Through The Sandglass

On the road in California 2 - canyons

Late in the evening in Berkeley, after four great days of wandering up California. Many stories to tell that require greater focus than I have right now, but will be the subjects of later posts. For now, Monterey, where we stayed last night, returning after more than twenty years. Cannery Row, its romantic and literary connotations now totally submerged in truly dreadful tourist claptrap (with the exception, of course, of the aquarium and one place that I'll be writing about later), still offers the opportunity to turn your gaze away from commerce gone mad and look out across the great sweep of Monterey Bay accompanied by the background songs of the sea lions.

We stayed on Cannery Row for the view, spectacularly available from the Spindrift Inn (no, this is not a commercial, but I would recommend it); the view above is from our room. And as you gaze out over Monterey Bay, either from there or from the stunning dune systems further up the coast (below), it's worth remembering that, hidden below the waters of the bay is one of the continent's great topographic features - the Monterey Canyon. A couple of weeks ago, I wrote about sediment budgets and littoral cells; for every segment of coast, along which a "river of sand" is moving, there is an end of the road for that sand where it is removed from the budget, essentially permanently taken out of the system, and the most common fate is that it is flushed down a submarine canyon and out into the deep ocean.

The Monterey Canyon is massive, its mile deep relief being comparable to that of the Grand Canyon, but two miles below the surface of the ocean; and it extends 95 miles out into the Pacific, ending in an apron of the sand and mud deposited after they have hurtled down its length. It has been estimated that a dump truck load of sand is flushed down the Monterey Canyon every 17 minutes. The dramatic scale and extent of the canyon and its subsidiaries are superbly imaged by Google Earth, below.

So the view westward from Cannery Row is enhanced by the thought of this hidden drama. But then again, processes on the beach on a scale orders of magnitude smaller can display their own, equally compelling and immediately accessible, canyon dramas.

On the road in California 1 - Kelso

Wow, what a day! Drove from Barstow to the Kelso Dunes and took a ramble for a couple of hours. The picture below proves I was there, but making it very far into this vast massif of dunes was, I must admit, beyond us (knees, general old age, limited water supply, and rapidly rising temperatures - both climatically and metabolistically). There is no word for the place other than spectacular.

 

The Kelso dunes are among those around the world that sing, boom, and hum, the mysterious granular orchestra which is much-studied but not really understood (conflicting views on this remakable phenomenon will probably be the subject of a future post). Our great triumph was to clamber well up the first great rampart of sand to fresh and essentially unvegetated dunes, find a slip face down which small avalanches were flowing, and hurtle down it - great booming noises arose from the sand! This was only the second time I'd heard this, and a first for my wife. I would describe the sounds as like those of a tuba (perhaps since I used to play one) or a bass bassoon, absolutely bizarre and wonderful.

For anyone visiting the dunes, a short drive afterwards to the old Kelso railroad depot, once a major stop on the Union Pacific Railroad, is a must. With a fascinating history, the place has been lovingly and inspiringly restored - and, in addition to the superb exhibits (including a recording of dunes spontaneously booming) there is a great soda counter which serves the most refreshing iced tea in the world. And don't miss the shop. Stocked with an extraordinary selection of books on the natural history of the region, it's run by Julia Cronk, the Area Manager for the Mohave National Preserve and a retired grader driver (folk to whom we owe a great deal - see my "Rippled Roads" post). Julia describes how she never had a chance to fully enjoy her lifelong love of books until she set up the shop - and her dedication really shows.

And, to end the way our walk in the dunes ended - we startled a jackrabbit which, after briefly freezing, took off across the sand. My desperate attempt to track it with my camera turned out to be successful.

Philadelphia sandy news, and a couple of commercials

I’m reporting from the Philadelphia suburbs at the moment and therefore enjoying all the news that’s fit to print in the Philadelphia Inquirer each morning. On a couple of days last week, arenaceous topics hit the front page (at least a diversion from the continuing reports of the imaginative uses of expenses by UK Members of Parliament). First, as I’m sure all readers must be aware, the Phillies are the current baseball World Champions and this is an understandable excuse for all kinds of ongoing celebrations; amongst these is the construction of a massive sand sculpture tribute in Franklin Square which, I’m sure, Ben would have admired.

 

And the beaches of the Jersey shore are gearing up for the Memorial Day weekend holiday, a kind of rehearsal for the summer season. Preparations include sand "grooming" (an activity that I somehow neglected to include in the book) and the completion of the removal of nearly 2000 military munitions that showed up on the shore after recent rounds of beach nourishment (as the article states, the Army Corps of Engineers “swears it has carted off the last of them” – hope they’re right, since just one missed might disrupt the holiday weekend). There’s a lesson there about beach nourishment and sand budgets (see my 13 May post), and the unpredictable consequences of removing huge volumes of sand from where they are supposed to be.

