoney et al., 1992); 5 (Hoernle et al., 1995), 6 (Danyushevsky et al., 1995); 7 (Granet et al., 1995); 8 (Gasperini et al., 2000); 9 (King & Ritsema, 2000); 10 (Hanguita & Hernan, 2000); 11 (Lundin, 2003); 12 (Condie, 2004); 13 (Seghedi et al., 2004); 14 (Davaille & Vatteville, 2005); 15 (Michon & Merle, 2005); 16 (Abouchami et al., 2005); 17 (Ritter, 2006); 18 (Ritter, 2006); 19 (Davies & Bunge, 2006); 20 (Krienitz et al., 2007); 21 (Falloon et al., 2007); 22 (Dobretsov, 2008); 23 (Ren et al., 2009); 24 (Beccaluva et al., 2010); 25 (Burov and Cloetingh 2010); 26 (Faccenna et al., 2010); 27 (Ballmer et al, 2011); 28 (Tosi & Yuen, 2011); 29 (Kumagai et al., 2008); 30 (Camp & Hanan, 2008); 31 (Hauri et al., 2004); 32 (Tan et al., 2011); 33 (Vatteville et al., 2009); 34 (Boschi et al., 2007); 35 (Merle et al., 2011); 36 (Farnetani et al., 2012); 37 (Rohde et al., 2013) ; 38 (Zhou and Dick, 2012); 39 (Tackley, 2008); 40 (Kipf et al., 2013) ;41 (Rychert et al, 2013), 42 (Kincaid et al, 2013), 43 (Webber et al., 2013) , 44 (Bianco et al., 2013), 45 (Yang and Leng, 2014) , 46 (Yamamoto et al., 2007) , 47 (Walters et al., 2013) , 48 (Wang et al., 2013), 49 (Hanan and Schilling, 1997) , 50 (Richards et al., 1989) , 51 (Thompson and Gibson, 1991) , 52 (Chung et al., 1998) , 53 (Mittelstaedt and Turcotte, 2006) , 54 (Shen et al., 2002) , 55 (Bell et al., 2004) , 56 (Thompson and Tackley, 1998), 57 (Ernst and Buchan, 2003) , 58 (Kogiso, 2007) , 59 (Courtillot and Fluteau, 2014); 60 (Thompson et al., 1998); 61 (Cordier et al., 2016) ; 62 (Kirdyashkin et al., 2016) ; 63 (Bell et al., 2013) ; 64 (Ito, 2001) ; 65 (Gill et al., 1992) ; 66 (Mériaux et al., 2016) ; 67 (Mériaux et al., 2013); 68 (Safonova et al., 2015) ; 69 (de Quay et al., 2017) ; 70 (Oostingh et al., 2017).–Michele Lustrino

People, including scientists, may be fundamentally wired up to resist allowing facts to change their mindsGillian R. Foulger
The new webpage by Chen et al. describes more geochemical/ petrological evidence that, in order to have OIB-like magma, the source must contain recycled material, not hot or very deep sources.–Michele Lustrino

I concur with Milidragovic et al. that water plays and important if not principal role in generation of high-Mg mafic and ultramafic melts. I think water is important not only in arc settings, but also flood basalts could not be generataed without this agent.–Alexei Ivanov

Manuel Curzi, University of Rome, provides the results of a natural laboratory experiment to demonstrate the development of plumes…

Click on me

Check out the Wikipedia Talk:Mantle plume controversy page and add your three ha'pence worth–or 10¢ if you work in bucks.–Gillian R. Foulger
Dear WM, A new gravity map shows thousands more of seamounts, mostly not in linear chains, as summarized in this news article. The great majority of seamounts are scattered across the oceans in independent groups and individual volcanoes. They are not part of linear volcanic chains, and we should note that magmas of most seamount volcanoes appear to be similar and must form the same way. This fact does not support the wildly generalized models in which intraplate volcanoes are created by narrow, deep mantle plumes. Instead, we must develop models that link lithospheric structures to linear volcanic chains where such exist, and also allow most volcanoes to form as individual features, all in a common origin from the upper mantle.–Greg McHone
Dear WM, in the recent paper by Courtillot & Fluteau, the 59th plume type is defined–the "killer plume".–Michele Lustrino

Dear WM, Although the paper "Burov, E. & T Gerya, Asymmetric three-dimensional topography over mantle plumes, Nature 513, 85–89 (04 September 2014) doi:10.1038/nature13703" purports to show that plumes can break up continents if the continent is pre-weakened by plate tectonic forces, what it actually shows is that if one artificially inserts a 200 km sphere below the continent with an excess temperature of 200-600°C then one can break a pre-weakened continent. The 200-km sphere appears out of nowhere, as a deus ex machina. The same method was used by Cordery et al to obtain melting under thick plates.–Don Anderson


Dear WM, It is curious that the same tomographic features have been interpreted in completely different ways. Faster than average seismic wave-speeds in the TZ have been considered to indicate ancient subducted slabs (Piromallo & Morelli, 2003; Handy et al., 2010). The same features, on the other hand, have also been interpreted as a volatile-free mantle plume head trapped in the TZ (Lavecchia & Bell, 2012; Bell et al., 2013).– Michele Lustrino

Dear WM, Interesting article in the most recent Economist publicising a Nobel laureate’s jaundiced views on “luxury journals” (Science, Nature and Cell). Seems like the groundswell of discontent is growing.–Andy Moore

Discussion of Dehydration Melting

Discussion of Heat

Dear WM, Some website readers might find this quote amusing. Tozer (1973) objected to the use of the word "plume" because of prior usage and connotations. However, the various definitions of "plume" and its antecedents in French, Latin, and German seem to provide enough flexibility to describe the phenomenon, its implications, and its raison d'être on the one hand and its inventors, supporters, and detractors on the other: Plume (English, from French and Latin, pluma) — a feather, a long handsome feature, a token of honor or prowess; a prize; to pride or congratulate; to preen. Plombe (Germanic) — a plug. Plombe (Old English from West Germanic) — something especially desirable, as a good position; panache (French) — trail, stripe, swagger; fumée (French) — smoke, fumes, steam; fumer (verb) — to fume, to dung, to manure; plumitif (familiar) — scribbler, pen-pusher.–Don Anderson

Dear WM, I would like to bring to your attention a recent letter and commentary posted on The Telegraph newspaper website "Nobel winners say scientific discovery 'virtually impossible' due to funding bureaucracy".–Andy Moore

Dear WM, I recently came across the paper by Don Anderson in the Australian Journal of Earth Sciences "The persistent mantle plume myth". It is an informative, entertaining and devastatingly logical demolition of the plume 'hypothesis'. The author provides a cogent summary of what is wrong with the physics of plumes, as well as delving into the philosophical and psychological aspects of the plume story. In the almost indiscriminate invocation of plumes in many LIP and ore-deposit studies, plumes appear to have the same role as the Joker in a pack of cards: something that can be pulled out to trump any other card (hypothesis). Probably one of the most maddening aspects to plumes is the apparent lack of agreed upon criteria that can be used to test the model and its alternatives. For example, magmatism related to a plume should be an intense, very short-lived event. Apparently. Unless of course the magmatic event is prolonged, in which case the magmatism may be related to a cluster of plumes or a superplume! It is this polycephalic aspect to the plume story (in more ways than one) that raises the most questions about its legitimacy as a hypothesis.

Don Anderson's paper is also notable for its reference to various plume models published in some of the most elite journals, such as Science and Nature. Like others I pretty much gave up on those journals some years ago, finding them speculative and unhelpful to progress. Unfortunately, many still seem to regard papers in these journals as gospel, rather than somewhat subjective and unreliable material at the "frontier of science" that has been made widely available.–Steve Sheppard

Dear WM, This recent paper published by Mallik & Dasgupta concludes "mantle potential temperatures of 1330-1350°C appear sufficient to produce high-MgO, primitive basanite-nephelinite if carbonated eclogite melt and peridotite interaction is taken into account.".

This is more evidence that the geochemistry of mafic Mg-rich alkaline rocks can be explained with "normal" temperature, simply assuming a non-pyrolitic mantle source.–Michele Lustrino

Dear WM, Regarding the rapid eruption rates in flood basalts, I offer the following comment. Megacryst zircons from kimberlites record a range of ages from approximately the date of actual kimberlite eruption to about 5-10 Ma earlier than eruption (and sometimes more) (Data in Moore et al, 2008, EPSL 268:151-164, Fig.1). I am aware of unpublished data which shows the same relationship. Megacryst suites from individual kimberlites apparently crystallize isobarically over a wide temperature range, although the depth of formation differs from one kimberlite to another.

While there is considerable debate regarding the origin of the megacryst suite, field, petrographic and experimental evidence suggests a close genetic link between megacrysts and the host kimberlite. However, irrespective of the origin of the megacrysts, this suite reflects an isobaric magmatic event in the mantle over a time period of the order of 10 Ma immediately prior to kimberlite eruption. One possible interpretation of the range in megacryst zircon ages is that they reflect a period of kimberlite melt accumulation in the mantle, with eruption only occurring once a critical volume of melt has accumulated.

