Plumacy Reprise

Peter R Vogt John C Holden

Plumatic Asylum, Omak, Washington

Key Words: Adhocity; Allwetspot; Aplumatic; Auto-obliteration; Fertile Earth Mother (or Regurgitation) hypothesis; Geobleme; Geohyperbolae; Geophallic; Great Aplumatic Challenge; Hannukah Oil Lamp Effect; Hypothesis radiation; Loch Ness Monster Principle; Neoastroblemicist; Notsofixed; Notsohotspot; Numeroplume; Platonics; Platonizer; Ploomz; Plumacy; Plumatic; Plumology; Plumotaxonomist; Protoplume; Superduperplume; Tomograph; Tomoplume; Wundergeologist

Key Acronyms: AGU, BS, B&W, DSDP, DVD, FNA, FORTRAN, GAC, GSA, HOLE, IELW, JCH, LAGS, LIP, LNMP, MOR, MWHM, NOAA, NSF, OHLP, OJP, SUV, UK, US, VSR

Introduction and History

We offer a long-overdue reprise (a cognate of reprisal) of Holden and Vogt (1977; reproduced in this book in all its corny details). We try to offend as many authors as possible, including ourselves, but don’t take too many sides between the plumatics (Believers) and the aplumatics (Non-Believers) who, as this volume and P3 demonstrate, are mounting the Great Aplumatic Challenge (GAC; pronounced GACK!). We try to navigate our paper (the raft in Figure 1) through this swamp of controversy. Meanwhile, even plumes are no longer sure of their existence (Figure 2).

The term plumacy covers not only the “science” (plumology; Hamilton, 2005), but also the psychology and scientology of plumatics, and the pseudoscience, Christian science and social science of plumes (sometimes misspelled ploomz by orthographically challenged aplumatics). However, we hope this new paper will finally lay to rest any doubts about the existence or nonexistence of mantle plumes, just as Dietz and Holden (1987) finally laid to rest any doubts about Creationism. May doubts and doubters rest in peace! 2

In this paper we follow the usual suspects and distinguish between the observable surface manifestations, traditionally called “hotspots”, and the conjectured deep mantle plumes proposed by Morgan (1971, 1972) to underlie sites of hotspot igneous activity or swell development. However, given the very, very slowly accumulating heat flow evidence (e.g., DeLaughter et al., 2005; McNutt, 2003) that hotspots (unlike their students) are really not so hot, we call them, in the new tradition of rediscovering Old English/Proto-Germanic agglutination (hot spot=hotspot), notsohotspots. Hot lavas, after all, can be formed and erupted simply by depressurization, and some mantle melts more easily than other. For example, a small amount of water reduces melting points. Some notsohotspots may really be allwetspots, or are those postulating this idea all wet?

Long after the last yellowed, bescribbled xeroxes of Holden-Vogt masterpieces finally peeled off the office door of a paleograduate student long moved on to a tenured professorship at McDonald’s Big Mac University, some may believe we are long deceased. Why else would we delay this reprise for 30 years–because of repeated rejections by narrow-minded journal editors? Not so–we never gave them the pleasure! We have simply been monitoring the rate at which plumacy (oxymoronically dubbed “plumology” by Hamilton, 2005) is advancing as a science, and decided to revisit plumacy only every 30 years. Even so, readers will immediately note that most of our 1977 figures (not to be dismissed as “cartoons”) remain perfectly valid today.

While the various mantle devils (a Holden specialty, perhaps reflecting his ancestry) depicted in Holden and Vogt’s Figures 6, 7 and 10, God in Figure 5, and Mickey Mouse in Figures 3 and 6 do not age, the authors–as well as “plumepop” Jason Morgan (Figure 1 of that paper and Figures 1 and 3 of this paper) have aged a bit. Morgan equated plumes to pipes, so back then we showed him smoking a 1000 km long plume/pipe. But was Jason just blowing smoke, his mantle plume concept a pipe dream? Or will aplumatics one day have to put plumes in their pipes and smoke them? In any case, Prof. Morgan has stuck to his guns–or plumes–and still has a large following of plumatics, although the heat flow community has cooled to piping hot plumes. Yes, plumes have cooled down since 1977–but their friends and foes are hotter than ever–at least under their collars.

Why did Holden and Vogt dare to enter the ploomz swamp in the first place–as we do again (Figure 1)? For one thing, because we both had jumped on the mantle plume (Morgan, 1971) bandwagon early–in the case of Holden, even before there was a band or even a wagon. We modestly failed to note this historical fact in Holden and Vogt (1977), but now the truth can be told. (If it’s published, it must be 3 true!) Probably unknown to modern researchers who don’t cite, let alone read, papers from the last millennium, Jack (back then called John) Holden co-starred with our late friend and mentor, Bob Dietz (1914-1995). With smug modesty we quote from geohistorian William Glen (p. 99, 2005):

“The influence of Dietz and Holden’s 1970 Pangaea reconstruction paper on bolstering the theory of fixed mantle plumesis difficult to exaggerate”

Dietz and Holden (1970a,b) had based their Pangaea reconstructions directly on Wilson (1963)–like referring to Moses’ rock tablet instead of the Holy Bible. The pair had not yet heard of mantle plumes–because mantle plumes would only be proposed later (Morgan, 1971). In fact, who knows but that the father of mantle plumes, Morgan (1971), was in part led to ploomz by the “fixed thermal centers” of Dietz and Holden (1970 a,b)? That makes one of us (JCH) a possible grandfather of mantle plumes–or at least a disreputable stepgranduncle.

The late Bob Dietz lived on to see the fixity of his “fixed thermal centers” challenged, so we imagine his ghost is still trying to nail down the Tristan da Cunha hotspot (Figure 4), a fixed point in the Dietz-Holden reconstructions.

Actually, as Wikipedia reminds us, Dietz began to think about these things much earlier–ten years before the Wilson (1963) paper. According to a Dietz biography, this Wundergeologist spied through the welter of Pacific seamounts “the Emperor chain of seamounts that extended from the end of the Hawaiian Island-Midway chain” and “speculated over lunch with Robert Fisher in 1953 that something must be carrying these old volcanic mountains northward like a conveyor belt”. Many ideas are born over lunch, and we suspect they had a few drinks. Geohistorians have failed to note that this epic Dietz-Fisher lunch gave birth to both sea-floor spreading/plate tectonics and hotspots/mantle plumes!