 

I’m now heading out to California since the Long Beach Aquarium have kindly invited me to give a talk next week (announcement here) and we’ll be making a bit of a California holiday out of it. Plans include the Kelso and Oceano Dunes and some classic tafoni, as well as continuing research into the relationships between geology and wine. I hope to be able to blog from the road, so bear with me. Meanwhile, if you are at a complete loss for something to do, I recently did an interview for the New England Public Radio station, WICN, which can be listened to at http://wicn.org/audio/inquiry-michael-welland, and then there’s always the Goodschist podClast from a London pub a couple of weeks ago in which several of us conducted a rambling discussion of the K-T extinction which somehow or another rambled its way into creationism. And, for those readers in the UK and Europe, the Oxford University Press edition of the book is due out the beginning of August, but can be pre-ordered from Amazon.co.uk at a 50% discount! It has a different title – there’s a story behind that which I might reveal at a future date…….

Stuck in the sand - a long way from anywhere

 

The image above is a geologist’s bad dream, the vehicle’s wheel churning uselessly in the sand. But this is also NASA’s bad dream, for the vehicle is Spirit, one of the tenacious and hard-working Mars Rovers that have been trundling around the red planet for five years more than they were expected to. Spirit had suffered a front wheel failure some time ago, so has been driving backwards ever since, dragging the non-rotating wheel behind it. But now Spirit is stuck in the sand – and look at how stuck that wheel is and how powdery the sand is. "Spirit is in a very difficult situation," JPL's John Callas, project manager for Spirit and its twin rover, Opportunity, said. "We are proceeding methodically and cautiously. It may be weeks before we try moving Spirit again. Meanwhile, we are using Spirit's scientific instruments to learn more about the physical properties of the soil that is giving us trouble." The project team are building a sand-filled replica model to experiment with possible solutions, but looking at that image, you can just feel the predicament. And then there is a concern that the rover has dug itself in so far that the chassis is high-centred - stuck on an underlying rock (I sympathise – been there, done that – but not on Mars).

For the early Mars landing missions, NASA sought the expertise of Ralph Bagnold (see my post on The Man who Figured Out how Deserts Work) and it was Bagnold who pioneered desert motor vehicle travel. Among his many contributions were, of necessity, ways of extricating oneself from soft sand. He started out using rope ladders (see illustration at left, below) to help his Model T and Model A Fords continue on their way, but he then hit on the idea of using lengths of metal roofing material (below, right) that evolved into the lightweight aluminium sand tracks that we use today.

 

I was personally grateful for this innovation on any number of occasions during our retracing of Bagnold’s 1938 Western Desert Expedition a couple of years ago. However good the driver, and however fast you drive over firm sand (with dramatically deflated tyres), there comes a point when the fickle and unpredictable behaviour of granular materials will do you in. A couple of examples below, the modern versions of Bagnold’s sand tracks being put to use on the left. An aside on the photo on the right: we were fortunate to have several women on the trip, two of whom were named Jane. The substantial lady in the foreground is one, and our Egyptian crew decided to distinguish between the two by naming one “Jane” and the other “Double Jane.” Double Jane, thank heavens, thought this was hysterically funny.

And all of this reminds me of a movie I recently watched on DVD – Japanese Story. This is ultimately a tragic tale, but I was for a while entertained by a female geologist (Toni Collette) in a leading role (a rare event, male or female). This is the movie in which, on being required to  act as chauffeur for a visiting Japanese investor in the Australian mining operation she works for, she delivers with fervour the classic line “I’m a bloody geologist, not a geisha!”  I soon began to realise, however, that the makers of the movie had not bothered to talk to a real geologist to figure out how this character might behave (she took no notice whatsoever of fantastic outcrops she was driving past, for example). But the ultimate absurdity was when she got her truck stuck in the sand. She revved the engine and tried to drive forward, all the time embedding the rear wheels up to the axles. Now I have a habit (which, yes, I am completely aware is pointless) of shouting at the TV, and I found myself hurling advice. But to no avail. She subsequently burnt out her winch trying to use a sand anchor. Now I appreciate that this scene was necessary for the dramatic progression of the story line, and the these two people had to spend time together marooned in the desert. But did it have to be at the cost of making geologists look incompetent?