Episodes of kimberlite eruption in southern Africa also seems to follow continental epeirogenic episodes by about the same period (5-10 Ma) that is recorded by the zircon megacrysts. Further, these epeirogenic events appear to be roughly synchronous with reorganization of mid-oceanic spreading regimes around southern Africa. Post-Gondwana kimberlite and other alkaline activity in southern Africa thus seems more readily explained by tectonic melting triggers than plumes. In essence, the zircon dates suggest that the "anomaly" of disparate melting rates and eruption rates is not an anomaly at all, at least for kimberlites. But maybe also a great deal of other magmatic activity.–Andy Moore

Dear WM, I would like to bring your attention to this analysis of the thermodynamics of Hell. I wonder if this information is relevant to plumes.–Andy Moore

Dear WM, It has long been taught in geophysics and planetary physics courses, but not in mantle geochemistry courses, that the Earth started hot and was extensively differentiated during accretion. This knowledge goes back to the extremely influential papers of Francis Birch, including his classic 1952 paper, his 1965 Presidential Address and his energetics-of-core-formation papers. These papers form the foundations of modern geophysics but they are the antithesis of the Urey school of geochemistry (Urey, 1952) which produced many advocates of cold accretion, primordial Earth, crustal growth, continuous differentiation  and undegassed mantle. Thus, 1952 was a pivotal year for both mantle geophysics and mantle geochemistry. The two sciences diverged from that point on.

Schilling (Nature 242, 1973, page 565) states "Contrary to earlier views (Birch 1965), the model implies that plumes are transporting to the Earth's surface more primordial mantle material(s) than present in the low-velocity layer lying beneath those mid-ocean ridge segments remote from plumes." This was the nucleus of the geochemical version of the plume hypothesis. Tatsumoto (1978) and O'Hara (1973) almost immediately showed the flaws in Schilling's argument, and Tozer (1973 ) demonstrated the fluid dynamic implausibility of the geochemical model. Birch’s papers had already demonstrated that classical physics ruled out the assumptions in what became the canonical model of geochemistry.

The Birch ideas were extended to mantle geochemistry by Tatsumoto, Armstrong and Kay who developed top-down models of geochemistry. The mass balance associated with hot accretion and early differentiation was developed in many early papers and summarized in Chapter 8 of Theory of the Earth and Chapter 13 of New Theory of the Earth. The mass balance shows clearly that the whole mantle had to be processed to form the crust plus the kimberlites and carbonatites.–Don Anderson

Dear WM, The list of plume types, last updated in 2007, comprises fossil, dying, recycled, tabular, finger-like, baby, channelled, toroidal, head-free, cold, depleted residual, pulsating, throbbing, subduction-fluid fluxed, refractory, zoned, cavity, diapiric, starting, impact, incubating, incipient, splash, passive, petit, primary, real, secondary, satellite, strong, weak, tilted, parasite, thermo-chemical, asymmetric, fluid dynamic, depleted, stealth, lateral, CMB, shallow, 670-, mega-, super-, mini-, cacto, cold-head, headless, implausible (IMP), and plumelet.

It is ironic that Paul Tackley, in his review of P^3 in Science, criticized non-plume theories on the grounds that there are so many "special cases"!–Don Anderson

Dear WM, I would like to bring to your attention our new invited review paper Franke, D., Rifting, lithosphere breakup and volcanism: Comparison of magma-poor and volcanic rifted margins, Marine and Petroleum Geology (2012).

Key points are:

  • Reevaluation of volcanism during rifting and continental breakup;
  • Magma-poor and volcanic rifted end-member margin types are discussed;
  • Study of the Laptev Sea, the South China Sea and the southern South Atlantic;
  • Implications on the formation of rift-onset and breakup unconformities;
  • A major controlling mode of hot-spot related mantle processes cannot be observed.

Dieter Franke

Dear WM, In continuation of the theme of Anatomy of a Fallacy by E. Cañón-Tapia, further discussion of the logical fallacies underlying the canonical models of mantle geodynamics and geochemistry is given in the pages listed on the webpage General Theory of Plate Tectonics. This subject is also treated in the paper Anderson, Don L. (2002) Occam's Razor: Simplicity, Complexity, and Global Geodynamics. Proceedings of the American Philosophical Society, 146 (1). pp. 56-76. ISSN 0003-049X. –Don Anderson

Dear WM, Rampone, E., A.W. Hofmann, A global overview of isotopic heterogeneities in the oceanic mantle, Lithos, 148, 247-261, 2012. is a very important paper. First, it is the definitive explanation of how heterogeneous Earth's mantle is. Hofmann was among the first to propose a model to explain the extremely radiogenic 206Pb/204Pb isotopic composition of a rare group of OIB as consequence of deep recycling of slabs down to D'' depth. His 1988 paper, as well as his 1997 Nature paper and his 2003 Encyclopedia of Geochemistry paper are considered seminal by the geochemical plume-advocate community.

In the present paper, however, the word "plume" does not appear. The heterogeneities in Earth's mantle are attributed to poor homogenization of the upper mantle instead of to the arrival of deep, hot mantle plumes. That the MORB source is heterogeneous is definitively stated, in direct conflict with the old idea that MORB source is homogeneous.–Michele Lustrino

7 May, 2012,
Click here for a review by Don Anderson of the book "The Eruptions That Shook the World".–WM

4 May, 2012
Dear WM, Please add a link to my web page on the Ethiopian Rift Valley in my mantleplumes webpage. –Giacomo Corti

30 April, 2012
Dear WM, I would like to draw your attention to this article "A hotspot alternative" recently posted on about.com.–Phil Gibbard

31 March, 2012
Dear WM, I think it would be a good idea to post the classical paper by Roeder & Emslie (1970) which, for the first time, defined the correlation of Mg/Fe between olivines crystallizing from basaltic melts. It is a very old paper, but all Tp estimates are based on this paper. Considering that the alleged higher Tp of mantle-plume-derived melts are based on the presence of high-Mg olivines, interpreted as an evidence for high-Mg liquids, and, consequently, higher than "usual" temperatures (to extract more Mg from peridotites) it would be instructive to have such a paper posted on the site.–Michele Lustrino

29 March, 2012,
Dear WM, We have two hard constraints on the temperature of the mantle, the P and T of melt extraction at Hawaii and at ridges. These constraints require that the geotherm at ridges must graze the volatile-free lherzolite solidus at about 60 km depth. The standard complaint against this hard constraint is that we are missing this or that component. But at these low pressures, we now have data in 6-space (CaO-MgO-Al2O3-SiO2-Na20-FeO) and 98% of the composition of basalts so it is unlikely that any unmodeled component or other will change the conclusion much. At Hawaii, there is one published trend of olivine-controlled crystallization (Clague), which requires melt extraction at much higher pressures. The olivine-rich end of thIs trend intersects the experimentally-determined trend of pressure vs initial melt composition at about 5 GPa. So for this trend, the melts come from about 150 km depth, and the geotherm at Hawaii must graze the geotherm at about this depth. In my recent J. Pet. paper, for higher pressures, I assumed a 1500 C adiabat at Hawaii. For ridges, I connected the 60 km point on the geotherm at about 1.3 GPa with what I assumed was a fairly uniform temperature (a 1500 C adiabat) at great depths. Except for the temperature constraint at ~1.3 GPa. My guess that temperatures at great depth are fairly uniform could easily be wrong. But I feel very secure about the two different P-T ranges for melt-extraction at Hawaii and MORBs.–Dean Presnall

28 February, 2012
Dear WM, There have been several papers on seismology around Hawaii published recently. There are various predictions for what the observations should show, if there is a plume. These include low absolute velocities, depressed 410, elevated 650, a parabolic trend of azimuthal anisotropy and shear wave splitting, ponding under 650 km, and a dragged and sheared slow plume head extending to the NW. Thus, from seismology, the plume idea is eminently testable. Recent papers show that none of these predictions are true and different, detailed rationalizations have been offered for each failure. Thus, the plume hypothesis cannot be falsified.

The polarization anisotropy of the Pacific, is not due to LPO or oriented olivine. It is due to oriented melt-rich lenses. The prediction is that azimuthal anisotropy should be much less than the radial, as observed. If the plate direction is EW the fast direction is to the W, dipping down slightly to the W, and SH is faster than SV by more than the splitting delay, as observed.

Attributing the observed anisotropy to fossil anisotropy is a cop out. The predicted asthenosphere flow in the plume model is to the NW but all indications are that the trend of the volcanic chain is not in the direction of plate motion over the mantle.

When properly interpreted, anisotropy is a powerful constraint. For example, the LLAMA model suggests that the melt content is 1- 2%, something that cannot be inferred with confidence from the seismic velocities themselves. It also shows that orientation of olivine cannot be the explanation for seismic anisotropy.–Don Anderson

2nd October, 2011
Dear WM, The data published in nearly all the petrology/ geochemistry papers on basaltic rocks can be explained without invoking any thermal anomaly. The presence of mantle plumes is not necessary and, in many cases, it is in disagreement with the investigated phenomenology. An example is the recent paper published in G3 by Beier et al. on Louisville seamounts. The authors state, "Unlike Hawaiian volcanoes, Louisville volcanoes appear not to pass through a sequence of evolutionary stages characterized by older tholeiitic basalts overlain by incompatible element enriched alkalic and silica-undersaturated lavas". Moreover, they state "The youngest lavas from a given Louisville seamount tend to have the least enriched incompatible element compositions." They interpret these features (in contrast with the plume theory) in the following way: "This unusual chemical evolution may be the result of re-melting of heterogeneous hot spot mantle that was partially depleted during the earlier, age progressive stages." These are ad hoc solutions. Interestingly, the authors say "Large fracture zones apparently had no significant effects on the composition of Louisville magmatism." even though the Louisville seamount chain is parallel to the large Heezen and Tharp fracture zones. The authors continue: "magmatism at several Louisville volcanoes took place over a protracted period of time, with temporal chemical variations among the lavas erupted on a particular seamount.". The igneous activity on each seamount seems to last from 10 to 23 Ma, much longer than other typical Pacific seamounts.

