Through The Sandglass

Guest post: a gallery of sand photographers' styles

 
Kurt Meyer writes:

SHOOTING SAND

For the last 15 years, on and off, I have been collecting sand. The “off” times resulted from not having an answer to the question, ‘what do I do with all of this sand?’ I have tried various methods of displaying my sands as you can see below. Two-ounce bottles with overhead lighting being the best. 

But the only people who could regularly view the display were my wife, the neighbors, some family and my dog, Zena, and she could care less. In fact, anything that draws attention away from her is not well tolerated.

Things got interesting again, however, when I decided to try my hand at getting pictures of my sands. At first, I tried a digital microscope and although it turned out to be an interesting exercise, the quality just wasn’t there. The edges, for example, are usually blurry, the definition is often lacking and the color is rarely true. These problems would even be too much for a Photoshop package. You can, however, get a good idea of what is lurking in your sand sample at 20x, as in this image of sand from Fintragh beach, but it is not suitable for framing.

Today I still use the digital microscope but only for screening sand samples. It is pretty good at predicting which sands will be “photogenic.”

My first foray into serious sand macrophotography began with my purchase of a used Nikon D70. The following picture was taken with that camera body and a 60mm 1:1 lens. Even though the sensor is only a 6.1MP it still provides a pretty good image. This photo is of one of the famous green sand beaches in Hawaii, Pocket Beach to be exact. The olivine, lava and coral make a striking image [at the head of this post - MW]. 

At any rate, this new photographic endeavor answered the big question, ‘what do I do with all of this sand?’ Answer, SHOOT IT.

There are a number of photographers who do outstanding sand photography. I would like to showcase several of them. This is, by no means, an exhaustive list. This only reflects the photographers that have posted images on my website, Tropics of Sand. I will attempt to compare and contrast their styles. As you will see, the top photographers all have their own style. Over and above the camera equipment used, the thing that defines a photographer is their approach to getting the shot. All of the images that you will see below are unique to the photographer. I can tell a Heider photo from a Couette and a Sepp from a Kenney in the blink of an eye. I am sure that you will, too.

SAND PHOTOGRAPHERS

(click images to enlarge)

Leo Kenney: Large field, great clarity

Leo is a veteran of creating outstanding sand calendars and posters. He has a prodigious collection thanks to the fact that he has a legion of former students who dutifully send sands to him from their travels (cheater). Leo tends to zoom out a bit which produces a larger field than most. He uses a Canon 1-5x lens that allows him to get that clarity. Leo’s Picasa Web albums are here.

 
Clockwise from top left: Miller’s Point, Cape Town, South Africa; Monticello, Corsica; Jeffrey’s Bay, South Africa; Rye, New Hampshire. Center: Cap Lardier, France.

Siim Sepp: Great definition of full field shots and individual grains.

Siim also uses the Canon 1-5x lens although Siim does more close up work. He uses a full field for some of his photos but he also shows exploded views of individual grains of sand elements. Siim has a “how-to” on the mechanics of getting a sand photo on his website, Sand Atlas. On that site, he also provides geological information on sand composition that is very informative.

 
Clockwise from top left: Diamond Head, Hawaii; Sapphire crystals, Songe, Southern Tanzania; Zakynthos, Greece; Waddell Sea floor (-3500m), Antarctica (Globigerina forams, yellow circles);  Center: Glass Beach, Kaui, Hawaii.

 

Alexander Heider: Tight shots, great color.

Herr Heider gets excellent close ups of his sands without sacrificing detail. As you can see in this series of sands from Ireland he is able to keep detail at close range. He also agonizes over white balance which gives very exacting color to his images. His tight shots and true color make his photos stand out.

 
Clockwise from top left, an Irish selection: Ardmore, Waterford; Ventry Strand, Dingle Bay; Dooagh, Achill Island, Fanore, Galway Bay; Center: Fintragh Bay, Killybegs.

 

Alain Couette: Soft shots, great detail.

Alain will not reveal what he uses as a lighting source but whatever it is, it gives his photos a “soft” look and it is also rich in detail. Alain has numerous images on his website, Arénophile ou Psammophile? He has sand pix plus images of forams that are very interesting. Alain has a distinctive style that I would recognize anywhere.

 Clockwise from top left: Boracay Island, Angol, Philippines; Nusa Lembongan, Ceningan Island, Indonesia; Rio Grande do Norte, Fernando de Noronha Island, Brazil; Luzon island, Nasugbu, Philippines; Center: Sanur, Bali, Indonesia

 

Carla Lagendijk: Daylight shots, great variety and picture perfect color.

