Through The Sandglass

Sunday sand: Pago Pago critter-bits

 
 
This week’s sand is from Faga'alu Beach, near Pago Pago, the capital of American Samoa, and is simply a great example of a sand of almost entirely biogenic origins. Bits of coral, sea urchin spines, grains that are quite possibly fragments of bryozoa (although my marine biological knowledge is not extensive) – and our old friends, foraminifera, including the wonderful miniature stars; these latter are the species Baculosypsina, and there are some great stories related to them – but that’s for another day.

The Samoan islands are volcanoes emerging from the depths of the southeast Pacific Ocean, close to the chaos of the great plate boundaries that – as recently in New Zealand – can cause widespread devastation. When the plates are quiet, these Islands have all the characteristics of a Pacific paradise, white sand beaches often fringed by reefs. Faga'alu Beach, the origin of today’s grains, is one such place. As you can see in this Google Earth image, the beach has developed along a strip of rocky shoreline sheltered from the waves by the barrier of the reef. And it’s the reef and its environs, rather than the rocks, that provide the sand.  

  
In this spectacular photo from the air (credit below) reefs can be seen all around the bay of Pago Pago: the town itself is at the head of the bay in the distance, Faga'alu Beach is at the left of the picture.

But when the plates stir, havoc ensues. On September 29, 2009, a major earthquake struck close to Samoa and triggered a tsunami that devastated large areas of the islands. In coastal topography like this, the amplitude of the tsunami would be magnified as it sweeps into the confines of the shallow waters of the bay, and the results catastrophic. In some areas, the tsunami wave reached nearly fifty feet above sea level, and there were, as is often the case, several successive waves, the ocean withdrawing before pounding back onshore again. There are some remarkable videos of the 2009 Samoan tsunami available on YouTube – see, for example, this one, with links to others; a dramatic animated model of the way the waves sweep across the Pacific was generated by NOAA and can be seen here. Incredibly, it was not just one earthquake that caused this, but three. The first, magnitude 8.1, triggered two further 7.8 magnitude events within a couple of minutes. This kind of event – what has been referred to as a “triple whammy”- had not been seen before and was described in detail a year later.

Pacific island sands – paradise beaches waiting to be churned by the paroxysms of plate tectonics.

 

[The sand sample was kindly provided by Christopher Maslon. The photograph of the bay of Pago Pago is from http://www.pbase.com/aqohana/image/24407276; I attempted by two different routes to obtain explicit permission to use this image, but received no reply. I trust that I have caused no offense by using it.]

Second Grade

 
An audience of a couple of hundred on the Queen Mary 2? A few flutters of nervousness. The Gottingen Literary Festival? Despite giving an introduction in German to an illustrious group, merely a tangible increase in adrenalin. I have to admit that I enjoy giving talks and, having done so many, the days of the fear of public speaking are long gone. But when a neighbourhood friend in suburban Philadelphia asked if I could come in and talk to her second grade class, stage fright would be an understatement; rather I felt a gathering sensation of something verging on terror.

But I needn’t have worried. Kids of that age are curiosity engines, their enthusiasm infectious, and it was a totally memorable experience. I was, of course, helped by the fact that my topic was one immediately accessible to kids, and that they had already done some investigation of sand. Add to that the imagery that sand has to offer and the wonderful fact that every classroom seems now to equipped for Powerpoint, and the time flew by. I was also set at ease – and surprised – by first having to autograph everything and anything that was available, mostly the kids’ workbooks, but it was the first time that I had signed a glasses case.

The enjoyable memories of the occasion were wonderfully enhanced by the fact that the teacher had all the kids write up and illustrate what they had learned – and then presented me with the results. A real treasure! And so this post is essentially written and illustrated by these kids. In the header above, I believe that the picture on the left is of the event itself – me, the class, and Powerpoint. Here’s a photo of the reality (scary, huh?):

 
I am amazed by what these kids took in, and how they illustrated and wrote about it.

The diversity of sands, the critters that live in sand – and erosion! And they really took to my recommendation of always taking a magnifying glass to the beach.

 

And the idea that, between the sand grains of a beach, is a miniature zoo seems to have struck a chord:

I will simply select some quotes from the written reports – I couldn’t possibly include everything, so my apologies to anyone whose work does not appear; note, by the way, the interest in the physics of granular materials:

The guy that taught us about sand is Mr. Welland

Sand is an interesting thing to learn about. And that is what Mr. Welland told me.