Similarly, igneous activity on some Canary islands lasted for more than 60 Ma and, despite this, it has been considered as evidence for a fixed mantle plume impinging beneath the NE Atlantic lithosphere. It seems not to matter what is observed–plumes survive anything.–Michele Lustrino

6th October, 2011
Dear WM, The papers Zhao et al., Origin of the Changbai intraplate volcanism in Northeast
China: Evidence from seismic
tomography, Chinese Science Bulletin, 49 ,1401-1408, 2004
, and Wortel & Spakman, Subduction and Slab Detachment in the Mediterranean-Carpathian Region, Science, 290, 1910-1917, 2000, along with various of Marjorie Wilson's, justify the statement "all the volcanoes in Europe, North Africa and China that have previously been attributed to plumes are now recognized as natural results of plate tectonics." These areas are similar to Yellowstone-CRB in that enormous volumes of oceanic crust and plate have been shoved under these regions.–Don Anderson

26th June, 2011
Dear WM, The recent paper by Christoffersson & Husebye (2011) shows that ACH tomography does not work. This is confirmed by the recent work at Hawaii by Cao et al. (2011), who show that the structures formerly claimed to exist beneath Hawaii on the basis of ACH do not exist after all.–Don Anderson

3rd June, 2011
Dear WM, The recent paper in Science by Cao et al. (2011) destroys the previous Science papers that "proved" the existence of a plumes under Hawaii, by authors such as Wolfe and Montelli. It confirms results published in an old and excellent paper by Katzman et al. (1998), which uses a more data and advanced theory and comes to an opposite interpretation of the final results. Katzman et al. (1998) use a lot more than just SS and also allow for anisotropy.

The "hot-megablob" 2000 km W of Hawaii is one of many in the Pacific that have nothing to do with "plumes" or particularly hot mantle. There are lots of places in the world, Pasadena is one, with thinner (hotter) transition regions.

I encourage you to read the attached and compare it with the recent Science paper.–Don Anderson

16th March, 2011
Dear WM, I followed your suggestion and acquired a free instructor's evaluation copy of your book "Plates vs Plumes" from Wiley-Blackwell. I'll be teaching a 1-unit nonorthodox-geodynamics course in the fall, and will seriously consider your book.

21st Feb., 2011
Dear WM, I would like to bring to the attention of website visitors a new journal recently established, the Journal of Universal Rejection (JofUR). For those wishing to submit papers criticising the plume hypothesis, this might provide a quick route through the publication process up.–Peter Vogt

Discussion of the webpage "The highly magnesian dike rocks of Vestfjella (W Dronning Maud Land, Antarctica): implications for sublithospheric mantle sources & the origin of the Karoo LIP." has been moved to a separate Discussion page.–WM

29th Sept., 2010
Dear WM,
I would like to bring to your attention the recent paper by Thiede & Vasconcelos (Geology, 38, 747-750, 2010), showing that the apparent 11-Ma year younging of the Parana basalts from west to east is an analytical artefact. The entire sequence is the same age with an error limit of ± 1Ma. The apparent younging from previous, incorrect results was ascribed to passage over a plume, so this model now has to be abandoned.–Andy Moore

21st Sept., 2010
Dear WM, A recent paper argues that the Siberian Traps and the NAIP were active for 250 Ma and "this rules out an upper mantle explanation and requires a deep mantle plume explanation". Thus, a short duration (1 Ma), a moderate duration (3 Ma) and a long duration (250 Ma) are all used as arguments for a plume origin. Smirnov & Tarduno just use the long duration as a plume diagnostic. This confirms, again, that the plume hypothesis cannot be tested or falsified as it stands. The updated list of plume variants now includes fossil, dying, recycled, tabular, finger-like, baby, channeled, toroidal, head-free, cold, depleted residual, pulsating, throbbing, subduction-fluid fluxed, refractory, zoned, cavity, diapiric, starting, impact, incubating, incipient, splash, passive, primary, secondary, satellite, strong, weak, tilted, parasite, thermo-chemical, asymmetric, fluid dynamic, depleted, stealth, lateral, CMB, shallow, 670-, mega-, super-, mini-, cacto-, cold-head, headless, petit, implausible (IMP), zombie, plumelet, pizza, spaghetti and flattened-onion plumes. Many plume models now involve 2000-5000 km of lateral flow, an attribute of many non plume models. The number of plume types is now essentially identical to the number of generally accepted plumes in plume catalogues and 8 times more than what are considered to be “primary” plumes.–Don Anderson

New journal:

Rejecta Mathematica

Article in The Economist

19th Sept. 2010
Dear WM, Visitors to the website might be interested in this quote, from Davis (1926): "It has been remarked that the majority of astronomers explain the craters of the moon by volcanic eruption–that is, by an essentially geological process–while a considerable number of geologists are inclined to explain them by the impact of bodies falling upon the moon–that is, by an essentially astronomical process. This suggests that each group of scientists find the craters so difficult to explain by processes with which they are professionally familiar that they have to recourse to a process belonging in another field than their own, with which they are probably imperfectly acquainted, and with which they therefore feel freer to take liberties.”–Bruce Julian
Davis, W.M., Biographical memoir of Grove Karl Gilbert, 1843-1918, Mem. Nat. Acad. Sci., 21, 5th Mem., 303 pp., 1926.

11th Sept. 2010
Dear WM,
I would like to bring your attention to an interesting article posted on the website of the Santa Fe Institute "Modeling shows scientific peer review system sensitive to bad refereeing"– Romain Meyer

23rd April, 2010
Dear WM, There have been numerous ad hoc attempts to explain why bathymetry violates the square-root-age relation after 70 Ma but none of them are consistent with the continued growth of the seismic lid across the whole Pacific. The latest attempt to unflatten the seafloor is in the issue of Science that hit the stands on April Fools Day 2010 but has a publication date one day later. I discuss the flattening problem in the attached document.–Don Anderson

22nd April, 2010
The process by which science advances is a conservative one. That is, each step of the way involves documentation that the new information is reproducible and consistent with the existing body of knowledge. For most day-to-day operations of science, this approach is reasonable and successful; inaccurate observations and incorrect deductions are weeded out, and accurate observations and deductions are added to the fabric of knowledge. However, when new observations or arguments do not fit into the existing paradigm, there is a strong tendency for them to be rejected by the scientific community. The larger the shift of paradigm required to accommodate the new information, the more harsh and emotional is likely to be the rejection.–Harry W. Green, from "Psychology of a Changing Paradigm"

12th March, 2010
Dear WM, I am comparing different scientimetric systems; ISI Thomson (their impact factor system) and two new systems (SNIP and SJR) provided by SCOPUS, for Earth Science journals. To test these systems I need a selected pool of journals, which are considered to be the top journals among researchers.

In order to do this I created an on-line voting system with a list of 200 Earth Science journals. Science, Nature and Nature Geosciences are not included for obvious reasons and some other journals are absent because they are not covered by all three systems. I would be most grateful if website visitors would visit this site and vote.–Alexei Ivanov

24th Feb., 2010
Dear WM, I send this published paper for listing on the website. We met briefly when you gave a talk at Univ. Wisconsin a few years ago. I was "plume neutral" before I started the project, working on a major shear zone in the western US (western Idaho shear zone). An inadvertent outcome of our work was the suggestion that the Yellowstone (and Newberry) hotspots seem to initiate on the Mesozoic shear zone (perhaps on the termination of the shear zone) and the Columbia River basalt feeders seem to follow the shear zone exactly. So, I found myself increasingly thinking that the initiation of the hotspot was a result of plate tectonic processes (I can't say anything about the Yellowstone hotspot at present - only the initiation). Anyway, here is a contribution from the structural geology angle if it is of interest.–Basil Tikoff

19th Dec., 2009
Dear WM, I found an old paper entitled “The Method of multiple working hypotheses” by T.C. Chamberlin published in Journal of Geology, 5 (1897) 837–848. It has close bearing on current debates on the mantle plume hypothesis. The mantle plume hypothesis has often been linked to the origin of oceanic island basalts (OIB) and continental flood basalts (CFB), with potential implications for the composition of the lower mantle and even the core-mantle boundary layer. The debates centered on this issue closely mirror imperfections of our knowledge of mantle geochemistry. The issue of the origins and evolutionary mechanisms of oceanic and continental basaltic magmas is a vast subject. For anyone who wants to argue for/against the mantle plume hypothesis, it is necessary to clarify the positions of those said to hold divergent views.

