The story of the bands

Something that strikes me about many scientific discoveries is how they so often come from someone noticing something the rest of us had overlooked or thought insignificant -- and afterward, most importantly, the person asking, "Why?"

A now-familiar example of this is the discovery by the father-and-son team of Luis and Walter Alvarez of the thin iridium-bearing clay layer at the boundary between Cretaceous rocks and Paleocene rocks -- analysis of which led to the discovery of the dinosaur-killing Chicxulub Meteorite Impact.  Without their questioning why there was a narrow layer of heavy-metal-enriched clay at the boundary, everywhere on Earth where there are rocks of that age, we might never have found out about one of the major events in the history of life on Earth.

Another example, less well known, has to do with the banded iron formations found in locations all over the world, including Australia, Brazil, Canada, India, Russia, South Africa, Ukraine, and the United States.  They're striking in appearance, sometimes hundreds of meters thick, with alternating layers of light-colored iron-poor and dark, reddish-brown iron-rich chert or limestone.  Here's an example from near Fortescue Falls in Western Australia:

[Image licensed under the Creative Commons Graeme Churchard from Bristol, UK, Banded iron formation Dales Gorge, CC BY 2.0]

Most of us, I think, would say "pretty rock formation" and leave it at that; a smaller number would recognize the fact that they were sedimentary, and wonder why the colors alternate.  Geologist Preston Cloud, though, took it several large steps farther -- and what he came up with is a little mind-blowing.

What first struck Cloud as curious about banded iron formations is that they're all about the same age.  Regardless of whether they're in Australia or Ontario, just about every banded iron formation studied was deposited around 2.4 billion years ago.  But what could create this pattern not just in one location, but in widely-scattered spots all over the planet?  Whatever the process was must have happened everywhere simultaneously -- and rapidly.

Cloud's hypothesis, which is now well-accepted, is that banded iron formations represent the fingerprint of something called the Great Oxidation Event.  Here's basically what we think happened.

Early living things were largely scavengers, living from abiotically-produced organic compounds dissolved in seawater (and the decomposing bits of dead cells).  These compounds were abundant -- an anoxic atmosphere, rich in reducing compounds like ammonia, methane, and carbon monoxide, together with an energy source like ultraviolet light, generates organic compounds of all sorts.  (As the Miller-Urey experiment conclusively demonstrated.)

But there's always competition between species, and sometimes mutations can create proteins or structures that allow organisms to able to access resources faster or more efficiently than their neighbors.  And that's what happened when a single-celled bacteria evolved a gene to produce chlorophyll, which can quickly capture energy from visible light and store it as chemical energy.

In other words: photosynthesis.

This had only one downside, but it was a huge one.  Photosynthesis generates molecular oxygen.  Oxygen is highly reactive, a strong oxidizer (thus the name), and tears apart organic compounds as quickly as they form.  The presence of oxygen, first dissolved in seawater and then liberated into the atmosphere, did three things.

First, it shut off the abiotic production of excess organic compounds, eliminating the food source for most of life on Earth.

Second, it was directly toxic to most cells, except for the (very) few which had detoxifying enzymes like superoxide dismutase to cope with living in an oxygenated environment -- or which were capable of metabolizing it, using a pathway we now call aerobic respiration and which we have become completely dependent upon.  (It's amazing to think about, but our energy-production system originally evolved as a way to mitigate the poisonous effects of molecular oxygen.)

Third, the oxygen reacted with dissolved ferrous (II) ions in seawater, and altered them to mostly-insoluble ferric (III) ions, which settled out on the ocean floor.  This process, however, bound up the available oxygen, so the reaction dropped oxygen levels, and for a while any iron eroded into the oceans was dissolved as ferrous ions again.  But eventually the photosynthesizing bacteria pumped out enough oxygen that the iron precipitated once more.  The result: alternating layers of iron-poor chert when the oxygen levels were low, and iron-rich chert when the oxygen levels rose.