Sand is made out of really tiny rocks. Sand just looks brown. But it is really not. If you look up close you can see beautiful shiny and different colored rocks.

Sand is great, it feels so smooth but really it’s tiny bits of rock...I love sand and I never leave the house without a magnifying glass... There are also bugs, insects, and creatures.

A lot of things live in sand.

Sand might act like a liquid but it is a solid. That’s why sand is awesome.

I learned that storms and stuff break rocks and turn into sand. I learned that in Hawaii there is black sand. I learned that there is red and pink sand.

I learned that sand is made out of shells and rocks...desert sand is made out of little balls. Sand is fun to play in.

p.s. Make sure you have a magnifying glass with you when you go to the beach.

Some sand is shells and the sand breaks up into pieces and it makes sand. Sand is interesting to learn about. Animals live in sand.

I learned that there are no two sand pieces alike. The sea crashes against the rocks and makes tiny pieces.

Sand is tiny tiny rocks but it is weird because it is like a solid and a liquid. Little bugs live in the sand. They cleaned up the dirt.

Waves wash on rocks and small pieces fall off the rock. The small shells of small creatures can be sand too, when the creatures die. But is sand a liquid or a solid? That is still a mystery.

Never leave the house without a magnifying glass if you are looking at sand. Sand will not stick without water... I learned a lot from Mr. Welland. I like sand.

And as I was getting ready to leave, one question threw me: “I thought that sand was a kind of polymer?” Second grade?

So many many thanks to this class – you were brilliant and I enjoyed myself enormously – I look forward to coming back!

 

[Note that the photograph of the class is published here with permission – I had originally blurred individual faces, but I was pleased to be told that this was not necessary.]

 

 

 

Sunday sand: a Himalayan river

 
Most of the “Sunday sand” posts so far have come from beaches around the world (with the exception of last week’s desert location); there’s an obvious reason for this – beaches are specific destinations (sand being a key characteristic), they provide the opportunity for intimately communing with sand, and they are thus obvious places for collection of the stuff – by me or my circle of arenokleptomaniacal friends.  But, moving upstream, river sands are equally fascinating and diverse, representing the material as it travels along these highways from its source to the ocean. Close to the source, these are dramatically dynamic, high-speed highways, and nowhere is this more apparent than in the Himalayas.

The sand above comes from Bhutan and shows the distinctive character of young river grains: sharp and angular, not yet smoothed by the buffeting of the journey, and an exotic mix of ingredients, rock fragments, mineral grains not yet rotted into clay. Plus a wide range of grain sizes, not yet sorted and winnowed as currents wax and wane. These are sand grains flushed along by rapid mountain torrents, left, briefly, along the banks as flood waters subside. These particular grains, newly born in the Himalayas, come from the River Torsa (also spelt Torsha and also known as Machu, or Mochu, and Amo Chu - the word "Chhu" means "river" or "water" in Dzongkha, the official national language in Bhutan). The Torsa rises from the Chumbi Valley in Tibet, China, and flows through Bhutan and into India before joining the massive system of the Brahmaputra and onwards to the Indian Ocean.

In Bhutan, the youth and dynamics of the Torsa are also illustrated by its large-scale morphology – its flood plain is wide, covered by multiple channels winding sinuously around bare, elongate oval islands of sand and gravel. The appearance is one of a rough braid, and indeed this is referred to as a braided river, typical of youth and dynamism, water and huge cargoes of sediment continuously sculpting an ever shape-shifting landscape. This photo shows a typical braided river pouring out the Brooks Range in Alaska:

Google Earth shows clearly the broad, braided nature of the Torsa in Bhutan:

But these images (thanks to the wonders of Google Earth’s historic imagery feature) also show the dramatic and rapid changes that occur in this kind of river system: the two images are but fifteen months apart, but look at the way in which all the channels have shifted, new channels formed, old ones disappeared, sand banks changed. Every year, with the monsoon rains, Himalayan rivers such as this create catastrophic floods, changing the landscape and causing devastation. Look at the two images below – in December 2004 there was a village on the bank of the Torsa, but little more than a year later there’s virtually no sign of it, swept away in the floods.