For the record, J. Holden still retains–out of reach of marauding mountain lions and eager collectors–and regularly polishes and strokes the globes used in those 1970 Eulerian analog reconstructions of Pangaea. Back then, mirabile dictu, geoscientists could move plates around without digital computers! When the Antique Road Show finally comes to Omak, those globes will be there!

And, only a year later (before Morgan, 1972), Vogt (1971) published unambiguous (to him, but ambiguous to others) seafloor evidence in the form of “V-shaped Ridges (VSRs)” that hot upper mantle flows under the Reykjanes Ridge “pipe” away from Iceland. Thus, VSRs supported Morgan’s (1971) plume hypothesis (see 4

Jones et al., 2003, and Vogt and Jung, 2005 for basically unchanged interpretations).

Unlike the hotspot fixity ideas (Figure 4) of Dietz and Holden (1970a,b) (which survived for a full 3 years, not refuted until Molnar and Atwater, 1973), VSRs were ignored or dismissed for many years. At one unforgettable early 1970s Princeton seminar, an impudent, “brilliant”, but here unnamed Princeton graduate student even asked Vogt if the “V” pattern was not rather an artifact of plotting ridge-axis-parallel features on a Mercator map! (Finally, years later, the Reykjanes VSRs were rediscovered by Cambridge University, where R. White militarily renamed them “chevrons”; e.g. White and Morton, 1995).

Considering Figure 4 of Holden and Vogt (1977) and the abundance of fish around Iceland, we suggest the pattern of nested VSRs better resembles the ribs of an Icelandic cod skeleton than spineless chevrons, with the Reykjanes Ridge spreading axis as its backbone. To this day, the VSRs south of Iceland stick in the craws of aplumatics, who have few alternative interpretations: Are these plume skeptics being asked to swallow a fish or just a big fish story?

We begin by identifying a few of the trends that have developed in the three decades since Holden and Vogt (1977):

The Radiation of Plumes: Still More Evidence for Evolution

The most obvious plumatic development has been what Anderson and Natland (2005) lament as “a large number of ad hoc modifications, such as incubating plumes, fossil plumes, plumelets, superplumes (more about those below), lateral plumes, secondary plumes, chemical plumes, radially zoned plumes, and so on”. The “so on” includes wandering plumes (Figure 5). Seismic tomography–if interpreted in terms of plumes (seek and ye shall find)–has further multiplied the possible plume species (what we here call tomoplumes; e.g., Bijwaard and Spakman, 1999; Montelli et al., 2004; and Dziewonski, 2005), and numerical modeling (e.g., Phillips and Bunge, 2005) shows a great variety of plume-like upwellings (what we here call numeroplumes) from a thermal boundary layer in the mantle, especially the Core-Mantle Boundary. However, numeroplumes apparently cannot arise by internal mantle heating. Radiation (the evolutionary kind) has created many species, subspecies and races of tomoplumes and numeroplumes–a challenge to plumotaxonomists. The various types of plumes are multiplying and evolving even as we write–but the process (sexual reproduction? Dividing like amoebae? Virgin birth?) is not understood. Differences in size, 5 shape, and color help the layman distinguish the species. However, readers should remember that numeroplumes, although interesting and beautiful, are only virtual plumes–like the belly dancers and gunships in videogames. However, both tomoplumes, which being based on real data must be real, and numeroplumes owe their evolution and radiation since Holden and Vogt (1977) to the evolution of computers with ever more memory and computation speed.

Human fantasy and the enormous volume (920,000,000,000,000,000,000 cubic meters) of Earth’s mantle allows room for almost every imaginable mantle structure, composition, and process, including plumes (e.g., Figure 9 of Holden and Vogt, 1977; Figure 1 of Anderson, 2005; Figure 8 of Ivanov and Balyshev, 2005; Figure 8 of Smith, 2005; and Figure 1 of Lay, 2005). Figure 1 of Anderson (2005) made the ‘cover our butts–they can’t both be wrong’ cover of P3, an astonishing accomplishment, given that Anderson was only the fourth editor. The controversial P3 tome may someday rank with Darwin’s 1859 “Origin of the Species”, Morgan’s “Plate motions and Deep Mantle Convection”, and the even more controversial but less well known opus published by Morgan a decade later: “The Aquatic Ape” (Morgan, 1982). Lay’s Figure 1 attempts to find a middle ground in the split lobotomy shown on the P3 cover. Some of the Layman’s plumes rise from the CMB, while others emerge like large hatched worms from the tops or flanks of giant manure piles in the lower mantle, which resemble that strange object (a giant sea cucumber with flattened ears?) labeled “Ancient” in the “Plate Model” of Anderson (2005). This object was supposed to be a superplume (G.R. Foulger, personal communication, 2007)–but deep mantle superplumes are actually acceptable to Prof. Anderson, so long as they don’t crash the plate tectonic party.

The aplumatic community dismisses as largely untestable adhocity–as a bunch of moving targets (and moving plumes)–the above wealth of plume variants. These all evolved in a mere 35 years from the simple protoplume, which like Minerva/Athena “leapt forth from his brain fully formed” (from Ancient Greek, by way of Wikipedia) from the mind of Morgan (1971, 1972). We don’t know whether, like Zeus/Jupiter, W. Jason suffered from headaches during his mental pregnancy, but we can imagine the Great Aplumatic Challenge must be a real headache for the retired professor.

However, skeptics fail to understand that Darwin also speaks to mantle plumes! We have simply had a hypothesis radiation from simple, geophallic Morganian protoplumes. The “drivers” in this evolutionary radiation have been new and different data, good data and bad data, as well as good and bad ideas. After all, we humans now enjoy and try to preserve thousands of species of birds, all 6 presumably descended from an Archeopteryx-like proto-bird. (They may deny it, but plumologists/plumatics and plume skeptics/aplumatics are both descended from the same early Mesozoic mammals in a series of evolutionary spurts called radiations, one after the Cretaceous/Tertiary extinction–perhaps caused by the deniable (Sheth, 2005) Deccan plume head–and another during the Late Paleocene Thermal Maximum.)