Carla is one of the pre-eminent sand photographers today. As you can see her shots are very rich in detail. This is not due to the lens but the fact she shoots her photos in daylight, the sun illuminating every nook and cranny which in turn provides outstanding definition. The other thing that separates Carla from the pack is her prodigious collection. She has sand from anywhere you can imagine which greatly increases the chances of having outstanding material to work with. Below are 4 shots that typify her style, and of course, no examination of Carla’s work would be complete without a sample of one of her “selections”. These are selected bits of coral, forams, shells, etc., from various sand samples. I hesitate to use more than one for the simple reason that they are too awesome. If you can look at these all day, why would you look at anything else?

 Clockwise from top left: Bahia de Samana, Dominican Republic; Myrdal, Vik, Iceland (olivine and obsidian); Al Bustan, Oman;  Brétignolles, France; Center: Enubuj Island, Kwajalein Atoll, Marshall Islands.

 

Kurt Meyer: Exploded views, contrasting backgrounds.

I now use a Nikon d1500 with the same 60mm lens. What I like to do with my photos is create an edge where heavy minerals or carbonate elements can be isolated from the main body of sand allowing for a better view of the individual grains. This has been dubbed the “black corner” technique. The 5100 has a 16.2 MP sensor that will enable you to enlarge photos without losing definition. Also, I use black or other colored glass as a background to provide contrast.

 
Clockwise from top left: Cape Point, South Africa; Dondra Beach, India; Mardakyan, Azerbaijan; Grand Ile, France; Center: Point Reef, Vanua Levu, Fiji.

 

You can see more photos by all of the above photographers on tropicsofsand.com. I would love to add more images this weekend but Zena has other ideas.

 

[All images reproduced with the photographer’s permission, composite formats by MW.

Kurt is based in Pennsylvania, and writes that while he has been photographing sand for the last three years, he has collected it for “15 odd years.” Nothing odd about that as far as I’m concerned, but perhaps those years were odd in other ways, and sand collecting represented an opportunity for normality. Interestingly, he enjoys diving for samples. Anyway, thanks Kurt for all the effort in putting this together – and thanks to all the arenophile photographers who contributed to this piece.]

Sand critter guest post: the South Texas sand crab

By Zen Faulkes

South Padre Island in Texas has a world-class beach, with lovely fine-grained sand that is wonderful to walk on. The sand grains close up seem to be mostly grains of light or transparent quartz, with just the occasional bit of shell grit. At least, that’s what it looks like to my completely untrained eye.

 
I personally am not so much interested in the sand, however, as some of the creatures living in it. I have been spending the last few years digging around in the beaches there, studying a small local sand crab, Lepidopa benedicti. Because they are so little known, the species doesn’t have a common name; the entire superfamily is generally called “sand crabs” or “mole crabs.” I got started working with sand crabs for my doctoral research because I was interested in how they are able to dig so quickly and efficiently into the sand, and why they couldn’t walk like other crustaceans (Faulkes & Paul, 1997a, b).

  

For the last couple of years, I have been studying these crabs more from an ecological viewpoint. During my regular collections, I eventually made a conscious mental note of something that is incredibly obvious when you say it out loud. Some of these crabs are white, while others are almost a battleship gray.

 
When I looked in the scientific descriptions of these species, the colour of this particular species was never mentioned, and other Lepidopa species were usually described as white. Why are they different colors? We often think of colours as being important signals for animals; think of warning colours, for instance. Sand crabs spend almost all of their time buried in sand. In ten years of digging on this beach, I have seen these sand crabs above the sand twice (weirdly, on the same day!), and even then only for a couple of seconds. The crabs have small, poorly developed eyes. It seemed unlikely that they are using these different colors to signal each other.

Although the eyes of some sand crabs are small, they sometimes take note of their surroundings. Some very nice experiments with sand crabs showed how environmental factors can affect colour. For instance, mole crabs (Hippa) are found on either white coral beaches or black volcanic beaches, and they tend to match their background. What’s even cooler is that you take an animal from a white beach, and put it into black sand, and wait, it will tend to darken up after it molts (picture from Bauchau & Passelecq-Gérìn 1987; see also Wenner 1972).

This doesn't seem to explain the color differences I'm seeing in the local sand crabs, however, because they’re all being collected from one beach, which is a light tan as far as the eye can see.