These are destructive events that happen every year, but periodically they occur on such a devastating scale that they receive worldwide attention. On the other great Himalayan river system, the Indus, last year’s appalling floods in Pakistan were such an event. One understandable reaction is to build dams in an attempt to control the floods (and generate hydroelectric power) – but, as I wrote last year, the complexities of these giant river systems is so great that, more often than not, more problems are caused by these solutions than are resolved. Water supplies, flood control, and power generation in the Himalayas are fundamental issues being addressed by major projects in India, Pakistan, China, Tibet, Nepal, and Bhutan (a dam on the Torsa is currently being planned); each country’s needs and resources are often in conflict and the challenge is a truly geopolitical one.

My original intention with these Sunday Sand posts was simply to catalogue some of the dazzling variety of our planet’s sand grains – but every sand grain has a story to tell and so I find myself rambling off into these tales. Oh well….

 

[These Bhutan sands were among the many collected on their world travels by two very cherished family friends. Sadly (the word hardly seems adequate), Laurie passed away suddenly last year – while travelling. Libby continues her travels and I shall always be grateful for the enthusiasm and devotion shown by two of my favourite arenokleptomaniacs.]

A long-tailed black swan visits

A quick visual inspection of the visit stats for this blog reveals a rather startling anomaly: in general a typical day will see a couple of hundred visits, but when I first checked on Tuesday morning the figure was well over 2000 and ended the day close to 4000. I was, to say the least, astonished. There was also highly anomalous twitter and facebook traffic, and it rapidly became clear that all this excitement originated from a post on Reddit, which in turn originated from this, about the extraordinary sand art of Andrew Clemens. This became linked to a very recent episode of Antiques Roadshow broadcast from Des Moines, Iowa, where the State Historical Society hosts a collection of Clemens’ work and kindly gave me permission to reproduce images in the book. This all led to a cascade – indeed, an avalanche – of links and the unprecedented, unpredictable, and unique event on this blog.

The segment on the TV program is well-worth watching – for the moment, at least, it’s available on the New Hampshire Public Television site – the discussion of Clemens begins at around 22 minutes.

What happened has, when I think about it, always been within the universe of possible events, but well outside the historic metrics and the limited world of expectations – hence this post title. When I wrote the “Sandpile world” post last week, little did I think that this would be dramatically illustrated by imminent events on the blog itself!

 

[By the way, Sandglass will shortly be travelling to distant parts – a couple of posts have been pre-scheduled for the coming week, and I hope to be reporting “live” soon thereafter.]

Splashing around on Mars

The last Sunday Sand post returned to the ever-fascinating work and exploits of Ralph Bagnold; after writing it, I was catching up on arenaceous research news and there he was again – on Mars, so to speak. A recent press release from the Planetary Science Institute and the Mars HiRise imaging team announces “to their surprise” that seasonally repeated imagery reveals that the polar dunes of the planet are constantly changing. Why should this be a surprise? After all, dune systems on Earth are among the most dynamic landscapes on the planet – why should Mars be any different? Well, there are important differences, as we shall see, but that Martian dunes have been “long thought to be frozen in time” is the real surprise – and is shown to be unfounded. Yes, seasonal icing stabilises the dunes, but melting and degassing causes instability – and the wind re-sculpts the surface.

Nor should we be surprised that Bagnold enters the arena of this debate for, while his seminal work on the physics of windblown sand was first published seventy years ago, it remains the foundation of aeolian research today, his basic equations and analysis of processes refined but essentially unchanged. And we should also not be surprised that his work applies as well to Mars as it does to Earth – after all, he was called in as an advisor to NASA during the planning of the early Mars missions and, in 1974, he published a paper with Carl Sagan comparing transport on the two planets:  

 
In this paper, as apparent in the abstract, the interest is in threshold velocities of the wind – how strong a wind is necessary to move sand? This is a complex topic, but Bagnold’s work on Earth reveals the keys to understanding sand dynamics on Mars, as revealed by this recent press release – particularly when combined with research results published last year.

But first, back to Bagnold basics. During his extraordinary expeditions, he closely observed the characteristics of dune architecture and movement, and came to appreciate that there were a number of fundamental questions that, at that point, had not been answered. One of the most basic of these questions was why do dunes form at all? Why is the sand not spread evenly over the desert floor? Whether on Earth or Mars (or, indeed, Venus or Titan), dunes appear to be self-accumulating, seeming to vacuum up sand from the bare stony areas between them – they grow by attracting more sand. “Why did they absorb nourishment and continue to grow instead of allowing the sand to spread out evenly over the desert as finer dust grains do?” was one of Bagnold’s questions. This was, he thought, something that “could be explored at home in England under laboratory-controlled conditions” - and so began his rigorous science. Two of the most important revelations of Bagnold’s work are the process of saltation and the role of two different threshold velocities for the wind.