Eventually, of course, the oxygen rose and stayed high.  By this time, damn near all life on Earth had died; the only ones left were anaerobes that could hide (like the bacteria we still have in deep-sea mud and other anaerobic habitats), and aerobes like our own ancestors that had metabolic pathways to cope with the presence of oxygen.

And the alternating pattern of light and dark layers in banded iron formations chronicle the rising and falling of oxygen during one of the pivotal moments of Earth's prehistory.

Certainly a large part of being a successful scientist is intensive training in a specific field, but I think sometimes there's not enough attention given to another facet of it -- the role of creativity.  The scientists who make important discoveries are usually the ones who notice things the rest of us might just walk past, wonder about them, and most importantly, draw connections between disparate realms to find answers (in this case, geology, chemistry, and biology).  Without this combination of technical knowledge, curiosity, and insight, we would know far less about the universe we live in -- and what an impoverished understanding we would be left with.

****************************************

Quantum pigeons

I have a fascination for quantum physics.  Not that I can say I understand it that well; but no less than Nobel laureate and generally brilliant guy Richard Feynman said (in his lecture "The Character of Physical Law"), "If you think you understand quantum mechanics, you don't understand quantum mechanics," so I figure I have a pretty good excuse for my lack of deep comprehension.  I have a decent, if superficial, grasp of such loopy ideas as quantum indeterminacy, superposition, entanglement, and so on, but that's about the best I can do.  At least I understand enough to find the following joke absolutely hilarious:

Heisenberg and Schrödinger were out for a drive one day, and they got pulled over by a cop.  The cop says to Heisenberg, who was driving, "Hey, buddy, do you know how fast you were going?"

 
Heisenberg says, "No, but I know exactly where I am."

 
The cop says, "You were doing 85 miles per hour!"

 
Heisenberg throws his hands in the air and responds, "Great!  Now I'm lost."

 
The cop scowls at him.  "All right, pal, if you're going to be a smartass, I'm going to search your car."  So he opens the trunk, and there's a dead cat inside it.  He says, "Did you know there's a dead cat in your trunk?"

 
Schrödinger says, "Well, there is now."

Thanks, you're a great audience. I'll be here all week.

In any case, the topic comes up because of a paper in Proceedings of the National Academy of Sciences called, "Experimental Demonstration of the Quantum Pigeonhole Paradox," by a team of physicists at China's University of Science and Technology, which was enough to make my brain explode.  Here's the gist of it, although be forewarned that if you ask me for further explanation, you're very likely to be out of luck.

There's something called the pigeonhole principle in number theory, that seems kind of self-evident to me but apparently is highly profound to number theorists and other people who delve into things like sets, one-to-one correspondences, and mapping. It goes like this: if you try to put three pigeons into two pigeonholes, one of the pigeonholes must be shared by two pigeons.

See, I told you it was self-evident.  Maybe you have to be a number theorist before you find these kind of things remarkable.

[Image licensed under the Creative Commons Razvan Socol, Rock Pigeon (Columba livia) in Iași, CC BY-SA 3.0]

In any case, what the research showed is that on the quantum level, the pigeonhole principle doesn't hold true.  In the experiment, photons take the place of pigeons, and polarization states (either horizontal or vertical) take the place of the pigeonholes.  And when you do this, you find...

... that when you compare the polarization states of the three photons, no two of them are alike.

Hey, don't yell at me.  I didn't discover this stuff, I'm just telling you about it.

"The quantum pigeonhole effect challenges our basic understanding….   So a clear experimental verification is highly needed," study co-authors Chao-Yang Lu and Jian-Wei Pan wrote in an e-mail.  "The quantum pigeonhole may have potential applications to find more complex and fundamental quantum effects."

It's not that I distrust them or am questioning their results (I'm hardly qualified to do so), but I feel like what they're claiming makes about as much sense as saying that 2 + 2 = 5 for large values of 2.  Every time I'm within hailing distance of getting it, my brain goes, "Nope.  If the first two photons are, respectively, horizontally polarized and vertically polarized, the third has to be either horizontal or vertical."