The supposed divergence here includes not only acceptance/rejection of the evidence for the existence of mantle plumes (and the implications for the geochemical nature of their postulated ultradeep mantle sources), but also confidence/doubt in the applicability of the plume hypothesis to the origin of continental mafic rocks. The view that this position is somehow subjective may arise from confusion between objective reality (the existence of geochemical varieties of OIB and CFB ) and a human construct (a cherished but subjective model for the origin of observed features). The problem appears to be one of “academic affection” in the method of multiple working hypotheses (Chamberlin, 1897). On one hand, when a model has assumed the status of reality in the minds of its adherents, the whole system under discussion is viewed in the context of the model and thus there is great resistance to any attempt to challenge it.

Investigations predicated on this type of thinking can only lead to self-reinforcement of the initial ideas. Science, on the other hand, requires us to attempt to break out of such modes of thinking, by attempting to falsify models. In this regard, the mantle plume hypothesis has been well and truly falsified ( Anderson D.L., 2007. New Theory of the Earth. Cambridge University Press, Cambridge, 384 pp), but this has little bearing on the reality of OIB and CFB on Earth. This is particularly so for OIB-like mafic rocks on continents, which may have important implications for the tectonic development of the continental lithosphere in which they occur (e.g., Zhang J.-J., Zheng Y.-F., Zhao Z.-F., 2009. Geochemical evidence for interaction between oceanic crust and lithospheric mantle in the origin of Cenozoic continental basalts in east-central China. Lithos, 110, 305-326).–Yong-Fei Zheng

28th Sept., 2009
Dear WM, I will reverse my color scale–to make Bruce happy–Rob van der Hilst

28th Sept., 2009
Dear WM, Concerning the recent Science article "Scoping Out Unseen Forces Shaping North America", Science magazine doesn't seem to proof-read its figure captions. The caption to the "What a drip!" figure says that blue colors represent slower waves and reds represent faster, the opposite of the essentially universal convention. The blue anomaly in their picture, however, has HIGH wave speeds, as the text makes clear.–Bruce Julian

14th Sept., 2009
Dear WM, Rejectica Mathematica–I love it. I suggest for us, Acta Geophysica TrashicaChris Scholz

28th Aug., 2009
Dear WM, I recently discovered your website. What a great resource for the public!

I am a professional geneticist and an amateur naturalist with an interest in geology. I give geology walks in a local park in Seattle, Washington, USA as a volunteer. Even as a (non-geologist) scientist, I have trouble finding, accessing, and understanding professional geology papers in order keep up with current thinking on the formation of the American Pacific Northwest. Your website is a pleasure to read. Free access and a focus on models and controversies allows an amateur like me to get much better understanding of the field than I have generally been able to get through always-out-of-date popular geology books and my limited access to and awareness of published papers.

The various articles are also generally clear and clearly illustrated. Obviously the more knowledge of geology one has, the more one can understand and glean from the articles, but as a self-educated amateur, I am pleased to find them relatively easy to read.

Thanks so much for providing this resource!–Paul Talbert

20th Feb., 2009
Dear WM, An interesting piece of work was recently published: Polyakov V.B. Equilibrium iron isotope fractionation at core-mantle boundary conditions. Science, 323, 912-914, 2009 on the theory of stable isotope fractionation with implications for iron isotopes in the Earth and other planets. It appears that enrichment of the Earth and Moon by heavy iron isotopes compared to Mars, Vesta and chondritic meteorites can be explained by equilibrium fractionation of iron isotopes at pressures of the Earth’s core-mantle boundary.

This new model has two important implications for Earth sciences. First, it suggests that the separation of iron, which formed the Earth’s core, happened at high pressure and not in a shallow magma ocean. Second, it suggests that plumes, if they originate at the core-mantle boundary and feed ocean-island volcanism e.g., at Hawaii, could be distinguished from shallow-sourced magmatism by iron isotope measurements in OIB and MORB basalts.

The core contribution at Hawaii postulated from earlier Re-Os isotope work was ruled out by a later tungsten isotope work (Scherstén A., Elliott T., Hawkesworth  C., Norman M. Tungsten isotope evidence that mantle plumes contain no contribution from Earth’s core. Nature, 427, 234-237, 2004so this could provide a new investigative approach–Alexei Ivanov

11th Feb., 2009
Dear WM, I would like to draw the attention of website visitors to the NY Times article "Darwinism Must Die So That Evolution May Live". Are there are some parallels to be drawn in plume science?–Andrew Alden

5th Feb., 2009
Dear WM, I would like to update website visitors on the progress of our initiative to donate copies of the P4 book. I just received this photo showing the presentation by the Alumni Association, of copies to Obaferni Awolowo University, Nigeria.–Donna Jurdy

29th Dec., 2008
Dear WM, In many recent plume-advocacy papers plumes are not the essence of the story and none of the data requires them, yet “the plume” is in the title and the conclusion. Putting a plume in for the hell of it is “gratuitous plumeology”. Such a plume is a ”zombie plume” since there is no evidence for it, and it therefore cannot be refuted or killed! Examples include Konter et al. 2008; Cadoux et al. 2007; Sen et al. 2008.

All indications in these papers point to asthenospheric and metasomatic shallow sources and against any deep, hot source. Some involve no connection between flood basalts (plume heads) and volcanic islands (plume tails), yet plumes and plume heads are prominent in titles and abstracts, and are sometimes only there. The data would be equally well satisfied by melting of cold mafic chunks and the conclusions would make equal sense if “plume” were replaced by “delaminated crust”, “Reunion-like isotopic source”, “metasomatised mantle” or “heterogeneity”, and so on.

Temperature, heatflow, depth and origin in a thermal boundary layer are the defining characteristics of a mantle plume, but are usually not mentioned or constrained in any way in plume-advocacy papers. The data are almost always consistent with ambient temperature, and non-plume tectonic events, such as delamination, rift or edge-driven convection, or metasomatism, and often even interpreted in those terms. However, they are usually implied to have occurred co-incidentally with, been caused by, or been an intricate part of an assumed plume. Such an approach at best lacks innovation and at worst is unscientific and hampers progress.–Don Anderson

17th Nov., 2008
Dear WM, I would like to bring to your attention a new branch of science–"zombie science". It is discussed in the paper "Charlton, B., Zombie science: A sinister consequence of evaluating scientific theories purely on the basis of enlightened self-interest, Medical Hypotheses, 71, 327-329, 2008." In a nutshell, "zombie science" is science that is dead but will not lie down. –Don Anderson

27th Oct., 2008
Dear WM, I would like to highlight a comment posted on my blog on the paper Konter, et al., One hundred million years of mantle geochemical history suggest the retiring of mantle plumes is premature, Earth Planet. Sci. Lett., in press, 2008. I think the comment might be of interest to visitors to your website.–Rex Pilger

5th Sept., 2008
Dear WM, An article by Drs. Ingrid Ukstins Peate and Scott Bryan in the current issue of Nature Geoscience would be interesting for geologists involved in the mantle plume debate. It is entitled “Re-evaluating plume-induced uplift in the Emeishan large igneous province”.–Todd Rainey

24th August, 2008
Dear WM, As part of my "Integrating Research and Education" project (funded by NSF), we did a number of "guided discovery exercises" for students to explore interesting and important topics. Kent Ratajeski did a nice unit on "Is Yellowstone Volcanism Caused by a Deep-Seated Mantle Plume?". Please feel free to link to our metadata page about this site if appropriate on your Mantle Plumes site.–Dave Mogk

22nd August, 2008
Dear WM, I propose that the well-known acronym “OIB”, for “ocean island basalts”, is henceforth used to denote “oceanic intraplate basalts”.

There are two reasons for my proposal:

(i) Islands are merely the tops of submarine volcanoes and the term “ocean island basalt” does not include the thousands of seamounts that lie scattered throughout the Pacific and other ocean basins. Most of these seamounts do not define systematic chains, a fact that is of relevance to the plume hypothesis (the “galaxy effect”).

(ii) The term “ocean island basalt” by itself does not say anything about the intraplate origin of the islands in question. There are oceanic island arcs related to subduction which are a plate boundary phenomenon. “Ocean island basalt” should include the basalts of the oceanic island arcs, inasmuch as they are “oceanic”, “islands”, and erupt “basalt”. Thus, OIB and IAB are not really exclusive.

Of course, there are rocks other than basalt in arcs, and I am happy if even the “B” is replaced by something general – simply R for “rocks?”.

But if the term "OIB" is to be continued, then, to avoid these problems, and to ensure terminological accuracy, OIB should be used for “Oceanic Intraplate Basalts”. If used in this way, the term means that the said basalts are “oceanic”, and formed by “intraplate” mechanisms, and therefore island arc basalts (IABs) would be automatically excluded.