Spirit could use help from Ralph Bagnold more than Toni Collette.

[Spirit image courtesy of  NASA/JPL-Caltech; see New Scientist article here; Ralph Bagnold photos by kind permission of Stephen Bagnold]

The Story of Sand - in cigarette cards

Back in the old days when smoking was not only not politically incorrect but positively romantic and character-enhancing (think Bogart, think Bergman, think Bacall – and those are only the “Bs”), cigarette manufacturers came up with all kinds of interesting marketing ideas. In the second half of the nineteenth century, American purveyors of tobacco came up with the idea of using the card that provided stiffening to the paper pack to carry advertising. Then, in 1894, Ogden’s, a British company operating out of Liverpool, came up with the idea of putting interesting pictures on the cards; this evolved into producing themed sets of cards with an illustration on one side and information on the other – the first complete set came out in 1904. This generated, as baseball cards would also, a following of collectors (who presumably became increasingly heavy smokers as the compulsion to complete a set grew). Sporting heroes, historical themes, and the natural world were the main subjects of different series, but there were also some unique topics – in 1938 one company produced a set titled “Air Raid Precautions.” They were all entertaining and often educational.

All of these have today become collectors’ items (I’ve seen the habit described as “cartophily” – as in “I confess that I’m a cartophiliac”). But what does this have to do with my particular topic? Well, in 1934, Ogden’s produced a series of cards titled “The Story of Sand,” a set of fifty different topics. A complete set in decent condition goes for around $90 – and, of course, I have one. The theme and the diversity of topics covered essentially anticipated my book by seventy years – or perhaps my book is simply a reprise and an update. Essentially all of the topics covered in the set of cards have found their way into my book somewhere, but this is, as much as anything, simply a reflection of the diversity of roles that sand, the unsung hero, plays. Of course, one of my favourites is the hourglass card – a reminder of the short duration hourglass that Queen Victoria had installed next to the pulpit at Windsor Castle.

 

And also among my favourites is “The Sand Diviner”

 

and below a selection of some of the rest of the series. Out of the fifty, I have several more favourites – these may well form the subject of a later post.

 

Beach Nourishment and Sediment Budgets

I’m in the US at the moment (outside Philadelphia to be more precise), visiting family and preparing to give a talk in a couple of weeks time at the aquarium in Long Beach. Readers of this blog can probably guess the general topic, but I wanted to give the talk a Californian flavour (or flavor), as well as putting more of an emphasis than usual on things marine. The California coast is a varied and dramatically dynamic one, and is much-studied. In looking into data on sediment movements for the region, I came across several extraordinary resources on the web. First of all, of course, the USGS: Open-File Report 2006-1219 documents historic shoreline change and  sediment movements along the California coast. Then there are a number of reports from the Institute of Marine Sciences at the University of California, Santa Cruz, together with the California Coastal Sediment Workgroup and the state Department of Boating and Waterways, for example Littoral Cells, Sand Budgets, and Beaches: Understanding California’s Shoreline and the California Coastal Sediment Master Plan Status Report. These, and the associated publications, are incredible goldmines of information, massive amounts of data distilled, explained, and discussed that evaluate the ledgers of sediment movement along the Californian Coast. They define an measure sediment budgets, the incomings and outgoings for segments of the coast.  

As with any budget, there are inputs and outlays: sand is added and removed. If there is a surplus, sand is deposited; if there is a deficit, erosion and land loss prevail. Understanding the sediment budget for a given location on the coast is key to defining both natural processes and the consequences of human interference, the budget measuring input of sediment versus removal, directions of transport, and volumes and variations with time of year. Here are some headline numbers for the average annual sand contribution to the California Coast (the standard measurement is in cubic yards: 100,000 cubic yards of sand would build a mile of beach 100 feet wide and five feet deep, or fill 5,000 large dump trucks):

• rivers – 5,695,000 cubic yards per year (72%)
• cliff erosion – 335,000 cubic yards per year (4%)
• reworked out of coastal sand dunes – 528,000 cubic yards per year (7%)