But apparently that's not true. Emily Conover, writing for Science News,writes:

The mind-bending behavior is the result of a combination of already strange quantum effects.  The photons begin the experiment in an odd kind of limbo called a superposition, meaning they are polarized both horizontally and vertically at the same time.  When two photons’ polarizations are compared, the measurement induces ethereal links between the particles, known as quantum entanglement.  These counterintuitive properties allow the particles to do unthinkable things.

Which helps.  I guess.  Me, I'm still kind of baffled, which is okay.  I love it that science is capable of showing us wonders, things that stretch our minds, cause us to question our understanding of the universe.  How boring it would be if every new scientific discovery led us to say, "Meh.  Confirms what I already thought."

****************************************

The problem with intercessory prayer

There are many things I don't get about religion, but one of the ones I understand least is the idea of intercessory or petitionary prayer -- prayer that has as its intent to alter the course of something unpleasant like an illness or run of bad luck.

The Bible is full of examples of intercessory prayer, of God's wrath being turned away by a devout word in the Divine Ear.  In the episode of the Golden Calf (Exodus chapter 32), God apparently intended to destroy the Israelites for idolatry, but his judgment was altered by Moses' plea.  Even Sodom and Gomorrah, those pinnacles of depravity from the book of Genesis, would have been saved had Abraham found ten or more "righteous men" there.

All of this, to my admittedly unqualified ear, sounds as if God could change his mind.  The problem, so far as I can frame it, is this; in the typical Christian model of how things work, God is changeless, eternal, all-good, and all-knowing.  As such, the whole idea of a person's prayer altering the course of what God wants is a little silly.  God presumably already knows not only what is the best outcome, but knows what will happen; why would the prayers of one person, or even of everyone on Earth simultaneously, change that?  And what happens when you have equal numbers of devout people praying for opposite outcomes -- like what happens in the United States at every high-stakes sports event?  Does God simply tally up the number of prayers, or does the intensity of the prayers count?  Or the piety of those who are praying?

Old Woman in Prayer by Gerrit Dou (ca. 1630) [Image is in the Public Domain] 

So, in my effort to understand this idea, I turned to C. S. Lewis.  Even if I usually disagree with Lewis' conclusions, I find him to be generally rational, and certainly a clear, sober-minded writer on the subject.  Here's what I found, from his essay "Does Prayer Work?":

Can we believe that God ever really modifies His action in response to the suggestions of men?  For infinite wisdom does not need telling what is best, and infinite goodness needs no urging to do it.  But neither does God need any of those things that are done by finite agents, whether living or inanimate.  He could, if He chose, repair our bodies miraculously without food; or give us food without the aid of farmers, bakers, and butchers, or knowledge without the aid of learned men; or convert the heathen without missionaries.  Instead, He allows soils and weather and animals and the muscles, minds, and wills of men to cooperate in the execution of His will.

So far, sounds like the God/No God models look kind of the same.  But Lewis goes on to say:

I have seen it suggested that a team of people—the more the better—should agree to pray as hard as they knew how, over a period of six weeks, for all the patients in Hospital A and none of those in Hospital B.  Then you would tot up the results and see if A had more cures and fewer deaths.  And I suppose you would repeat the experiment at various times and places so as to eliminate the influence of irrelevant factors.

The trouble is that I do not see how any real prayer could go on under such conditions.  “Words without thoughts never to heaven go,” says the King in Hamlet.  Simply to say prayers is not to pray; otherwise a team of properly trained parrots would serve as well as men for our experiment.  You cannot pray for the recovery of the sick unless the end you have in view is their recovery.  But you can have no motive for desiring the recovery of all the patients in one hospital and none of those in another.  You are not doing it in order that suffering should be relieved; you are doing it to find out what happens.  The real purpose and the nominal purpose of your prayers are at variance.  In other words, whatever your tongue and teeth and knees may do, you are not praying.  The experiment demands an impossibility. 