Comments are welcome.Hetu Sheth

6th August, 2008
Dear WM, I find the article: Gutierrez-Alonso, Gabriel; et al. 2008 Self-subduction of the Pangaean global plate, Nature Geoscience, 1, 549-553 an intriguing and thoughtful attempt to explain the initiation and pattern of the break-up of Pangaea on the basis of a "platonic" interpretation of plate tectonics geology. I recommend that it be listed under “A glance at today’s paper” on the MantlePlumes site.–Todd Rainey

2nd July, 2008
Dear WM, I find it interesting that two new papers listed in the Recent Scholarly Articles section of this website both invoke secondary, non-plume mechanisms together with primary, plume-related ones to explain the origin of volcanism around Samoa (Koppers et al., 2008) and the Columbia River (Camp & Hanan, 2008). Apparently, plume advocates are increasingly influenced by non-plume mechanisms for generating melting anomalies such that hybrid models are increasingly appearing in the literature.–Don Barrie

30th June, 2008
Dear WM, For those interested in Pacific geology, the Smithsonian Institution has recently scanned and placed on line ALL of the U.S. Exploring Expedition reports. These were originally issued only in a printing of 100, and are rare birds indeed. J.D. Dana's report on Geology is v. 10 of 23 volumes. There are 4 separate indices for the one volume, plus an Atlas of plates. Ch. 7 has Dana's review of Volcanic Action in the Pacific, in which he propounds his fissure-control theory of linear chain volcanism. Ch. 3 on Hawaii also develops some of these ideas.

The URL is:

Jim Natland

9th May, 2008
Dear WM, I bring to your attention our recent paper Clouard, V. and M. Gerbault, Break-up spots: could the Pacific open as a consequence of plate kinematics?, EPSL, 265, 195-208, 2008. Two comments were also published, one in Nature Geoscience, and the other one in New Scientist. I would like to thank you very much for your management of the useful "mantleplumes" website.–Valerie Clouard

7th March, 2008
Dear WM, Andrew Alden, the host of the science blog About.com (Geology) has posted another interesting discussion of hotspot models "A Hotspot Alternative". This news website is a popular source of geological information from a very respected educator.–Greg McHone

29th Feb, 2008
Dear WM, A Russian saying is that bad is the scholar who doesn ’t want to become a great scientist. In his recent correspondence to PLoS Computation Biology ‘On the process of becoming a great scientist’ Morgan Giddings provides an excellent recipe for how to achieve this. We need to be open to challenging ideas, courageous enough to speak out irrespective of our age or status, and wise enough to encourage others to do the same, even if it flies in the face of our own theories.–Alexei Ivanov

28th Jan, 2008
Dear WM, Check out the movies of plume convection at Westfälische Wilhelms Universität Münster (click on the pictures).–Jack Holden

10th Jan, 2008
Dear WM, This is one of the most informative websites I've visited. It has been a tremendous help in keeping up with the latest literature.
Keep up the good work.–Vince Neall

7th Jan, 2008
Dear WM, PDFs of most of my publications since 1958 are now available on line.–Don Anderson

5th Jan, 2008
A paper entitled "Siberian flood basalt magmatism and Mongolia-Okhotsk slab dehydration", authored by Konstantin Litasov and myself, is posted for public view in Nature Precedings service. Any comments are welcome.–Alexei Ivanov

3rd Jan, 2008
Dear WM, The current issue of Scientific American has an article on "moving" hot spots that may be of interest to website visitors–"Hotspots Unplugged". Refreshingly, this article takes a less dogmatic approach to hot spots than most articles aimed at lay readers. Thanks for your informative MantlePlumes website! –Steve Russell, Seattle

8th Dec, 2007
Dear WM, Visual inspection of tomographic cross sections has led to widespread acceptance of whole mantle convection, deep slab penetration and deep mantle plumes. What are the odds that one could find such cross sections, even if the mantle had completely random structure? Considering the resolution of long period tomography, one expects , for a completely random mantle, about 4 mantle crossing alignments of either red or blue colors. This is not too different from the expectations of obtaining a flush or three cherries in various well known games of chance.

The odds of drawing a flush (5 cards of the same color and symbol) in poker are about 1 in 550. In tomography one usually uses about 4 colors. A mantle with 7 independent layers would be equivalent to 7 cards. If one had a vertical alignment of 5 reds, some would certainly declare that a plume had been found; 5 blues would be evidence for whole mantle convection and a throughgoing slab. Considering the resolution of global seismology one expects 1 or 2 whole mantle ‘plumes’ and ‘slabs’ even if the mantle is a random number generator. – Don Anderson

24th Nov, 2007
Dear WM, Bourdon et al. (2007) state “Anderson and Natland favour the idea that all plumes originate from the core–mantle boundary.” My befuddlement at this conclusion is summarized by something Johnny Carson used to say with his classic straight face on the Tonight show, usually in response to some non sequitar from Doc Severinson: “I did not know that.”– Bob Stern

29th Oct, 2007
Dear WM, The “lower mantle” proper starts at about 1000 km (Bullen's Region D). There has been enormous semantic and logical confusion, with some investigators assuming that if slabs sink below 650 km they enter the “lower mantle” and “therefore” sink to the core mantle boundary. Slabs can sink below 650 km and still stop at 800-1000 km as shown by numerous papers. This appears to be an important geodynamic boundary. Slab pull gets very weak below 300-400 km.

The “upper mantle” and the Transition Region (Bullen’s Region C) contain two major seismic discontinuities, several low velocity zones, and much seismic scattering.

Slabs sinking below whatever depth must be replaced but not necessarily by narrow upwellings. The mantle below 410 km, or 500 km, or between 650 and 1000 km is displaced upwards as slabs sink into it. Even without slabs, radioactivity gives broad diffuse upwellings and narrow downwellings. A mantle heated only from below will give narrow upwellings (if pressure and radioactivity are ignored, as in much plume modeling) and diffuse downwellings, as Morgan pointed out in his plume papers. There is no mass balance or chemical reason for having slabs return or be part of a closed cycle. Delaminated lower crust can, however, recycle on a short timescale.

I see no evidence or reason to invoke the mantle below 1000 km for anything having to do with surface tectonics or basalt. –Don Anderson

4th Oct, 2007
Dear WM, Please post this additional Powerpoint presentation "The Circum-Mediterranean Anorogenic Cenozoic Igneous Province" by myself and Marge Wison.–Michele Lustrino

2nd Oct, 2007
Dear WM, The list of plume types assembled by Michele Lustrino and Eugenio Carminati considerably enriches the plume vocabulary. The updated list now includes fossil, dying, recycled, tabular, finger-like, baby, channelled, toroidal, head-free, cold, depleted residual, pulsating, throbbing, subduction-fluid fluxed, refractory, zoned, cavity, diapiric, starting, impact, incubating, incipient, splash, passive, primary, secondary, satellite, strong, weak, tilted, parasite, thermo-chemical, asymmetric, fluid dynamic, depleted, stealth, lateral, CMB, shallow, 670-, mega-, super-, mini-, cacto, cold-head, headless, petit, implausible (IMP), and plumelet!

The number of plume types is now essentially identical to the number of generally accepted plumes in plume catalogues and 8 times more than the primary, or real plumes (oops! That’s another one).–Don Anderson

10th Sept, 2007
Dear WM, I'm quite intrigued by all the fascinating ideas that are developing. It's an exciting time and I'm disappointed that the new edition of the introductory geology text I use still relies heavily on plume theory to explain almost everything from LIPs, to aulacogens, to aseismic ridges, to the breakup of Pangea.

The tide seems to be turning even for textbook writers, however, as evidenced by the following statement, found in the chapter on plate tectonics: "Of the forty-five hot spots identified on Earth, only twelve show evidence of a deep, continuous plume in the underlying mantle." (Carlson et. al. 2008, Earth Revealed, Physical Geology, 7th ed., McGraw Hill).

Still a dubious statement, of course, but progress, perhaps.–Don Barrie

7th Sept, 2007
An Implausible Mantle Plume (IMP). I like It! A new category of plumes or non-plumes, to join cavity, diapiric, starting, impact, incubating, incipient, splash, passive, primary, secondary, satellite, parasite, thermo-chemical, fluid dynamic, depleted, stealth, lateral, super-, mini-, cacto, cold-head, headless, petit and baby plumes, and the plumelet, hot head, cold head and headless subspecies. Each, including IMPs, is the result of an after-the-fact observation or failure of a prediction. An IMP, of course, is of the family of devil's advocates and Maxwell Demons, both relevant to plumes. I am certainly an advocate of imps, the little devils!– Don Anderson

3rd Sept, 2007
Has anyone compiled a data set for lithophile isotope compositions of mineral separates (ol, cpx, opx) from mantle rocks similar to the work by Mattey et al., (1994: Oxygen isotope composition of mantle peridotite) that can be used as a proxy for mantle compositions to compare with conventional basalt compositions (e.g., Zindler & Hart, 1986)?Sami Mikhail

20th July, 2007
The cover for the forthcoming P^4 book (to be printed in August) may be viewed by clicking here. Please send your comments to the website manager.
Comments to date:
1. "It's wild". - Jack Holden
2. "awesome". - Ian Norton
3. "AWESOME". - Scott King
4 "It's very good! Much better than a photo of a volcano or another section through the Earth." - Godfrey Fitton
5. "Looks great!!! " - Erin Beutel
6. It seems to me to be looking at the earth and at the special volume and saying "what the hell have I done???" - Scott King
7. The cover page appears to convey that it is a "mental
plume". The cover page is the most appropriate one to represent the mantle plume debate. - Senthil Kumar
8. I find the cover GREAT.– Michele Lustrino
9. You must be joking about the cover. It is embarrassing.– Anonymous
10. Very impish. Whose cartoon is it?–Jim Natland
WM: The cartoon is Fig. 2 from Ch. 45 of the book.
11. The proposed cover cartoon
is fine for a chapter intended to be humorous and witty. It's too informal
for the cover of such a serious volume.– Anonymous
12. There's simply nothing - no matter how wonderful - that EVERYONE will like. It does not exist.–Donna Jurdy