Another idea that came to mind was that this was related to whether an animal was a male or female. That also turned out not to be the case, as each colour had an even split of sexes.

But two pieces of evidence suggest that these colours are not just incidental. There are more gray sand crabs than white ones. And the gray ones tend to be larger than the white ones, although there is overlap (data from Nasir & Faulkes 2010; carapace drawing by Boyko 2002).

Something that might help sort out this puzzling little question would be to look at other populations. The animals I have collected over the last few years are nowhere near the largest on record for the species. The largest individuals in this species have been found on the Atlantic coast of Florida (Boyko 2002). The average size of sand crabs there is about the size of the biggest individuals I’ve found on South Padre Island. And it makes me wonder, if the Atlantic L. benedicti are that much bigger, are they more likely to be that dark battleship gray?

References

Bauchau AG, Passelecq-Gérìn E. 1987. Morphological color changes in anomuran decapods of the genus Hippa. Indo-Malayan Zoology 4(1): 135-144.

Boyko CB. 2002. A worldwide revision of the recent and fossil sand crabs of the Albuneidae Stimpson and Blepharipodidae, new family (Crustacea, Decapoda, Anomura, Hippoidea). Bulletin of the American Museum of Natural History 272(1): 1-396. http://dx.doi.org/10.1206/0003-0090(2002)272<0001:AWROTR>2.0.CO;2

Faulkes Z, Paul DH. 1997a. Coordination between the legs and tail during digging and swimming in sand crabs. Journal of Comparative Physiology A 180(2): 161-169. http://dx.doi.org/10.1007/s003590050037

Faulkes Z, Paul DH. 1997b. Digging in sand crabs (Decapoda, Anomura, Hippoidea): interleg coordination. The Journal of Experimental Biology 200(4): 793-805. http://jeb.biologists.org/cgi/content/abstract/200/4/793

Nasir U, Faulkes Z. 2011. Color polymorphism of sand crabs, Lepidopa benedicti (Decapoda, Albuneidae). The Journal of Crustacean Biology 32(2): 240-245. http://dx.doi.org/10.1651/10-3356.1

Wenner AM. 1972. Incremental color change in an anomuran decapod Hippa pacifica Dana. Pacific Science 26: 346-353.

 

[“Doctor Zen” first got in touch with me in the spring of last year to kindly point me to some research on bubbles behaving like granular materials. I had a look at his personal web page at the University of Texas-Pan American, and discovered his research interest in decapod crustacean behaviour, in particular the unusual crayfish, Marmorkrebs; I was particularly interested in his work on crustaceans digging in sand – the slipper lobster video on his site is strangely compelling. I asked if he would contribute a guest post and he kindly agreed. I hope that readers find this as fascinating as I do – I’m reminded of some of the intriguing evolutionary questions raised by beach mice and the bleached earless lizard. Thanks, Zen, for this – well worth waiting for!].

Guest post: psammophilic chanterelles

Dear Michael,

In the past week, I've been the fortunate recipient of six new samples for my sand collection! From Florida and Alaska, they are welcome additions to my collection. It now spans both poles and every continent save Australia. (Australia, anyone?…)

I've always enjoyed just looking at my samples and reflecting on their origins, but as I have told you, reading Sand has made the collection so much more meaningful and interesting. And as I have come to realize how ubiquitous and unappreciated sand really is, barely a day has passed that I haven't observed some satisfying psammophilic signals in my surroundings! Thank you, again, for sharing your knowledge.

According to my calendar, our first conversation roughly coincided with the emergence of a rather spectacular "bloom" of the eastern smooth chanterelle mushroom (Cantharellus lateritius) in the woods behind my home. Rivalling its more famous cousin, the yellow chant (C. ciborium, a.k.a. the pfifferling or girolle), this mushroom is beautiful and tasty. It temporarily became the focus of my spare time, and I would walk the dog or take my children into the woods for some quality mushroom gathering before the season slowly ended two weeks later.

We happen to live on a hill in Northeastern Ohio. It's a little college town, surrounded by pastures, Amish communities, and forest. Most of the land on "The Hill" was burned and clear-cut in the early 19th century for farmland, and eventually became the home of a theological seminary that evolved into a modern-day college. Somehow, a few small tracts of forest remained untouched and to this day represent some of the largest stands of virgin beech-maple forest in the state of Ohio.