What brings this up today is that a team in Brazil did exactly what Lewis suggests -- not with "properly trained parrots," but with a group of the devout who were told to pray for a group of COVID-19 sufferers, and who were honestly desirous of a positive effect.  The people doing the praying weren't told not to pray for the other group; in the setup of the experiment, they didn't even know the other group existed, so this circumvents Lewis's objection that the prayers wouldn't be valid because the people praying would only be "doing it to find out what happens."

The results, which appeared this week in the journal Heliyon, found zero difference in the survival rate, severity, or rate of complications between the prayed-for and not-prayed-for groups.

I am very curious as to how a Christian would explain why, if intercessory prayer works at all, the prayed-for group didn't show a lower risk of complications or death.  "Thou shalt not put the Lord thy God to the test," perhaps -- but all that means is that the scientists running the experiment were sinning, and you'd think God wouldn't be petty enough to let the prayed-for group suffer and die just to get back at the researchers.

Plus, there's the consideration that if ever there was an opportunity for God to show that what the Christians claim is correct, this is it.  You would think that if presumably God wants people to believe and to pray (and in fact Christians are positively commanded to pray, in a variety of places in the Bible), some sort of results would have been forthcoming.

You get the impression that even Lewis was a little uncomfortable on this point.  He said, "Prayer doesn't change God -- it changes me."  Again, I have to wonder how this would work.  How would praying for something to a deity whose mind I can't change, who knows what is "supposed to happen" and who will do what he chooses regardless, have any beneficial effects on me?  Imagine a parent whose mind could never be swayed by his children's requests -- and telling the children, "You should ask anyway, because it's good for you."

While I am not religious (obviously), I can at least understand the concept of other sorts of prayer -- prayers for enlightenment, prayers for understanding, prayers for courage.  But I really have no clue what the possible logic could be to praying for intercession, other than "the Bible says we have to -- never mind why."  Perhaps some reader will have a good explanation of it, but on the face of it, it seems like the most pointless of pursuits.

****************************************

Message in a bottle

Ever heard of a witch bottle?

Witch bottles are magical items that are a type of apotropaic magic -- spells meant to ward off evil (the word comes from the Greek αποτρέπειν, meaning "to turn away from").  The idea has been around for a long time; if someone tries to use an evil enchantment on you, you can respond with a defensive spell of your own, and it might even rebound on the person who was trying to hex you.  One of the first written accounts of a witch bottle is in seventeenth century English clergyman Joseph Glanvill's book Saducismus Triumphatus, or Evidence Concerning Witches and Apparitions, wherein we hear about a man whose wife was sick and who kept getting visited by the apparition of a bird that would flutter in her face, because apparently that was a thing in seventeenth-century England.  The man was given advice by an "old man who traveled up and down the country," who said the cure was to have the sick woman pee in a bottle, then add some pins and needles, then cork it up tight and put it in the fire.

Which, I have to admit, is at least a creative solution.

The first time it didn't work because the heat made the air in the bottle expand and blew out the cork, which must resulted in a situation that was unpleasant to clean up.  But they tried a second time, and it worked -- and had an interesting result:

Not long after, the Old Man came to the house again, and inquired of the Man of the house how his Wife did.  Who answered, as ill as ever, if not worse, and still plagu'd by birds.  He askt him if he had followed his direction.  Yes, says he, and told him the event as is above said.  Ha, quoth he, it seems it [the spirit which was troubling them] was too nimble for you.  But now I will put you in a way that will make the business sure.  Take your Wive’s Urine as before, and Cork, it in a Bottle with Nails, Pins and Needles, and bury it in the Earth; and that will do the feat.  The Man did accordingly.  And his Wife began to mend sensibly and in a competent time was finely well recovered; But there came a Woman from a Town some miles off to their house, with a lamentable Out-cry, that they had killed her Husband.  They askt her what she meant and thought her distracted, telling her they knew neither her nor her Husband.  Yes, saith she, you have killed my Husband, he told me so on his Death-bed.  But at last they understood by her, that her Husband was a Wizard, and had bewitched this Mans Wife and that this Counter-practice prescribed by the Old Man, which saved the Mans Wife from languishment, was the death of that Wizard that had bewitched her.