15th June, 2007
Dear WM, I thought this might be of interest – an abstract indicating continental crust underlies Iceland. – Mark Jancin
4th June, 2007
Dear WM, Please visit largeigneousprovinces.org and click on May 2007 LIP of the Month article for a brief introduction to and summary of our ongoing Deccan dyke work.– Hetu Sheth
24th May, 2007
Dear WM, Cambridge University Press has just mailed out the New TOE. The advanced posting on the Caltech Library website will soon be removed. – Don Anderson
9th May, 2007
Dear WM, GSA have sold 856 copies of the P3 book to date and 169 remain in inventory. We expect all copies to be sold in the next 12-18 months. I think this book is an all-time bestseller! I think the only people who do not love it are the folks who have to carry the shipments. Current prices are:
GSA members–$63.00,
Jeanette Hammann (GSA)
1st April, 2007
Dear WM, You deserve an award for facilitating a refreshingly well-tempered international discourse on geodynamics that I'm quite sure would never have happened otherwise. If the true goal of science is to advance knowledge and understanding, genuine dialog should be at its heart. Failure to compare notes continues to promote blind elephantology. What we all too often get, however, and particularly in areas of controversy, is a heady mix of preaching to the choir, broken-record repetition, selective listening and ad hominem mischief. Many thanks for both the relief and the excitement. To tide you over until an award from an organization of stature appears on your doorstep, I provide here one of my own making, suitable for hanging. – Jeremy A. McCreary, Colorado School of Mines
20th March, 2007
Dear WM, Visitors to the website might be interested in this review of P4 by Andrew Alden on www.about.com. – Don Anderson
13th March, 2007
Dear WM, Here is a pdf of an article I recently wrote for Geographical about volcanoes.– Charlie Furniss
12th March, 2007
Dear WM,
I am a non-geologist admirer of your website, P3 book, and just about anything related to alternative interpretations of hot spot/plumes theory. My interests mostly lie in presenting opposing views to my introductory ocean-ography students, at least to the extent of painting the broad brush-strokes of the arguments.

I wondered if anyone had a “rebuttal” for Pilger’s recent paper, The Bend: Origin and Significance, in the GSA Bulletin. He seems to argue quite persuasively for a Hawaii plume-generated hot spot versus an intraplate stress origin. In any case, if one is in preparation, I would love to hear the counter-arguments.

Thank you for your outstanding web site.–W. Sean Chamberlin, Ph.D., schamberlin@fullcoll.edu
12th March, 2007
Dear WM, Just a reminder of the IODP/JOI LIPs workshop to be held in Coleraine, Northern Ireland, 21-26 July 2007. A three-day planning meeting for future scientific ocean drilling investigations of LIPs, the workshop will also include a one-day field trip (Giant's Causeway, etc.). IODP/JOI will cover all expenses for participants, including travel. See www.iodp.org/lips for more details and online application forms, the latter due by 15 March 2007.– Mike Coffin
28th Feb, 2007
Dear WM, For a short period of time, prior to publication, the entire text, figures and tables of my new book "New Theory of the Earth" (Cambridge University Press) will be freely available from the web. Upon publication, in one months time, it will be removed from open access.– Don Anderson
4th Feb, 2007
Dear WM, Here is a new review of the P3 book written by Jean Bedard and published in Elements.–Hetu Sheth
6th Jan, 2007
Dear WM, here is an interesting exchange from this week's Science– "Another nail in which coffin?". It's now openly admitted that geochemistry is not going to prove or disprove the existence of plumes.– Anders Meibom
29th Dec, 2006
Andrew Alden is right up to date on his website http://geology.about.com/Don Anderson
15th Dec, 2006
My recent contribution regarding the definition of plumes is prescient. My fear was that plumologists would just refine plumes as 'anything', declare victory and go home. The recent Nature paper by Bourdon et al. does just that. I include a comment on this subject: "Plumes are redefined by plumologists!".There is a danger that all evidence is simply swept into the plume bin and confirms the idea. – Don Anderson
3rd Dec, 2006
2007 promises to be the Year of the LIP, with many conferences and workshops planned. Visit Forthcoming Conferences page for details. – WM
17th Nov, 2006
Dear WM, Please advertise our new paper "The nature of Cenozoic upper mantle plumes in east Siberia (Russia) and central Mongolia" by Y.A. Zorin and others, on the website. – Alexei Ivanov

17th Nov, 2006
Dear WM,
The MantlePlumes.org coffee mugs are superb and I like them a lot. As they are strongly motivating and remind one to work hard to find the real reasons for "hotspots" during every coffee break. And the flavor of the banana doughnuts from Ft. William is all around. – Romain Meyer

10th Nov, 2006
Dear WM, I am not a professional geologist, but I am the Science teacher for Grades 6-8 at my school, so it's made me a bit of a "jack of all trades" in the sciences. It has always been my goal to make sure my students get the latest thinking on any given subject, even if that means contradicting often-out-of-date textbooks.  MantlePlumes.org has given me some good information on its topic, one which my 6th graders were discussing only a month ago. Reading the basic papers and articles on the subject has shown me that there is enough evidence to question the "plume paradigm."   Such questioning is at the heart of scienctific inquiry, a fact which is not lost on my inquisitive students. They are frequently amazed (and occasionally nonplussed) to learn that something in their textbooks might be outdated in light of recent ideas–a good lesson to them on the nature of science and the need to always keep the mind open to new ideas and observations. –Blake H. Lindsey, Oro Loma School, Dos Palos, California
9th Oct, 2006
Dear WM, I comment on the paper Allen, M.B., Anderson, L., Searle, R.C. & Buslov, M.M., J. Geol. Soc., Lond., 163, 901-904, in press just contributed by Mark Allen. The pattern of grabens suggests that there was oblique tension. Their conclusion is that this was independent of a mantle plume, so they do not need a mantle plume to explain the tectonic pattern. Extension is not evident from the lithospheric thickness 3D model of Pavlenkova, but extension is logical because of the grabens. Anyway, there was active displacement of large lithospheric blocks in the Permian and Triassic. This is also the result expressed in a paper from Walderhaug et al. on Taimyr. – Alexei Ivanov
5th Oct, 2006
Dear WM, Here is a contribution on the West Siberian Basin. Our results suggest that the Siberian flood basalts were erupted during right-lateral oblique extension between the Urals and the Siberian craton, centred on a triple junction in the NE of the West Siberian Basin. The full citation is Allen, M.B., Anderson, L., Searle, R.C. & Buslov, M.M., J. Geol. Soc., Lond., 163, 901-904, in press. – Mark Allen.
30th Sept, 2006
Dear WM, A comment on the post-perovskite phase change at D":
1. If PPv is very iron rich, or has high lattice (high P, high Fe) or radiative conductivity, (high T) it is stable,
2. If D" is strictly a phase change (which few people believe) and is
exothermic then it can become unstable at high T,
3. If it has very low thermal expansivity it can be stable,
4. plume advocates are not worried either way; either PPv is D" and goes unstable, or it is stable and the next layer up is the plume source ('explaining' why plumes do not see the core in Os isotopes),
5. PPv is probably not the whole lower mantle so some of the things used as evidence cannot be,
6. Because pressure drives down alpha and PPv soaks up iron and gets dense, it is unlikely that it can get hot enough to become buoyant. An aside, a little known fact; a mantle heated from below is less hot and has less variable T than a mantle heated entirely from within. If you wants really hot upwellings one does not want to heat the mantle from below. If hotspots are really hot, one wants all the heating to be internal but this makes very broad upwellings. – Don Anderson
25th Sept., 2006
Dear WM, Attached is a short article "Rising Plumes in Earth’s Mantle: Phantom or Real?" in Science by Richard Kerr. Another 10 years of controversy – oh my! – Dan Bloomberg
19th Sept., 2006
Dear WM, You might like to highlight the useful new book Earth's Deep Mantle: Structure, Composition, and Evolution, edited by Rob D. van der Hilst, Jay Bass, Jan Matas, Jeannot Trampert. – Don Anderson
18th Sept., 2006
Dear WM, It would be helpful for readers to compare Tackley's review with that of Alden for About.com, with which I have far more sympathy. – Hetu Sheth
18th Sept, 2006
Dear WM, Here is an online preprint of a paper my colleagues and I have in press on the Nandurbar–Dhule mafic dyke swarm, Deccan Traps. –Hetu Sheth
15th Sept., 2006
Dear WM, Here is a comment on the recent important paper by Busse et al. "A simple model of high Prandtl and high Rayleigh number convection bounded by thin low-viscosity layers", Don Anderson
13th Sept., 2006
Dear WM, Here is my comment on the recent review of Plates, Plumes, and Paradigms by Paul Tackley, redently published in Science. – Don Anderson
13th Sept., 2006
Dear WM, Here is a comment on the recent review of Plates, Plumes, and Paradigms by Paul Tackley, published in Science.– Warren Hamilton
11th Sept., 2006
Dear WM, Here is a new contribution to the LIP classification discussion page. – Sami Mikail
6th September, 2006
Click here for a review of Plates, Plumes, and Paradigms, published in Science. Comments are solicited, and will be posted in this column.– WM
5th September, 2006
Dear WM, Here is a contribution to the LIP classification discussion page. I have somewhat different ideas on this problem from some of the other contributors. – Romain Meyer
2nd September, 2006
Volcano noble gas database:
A new USGS online database: USGS-NoGaDat – A Global Dataset of Noble Gas Concentrations and Their Isotopic Ratios in Volcanic Systems, by A.A. Abedini, S. Hurwitz, and W.C. Evans, U.S. Geological Survey DigitalData Series, 202.: http://pubs.water.usgs.gov/ds202/
– WM