First, saltation. From the Latin verb “to jump,” this is the process whereby sand grains move in the wind by individual leaps, and, landing on a hard surface, bounce off again; if a grain lands amongst other grains on the surface of a dune, the impact kicks some of them up into the wind and the crowd of flying grains grows. It is these two contrasting behaviours – bouncing versus splashing – that explain the self-accumulating nature of dunes. Over a hard surface of rocks and pebbles, the trajectories of individual grains are high into the air, and they keep on bouncing. As soon as they hit a soft surface of a dune, they kick off more grains, but the trajectories are lower and shorter – the dune grows. Here’s Bagnold’s original illustration of this:

 
So, saltation is the key activity of windblown sand. But how does it start? Clearly, if the wind blowing over a surface of sand is strong enough, it will nudge, roll, and pick up grains until the self-sustaining process of saltation begins. The wind speed at which this starts Bagnold referred to as the “fluid threshold” – and it represents a pretty strong wind. But, once grains are saltating and being kicked up into the wind, it only needs a slower velocity to keep the process going – lower the wind speed to the point where all grain motion stops, and that is the “impact threshold,” the minimum velocity to keep sand in motion – and it’s much lower than the fluid threshold.

So, back to Mars. The three sequential images at the head of this post show clear changes in the dune as the thawing of winter carbon dioxide ice destabilises the structure. The caption is as follows:

Three images of the same location taken at different times on Mars show seasonal activity causing sand avalanches and ripple changes on a Martian dune. The High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter took these images, centered at 84 degrees north latitude and 233.2 degrees east longitude.  Dune fields at high latitudes are covered every year by a seasonal polar cap of condensed CO₂ (dry ice). 

The sequential images, which each show an area 285 meters by 140 meters, depict the before and after morphology of the dune in one Mars year, with new alcoves and extension of the debris apron on the slipface, or steeply sloping leeward surface, of the dune caused by the grainfall, and new wind ripples on the debris apron.

The top image was taken first, in the Martian summer when the dunes were free of seasonal dry ice.  The middle image was acquired in the spring when the region was covered by a layer of seasonal ice.   Spring evaporation of the seasonal layer of ice is manifested as dark streaks of fine particles carried to the top of the ice layer by escaping gas.  Gas flow under the ice as the ice sublimates – changes from solid to gas – from the bottom destabilizes the sand on the dune, and causes the sand to avalanche down the dune slipface.

 The third image shows the resulting changes revealed the following summer after the frozen layer of ice was gone.  Comparison of the middle and lower images shows the correlation of seasonal activity with locations of change of dune morphology. 

The emphasis here is on the avalanches down the side of the dune. But these are – hardly surprising – gravitational effects, even under the relatively low gravity of Mars; what is perhaps more surprising is the brief mention of “new wind ripples on the debris apron.” Conventional wisdom and standard Martian climate models had held that wind speeds on Mars were rarely adequate to cause sand movement; measurements from landers confirmed relatively modest winds – and yet sand grains have accumulated on the deck of Spirit, the stuck rover, and now we see dynamic ripples.  

Enter, firmly in the footsteps of Ralph Bagnold, Jasper Kok, an atmospheric physicist at the National Center for Atmospheric Research in Boulder, Colorado (previously at the University of Michigan). Last year, he published the results of his work on sand transport on Mars and the key roles of different threshold velocities. He pointed out that the focus of Martian modelling had been on the fluid threshold, the velocity required to start saltation, but that little attention had been paid to the impact threshold, above which any saltation already happening would be sustained. His work demonstrated that “"While it is very difficult for the wind to lift sand grains, once the wind does become strong enough to start blowing sand on Mars, the sand will keep bouncing, even when the wind speed drops by up to a factor of 10." Because of the thin atmosphere (and coupled with the low gravity), while Martian sand grains need hurricane-strength wind speeds of 150 km/h to start moving, they will keep bouncing over the surface at wind speeds of just 15 km/hour. The conspiracy of the difference in parameters between Earth and Mars means that the fluid thresholds are little different – but the impact threshold is far lower of the red planet: windblown sand processes are alive and well – and, now, observable. Take into account different grain sizes and differing saltation trajectories, and Kok’s work (see references at the end of this post) also begins to explain the smaller dunes apparently typical of Mars, and the complex relationships between sand and dust movement, not to mention dust devils.