Apparently other things that people sometimes put in witch bottles were hair, blood, fingernail clippings, red thread, written charms, feathers, dried herbs and flowers, and money.

The reason this comes up is that apparently there are still people who believe in this, because there's a beach in southern Texas where a guy keeps finding what appear to be modern witch bottles.  He's found eight of them thus far, all filled with odd items -- sticks and leaves seem to be the most common.

[Image licensed under the Creative Commons Malcolm Lidbury (aka Pinkpasty) , Witch Bottles Curse Protection, CC BY-SA 3.0]

Jace Tunnell, Director of Community Engagement at the Harte Research Institute, has spent years scouring the beaches of South Padre Island for anything odd that's washed up, and starting about six years ago, he began finding sealed bottles that evidently had been out there adrift for a long time, given the fact that some of them had barnacles on them.  After studying the currents, he believes they may have come from as far away as the islands of the Caribbean, or perhaps even West Africa.

"I don't open the bottles," Tunnell said.  "In fact, my wife won't even let me bring them into the house.  The theory is that if you open it you can let the spell out, whatever the reason the person had put the spell in there.  They're counter-magical devices, created to draw in and trap harmful intentions directed at their owners, so it's best to leave them sealed."

The fact that some of them could contain piss and rusty needles is another good reason to leave the tops on.

Predictably, I don't think there's any other particularly good reason to be concerned about them.  You have to wonder, though, how these superstitions get started, and (especially) how they persist despite the fact that they don't work (notwithstanding accounts like the one from the estimable Mr. Glanvill).  I wonder if it's because sometimes the "cursed" person does get better after the counter-curse, and to the credulous this is sufficient proof, even though it is an established scientific principle that the plural of "anecdote" isn't "data."

Although you have to wonder about the sanity of the first person who came up with the idea of peeing in a bottle full of pins.

In any case, if you find a sealed bottle washed up on the beach, it's probably best just to deposit it in the nearest trash can and not worry about it.  Unless it contains money, in which case open that sucker right up.  Call me greedy, but I'd risk being plagu'd by birds if the price was right.

****************************************

Analysis of a cataclysm

Any idea what volcano is responsible for the largest known eruption?

Krakatau?  No.  Vesuvius and the Campi Flegrei?  Not even close.  Tambora or Toba?  Nope.  The Yellowstone Supervolcano?  Closer, but still not right.

The biggest volcanic eruption on record came from an extinct caldera I'd never heard of until a friend and loyal reader of Skeptophilia mentioned it a couple of days ago.  It's the La Garita Caldera in southwestern Colorado, near the little town of Creede, and when it last erupted -- during the Oligocene Epoch, on the order of 28 million years ago -- it did so with an estimated force of 250,000 megatons, which is five thousand times the explosive force of the largest nuclear weapon ever detonated.

The eruption resulted in something called ignimbrite -- a rock layer created from a frozen pyroclastic flow.  When a volcano powered by viscous high-silica (felsic) magma erupts, it's usually explosive, quite unlike the runny, flowing lava from one made of low-silica (mafic) rock.  Instead of creating a liquid flow, the force of the eruption pulverizes the magma and surrounding rock, creating a superheated cloud of ash, dust, and volcanic gas that then rushes downhill, incinerating anything in its path.  This is what did in Pompeii and Herculaneum in 79 C. E., and more recently, occurred during the devastating eruption of Mont Pelée on Martinique in 1902 that killed thirty thousand people in the space of a few minutes.