Charles Darwin will ultimately decide which of the many plume and non-plume hypotheses, tomoplumes and numeroplumes, will survive to be reproduced in future textbooks. In the meantime, as we preserve biodiversity, shouldn’t we also preserve plumodiversity? The difficulty or impossibility of disproving some plume variants (e.g., Anderson and Natland, 2005) simply helps maintain plumodiversity and keeps our planet interesting, our journals full, our conferences attended, and our grants funded! As long as debate continues, our planet is really many planets–one real and a whole solar system of virtual ones! It will be a boring world indeed when the one real planet stands up!

As for semantic confusion about terms like “plume” and “hotspot” (Anderson and Natland, 2005), that’s no big deal either. It’s simply “fuzzy semantics”, and like “fuzzy math” should not be confused with “fuzzy thinking”. After all, a plume by any other name is still a plume!

Age Progressions, Younging and Aging along hotspot tracks–Do we suffer from too many data?

In a field famous for researching stuff that happened unimaginably long ago, plumatics have refreshed the lexicon by speaking of “younging directions” and “younging rates” along hotspot tracks, as if they had reversed the very arrow of time. Most of us would be happy to young in any direction! Perhaps the younging of volcanoes leads us to the mantle plume as the fountain of youth, its overhead lava fountains giving birth to reddish infant rocks ever so briefly of ZERO AGE.

The Morgan mantle plume hypothesis involves plume fixity–already downgraded to relative fixity by Molnar and Atwater (1973)–and then an age progression along the supposed track. The original plume hypothesis made some specific and testable predictions–and early data seemed to pass the test. However, many a great theory has been destroyed by too many data, and age-dating volcanoes has become as troublesome and error-prone as age-dating certain ladies. In the good old days, two age dates along a chain sufficed, and had a 50% chance of capturing the right younging direction. The odds were even pretty good, with the large error bars of 7 whole-rock K-Ar dates on ancient rotten, worm-infested basalt, that those dates would fit predictions of fixed hotspot models.

Then came more and more age dates, filling the scatter-plots with clouds of data, like swarms of killer bees, only comprehensible if hotspot volcanoes erupt any time and any place along the track, or anywhere else for that matter. Inconsistencies began to arise, even for the most “Hawaiian-looking” seamount chain in the Atlantic (the New England Seamounts; McHone, 1996). Things went downhill for the chain, plumologically speaking, after the first age-vs distance scatter plot (published in DSDP Volume 43; Tucholke and Vogt, 1979) was later shown to be based on data fabrication by a brilliant but over-enthusiastic Woods Hole/MIT plumatic graduate student.

The biggest blow to hotspot fixity was the failure of age dates along the Emperor Seamounts to conform to formation at the present site of Hawaii. After we learned that “HowEYE” was actually “HaWAH’ee”, a pillar in the Temple of Plumacy began to crack! Now the truth is out–plumes have been liberated to wander (e.g., the downgraded Italian plume; Figure 5), or even streak along singlemindedly in the Earth’s mantle, perhaps floating balloon-like in the mantle wind, before settling down at one spot, carefully chosen to overlie a lower mantle seismic wavespeed anomaly (see under “intelligent plumes” below). Even the most famous bend on the planet, the Hawaii-Emperor Bend, became like its students “slower and older” (Sharp and Clague, 2006). The bend had begun to move in time, after sitting peacefully at 43 Ma sharp for many years. Just recently it has begun to age–at least a million years per year–and is now a grizzled 50 Ma.

Plumatics should however be relieved that Ajoy Baksi (this volume) is discarding one isotope age date after another, reducing bloated datasets to very small sizes or nil. This reverse trend can bring us back to the early golden age of plumacy, before the data explosion began to misfit predictions and thereby undermine theories plumatics know to be right.

Superduperplumes and other Geohyperbolae

Yet another trend of the last 30 years is increasing use of geohyperbolae. It seems that normal terms with adjectives (or letting the numbers speak for themselves) no longer suffice. For example, topographic swells (rises) were known (about as well as today) at the time of Holden and Vogt (1977), but then came the snap-off-your- tongue “superswells” (e.g., the South Pacific superswell, McNutt and Fisher, 1987). A few years later, superswell scientist Marcia McNutt (et al., 1990) dubbed 8 the inferred–albeit nonexistent–Cretaceous “Darwin Rise” an ancient superswell. Of course, superswells require superplumes, also called megaplumes (e.g., Dziewonski, 2005; Anderson and Natland, 2005), and the superplume below Africa is also called the Great African Plume, but may recently have been downgraded to a mere superpile (Figure 6; Garnero et al., this volume). Superplumes, like Superman (created in 1932 and still wearing blue and red, like political maps of the US or tomographic maps of seismic wavespeed in the mantle), can accomplish the seemingly impossible, as illustrated by Cox and Van Arsdale (2002), who attribute the very Mississippi Embayment to a “Cretaceous superplume event”. And what on Earth besides superplumes could “control magnetic reversal frequency” (Larson and Olson, 1991)?

Meanwhile, the Mid-Oceanic Ridge community was not to be outdone, hyperbolically speaking. Early papers had distinguished between slow and fast- spreading ridges, but then the East Pacific Rise ca. 10-20˚S became a superfast spreading center, even as the long Cretaceous period of normal polarity became–you guessed it–the Cretaceous superchron. And while marine scientists have known since the late 1960s that the Southwest Indian and Gakkel (Mid-Arctic or Nansen) ridges were spreading slowly (7 to 15 mm/a total opening rates), more recent authors decided this qualified as ultraslow (e.g.., Michael et al., 2003) or superslow (Mendel et al., 1997). This forced the senior author to find another term for the Terceira Rift, opening at only 4 mm/a, still slower than ultraslow/superlow. Vogt and Jung (2004) thus introduced “hyperslow” to the plate kinematic lexicon. About the same time, long MOR segments–e.g., along the Southwest Indian Ridge- became supersegments.

We don’t yet know what plumatics will call the small or slow end of the mantle plume spectrum (mini-, micro- or even nanoplumes?), although minihotspots have already been discovered and named petit spots (Hirano et al., 2006)). However, given the difficulty of finding or disproving even macroplumes, wouldn’t disproving miniplumes be as challenging as looking for midget Loch Ness Monsters (discussed further below)?