So, once again, conventional wisdom is out the window, but the wisdom of Ralph Bagnold endures; in Kok’s papers, the bibliography includes citations of Bagnold’s work from seventy years ago – how often do you see that?

 

[Read Jasper Kok’s papers here and here, and reports of his work at Physics World and Wired Science; for summaries of the recent HiRise sequential imaging, see, for example, Mars Daily and Wired. Images and more at http://hirise.lpl.arizona.edu/]

Sunday sand: Bagnold's grains

Classic sand grains of the desert dunes: fine-grained, some rounded, some quite angular, but all smoothed and frosted by, of course, the process of sand-blasting; and all with that veneer of iron mineral colouring. These are typical of virtually all desert dunes, but they come from, what is for me at least, a special place.

A couple of years ago, I wrote a piece about Ralph (pronounced, as is common in the UK, “Rafe”) Bagnold, and called it “The man who figured out how deserts work.” An explorer, soldier and scientist, he was an extraordinary individual, in the late 1920s and early 1930s pioneering long-range motorised desert travel, before laying the foundations of today’s understanding of desert sands, helping turn the tide of the war in North Africa, and then turning his attention to sand transport by water.

Having established the quantitative basis of wind-blown sand transport in the laboratory, in 1938 Bagnold set off on an expedition to revisit one of his old haunts in the Libyan Desert of southwest Egypt and test his lab results in the field. His base camp was set up beneath the cliffs of the vast plateau of the Gilf Kebir, the border of Libya just to the west and that of Sudan not far to the south. He chose an ideal field lab, camping along the flanks of a huge lee, or falling, dune, where the sand blows southward from the Great Sand Sea, and spills over the edge of a row of cliffs to form a long and elongate dune:

 
I was lucky enough, on what can honestly be described as a trip of a lifetime, to join an expedition in the footsteps of Bagnold’s 1938 venture and we visited the site of his base camp. In the top picture you can see the dune streaming off to the south, where, at its tip, it breaks up into smaller dunes (see the Google Earth image above, right). My colleagues are clustered around what are clearly the remains of a shelter that Bagnold’s team built (bottom, left), somewhat the worse for wear some seventy years on, but still not covered in sand – the dune largely passes them by. And the Shell kerosene cans used by the expedition are still lying around. Was this one opened by Ralph Bagnold? It’s from here, a special place, that the grains at the head of this post come. The sand grains that Bagnold slept on and worked with are likely long blown off on their travels to the south, but even so….

Some of Bagnold’s most important field measurements at the Gilf Kebir were wind velocities and the associated sand movement under different conditions. Here are a couple of photos of him at work there (courtesy of Stephen Bagnold), the one at left taken in a slight sandstorm:

 And here, in his own words from his autobiography, he describes such work:

My work necessitated waiting for a sand storm to blow up.….A heavy one blew up within a few days. I was well prepared for it except, alas, I had lost my sand goggles. I spent some very uncomfortable hours sitting in the open, directly exposed to a violent sand blast, trying to keep my eyes open while taking readings from an array of gauges and sand traps. The purpose of eyelashes was very evident. Fortunately, I managed to get some reliable measurements which nicely confirmed my wind-tunnel measurements made in London.

This was Bagnold’s last desert expedition – he had other things to keep him busy - but he wrote of being at home in England:

And then comes some trivial sense-impression—the hot-varnish smell of a car standing in the sun, a cloudless sunset, the finding of sand grains in the pocket of an old coat. Out comes the map again; and the eye hovers over some blank space still father away which nobody has yet reached. Happy calculations follow about petrol and distances—dreams of just one more desert trip.

I know what he meant – after all, where else can you wake up in the morning to a view like this?

It's a sandpile world

 
One of the – many – entertaining research themes for my book was the role that sand plays in the imagery of our imaginations. Large numbers, very small things, ephemerality and change, time and eternity – and unpredictability. The icon of this blog, the sandglass, is an immediately accessible laboratory for thinking about many of these things – I always take along one from my collection when I’m giving a talk, a deceptively simple illustration of complex things. The most interesting part of a sandglass is, of course, the lower chamber, the growing pile of sand, the tumbling of a single grain, the sudden avalanches. Sandpiles provided, both literally and figuratively, the basis for the extraordinary book by the physicist, Per Bak, How Nature Works: The Science of Self-Organized Criticality; in an earlier post, I wrote a little about this book and the idea that our brains operate in the realm of self-organized criticality, cascades of neuronal activity behaving like avalanches down a pile of sand. And so, when I saw an article from the Seed Magazine website titled “On adapting to sandpiles,” I was naturally intrigued.