An ignimbrite forms when the pyroclastic flow loses speed and settles, and the ash, pumice, and glass shards (still plenty hot) fuse together to form a solid layer of rock.  If you've seen pictures of Pompeii (or better yet, been there) you can picture what this looks like, and your mental image is probably of something like a meter's worth of consolidated ash.

The La Garita Caldera eruption produced an ignimbrite an average of a hundred meters thick.

The amount of rock and magma blown to smithereens in the eruption is estimated at around five thousand cubic kilometers -- compare that to the one cubic kilometer blown skyward when Mount Saint Helens erupted in 1980, and you have an idea of the scale.  The resulting rock formation, the Fish Canyon Tuff, covers 28,000 square kilometers.

[Image is in the Public Domain courtesy of photographer G. Thomas]

The most interesting part of this is what caused the eruption.  It's part of the larger San Juan Volcanic Field that was created when the center of the North American continent was stretched and cracked by the Rio Grande Rift.  This is a long, north-south trending fault running from northern Mexico up through New Mexico and into central Colorado, and was responsible for a number of eruptions between forty and eighteen million years ago (although none as big as La Garita).  The reason for this fault, in the middle of the stable continental craton, is still being puzzled over by geologists, but here's one possible explanation.

Starting during the Cretaceous Period, a huge slab of oceanic crust called the Farallon Plate subducted underneath the North American Plate.  This had a couple of major effects -- cementing a number of island arcs onto the west coast of North America (called suspect terranes because they don't have the same geology as the neighboring land they're welded to), and triggering the Laramide Orogeny that created at least parts of the Rocky Mountain Range.

[Nota bene: the geology of the Rocky Mountains is ridiculously complicated, so what I'm presenting here is a vast oversimplification.  If you want a great overview of it, as well as the geology of other parts of North America and the people who study it, a good place to start is the excellent quartet of books by John McPhee, Rising From the Plains, Basin and Range, In Suspect Terrain, and Assembling California.]

In any case, the Farallon Plate was eventually consumed by the subduction zone, leaving only three small pieces still in existence -- the Gorda, Juan de Fuca, and Explorer Plates, which I considered in my post about the Cascadia Fault a month ago.  The rest of Farallon is now underneath western North America.

And, more germane to our topic, the rift zone that powered it eventually got dragged underneath as well.  This meant that the force pushing the Farallon and Pacific Plates apart was now beneath the North American continent.  The result was that the continental crust was stretched, creating a topography called horst-and-graben (or basin-and-range), where extension cracks the rock layers and some of them sink downward, creating an alternating step-up and step-down landscape that you see all over Colorado, Utah, and Nevada.

But along the Rio Grande Rift, the cracks ran so deep that it didn't just cause earthquakes and topographic change.  The fault went down far enough that magma upwelled into the fissure, resulting in a chain of volcanoes -- the aforementioned San Juan Volcanic Field, one of which is the cataclysmic La Garita Caldera.

Eventually -- and fortunately -- the convection current powering the spreading center ran out of steam due to friction with the thick, cold continental crust, and the whole thing simmered down.  The last ignimbrite from the San Juan Volcanic Field is about eighteen million years ago, and the entire area has been geologically quiet since that time.

Whenever I find out about something like this, I'm awed by the power of which the Earth is capable.  We tend to flatter ourselves about our own capacity for controlling nature, but by comparison, we're pretty damn feeble.  Being reminded of this is not, of course, a bad thing -- especially since at the moment our activities stand a good chance of unleashing a backlash from the climate that could be nothing short of catastrophic.

It's best to keep in mind that in a war between nature and humanity, the odds are very much in favor of nature.

****************************************

It's not in the cards

When I was in college I went through a period of messing around with Tarot cards.  They were cool-looking, and the book I got that explained their meanings was steeped with arcane and mystical terminology.  The whole thing seemed ancient and magical and terribly attractive.  The fact that I was still living at home, in a staunchly religious Roman Catholic family which disapproved of anything smacking of witchcraft, only gave it that much more of a frisson.