In the recent geologic past, about 10K years ago, the hill was deposited by an enormous melting glacier. This glacier had scoured soil and rocks from the land below. Like a bulldozer, the ice pushed and lifted clay, sand, gravel and larger objects and dragged them southward as it advanced. In that load were millions of tons of rock from a series of earlier glaciers, themselves slowly gouging eastern Lake Erie from the shale and sandstone depression left over from the age of the dinosaurs. Eventually, the glacier melted, dumping piles of sand and rock material called "kames" and scooping out holes forming hundreds of "kettles" or small lakes which dot the area to this day. The streams running through the woods behind my house still bear sand that has only recently been freed from the sandstone boulders that form the hill. They will eventually enter the Ohio River in Pittsburgh before heading to the Gulf of Mexico to be compressed back to stone.

In between the glaciers and the clear-cutting, native Americans hunted deer, bear and turkey here. They gathered the available crop of raspberries and blackberries that are abundant. I like to think that they also enjoyed harvesting morels, oyster mushrooms, chanterelles and other fine edible mushrooms that still grow wild in the remaining forest.

The mushrooms grow here because they require unbelievably specialized habitats. Many are so specific that there is still no way to produce them commercially, and so the only way to enjoy them is to get out in the woods and harvest them personally. No one really knows, for example, what triggers each of the three (or so) species of morel to emerge -- what combination of nutrients, soils, moisture, etc. is required every spring to make them pop up, and eventually into, the mouths of their eager fans. So too, is the smooth chanterelle. We have observed it in isolated patches throughout the beech-maple forest behind my house. But mostly, it prefers oak. And mostly, it prefers paths!

As I mentioned, the forest here is dominated by beech and maple trees. However, species such as cottonwood and oak will occur if the soil conditions are right. Oak trees, and especially our local pin oak, Quercus palustris, live in habitats that are moist and comprised of clays and sands. As they grow, the roots form a network of tiny organic storage containers that the chanterelle can apparently tap without harming the tree, and perhaps even provide some unknown benefit in return. This is called a mycorrhizal relationship. So, the chanterelle, which is associated with the oak trees here, depends upon the sand and clay soil. But why paths? The best explanation I have read suggests that soil compaction plays a role. Where deer paths or human paths cross the sandy forest floor, the grains become more tightly packed near the surface where the mycelium of the fungus lives. So it bunches up at this interface between loosely packed and hard packed grains until environmental cues (temperature, moisture, and metabolic state) cause the fungus to fruit!

So, to tie this all together -- I've been enjoying the wonderful delicacy of chanterelle mushrooms collected from paths running below oak trees that are growing in sand and clay deposited by the retreat of a glacier thousands of years ago. Without that glacier, there would be no sand, no oak, no chanterelles!

I've attached a few pictures to jazz up my rambling. Thanks once again for transforming the seemingly mundane world of sand into something fascinating.

Rob Robertson

Hiram, Ohio

[I first heard from Rob about a month ago, another of those hugely pleasurable "out of the blue" e-mails that put me in touch with one of the readers of this blog. We shared thoughts and questions on Martian water and landforms, and, always seeking alternative voices, I asked Rob if he would like to write a guest post. I was delighted by his positive response and so here it is; modesty insisted that I contemplate how to deal with his complimentary comments, but it reads as it is, a personal letter, and much appreciated. So modesty was swallowed. And the discovery of the word the word "pfifferling" is to be treasured in its own right - I feel an omelette coming on.]

Modern mandalas: a guest post on the stunning art of Elvira Wersche

 
Tibetan sand mandalas, powerful images of ephemerality. Gathering, design, and dispersal, the never-ending journey of Buddhism and sand grains.

And recently, thanks to my arenophile friend, Carla Lagendijk, I have been alerted to a modern exponent of the sand mandala. Elvira Wersche’s works are faithful to both the art and the spiritual symbolism of the traditional mandala, at the same time created through dramatic modern designs. Carla was fortunate enough not only to witness one of these extraordinary performance art events, but also to meet and talk with the artist. It seemed natural that Carla should write of this herself – all that remains for me to do is to exhort you to watch the video she links to – it is compelling and hauntingly beautiful. Over to Carla:

During a few cultural weeks in June in Leiden, the Netherlands, I had the pleasure to watch a sand artist creating a sand mosaic, named “Shamseh”, on the floor of the “temple hall” in our Museum of Ancient History. Creating the mosaic should take her 3 weeks after which a special final performance with dance and music was going to follow.