The article is, I discovered, an interview with Joshua Cooper Ramo, discussing the thesis of his book, The Age of the Unthinkable: Why the New World Disorder Constantly Surprises Us And What We Can Do About It (2009). Ramo is a widely respected “strategic thinker” about the state of the world; he was Foreign Editor at Time Magazine before taking up his current role as Managing Director of Kissinger Associates, one of those global business/politics/strategy advisory organisations, founded by the eponymous Henry, whose day-to-day activities and clients are distinctly inscrutable (the only website I could find for “Kissinger Associates” is for a software company in Pennsylvania, owned by Darrell K.). The cast of characters at the New York consulting Kissinger Associates is lengthy and illustrious and their activities the subject of some discussion, but that’s not my point here. As the editorial review on Amazon states, Ramo’s book (which I will readily admit I haven’t read) addresses the idea that:

The traditional physics of power has been replaced by something radically different. In The Age of the Unthinkable, Joshua Cooper Ramo puts forth a revelatory new model for understanding our dangerously unpredictable world. Drawing upon history, economics, complexity theory, psychology, immunology, and the science of networks, he describes a new landscape of inherent unpredictability--and remarkable, wonderful possibility.

The introduction to the Seed interview runs as follows:

Joshua Cooper Ramo, managing director of Kissinger Associates, believes that we live in a “revolutionary age” defined by problems whose complexity, unpredictability, and interconnectedness increasingly defy our efforts at control. Global threats such as terrorism, pandemics, financial meltdown, and climate change, according to Ramo, demand a systems perspective that draws upon chaos science, complexity theory, and the theory of disruptive innovation. In his 2009 book, The Age of the Unthinkable, he calls for nothing less than a “complete reinvention of our ideas of security,” even the reversal of a “couple of millennia of Western intellectual habits.”

My immediate reaction to this is “fine, but ever since the popularisation of the strict science of chaos theory, far too much has been made of its potential applicability to almost everything, particularly by endless business gurus.” The imagery is seductive, but fidelity to the science is questionable at best.

But then imagery is an immensely potent stimulator of thinking and a powerful means of generating alternative ways of doing it. And, naturally, I’m all for sand imagery, so where is Ramo going with this? Here’s the relevant section from the interview:

You’ve often invoked a pile of sand as a metaphor for today’s complex world. What do you mean by that?
Think of a pile of sand, with additional grains being added every second or so. Scientists say such a pile is “organized into criticality,” since at any moment it can have a little avalanche as the sides get steeper. But the system is so complex that it can’t be modeled completely and—this is important—it’s nonlinear in that it can suffer a change in state under both big blows and tiny hits, like the addition of a single new grain of sand. That’s our world: Every second it gets more complex, like a sandpile. New financial instruments, terror groups, viruses, and innovations are ceaselessly falling onto our pile, making it really complex to model and basically impossible to predict. Small things—home mortgages—can have huge impacts. Usually by surprise. One thing I learned from writing the book and hanging out with people ranging from Hizb’allah terrorists to the guys who started Google is that it is possible to use this sort of cascading power to make tremendous changes. And since this kind of dynamic is inevitable, the challenge is to make positive avalanches.

Small things having huge impacts – the infamous flap of the butterfly’s wings. This imagery has always been compelling (and has always had at least some basis in the science – we do, after all, live in a world of power laws, long tails, and black swans). Watch the pile of sand in the sandglass and there is no way of predicting when the fall of one grain will precipitate a major avalanche.

And, although the book was published a couple of years ago, I can’t help but wonder if Seed’s publishing the interview now is a reflection of recent events in North Africa that were simply unimagined but a few weeks ago – a tragic, but nevertheless small, event in Tunisia triggering huge and profound change. The header for the piece reads “ In an era defined by instability, society must remain imminently flexible and turn disruption into a force for good” – an aspiration that must be applauded. 