So yes, True Confessions time: at one point in my life, I experimented with woo-woo-ism.  But don't worry, I didn't inhale.

What eventually pulled the plug on all of it was that when I talked about it with my friends, I started sounding ridiculous to myself.  I had to explain (when I was doing a Tarot reading for someone) that I was selecting a card to represent them based on their gender and appearance, and that this would establish a psychic connection between them and seventy-eight pieces of glossy card stock with weird designs that I'd bought for ten bucks in a local bookstore.  And in the back of my mind was this constant mantra of, "How the fuck could that actually work?"  I was able to shout the voice down for a while, but sooner or later, I had to admit that Tarot cards were nothing more than a pretty fiction, and any accurate readings I did could be attributed to a combination of chance, my prior knowledge of the person being "read," and dart-thrower's bias.

I still, however, own six Tarot card decks, including the one I got when I was in college.  The coolest is an Art Nouveau deck that is actually quite beautiful, with designs that remind me of one of my favorite artists, Maxfield Parrish.  I also have "The Original Dog Tarot" in which -- I shit you not -- the four suits are Bowls, Biscuits, Leashes, and Bones, and the Major Arcana include The Hydrant, The Dogcatcher, The Cat, and The Couch.

Purists would probably be pissed off about a Tarot deck that is clearly made up, but let's face it; it's all made up.  The infamous "wickedest man on Earth" Aleister Crowley claimed that the Tarot traces its origins back to an ancient Egyptian text called The Book of Thoth, but there's one awkward problem with this, which is that The Book of Thoth appears not to exist.  Undeterred, Crowley wrote his own Book of Thoth, because after all, as long as we're making shit up, we may as well do the job ourselves and not waste our time learning how to read actual Ancient Egyptian texts that might not even say what we were hoping they'd say.

Actually, the earliest Tarot cards come from some time around the fifteenth century, but at the time they seem to have mostly been used for playing games.  The first use of the cards for divination -- what's been called cartomancy -- isn't until around 1750, which seems awfully late for a practice that claims to be Esoteric Secrets From Antiquity.  The surge in popularity the practice had in the late eighteenth century was largely due to one man, Jean-Baptiste Alliette, who went by the extremely subtle and creative pseudonym Etteilla.  Alliette was an occultist who had a huge following amongst the nobility, and wrote a manual called Manière de se récréer avec le jeu de cartes nommées tarots (A Method for Recreating Yourself Using the Cards Called Tarots) which is the basis of all the "Tarot cards interpreted" books you see today.  Modern card decks, including the famous Rider-Waite deck, all derive from the standardization of the cards and suits by Alliette.

Lately, though, things have gone a bit off the rails, and I don't just mean obvious spoofs like my Original Dog Tarot.  If you search on Amazon for "Tarot cards" you'll find dozens (probably hundreds) of different decks, and a great many of them don't have the traditional suits, with fifty-six Minor and twenty-two Major Arcana.  There are divine feminine and divine masculine decks (some of which are highly NSFW), decks that are allegedly Norse or Celtic or Native American or Chinese or Japanese, decks centered around plants or animals or crystals or astronomical objects, queer decks and warrior decks and steampunk decks.

And -- if I haven't already made a strenuous enough point about this -- all of these were made up, most of them in the last fifty years or so.  None of them have the least thing to do with actual ancient wisdom passed down through the ages.

So there you are.  It hardly bears mention that I think divination simply doesn't work; much as it's a beguiling idea, there's nothing mysterious going on with Tarot card readers except how they manage to persuade so many people to fork over twenty bucks for a session.  Be that as it may, I'm gonna keep my decks.  For one thing, they're cool to look at.  For another, maybe I can do a reading for my dogs.  If the Ten of Bones turns up, they'll be thrilled.  That's a lot of bones.

****************************************

The lost forests of the Fens

It will come as no surprise to regular readers of Skeptophilia that I have a fascination for considering how the terrain of the Earth has changed over its history.  It's a topic I've come back to again and again as scientists piece together the shifting topography of the continents, molded by plate tectonics and glaciations and even the occasional meteorite impact.