Will the plume-slayers soon follow with their own hyperjargon?Iceland is by any measure a globally unique superhotspot (even if it’s not superhot, or even hot). If Iceland’s raison d’etre is instead the regurgitation of subducted Caledonian crust (Foulger et al., 2005), it must have involved supersubducted supercrust, otherwise why aren’t there more Icelands on our planet, given the plethora of plates subducted over the eons? However, plumatics lag behind MORmen like Ken Macdonald, who compared the Mid-Oceanic Ridge to an infinite onion. Although 9 the infinite plume has not been postulated, we may be dealing with an eternal plume controversy.

Hot Plumes Taking the Heat (but maybe not giving any)

It’s an understated understatement that mantle plumes, especially the deep ones, have taken a beating in recent years: If people like Don Anderson and Gillian Foulger keep chopping away (Figure 3), will even the Iceland pipe eventually lose its footing? Meanwhile papers are beginning to appear with negatives brazenly placed in their very titles. (Like most scientists, we only have time to read the titles of papers we cite.) Just to name a few examples: Gillian Foulger innocently asks “Why the current skepticism?” (when we know Foulger herself is largely responsible). Hetu Sheth (2005) finds “no trace of a [Reunion/Deccan Traps] mantle plume.” Rocchi et al. (2005) find “No plume, no rift magmatism in the West Antarctic Rift”. On that deceptively named Internet tabloid, www.MantlePlumes.org, a web page headline screams “STILL NO ITALY PLUME!”, while author A. Peccerillo says “No Thanks” to the Italian plume (Peccerillo and Lustrino, 2005). Aplumatic Anderson (2000) finds “no role for mantle plumes” in the upper mantle’s thermal state. Fairhead and Wilson (2005) ask: “Do we need mantle plumes?” (“Not really”, we knew their answer to be). Ritsema and Allen (2003) find plumes “elusive”. Heatflow experts found that hotspots weren’t so hot (e.g., De Laughter et al., 2005), and even the heat flow variations over that hotspot’s hotspot, Hawaii, were found by McNutt (2002) to reflect mere porewater movement, “not plume properties.”

Hamilton (2005), following the declaration of airports and restaurants as smokeless, examined 21 Galileo-mission radar images of the Venusian surface and declared the entire planet (Venus) “plumeless” (Figure 7), although he hedged this (p. 789) with “no need for plumes”. Nit-pickers point out that there was no need for Warren Hamilton to exist either, but he does exist. (On some days, Venutian plumatic Donna Jurdy (Figure 7; Matias and Jurdy, 2005) probably wishes he didn’t.) Even on home planet Earth, Hamilton had announced only 3 years earlier, to a shocked and awed audience of geophysicists, that “Plumes do not exist” (Hamilton, 2002). Meanwhile, ignoring Mark Twain’s warning about premature obituaries, McNutt (2006) is pounding another nail in the plume coffin. Glen (2005) even went so far as to downgrade plumacy from paradigm to “quasi- paradigm”. Even notsohotspots have been questioned: Once a confirmed plumatic himself, waffler Vogt (1991) asked if Bermuda was not instead formed of non- hotspot processes. And (as befits his usual guarded ambivalence in discussing mantle plumes), Anderson (2005) carefully disguised his skepticism in a double 10 entendre: his paper’s title begins with “Scoring hotspots”, where we note that definitions of scoring include: “to cancel by drawing a line through, to cut so as to mark with scratches”, and “to berate, excoriate, castigate…” Thirty years before (Anderson, 1975), he had already castigated plumatics as “fumers, smokers, swaggerers, scribblers, pen-pushers, dungers and manurers” (reworded from Holden and Vogt, 1977).

We doubt, however, that true plumatics will be deterred by all this naysaying–indeed, they will only dismiss the naysayers as former US Vice- President Spiro Agnew (or, more likely, his speech writer) once famously dismissed his critics–as “Nattering Nabobs of Negativism”.

Plume Population Explosion and Crash

Holden and Vogt (1977) first noted with alarm the burgeoning plume population (from 20 in 1972 to 122 by 1976). Using state-of-art mathematics and card- punched FORTRAN II, we predicted that of the order 1 million would exist by the year 2000. Vogt and Holden (this volume) are happy to report that we overestimated, albeit only by two to three orders of magnitude (not too shabby in fields such as astronomy, astrology, social science and geoscience). However the actual plume population did reach “about 5200” at the end of the millennium (Malamud and Turcotte, 1999). Plumes had evidently reached an unsustainable population (like lemmings in the Arctic, rabbits in Australia, and humans on Earth), and turf wars among plumes began at depth, thus explaining the increased volcanic, seismic and tsunamigenic activity in and on the overlying plates in the last quarter century.

However, as sometimes happens with stock markets, oil supplies, real estate and the price of tulip bulbs, the plume population crashed (Figure 8), as already noted by geohistorian Glen (2005). Some would call it a “bubble effect”–bubbles bearing an uncanny resemblance to the heads of mantle plumes (e.g., Griffiths and Campbell, 1991). At present the mantle plume population may be as low as 5 or 6 (Courtillot et al., 2003). Alarmed, the Plumatic Asylum recently sued the US Government to force inclusion of mantle plumes as “Federally Endangered Species”. However, plumatics can hope that Stephen J. Gould’s “Punctuated Equilibrium” theory will apply to mantle plumes–small populations are able to evolve quite rapidly. In fact, we see evidence of this rapid evolution in the present volume. 11

While plumes have declined in number, plume (and no-plume) publications continue to explode. Special Paper 388 and the present volume have added yet more to the throng. Just from 1970 to 1984, the annual number of papers Np with “hotspot” or “mantle plume” as key words had risen from zero to about 75 (Figure 5 of Tucholke and Vogt, 1986). Anderson and Natland (2005) performed a similar search, showing an early 1970s peak and a sharp increase in plume publication rate after Griffith and Campbell (1991) revealed to all who would read their paper that plumes had heads and tails (the “heads I win, tails you lose” phenomenon). Further ballooning of mantle plume publications was inspired by Kellogg and Wasserburg (1990), who showed how 3He could be transported, like Josephinite, from the lower mantle by rising plumes, and why mantle plume-derived helium, being even lighter than light, also makes balloons rise faster and higher.