So does Ramo have any suggestions as to how this might be accomplished? Well, here’s his response to the question “How should global leaders adapt to a sandpile world? Where do you see our major weaknesses today?”:

There are two key adaptations we need to make. The first is understanding that the very things we want and need to be modern—biotech, communications networks, more efficient financial markets—make the world more dangerous and expose us all to risk. Which means that sandpile events—things like 9/11 or the collapse of Lehman Brothers and its implications—are now inevitable. So we need to accept that we will constantly be hit by the manifestations of an unstable world and focus less on trying to prevent them and more on boosting our own resilience. Second, we need to change how we make policy. Right now we make big decisions as if we were pulling a lever. But decision making has to be a persistent project: We need to constantly update and revise our thinking as if we were making software or iPods. Today we do “health care reform” or “Afghanistan policy” and then move on. That’s lethal. Policy has to be flexible and constantly adapted to fit a changing environment.

This is, I think, serious food for thought. But this is not a geopolitical blog – it’s just interesting to see yet another example of the stimulating properties of sand.

Sunday sand: a few of my favourite grains

Since I’m on the road, a short, but I hope visually enjoyable, post today. Several years ago now, an old geologist friend and fellow sand-enthusiast sent me a wonderful set of samples to begin my collection, and his ongoing encouragement contributed to my actually completing the book. We share Indonesian experiences, and several of the samples included sands from various parts of the huge archipelago – including these, which have remained some of my favourite grains, simply for their stunning photogenicity.

They come from the shores of Sumatra’s LakeToba and their beauty belies their catastrophic origins. They are pure quartz grains, weathered out of the Toba tuffs, great thicknesses of volcanic material blown out of one of the planet’s most devastating eruptions of the last couple of million years. The effects were globally destructive and nearly caused a premature end to the human race, so they are of considerable interest to archaeologists as well as geologists. Oxford University runs one of the projects investigating the story, and introduces it as follows:

The Toba super-volcano has erupted explosively a number of times over the past 1.2 million years. By far the largest and most destructive of these occurred around 74,000 years ago, and it is this ‘Youngest Toba Tuff’ or YTT eruption that forms the focus of this research project. At least 2800 cubic kilometres of volcanic material was ejected during this super-eruption, dwarfing historical eruptions such as Krakatoa and Pinatubo.  

The YTT explosion instantly destroyed all life in its immediate area, with intensely hot flows comprised of billions of tonnes of ash and rock, accompanied by a deafening noise and powerful tsunamis. It also sent hundreds of cubic kilometers of ash and gases high into the atmosphere, even as the volcano itself collapsed inwards to form a huge sunken caldera (now Lake Toba). The gases, including sulfur, circled the globe on air currents, while the ash spread out to the north and west fanned by prevailing winds. When the ash began to fall, it covered the Indian subcontinent and rained down into oceans from the Arabian Sea in the west to the South China Sea in the east… Gradually the earth cooled as the sun’s heat was reflected by the suspended gases, affecting rainfall and climates across the globe. Around this time the earth slipped rapidly into a dramatically cold portion of the ice ages, and while this was underway before Toba’s eruption, the super-volcano undoubtedly had an important influence.

At the time of the Toba eruption 74,000 years ago, humans shared the Earth with a number of similar species, including the cold-adapted Neanderthals and the dwarf Homo floresiensis. All these species made stone tools, gathered plants and hunted animals for their livelihood, and all survived the eruption and its after-effects. Nevertheless, when palaeo-climatic records are combined with genetic data that may indicate an abrupt decline in the number of humans (a genetic ‘bottleneck’) at about the time of Toba’s super-eruption, the possibility that we were driven to the edge of extinction deserves investigation.

There’s much hype and mongering of various kinds about “super-volcanoes,” but Toba certainly qualifies for our close attention.

And just as these sand grains are benign witnesses to these events, so is the apparently tranquil Lake Toba:

I enjoy these sand grain images so much that I find myself compelled to play about with Photoshop to further explore their designs….

 

[Lake Toba photograph by Mimihatam,under the terms of the GNU Free Documentation License] 

A sanctuary in the dunes

 
The tide did now its flood-mark gain,

And girdled in the Saint’s domain:

For with the flow and ebb, its style

Varies from continent to isle;

Dry shood o'er sands, twice every day,

The pilgrims to the shrine find way;

Twice every day the waves efface

Of staves and sandelled feet the trace.