2nd September, 2006
Click here for a report on the Great Plume Debate Conference in German; "Monsterjagd in der Tiefe", by Hilmar Schmundt, Der Spiegel, 36, 2005.– WM
27th August, 2006
Dear WM, There has been an amazing discovery of evidence for an impact structure on our very doorstep, near Santa Fe, NM. GSA 2006 abstract attached. – Wolf Elston
17th July, 2006
Dear WM, here is a paper on Kilauea and Deccan lava flows which may be of interest. – Hetu Sheth
15th July, 2006
Dear WM, Here is an interesting paper on NW Deccan geophysics: The seismic structure of the Saurashtra crust in northwest India and its relationship with the Reunion Plume by G. Surya Prakasa Rao and H. C. Tewari. – Hetu Sheth
14th July, 2006
Dear WM, Here is a recent letter published in Geotimes on the Global Ocean Mapping Project (GOMaP) – Peter Vogt
7th July, 2006
Dear WM, Here are two brief publications concerning plumes in the Baikal region and East Siberia and Central Mongolia. – Yuliy Zorin
15th June, 2006
Dear WM, Here is a PDF copy of my chapter "Plumeless Venus preserves an ancient impact-accretionary surface" in Plates, Plumes, and Paradigms, for posting on the website. – Warren Hamilton
13th June, 2006
Dear WM, The original interpretation of the 410 and 650 km discontinuities involved phase changes (e.g. Anderson, 1967). Despite this, the standard geochemical model attributes the 650 to the boundary between homogeneous convecting mantle and primitive undegassed lower mantle. The classical location of the lower mantle, Bullen's Region D, is, however, near 1000 km. Recent work suggests that eclogite may pond at a phase change and this may explain the highly variable nature of the discontinuities. There may be other chemical discontinuities in the mantle but they are not expected to be as large as the phase changes. Some authors argue that the phase change idea is new and this now introduces a conflict between geophysics and geochemistry. Just because the 650 is primarily a phase boundary does not rule out chemical boundaries at other depths. Discussions of mantle chemistry and dynamics should start with the early papers by Birch (1952) and Ringwood (his two books are nice summaries). – Don Anderson
9th June, 2006
Dear WM, I welcome Dr. Bonin’s valuable comment and thank him for pointing out the correct usage of some petrological terms. However, when he writes that “whether LIP terminology should be expanded, more precise and more detailed than the current definition of LIPs, or should retain its current somewhat loose definition, is a matter of personal philosophy”, I would point out that the distinction between granite and granodiorite may then also be considered a matter of personal philosophy [Ed: and the term "plume", also, perhaps; see Plume definitions page]. If loose terms are okay, then granite is a very good and perfectly satisfactory "loose" term for granite, granodiorite, trondhjemite, tonalite and charnockite etc. Nature is a continuum; any classification is necessarily artificial, and yet classifications and correct terminology are essential for a uniform scientific language and understanding. Denying this means denying the great practical utility of classifications such as mine, the alternative one by Bryan and Ernst, and all the very helpful igneous rock classifications by the IUGS Subcommission on Systematics of Igneous Rocks. – Hetu Sheth
8th June, 2006
Dear WM, Here is a Powerpoint presentation "Summary of Mantle Temperatures" which is a discussion of the current state of mantle temperature estimates. Recent developments in petrology have raised the estimates of 'normal' mantle temperature and their expected range. They are now consistent with geophysical estimates. In an internally heated mantle cooled by slabs the 'mantle adiabat' is a fiction. Everyone is free to use this powerpoint in lectures. – Don Anderson
7th June, 2006
Dear WM, Two Yellowstone hotspot papers are now available on the web:
A short link is: http://tinyurl.com/nabjb.– Ken Pierce
29th May, 2006
Dear WM, I read always with great pleasure and benefits the various contents of the mantleplumes website. Up to now, I have contributed only through the Liegeois et al. paper on W. African volcanism published in the P^3 volume. The recent discussion on LIP terminology is highly interesting, though becoming sometimes Byzantine, because the reasons why terminology should be updated are not always clearly stressed. Whether LIP terminology should be expanded, more precise and more detailed than the current definition of LIPs, or should retain its current somewhat loose definition, is a matter of personal philosophy. I look forward to reading more arguments to explain the rationale of the controversy. I am open to any discussion and formal decisions, if consensus is reached. I would like to offer some comments, on behalf of the IUGS Subcommission on Systematics of Igneous Rocks, which I chair currently. Bernard Bonin
27th May, 2006 Dear Jeremy, Yes, it is published in a recent paper "A cool model for the Iceland hotspot". I have also put my Powerpoint presentation on the website – feel free to use slides from it. – WM Dear WM, Following on from your recent lecture at the Colorado School of Mines, is that material (or some variation thereof) in print? – Jeremy McCreary
18th May, 2006
Dear WM, Here is a popular article commenting on the recent claim that a slab has been detected seismically at the core-mantle boundary. – Anders Meibom
11th May, 2006
Dear WM, A Carnegie announcement has just highlighted the very low velocity of Fe-rich post-spinel described by Wendy Mao and others (Mao, W. L., et al. (2006), Iron-Rich Post-Perovskite and the Origin of Ultralow-Velocity Zones, Science, 312, 564 - 565). This work suggests that the red things in D" are Fe-rich and dense, rather than hot - same story as for the big red "superplumes" in the lower mantle beneath the South Pacific and southern Africa – Dean Presnall

27th April, 2006
Dear WM, Richard Ernst has asked me to take responsibility for posting notices of upcoming conferences on the www.largeigneousprovinces.org website. I would like to ask all mantleplumes.org readers who are planning conferences on the following topics to contact me with a synopsis and I will post it on www.largeigneousprovinces.org and give them free publicity.

  • LIPs
  • The generation of silicic magma at LIPs
  • Plumes and LIPs (again)
  • SLIPs
  • The generation of mafic magma at SLIPs
  • The role or absence of  plumes for SLIP genesis
  • Back arc magmatism
  • Volcanic Rifted Margins
  • SLIPs and crustal building

Sami Mikhail

26th April, 2006
Dear Lapo, Many thanks for bringing this to my attention. I have added it to the "Banana Doughnuts" page. – WM
Dear WM, I have found your website useful in my research on the significance of finite-frequency vs. ray-theory tomography, in particular the "Banana Doughnuts" page. I would like to bring to your attention my recent article on this subject: "On the relevance of Born theory in global seismic tomography". – Lapo Boschi
25th April, 2006
Dear WM, I have written a report on the Great Plume Debate conference in Ft. William, Scotland last year, published in Russian Geology and Geophysics, and provide here versions in both English and Russian. – Alexei Ivanov
12th April, 2006
Dear Alexei, Don't worry, I have toned it down! Seriously, your piece underlines how vital it is for scientists to work closely with nationals and local experts when they study subjects abroad. The new globalisation facilitated by the internet and eased international travel should be fully exploited in this respect. – WM 12th April, 2006
Dear WM, I attached a brief technical comment on the volume of the Siberian traps . Please post it with the LIP classification discussion. Maybe it is worded too harshly? – Alexei Ivanov
7th April, 2006
Dear WM, I think this paper by Mao et al. on post-perovskite in D" should have a place on the website. It is the most recent of a series of papers that argue for this high-P phase to be a big part of D", obviating the necessity for very high-T conditions that could send plumes up. Keeps everything stable. Without unstable D", deep mantle plumes collapse. – Jerry Winterer

5th April, 2006
LIPs Commission meeting during IAVCEI conference in Guangzhou, China, May 14-18 2006, Monday May 15, 6-7 pm All LIPs researchers welcome. Please send suggestions for additional agenda items to Richard Ernst Note: The announcement made in GSA Today March 2006 that Richard is dead was greatly exaggerated. – WM

Agenda items:

  1. Defining LIPs-- discussion of recent progress toward an "official"
  2. Role of the LIPs Commission-- planned and future activities
  3. Expanding content on our website.