We dare not extrapolate plume publication rates into the future–with electronic storage and plenty of room on neighboring planets, there seems to be no physical limit to the number of potential papers published about mantle plumes or hotspots! As t approaches infinity, so will

∞ ∑(N p (t)Δt , 1970

the cumulative number of plume/nonplume publications. € We attribute the remarkable opposing trends of “plume” vs “plume paper” populations to the Loch Ness Monster Principle (LNMP), which we define here for the first time. Very few research or other papers are written about the salmon in Loch Ness–those salmon, although faster, smaller, and easier to digest, are like the now-familiar tectonic plates: Why study and issue papers or press releases about the known or obvious? Earth is round and plates exist, at least for the great majority of us (although some antique cars still sport Holden’s “Stop Continental Drift” bumper stickers). Meanwhile, innumerable papers and books, not to speak of news reports and films, have appeared and continue to appear on the search for the Loch Ness Monster, which, perhaps like the elusive mantle plume (Ritsema and Allen, 2003), lives unseen at depth, like the giant mantle carp in Figure 4 of Holden and Vogt (1977). We define the LNMP thus: “The number of studies conducted and articles published about a concept is inversely proportional to its plausibility”. However, we predict that even LNM researchers will at some point give up their search and simply declare the creature forever real, as in “Yes, Virginia, there are mantle plumes (and one lit up briefly under your bottom in middle Eocene times)”. 12

Evidence for the shape, color, behavior, and intelligence of mantle plumes

Holden and Vogt (1977; their Figure 3) already demonstrated that mantle plumes can speak to literate geologists (at least in Latin), using fracture patterns (see also under Crack Hypotheses below). If so, plumes must be alive. However, the mainstream geoscience community failed to recognize this, and only in later years even discovered that plumes have HEADS and TAILS (Griffiths and Campbell, 1991), and that they can move about and change their shapes and colors at will. Seeming to defy Reynolds Numbers and thermal diffusivities, mantle plumes are able to change real fast–from one paper to the next. To escape detection, they often masquerade as food items, making the mantle wrongly appear–to those fruity nutcakes who smoke what they shouldn’t–as marble cake or plum pudding (e.g., Anderson and Natland, 2005), made visible only when mathematically mixed with banana-doughnut kernels. Unfortunately, some plumes–barring unlikely errors in the superscience of seismic tomography–seem miserably deformed, staggering, tottering, twisted, Quasimodo-like creatures (e.g., Bijwaard and Spakman,1999; Zhao, 2004, Van der Hilst and de Hoop, 2005).

Computer coloring has also allowed advanced seismotomographers to elucidate plume color (which has so far eluded paleontologists studying dinosaurs). Typically, tomoplumes are recorded and digitally mastered on tomographs, which resemble paint-by-number paintings, as each color equates to a given numerical value of sound or shear-wave speed. Such tomographs are then published in coloring books and discussed in color bars. Unfortunately these books are precolored, preventing readers from exercising their own imaginations and coloring pencils to find their favorite plumes (as well as Mickey Mouse and Pluto) in the crazy patterns.

Most virile plumes turn out to be saturated red, but weaker, perhaps diseased or juvenile plumes can be yellow or even sickly greenish-yellow. This conveys the basic idea that plumes cause fluids to ooze out or be vomited from the Earth’s interior.

Negative plumes may also exist, and are blue (e.g., Phillips and Bunge, 2005). Blue negative plumes have their heads down (vs. looking up at the Heavens) as some politically Blue Americans allegedly do.

Plumatics found it especially demeaning for Anderson (1999) to dismiss colored tomoplumes as mere Rorschach (pronounced “raw-shock” according to Wikipedia) 13 inkblots. After all, modern psychiatrists score the inkblot tests of hapless patients according to their “level of vagueness” and take note of “any illogical, incongruous, or incoherent aspects of the responses” (Wikipedia). Endless graduate student hours fine-tuning computer codes, hours of supercomputer time inverting uncountable numbers of seismic recordings, and the result is just a colored inkblot? Next thing, unimaginative parade-rainers will be telling us the stars in the Big Dipper do not resemble a large bear! Fortunately for plumatics, Anderson’s (1999) paper appears to have been rejected by peer-reviewers, perhaps because he failed to realize that Rorschach was just the nom d’plume of an early plumatic. Ror is misspelled German for Rohr (pipe) and Schach means “chess”, so Freudian psychiatrist Hermann Rorschach (1884-1922) was playing games with pipes, as many still do today.

Returning to the question of plume color, we note that Dziewonski (2005) demonstrated with statistics (which Mark Twain taught are NOT LIES), that most plumes are “at home” in a red district of the lower mantle. Blue districts, he found, are pretty plumeless. Unfortunately, GSA’s editorial policy prohibits us from drawing political inferences from this observation. However, as we tend to associate red–not blue–with higher temperature (with apologies to Max Planck and astrophysics), the red color of plumes must mean they are warmer than the surrounding mantle, so we consider further debate over plume temperatures pointless.

In this paper, we further assume plumes are living beings, and represent them as such in Figures 1, 2, 5 and 9. Older readers will note a certain resemblance (Figure 9) to the “Schmoos” of the late Al Capp’s comic strip “Li’l Abner”, or to Halloween ghosts or Klansmen in white bed sheets. Granted, but such resemblances are purely coincidental. Readers should not assume from our B&W renditions, whether arrow-headed or not, that plumes actually resemble ghosts–but rather, that we are too cheap to pay for color illustrations. We also disavow any racial overtones in our depiction of plumes–shown by seismologists to be red–as white and black.

Given that some aplumatic readers still doubt the intelligence of plumes, we offer Figure 9 as proof. Young, growing plumes seek adventure and want to grow into the upper mantle, where they can speak up and be heard (at least by seismologists). However, being intelligent, they scan what’s overhead and naturally plan to seek out weak spots like rifts and previously active volcanic areas. An example of a teenage rebel plume is the Oregon High Lava Plains plume (OHLP), a ca. 15 Ma offspring of the Yellowstone plume (Jordan, 2005). The OHLP decided not to sit 14 still, but swam west, leaving a track 120˚ from the predicted one. In the last 5 Ma it has slowed down, however, and may be deciding to turn around and come back home. Only real super-dumb plumes would aim for and bump their heads against the bottoms of Pre-Cambrian Shields, and we may never know who they are!