So wrote Sir Walter Scott (clearly an observant geomorphologist) in his epic poem, Marmion, published in 1808. When I say “epic” this is a slight understatement: the work runs to 200 pages in its modern paperback form. The story is one of the greatest disasters in Scottish history, the battle of Flodden Field (1513), where an English army inflicted heavy losses on the Scots, killing King James IV and most of his nobles. The Saint is Saint Cuthbert, his domain Lindisfarne, or Holy Island, off the  coast of Northumberland in northeast England, and its style “varies from continent to isle” as a result of being cut off “twice every day” from the mainland by the tides. The island is holy as a result of its monastery, founded in the 7th century AD by Saint Aidan – Saint Cuthbert was a later abbot of the monastery.  

 
Being subject to the whims of waves and tides, the island is surrounded by swirling sand banks and is itself largely made up of sand and dunes, as can be seen in the google earth image above, and this superb aerial view:

 
Lindisfarne arose as my topic this week after my attention was caught by a headline in the Guardian newspaper last Thursday that read “Dunes, drains, and ditches: Britain’s 10 most important wildlife sites revealed.” Natural England, the country’s major conservation body, had published its list of the most important refuges for our rarest species, all of them designated Sites of Special Scientific Interest (SSSIs). I was, of course, delighted to find that sand hosts one of them – the dunes of Lindisfarne. The species in question is a helleborine, the common name for a number of orchids; but the dunes of Lindisfarne host not just any old helleborine, but Epipactis sancta. As the description by Natural England notes:

Lindisfarne helleborine – Epipactis sancta

Originally thought to be dune helleborine until genetic testing revealed it was sufficiently different to be ranked separately. Only found on Holy Island, where its 300 plants make it a rarer species in the world than the panda, this endemic orchid can grow to 2ft tall and has up to 30 flowers.

Only 300 plants and rarer than the panda…. I believe that the photo at the head of this post is of Epipactis sancta, and not the common or garden Epipactis paustris, or Epipactis dunensis – it comes from The Wildflower Society, and they should know – but I must admit that they all look rather similar to me. The Society describes the helliborines of Lindisfarne as follows (the delightfully named snook is the sandy area where the causeway from the mainland meets the island):

The dune slacks of the Snook held hundreds of Epipactis palustris (Marsh Helleborine) which is actually a fairly common Helleborine in this sort of habitat but arguably the most beautiful of all. The flowers of this Helleborine will often open so you can see the structures and colours inside…

The local rarity, another somewhat duller looking Helleborine, was for many decades known to us all as Epipactis dunensis. The taxonomists revisited the Helleborine scene some years ago and relegated it to a mere variety of narrow lipped orchid: Epipactis leptochile var dunensis. This is how it is currently named in many botanical books.

There was much rubbing out and muttering amongst WFS list compilers in those dark days because adding varieties ("varz") is the special province of only elite Parnassian cohorts who claim to have seen more than 2,000 species…

In 2002 genetic work by Squirrell et al. confirmed that Epipactis dunenis at Lindisfarne was indeed sufficiently different from other similar looking Helleborines to be given species rank and therefore a name of its own. This new name seems to be accepted by practising field botanists although it doesn't yet appear on the BSBI lists as Epipactis sancta.

It was duly sanctified as the Lindisfarne Helleborine (Epipactis sancta) although it is not known whether there was an appropriate holy watering ceremony directed by the Archbishop of York. It has the additional special status of being English Endemic species.

Having noted all that about distinct genetic differences, if you were to present Epipactis dunensis alongside Epipactis sancta in a herbarium my guess is that only a few of our enthusiasts would be able to tell which was which.

A few years later, as so often happens with taxonomists, the Dune Helleborine gained promotion back to the Premier League with its old name Epipactis dunensis. All those people who had seen it and then rubbed it off their lists now added it back not knowing whether laugh, cry or wait for the next change.

So, regardless of the hand-wringing and angst of argumentative botanists, the fact remains that the sands of Lindisfarne are a refuge for one of Britain’s rarest species – a matter of some satisfaction to your humble correspondent.

And I should avoid wandering off on a totally unrelated thread, but it’s worth noting that the monastery on the island is also famous for being the origin of the Lindisfarne Gospels, some of the most exquisite examples of illuminated manuscripts from the Christian tradition. They now reside in the British Library, having been saved from the savage raids of the dastardly Vikings:

  

 [Header image of Lindisfarne dunes by Nigel Chadwick, is licensed for reuse under the Creative Commons Attribution-ShareAlike 2.0 license. Aerial view of the island from http://www.ness-st.co.uk/holyisland.html and Northumberland Coast AONB]