But you have noticed that these numbers don’t add up to 100% – where does the rest of the sand, 17%, come from? Well, us – through what is euphemistically called “beach nourishment.” To maintain or enhance our beaches in the way that we like them, or to make up for the removal of sand that our interfering in natural budgets has caused, we find, every year and at some expense, 1,338,000 cubic yards of sand somewhere else and scatter it along the coast. Well, “scatter” is hardly the right term - “industrially pump” might be more appropriate (see the picture at the head of this post). This is not, of course, just a Californian habit, but an important activity on the other side of the country too.  Sand in gigantic quantities is dredged or pumped via monster hoses from offshore and sprayed onto the eroded beaches, at a cost of up to $10 million per mile. On the east coast barrier island chain, from the southern end of Long Island to southern Florida, the equivalent of 23 million dump trucks of sand has been spread over 195 beaches on more than seven hundred separate occasions. Virginia Beach has been “re-nourished” more than fifty times. A fundamental problem is not simply that this is treating the symptoms rather than effecting a cure, but that the wrong kind of medicine is often used. Beach sand is, after all, the specific local product of local processes, and replacing it with sediment dredged from offshore is replacing it with something else entirely—finer-grained sand, differently sorted sand, or mud. A typical “nourished” beach erodes much faster than a natural one. There are examples where the best sand has correctly been identified as that in tidal inlets—after all, it’s sand that derives from longshore drift along the beach. But remove that sand, and the only thing that is created is another problem—the next beach downstream from the inlet has a reduced supply: the budget is broken.

Any coast can be divided into natural segments within which the sediment budget is essentially self-contained, sediment transport in (sources) and out (sinks) are roughly in balance on average, and the component movements can be measured. These segments are littoral cells. The fundamental processes and numbers for any cell are naturally highly complex, and we can only begin to scratch the surface, so to speak, of quantifying sediment movements. But the kind of work described in the publications mentioned above is, even with all the associated uncertainty and unknowns, critical for understanding how our coasts work. And how we interfere with how they work. Dams impound sediment, sand and gravel are extracted from the system (some for beach nourishment), rivers are controlled, and urbanization stops sediment movement: we impact the budgets in a major (and rarely helpful) way.

This has been merely a surface scratching of the fascinating subject of sediment budgets and littoral cells, and I will no doubt return to these topics. But for now I’ll conclude with a graphic that I put together for the talk in Long Beach. I used data from the publications I mentioned to look at the San Pedro Cell, within which Long Beach is situated. If that particular stretch of coast were in its natural state, rivers would contribute essentially 100% of the incoming sand. As it is, they contribute just 41% – the rest is beach nourishment.

Dune quiz

What's wrong with the sign above? In the recent issue of Geology Today, Tony Waltham of Nottingham Trent University wrote about this roadside sign he had encountered in Oman, warning of dune encroachment. However, there's a slight error - clues in the inset photograph of barchans on the march across vehicle tracks and my own picture from Egypt's Western Desert below.

Dr Who and the Sands of Time

For those non-UK readers who are saying to themselves, "Dr Who?" and suspecting that this might be a version of the "who's on first?" routine, I'm referring to a British science fiction TV series. A distinctly cult series, if ever there was one. The first episodes were back in the early 1960s and it was revived,very successfully, a few years ago after a hiatus. The programme has a huge following, of all ages, and, of course, like all cult things, an industry surrounding it. "The Doctor" is a strange alien time-traveller, immensely old, but always looking like whatever actor is starring in any given series; there have been eleven Doctors over the years, every one of them the ingenious solver of bizarre problems, always able to, in the end, avert imminent catastrophe. As one actor moves on, he mutates, regenerates, into the new one. The Doctor travels about - through space and time - in the Tardis, which looks for all the world like an old UK police callbox (right), but open the door and inside it's huge, filled with all kinds of weird and wonderful  time-travelling propulsion and calculating contraptions.

These days, the programmes go out not on a regular schedule but as periodic, and eagerly awaited, specials. Last month, for Easter, we were treated to Dr Who and the Sands of Time (I know I'm a bit late describing this but I have been otherwise occupied with kitchen physics and proof-reading). It was filmed in February in Dubai - as the producer commented, "We always looked at going abroad. A beach in Wales, especially in February, would have just looked like, well, a beach in Wales." The typically strange story required the presence of a red double-decker London bus in the middle of the desert, so the BBC shipped one out to Dubai. Unfortunately, on arrival, a cargo container was dropped on it so the script had to be rewritten to incorporate its revised appearance. Then shooting was disrupted for some time by a major sandstorm - and in the story, blowing sand penetrates the engine of the bus, causing agonising delay and tension as the voracious aliens (not the poor guy in the picture, who was also stranded but was, sadly, consumed) approach.