It's tempting to think that you have to go back hundreds of millions of years to see a significant difference from what we have now, as we did in yesterday's post about the peculiar geology of Scotland.  In some cases, though, things have changed on a far shorter time scale, so recently that the remnants of the past lie right beneath the surface of the modern landscape.

The Fens are a region in eastern England, lying in Lincolnshire, Cambridgeshire, and Norfolk.  It's virtually all dead-flat and only a meter or two above sea level, so the whole area is prone to flooding -- water is controlled by a network of levees and drainage channels that crisscross the entire nearly four thousand square kilometer region.  You'd think this would discourage people from living there, but the opposite is true; it's been settled since Mesolithic times, mostly because of the excellent quality of the soil for agriculture.  The largest communities in the Fens are understandably concentrated on the highest ground, which are nicknamed "islands" (and in rainy periods, they sometimes are islands in actual fact).  The largest of these is Ely, a beautiful cathedral city that is now home to twenty thousand people.

Ely Cathedral [Image licensed under the Creative Commons Tilman2007, Ely-071, CC BY-SA 4.0]

It's a strange and surreal landscape, prone to long periods of fog and swirling mist, largely devoid of trees, dominated by wide grassy marshes that are home to a great variety of birds and other wildlife.  The region so impressed composer Ralph Vaughan Williams that he wrote his melancholy and evocative piece In the Fen Country to try to capture the otherworldly beauty of the place.

Wicken Fen, Cambridgeshire [Image is in the Public Domain]

What brings up this topic today is a study by researchers at the University of Cambridge that appeared in the journal Quaternary Science Reviews last week, which showed that only five thousand years ago, the Fens looked very different -- and traces of that vanished landscape still lurk right below the surface.

Farmers plowing the rich soil to plant crops such as grains, vegetables, potatoes, canola, and mustard frequently find their plows getting snagged on heavy logs that then have to be dug up and dragged out.  "A common annoyance for Fenland farmers is getting their equipment caught on big pieces of wood buried in the soil, which can often happen when planting potatoes, since they are planted a little deeper than other crops," said study lead author Tatiana Bebchuk.  "This wood is often pulled up and piled at the edge of fields: it's a pretty common sight to see these huge piles of logs when driving through the area."

Upon analysis, Bebchuk and her team found that nearly all of the wood came from yew trees -- many of them absolutely enormous, on the order of twenty meters tall.  Only five millennia ago, what is now the marshland of the Fens was a huge forest of yew trees.

Then, about 4,200 years ago, all of them suddenly died.

The reason, Bebchuk found, was a sudden influx of salt water as the world warmed following a cold period, and sea levels rose.  Within a generation the yew forests were nothing more than a vast expanse of bleached trunks, which ultimately fell and were buried in the marshy soil.  Replacing them was an ecosystem of salt-tolerant marshland grasses that still dominate the region today.

What's curious is that this coincided with significant events in other parts of the world -- a serious drought in China, and the collapse of the Egyptian Old Kingdom and the Mesopotamian Akkadian Empire.  Whether these are all directly related is, of course, impossible to say; it's rare that complex historical events have only a single cause.  Climate change may, however, been a significant contributor -- otherwise this is quite the coincidence.

"We want to know if there is any link between these climatic events," said Bebchuk.  "Are the megadroughts in Asia and the Middle East possibly related to the rapid sea level rise in northern Europe?  Was this a global climate event, or was it a series of unrelated regional changes?  We don't yet know what could have caused these climate events, but these trees could be an important part of solving this detective story."

It's fascinating, and a little scary, to see how rapidly things can change -- and if this doesn't put you in mind of what we're currently doing to the climate, it should.  Consider what landscapes we have today, places that seem like they'll never change, that might be drastically different fifty years from now.

I wonder what the scientists five thousand years in the future will piece together about our current world?

****************************************