If really lucky, a smart young plume sees a triple junction overhead, and heads for that, never mind the angle. Plumes MUST have some intelligence, otherwise why would the Shatsky Rise LIP be a triple junction trace (Sager, 2005), or the Azores Plateau (e.g., Vogt and Jung, 2004) the site of a modern triple junction? Why else would African igneous activity recur intermittently at the same sites over hundreds of millions of years (Bailey and Woodley, 2005)? New plumes below Africa evidently like to follow in the mantle footsteps of their granddaddies and great- great-grand-daddies, an observation which however appears to put an upper limit on plume intelligence. Finally, it was shown already by Vogt (1972) that plumes are able to communicate with each other over tens of thousands of kilometers–how else could they plan to rise in unison against those overbearing plates?

To be fair, we note that mantle plumes were first shown to be living, intelligent beings by Prof. Erin Beutel at the 2005 Fort William Chapman Conference. In one of the stimulating evening sessions, held in the hotel’s (licensed) dining salon, Dr. Beutel represented herself as a mantle plume, and to musical accompaniment by a Scottish Highland band, offered the Premier Performance of “The Dance of the Mantle Plumes”–did she learn this from Venutian plumes (Figure 7)? Being a bit vertically challenged, however, Dr. Beutel could only represent a scaled down (1:1,000,000) plume. We assume this was one of her NSF or NOAA-funded “professional outreach” activities. Hopefully Dr. Beutel’s “Dance of the Mantle Plumes”, which was immortalized on video tape by Dr. Bruce Julian, the official Conference Filmer-of-Unseemly-Behavior, will soon be released by the GSA and/or AGU as a DVD.

Although we are not certain, deep mantle plumes may also have feelings, and we should give them the benefit of doubt (as some of us conservatively assume human cells are equivalent to human beings). Plumes probably are not at all pleased being represented as deep-mantle Schmoos (Figure 9) or given low grades (e.g., Anderson, 2005; Courtillot et al., 2003; Figure 5 and 10), although they most probably prefer that to other representations (elsewhere or here and now) such as giant toadstools, water towers, pipes, thunderheads, umbrellas, mushroom clouds, piles (Figure 6), or phalluses. (The ghost of Sigmund Freud smiles knowingly at the many geophallic depictions of salt domes, magma chambers, and mantle plumes—probably reflecting the excessive amounts of time geoscientists spend in 15 the field or at sea on research cruises or glued to their computers). However, our mantle plume friends will agree that even depiction as toadstools, piles or phalluses is still preferable to outright nonexistence.

Has the “Multiple Working Hypothesis Method” Gone Mad?

In our poll on the K-T Boundary (Vogt and Holden, 1981), we noted the large number and wild variety of hypotheses that had been advanced for the extinction of dinosaurs. (Poll results remain unpublished because we still await more replies, although none have arrived in the last 20 years.) Evidently the Multiple Working Hypothesis Method (MWHM) had gone mad. However, shortly before we had finished our missive, the Alvarez et al. (1980) iridium spike had speared this hypothesis zoo–which had begun to resemble the extragalactic truck stop in “Star Wars”–into extinction. As is often he case in the Earth and other environmental sciences, the magic iridium spike was not found by testing the asteroid impact hypothesis, but was tripped over in the process of an unrelated study. Similarly, magnetic anomalies were not mapped in the 1950s and early 1960s to test sea-floor spreading. As plumatics trip the light fantastic, they have perhaps just not yet tripped over their equivalent of the iridium spike.

Can asteroid impacts melt rocks and cause LIPs and give rise to plumes?

It’s no secret that impacts convert kinetic energy into heat, and very large impacts on the Moon melted some of its green cheese, flooding impact sites with oceans of magma, the marea. However, geologists were slow to learn from lunologists. One down-to-Earth man stood out, however, Robert S. Dietz. This giant discovered most of what we know about the Earth today, including sea floor spreading, fixed hotspots (Figure 4; Dietz and Holden, 1970a; lunch discussion with Bob Fisher, 1953), the fact that Earth is more than 6010 years old at this time (Dietz and Holden, 1987), and, yes, that giant impacts occur and can melt the Earth’s crust (Dietz, 1961). Dietz called such large impact craters “astroblemes” (star wounds), for example that nickel mine up in Canada which earlier geologists had called the Sudbury Lopolith. Dietz (1986) topped it all when he showed ignorant geologists that a bolide triggered the Bahama Nexxus (whatever that is), the Newark series and related igneous activity along the eastern US margin (McHone, 1996), while splitting Pangaea and triggering sea-floor spreading! How much else IS there to explain? 16

Eventually other geologists began to realize that impactors could have melted Earth rocks (e.g., Green, 1972). Moreover, Alvarez et al. (1979) later exhumed terminal-Maastrichtian dinosaur bones and foram tests, washed off the stardust, and showed they all had died, terminally ill, of astroblemes. In recent years, the idea of large bolides melting large volumes of rock to form Large Igneous Provinces (LIPs) or even give rise to plumes has been revisited, if not yet rehabilitated (e.g., Jones et al., 2005). One problem faced by LIP- neoastroblemicists is that the LIPs and other hotspots seem never to be in the same place as the astroblemes, and contrariwise (Figure 11). This problem is being overcome with auto-obliteration, similar to what often happens to furry critters on roads and ultimately to SUVs once oil begins to run out. Jones et al. (2002, 2005) suggest the Ontong-Java Plateau, the largest heap of lava on the present Earth, could have formed by an asteroid striking young oceanic crust. However, most investigators, while scratching their heads over the OJP, consider it only a geobleme; and Jones seems not so far to have made a major impact.

Driving mantle convection models over the edge

While some authors have gone over the edge in their attempts to explain notsohotspots, King (2005), building on King and Anderson (1998), decided to go under it. Modeling the thermal convection that is generated in the asthenospshere by the thermal contrast between thick, cold cratonic lithosphere and thin new oceanic lithosphere, they predict downflow under the continental edge and upflow under the middle of the adjacent oceanic plate. Once an ocean has widened to 2000 km or more, this upflow (which to us looks more like sideways flow) generates off-ridge hotspots, they suggest. However, the author admits this model is no better at explaining the North Atlantic/Icelandic notsohotspot than the plume model. We are suspicious of papers in which the author(s) does (do) not claim to have explained everything with their model.