 

The show is highly creative and extremely well-written and the latest incarnation of The Doctor, David Tennant, has been superb (at the same time playing a highly-acclaimed Hamlet for the Royal Shakespeare Company). In every series, Dr Who has always been accompanied (platonically, of course, since he's an alien and this is prime-time TV) by a lissome female companion, sometimes just for one episode, sometimes for many. In the desert, this was Michelle Ryan, star of the remake of The Bionic Woman and English TV soap opera, fetchingly attired in a black cat-suit. But everyone knows that David Tennant's time is up, he is due to be regenerated by the end of the year. Everyone knows who his replacement is to be (this is news in the UK) and everyone, including, presumably, his replacement, is apprehensive - Tennant's time-travelling shoes (generally suede) are big ones to fill.

Dr Who and the Sands of Time, was good TV from every point of view, but, naturally, particularly mine given the place and the ubiquitous material. I have read that there is also a classic desert episode (I think I missed it, but then again, my memory...), in which the Tardis arrives in the Gobi Desert, just in time to meet Marco Polo on his way to visit the fabled palace of Kublai Khan. Forced to travel together, they witness "singing sands," the bizarre variety of sounds emitted periodically and spontaneously, by dunes. This is entirely accurate - in his description of his journey, Marco Polo tells of the spirits of the desert and the strange and terrifying musical and drumming sounds that they make. But undoubtedly more of that in a later thrilling Through the Sandglass episode.

[pictures from the Radio Times]   

More adventures of bacillus pasteurii - mending concrete

The efficiency with which bacillus pasteurii manufactures calcium carbonate and glues things together makes for ways in which our microbial friend can assist us beyond just preventing earthquake damage and sculpting deserts (see the previous post) and here's, literally, a concrete example. But I should point out here that the image above is quite unrealistic, simply a Sandglass photoshop special.

The recipe for basic concrete is simple and has been around for a long time. The ancient Egyptians knew how to make it (there is a lively debate as to whether the pyramids, at least in part, are made of concrete), and the Romans perfected the formula. The fundamental ingredients are around 75 percent sand and gravel, 15 percent water, and 10 percent cement. The cement, cooked from materials such as limestone and clay, is the chemical glue; the hardening of concrete is not simply due to drying, but involves complex chemical reactions. The physical characteristics of the sand, its size and shape, influence the properties of the concrete, but because of the importance of chemistry, the composition of the sand and the other ingredients is critical. The wrong impurities will ruin the quality of the concrete.

The global demand for concrete is massive: after water, concrete is the most consumed material on Earth. Every year, the equivalent of more than 400 million dump trucks of concrete is transported to construction sites. Every man, woman, and child on the planet “consumes” around forty times their own weight in concrete per year. Which is, of course, an average—for residents of the Western world, it’s much more, despite the fact that around half the world’s concrete production and consumption today is accounted for by China.

But concrete is vulnerable to deterioration, corrosion, and cracks, and the consequent damage and loss of strength requires immensely expensive remediation and repair. So, is there a way in which incipient microscopic fractures in concrete can self-heal? The answer, thanks to our microbial friend, would seem to be yes, through the process referred to as biomineralisation, microbiologically induced calcite precipitation (MICP). Around the world, research groups are working and collaborating on different approaches to turning this into reality, but the principle is quite simple. The chemistry of concrete is alkaline, but fortunately, bacillus pasteurii tolerates this - it simply needs nutrition, space to work, and a little encouragement. A team led by Henk Jonkers at the Delft University of Technology in the Netherlands are well on the way to accomplishing this, through actually mixing living bacteria, along with calcium lactate, an organic compound that such bacteria convert to calcium carbonate, into the concrete to begin with. They found that, as the concrete cured, incipient cracks were effectively sealed with calcium carbonate. There remain problems of keeping the microbes alive for a long period of time, and retaining sufficient microscopic space in the concrete for them to have room to maneuver, but progress is being made (the addition of clay to the mix provides a safe haven). And, importantly, the more effective this process proves, the less concrete we will have to manufacture and the lower the associated carbon dioxide emissions from making cement.

As a recent article in The Economist concluded, "If the process can be scaled up, it may be prove that the best way to preserve concrete is to infect it."

[for details on the work of Henk Jonkers, see http://www.tudelft.nl/live/pagina.jsp?id=8691221d-ebab-4841-97cb-1cfacad3a4bc&lang=nl, a recent conference presentation, a link to the abstract of the group's most recent paper here, and The Economist at http://www.economist.com/science/displaystory.cfm?story_id=13570058. For work at the South Dakota School of Mines and Technology, see http://adsabs.harvard.edu/abs/2001SPIE.4234..168R, at the S. V. National Institute of Technology in India, http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1285418, and for non-bacterial approaches, http://www.eurekalert.org/pub_releases/2009-04/uom-scf042209.php.]