31st March, 2006
Dear WM, The backtracking that most people perform for the Pacific is probably only half right – there is no hard evidence that the pre-50 Ma motion of the Pacific plate was in the direction of the Line Islands and Gilbert chains.  The ages of seamounts along these trends are all wrong.  These chains are mainly "new wine in old bottles" i.e., on old FZs and abandoned ridges. – Jerry Winterer
27th March, 2006
Dear Yoshiro, Thank you for this valuable contribution. It adds to the growing evidence that geochemistry can detect distinct, separate parts of oceanic crust being recycled, and that all the lithologies are not homogenised. This has important implications regarding the likely history of the crust during its time circulating in the mantle. I have permanently linked your paper on our publications blog (Recent scientific articles). – WM
Dear WM, I am interested in material cycling in the mantle. Your website is very useful for me. Last year, I published a paper that may be of interest: Nishio, Y., S. Nakai, T. Kogiso & H.G. Barsczus, Lithium, strontium, and neodymium isotopic compositions of oceanic island basalts in the Polynesian region: constraints on a Polynesian HIMU origin, Geochemical Journal, 39, 91-103, 2005.
Best regards – Yoshiro Nishio
21st March, 2006
Dear Don, This is an excellent idea, and such an initiative can be supported via a dedicated page. I encourage website visitors to notify me of material of this sort, and posting will be arranged. – WM
21st March, 2006
Dear WM, I encourage the posting, with comments, of old "groundbreaking" papers. One disadvantage of web publishing and searches is that we can miss the old papers and do a lot of rediscovery. I advocate resurrecting the classics and old good ideas that have been forgotten. In the plume business, in particular, people repeat arguments made 20 years ago and refuted 19 years ago. – Don Anderson

13th March, 2006
A new Powerpoint presentation has just been posted: Self-organized breakup of Gondwana: An argument against the deep mantle plume paradigm by James Sears. This is from a lecture he gave at Durham today, where he presents a novel model to explain the location of LIPs. – WM

10th March, 2006
Dear WM, Here are some recent papers of mine that may be of interest, on 1) volcanic passive margins, 2) flexure of the East Greenland volcanic margin, and 3) magma flow in the East Greenland dyke swarm. – Laurent Geoffroy
10th March, 2006
A vigorous debate is in progress about the new classification system for LIPs proposed by Hetu Sheth. Please join in. – WM
9th March, 2006
Dear WM, Here are two abstracts accepted by the IAVCEI 2006 meeting, one an oral presentation on Deccan/Emeishan uplift and the other a poster on LIP classification. – Hetu Sheth
6th March, 2006
Dear WM, Here is my EGU Vienna abstract "The Deccan beyond the plume hypothesis", which website visitors may find of interest. – Hetu Sheth
1st March, 2006
For seminar abstracts giving two totally different perspectives on the Icelandic volcanic province, see "What can the North Atlantic Large Igneous Province tell us about Mantle Convection?" at Rice and "No Plume Beneath Iceland" at the Colorado School of Mines. – WM
28th February, 2006
Dear WM, Your website is really interesting and full of pertinent information. I am a young chemistry student from Canada and I stumbled on this site from wikipedia.org. Geochemistry interests me so I was happy to see lots of different information, including the geochemical aspects of mantle plumes. Keep up this good work! – Luc-Henri Bourgoin,
Université de Moncton, Moncton, Canada.

27th February, 2006
Dear WM, Although I'm not quite halfway through the wonderful P^3 book, I've put up a review on my site at geology.about.com. In a few days I will adapt it and place it on Amazon. Also I'll mention it in my newsletter, going out early Monday, and on my front page tomorrow. – Andrew Alden
21st February, 2006
Dear WM, I have received email from the Volcano List about interesting sessions at the 2006 Goldschmidt Conference. The meeting could be of interest to us. – Mehmet Keskin
17th February, 2006
Dear WM, Attached is the link to a paper on the Sentinel Bluffs Member of the Columbia River Basalt Group. This paper might be of interest to readers of the website. It discusses the source of compositional variation and emplacement in the 10,000 cubic kilometer Sentinel Bluffs Member of the Columbia River Basalt Group. – Stephen Reidel
16th February, 2006
Dear WM, Some potentialy useful e-teaching resources for geochemistry and crystallography are described in these Goldschmidt Conference abstracts. – Don Anderson
9th February, 2006
Dear WM, On our educational website "Teach the Earth" we have developed a number of  “Compelling Research Questions”, one of which is the module on mantle plumes created by Kent Ratajeski, and focuses on Yellowstone. – Dave Mogk
5th February, 2006
Dear WM, Thank you for providing an easy link to the debate on finite frequency tomography and for adding a (preprint) comment to the research note by van der Hilst and de Hoop (2005). – Guust Nolet
3rd February, 2006
Dear WM, I just downloaded an article entitled “Slab-detachment beneath Eastern Anatolia: a possible cause for the formation of the North Anatolian Fault" by Faccenna et al. (2006). It is very interesting to see that people reach the same conclusion from a different point of view. – Mehmet Keskin
1st February, 2006
Dear Kamal, Thank you for these. I link to them here, and on the "Recent conference presentations" page. – WM Sharma, K., Intraplate Seismicity of the northwestern Indian shield: Implication for the reactivation of palaeo-tectonic elements, EGU General Assembly, Vienna, Austria, 2-7 April, Abstract EGU06-A-03253, 2006. Sharma, K., Development of Neoproterozoic Malani Silicic Large Igneous Province (SLIP) on fragmenting Rodinia Supercontinent: Implications for Non-Plume origin, EGU General Assembly, Vienna, Austria, 2-7 April, Abstract EGU06-A-05443, 2006. 1st February, 2006
Dear WM, I have sent abstracts for the forthcoming EGU-06 conference. The abstracts comment on the prevailing Plume Tectonics for the Intraplate seismicity of the NW Indian shield and for the origin of Malanis. Please display on the website. – K.K. Sharma
30th Jan, 2006
Dear WM, Here is the corrected TOC of the new AGU monograph "Earth’s Deep Mantle: Structure, Composition, and Evolution". Perhaps you could advertise the appearance of the book. – Don Anderson
28th Jan, 2006
Dear WM, The special volume for plumes looks great. It will be an excellent discussion forum. The paper on 'cold plumes' that I sent you in manuscript form last fall is out now. I attach a PDF reprint for your interest. With my very best wishes, – Hans-Peter Bunge
25th Jan, 2006
Dear WM, A breath of fresh air! Ian Norton has formulated nicely a model that makes plausible a plate tectonic and shallow explanation for the Emperor Seamount Chain. Here is a short comment with some thoughts that might stimulate a discussion. We still need to explain the volume of magma.– Don Anderson
21st Jan, 2006
Dear Ian, Thank you for this helpful remark about our "Recent scientific articles" blog. If you want a PDF offprint of any of the papers listed, and one is not linked to, please email the corresponding author requesting one in the first instance. If for some reason this does not work, e.g., if the authors cannot be reached, please email the website manager and one will be posted where possible. I have added a note to this effect at the top of the blog to make others aware of this new policy. – WM Dear WM, Just a comment: Those of us that aren't working for well-funded academia can't get the majority of the papers published these days: they're $30 a copy. Not the fault of mantleplumes.org, of course, but a nuisance in terms of reading more than an abstract or someone else's opinion or review of the work that's being done. – Ian Thomas, GeoSciSoft - Perth, Australia
20th Jan, 2006
Dear Gillian, Here is a world map with LIPs, sedimentary basins and locations of the main volcanic rifted margins. It could be useful for the plume-non plume community. – Laurent Gernigon
18th Jan, 2006
Dear Prof. G. R. Foulger, Thank you very much for your interest in my work and adding my papers into your homepage. I think that the homepage made by you is very good and it’s very helpful to acquire knowledge about mantle plume. I would like to send an abstract that is submitted for the International Conference on Volcanism (IAVCEI 2006 meeting in Guangzhou, China). I hope this abstract might have your interest. Best wishes, Zhong-Yuan Ren
16th Jan, 2006
Many thanks Nick. It has been posted in the "Students' Corner". Well done Sami - nice job. – WM 16th Jan, 2006
Dear Gill, Here is an essay by one of our 3rd year students, Sami Mikhail, for the web site – Nick Petford
15th Jan, 2006
Thank you for highlighting this requirement. A new page listing slide presentations has been established. Please remember to acknowledge the author(s) of materials borrowed from these slide shows. – WM
13th Jan, 2006
I am interested in knowing if there is a page that catalogues Powerpoint presentations for use by lecturers etc. I cannot find on your site any index of presentations. The section called Recent Presentations you would think would do this. If I want to give a lecture on history of plume theory, how do I find one? I found one (below) but the title tells me nothing. If I want to find a ppt presentation on Delamination, for example, how do I find it? – Frustrated Professor

13th Jan, 2006
Dear WM, Visitors to the website might find this powerpoint presentation useful. Anyone is welcome to use these slides – Alexei Ivanov Lecture at the Paleomagnetism & Geochronology Laboratory, Beijing (PGLB), China, January 11, 2006, given on occasion of my visit, sponsored by a PGLB visitor grant. Special thanks to Prof. R. Zhu and Dr. H. He.
12th Jan, 2006
A new pair of papers, Is the mantle heated from below or cooled from above?: The classical plume hypothesis; the lower thermal boundary layer & thermal plumes The Top-Down Model; the unstable upper boundary layer & mantle melting anomalies (or ... the Campell Soup model ... stir occasionally while cooking vs. Dinty Moore Stew ... everything in it, lumps and all,  stirring doesn't help) – Don Anderson
last updated 4th December, 2017