Can Platonics Explain Notsohotspots?

Most other non-plume explanations for notsohotspots attribute them to processes or properties involving plates and their interactions (Anderson, 2005). For example, lithospheric stress is blamed for cracking the Earth and forming “hotspot tracks”; localized volcanism is attributed to fertile patches in the upper mantle and to zones of plate weakness. Globally synchronized volcanism (Vogt, 1972) is attributed to episodic and ongoing reorganizations of plate motions, 17 causing episodes of increased mid-plate stress. Following Anderson (2005) and Plato, we call the “Plate Model” or “Plate Paradigm” Platonics and its practitioners and supporters Platonizers, who shave with Ockham’s Razor and dream of an idealized world where Newtonian physics explains everything. However, plumatics point to one definition of “platonic” as “of an academic nature, devoid of substantiality”

Cracked Models

Explaining mid-plate igneous activity in terms of cracks is not a new idea. Some otherwise respectable scientists continue to believe the Hawaiian chain is being formed by a crack forever propagating, in response to stresses within the Pacific plate, at a few cm/a towards the East Pacific Rise (Stuart et al., this volume). Finding the actual crack, however, has proved challenging to the stressed-out experts (Figure 12) other geologists–traditionally skilled at connecting two volcanoes with a straight or curved line (e.g., Vogt, 1974) to define the fracture required to support their pet structural model–have interpreted the pattern of Hawaiian volcanic centers as a response to regional stress fields (Jackson and Shaw, 1975). Holden and Vogt (1977, their Figure 3) played this same game, showing that plumes do “talk” to anyone willing to read the message in the cracks. After all, are volcano distributions that different from tea leaf patterns? A much more recent crack paper (Natland and Winterer, 2005) waffles (Neogenically) in the plume vs crack debate, but reads a different message in the Cretaceous “tea leaves”, that is to say volcanoes. Those authors posit that large numbers of western Pacific underwater volcanoes–now guyots and seamounts–erupted through diverse cracks (vs from mantle plumes) in the young Pacific plate.

We can’t offer more insight, and resist the temptation to put into print puerile puns such as “The Crack Hypothesis, advanced by half-cracked crackpots, may not be all its cracked up to be, although it cracks up plumatics”, not to speak of unprintable Freudian allusions.

The Regurgitation or “Fertile Basalt Mother” Hypothesis (Iceland)

Foulger et al. (2005; hereafter FNA) offer a different platonic, aplumatic model for Iceland, which has stubbornly clung to the MOR axis even as the latter is trying to get away from its embrace (e.g., Lundin and Dore, 2005). This (both the papers and the observation) has annoyed plumatics, who expected a bit more model compliance from their star ridge-centered hotspot. The FNA model explains why this notsohotspot is also notsofixed. 18

FNA attribute the “large melt volume to the remelting of subducted oceanic crust trapped in the Caledonian suture in the form of eclogite or mantle peridotite fertilized by resorbed eclogite”. This concept of a Fertile Earth Mother was first recognized by the Norwegian Vikings who settled Iceland and discovered its fertile basaltic soil (which however soon was washed into the Atlantic by overgrazing sheep, even after the Lord Himself became their Shepherd in 1000 AD). MOR is, after all, the Norwegian word for “mother”, so the Vikings also were first to speculate that life itself may have originated in ancient hot wet cracks.

We find it miraculous that subducted Caledonian crust was quietly carted along over the Earth in the cargo hold of the giant Pangaean Plate–at least 600 km thick (depth to base of present seismic anomaly!)—for the 300+ Ma between Caledonian subduction/suturing and the first Paleocene melting, even before Greenland and Eurasia had begun to pull apart. Another miracle is the seemingly inexhaustible supply of basalt magma–is the Iceland melt source a Hannukah-type oil lamp that miraculously burns for 7 days (where for God, of course one day may be at least 10 million years)? The Foulger et al “Hannukah Oil Lamp Effect” (HOLE) is explained by those authors as the result of the Caledonian suture’s “X” relation to the Mid-Atlantic rift, allowing the MOR to overlie subducted crust for ages…and ages….However, “X” also represents the unknown substance FNA were smoking when they came up with this idea.

FNA have gingerly stepped away from the dangerously but not anomalously hot partially molten mantle that many (e.g., Vogt, 1971; Jones et al., 2002; Sleep, 2002) think they know must flow along and under the MOR, driven by the along- ridge topographic head (as the “ridge-push” force acting on the plate at right angles to the MOR). FNA were not sure what to say about those pesky V-shaped ridges, long touted as evidence for such flow, so they didn’t say anything, because in fact their hypothesis only predicts the flow of mantle’s milk, not a stampede of its cows! But maybe it’s unfair to expect any theory to explain ALL observations!

A notoriously deferential scientist by nature, Foulger (2006) has also recently rehabilitated the brilliant but unfairly discredited ideas of geopioneers Alfred Wegener and V.V. Beloussov, neither of whom was fooled by Iceland’s surficial oddities like active volcanoes or Pleistocene-Holocene lava flows. They–and Foulger–knew, deep down, Iceland’s underlying truth: that continental crust must lie cleverly concealed under all those lava flows. Wegener also realized that places like Iceland are “in the way” of good pre-drift reconstructions, just as Iceland still 19 squats darkly in our way of our understanding of deep-Earth processes, taunting us all–platonizers, plumatics, astroblemicists, or whatever.

Conclusion: What Endgame Plumacy?

The plume debate is starkly defined: Deep mantle plumes (like Loch Ness monsters or God) either exist or they don’t exist–just as one is either pregnant or not pregnant. Discovering that second plume or second Loch Ness Monster wouldn’t make the front page. If plumes exist, their exact number and locations are not quite so interesting. In fact, there would probably have to be a reproducing population.

During the Fort William Chapman Conference discussions, D. Zhao was asked if seismic tomography would eventually resolve the issue. Zhao speculated that this could well happen within the next decade, when every last seismogram wiggle has been dialed into the inversion. We call this the IELW (invert every last wiggle) prediction (Figure 13), and have buried it in a time capsule.

We suspect that the deep mantle plume problem can’t be solved (or, resolved) with certainty except by detonating the world’s entire nuclear stockpiles and recording the signals around the world. As a relatively minor benefit to mankind, to provide “added value” besides settling the War Over Plumes, the threat of nuclear war and more mass extinctions would be simultaneously eliminated. This of course would cause massive unemployment among highly trained scientists, engineers, technicians, program managers, and nuclear test ban treaty junkies, not to speak of scientifically illiterate politicians. However, we offer this experiment idea in a spirit of cautious optimism that it won’t actually happen.

It’s also possible that a volcano somewhere has already coughed up a xenolith of a rock that has once actually seen and felt the Core Mantle Boundary. Who’s to say it ISN’T possible? A rock named Josephinite once claimed to have been carried up from the very core by a deep mantle plume, but Miss Josephine was exposed as a pretender. Short of such of a plumatic’s Philospher’s Stone, we doubt if geochemistry will ever solve the problem. Hordes of elements and isotopes have been shouting their messages at us for decades, but geochemists still haven’t deciphered what exactly they are saying. Of course, when we hear geochemists like Dr. Dean Presnall speak of “model-system phase relations in the CaO-MgO- Al2O2-SiO2-Na2O-FeO (CMASNF) systems”, do we know what exactly they are saying? (Readers will note we had two geochemical cartoons in Holden and Vogt (1977), but no new ones; we are just too confused.) High hopes had been pinned on 20

Helium-3, but even that light and noble isotope is sending ambiguous messages. No-one seems to be able to agree about who is wearing the trousers in it’s curious matrimony with Helium-4, or are “San Francisco values” at work here?

Modeling mantle convection has become ever more sophisticated (e.g., Phillips and Bunge, 2005) and includes ever more parameters, physical laws, possible effects and geometries, with ever smaller time steps and cell sizes in finite element calculations. All this has to happen with ever less research funding and a much smaller LAGS (a SAGS?) than when defined by Holden and Vogt (1977). The modelers (i.e., mostly the LAGgards working for them) are exploring the multidimensional jungle of parameter space–will the REAL parameter values (e.g., viscosity, thermal expansivity, radiation, density, composition, etc.) please come out of the jungle and identify yourselves to the explorers? But no matter how convincing numeroplumes may be, we still have to find their likenesses as tomoplumes. We predict that will probably happen some time between the next AGU and never in a million years.

Of course, the search for plumes may have a surprise or two–that “iridium spike” might be out there somewhere, waiting to be tripped over.

In the meantime, wanting to “prebut” any “impartially moderated” “Discussion” of this paper, in addition to completing it so late that no such discussion could take place, we also decided to end on a polite, conciliatory and even politically correct note. We celebrate plumodiversity by adapting multiculturalism and rainbow coalitions to the Earth’s mantle, which as we noted earlier has enough room for all contenders (Figure 14). We apologize to anyone whose pet theory or plume has not been bashed–there is room aplenty to add more–Figure14 is only one of an infinite number of different slices through a sphere.

Acknowledgments

The authors–armed with pepper and mosquito spray to ward off marauding bears, mountain lions, and mosquitoes, not to speak of black widow spiders lurking under outhouse seats–completed much of this work under the supervision of Prof. Gillian Foulger, Dr. Bruce Julian, the co-author’s wife, and ten cats, at the secret Plumatic Asylum headquarters hidden in an abandoned Hippie commune outside Omak, Washington. Foulger conceived the ideas of Figures 5 and 6, besides smuggling police mugshots of herself and other suspects to J. Holden. Recognizing the many contributions by Prof. Foulger, the Plumatic Asylum has conferred on her its 21 highest award: Honorary Senior Aplumatic Fellow. Foulger thus becomes the Nancy Pelosi of a previously male-dominated Plumatic Asylum.

This paper does not necessarily reflect the views of The Geologic Society of America, the Editors of this volume, the International Stop Continental Drift Society, The Naval Research Laboratory, The US Geological Survey, The Flat Earth Society, Princeton University, Cambridge University, or the authors. Plumatic Asylum Contribution 0000002. Planning has already begun for Contribution 0000003, due to be published in 2037.

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Figures

Figure 1 Authors Holden and Vogt as they try to steer their raft (this paper) through the swamp of controversy over deep mantle plumes.

Figure 2 “Do we exist or not?”–the deep mantle plume’s view of his/her predicament.

Figure 3 Iceland mantle plume, as modified from Figure 6 of Holden and Vogt (1977). Resemblance of humans (not to scale) to D.L. Anderson, G.R. Foulger and W.J. Morgan not coincidental.

Figure 4 The ghost of Robert S. Dietz (1914-1995) is still trying to fix the Tristan da Cunha hotspot, a key assumption in the continental reassemblies of Dietz and Holden (1970a,b) and later fixed-hotspot-based models.

Figure 5 Prof. A. Peccerillo flunks a hapless wandering Italian plume (see also Peccerillo and Lustrino, 2005)

Figure 6 Prof. E. Garnero (Garnero et al., this volume) diagnoses Earth with a case of deep mantle superpiles.

Figure 7 Two contrasting Venutian views: Hasn’t Prof. Hamilton made enough of an impact already? Is Prof. Jurdy seeing things?

Figure 8 The explosion and crash of mantle plume populations.

Figure 9 Mantle plumes (actually colored red or yellow) are born in the lower mantle, but then rise in this world, always on the lookout for lithospheric weak spots such as triple junctions, ancient igneous centers, and intra-continental rifts. Only dumb plumes bump their heads on Pre-Cambrian cratons.

Figure 10 Grading (scoring) deep mantle plumes.

Figure 11 Scientists searching for proof that impacts might cause LIPs or hotspot trailheads never seem to catch this secretive pair together.

Figure 12 Geo-zippergate: An otherwise reputable geoscientist still looking for the legendary Great Hawaiian Propagating Crack southeast of the Big Island and Loihi, unzipping the Pacific plate to let Hawaiian lavas flow out. 31

Figure 13 Seismotomographers looking for the plumatic’s Grail: tiny wiggles they can extract from the noise and invert into tomoplumes.

Figure 14 Multiculturalism and celebration of diversity: Opening the big, big mantle tent to every hypothesis. 32

Figure 1 33

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Figure 14