 
The artist was Elvira Wersche (German/Dutch). Her website: www.elvirawersche.com

She was creating her sand project of 6x7 meters in front of an ancient Egyptian temple, a very appropriate location. The inspiration for her kind of work she got many years ago during a visit to the Friday Mosque of Isfahan in Iran were she studied the fantastic designs on the walls.

About 10 days before the final performance I visited Elvira twice while she was working on her design. About 600 bags and bottles of sand were lying around and I could see how, sitting on her knees, she was carefully filling up the triangles. The geometrical pattern looks simple but at a closer look it has a very intricate, dynamic design of circles and triangles, which had been drawn on the floor beforehand.

She showed me the several kinds of sand. Some she had collected herself, most of it had been generously given by known and unknown travellers, sometimes combined with information about the origin of the sample: historical/ archaeological sites, holy places, deserts, sand from Iraq, Afghanistan, Egypt, Israel, etc.

She sometimes examines the content through a magnifying-glass but the structure of the sand is more important for her work. It is the history of mankind behind the location of the sand that fascinates her most and fits to the underlying idea for her projects. Sand is not only a product of natural geological processes but also a silent witness of the long development of the human race. It reveals a piece of earth history but also hides a lot of secrets. This is the mystical side of it.

But….. however fascinating this all is….. what about the grains??

I saw a lot of sandstone sand with lumps in it which of course needed to be sieved. Sand of volcanic origin, dark reddish sand which looked like laterite, desert sand from Mongolia, carbonate sand, even the snowy white powdery dolomite stuff with pyrite from the Lengenbach quarry in Switzerland. She also showed me some sand which was useless for her purpose: an Asian beach sand which almost completely consisted of larger foraminifera. Of course these little critters roll to all sides. As I was very interested, she gave me half of this material.

The third time we visited the museum was for the final performance.

That evening the mosaic should be wiped out, following the idea of the Tibetans with their mandalas (nothing lasts forever). However, the way it had been done was not at all Tibetan like, but probably more impressive. It made me feel a bit sad to see Elvira’s work being destroyed, knowing it took her 3 weeks on her knees to create this stunning piece of art but I must confess, it had been done in a delicate way by 2 young good-looking girls (twins), light-footedly dancing over the pattern and mixing the sand with their long black skirts (later with their hands) accompanied by dark tones of a strange musical instrument. It fascinated all the spectators. They were dead silent. Needless to say that the dust, hovering in the hall, partly contributed to the strange atmosphere!

website museum: www.rmo.nl. YouTube video: www.youtube.com/watch?v=LfGQhT0ZFTI

At the end of the performance we all received a bit of this mixed “world sand”:

It is clear that this sand contains a combination of grains, impossible to find together in nature. At first sight it already has too many different colours. Second: the shape of the grains is far too varied: angular, rounded, etc. Looking closer you can start an imaginary world trip through volcanic fields and over beaches, pass colourful sandstone areas and find yourself  back in quarries or sandpits.The pyrite is down in the middle. And even a white foram is in the right hand corner.

 

[The illustrations above are from Elvira Wersche's website, but are not from the performance that Carla describes; they are of Taqsim - Teilung, a 2009 work at the Landesmuseum fur Natur und Mensche in Oldenburg, Germany. The video is of the Leiden work, including the recycling by the twins. World Sand photo by Carla - thanks to her again for everything.]

Sunday Sands - Guest Post

Pete Newman is a geologist and an old friend and colleague; as an arenophile, he was not only an early and enthusiastic supporter of my idea for the book, but also provided me with some treasures from his granular collection, some of which featured as the first colour plate in the book, others of which have been the heroes of various blog posts (see below). I have been badgering him for a while for a guest post, and I’m delighted to publish it here – along with original artwork.

The Granule

Hi Mike—

Congratulations on your new job and on getting back to Jakarta!  Based on my own experiences there, I feel like you’re a lucky man.  Not only in general terms, but for an Oilman and Sandman like yourself, the grease and the granules must beckon strongly.  When I heard that you’d be posted there, I dug out my Indonesian sand samples to see which would be different enough to interest you.  You’re already aware of the unique foraminiferal beach at Sanur and the beautiful glassy quartz grains of the Toba beaches---those will be hard to top---but there is just so much variety in that country that you can’t have seen it all.  Let’s see if any of the following three granule types will expand your sand catalog.

       1) I believe that I’ve previously mentioned the cute little “hopper” quartz crystal grains that I found in sand bars along the Bikis River in Kalimantan Timur.  Now I’ve just found some nice hand-drawn illustrations of these in my files, originals that were done by an Indonesian illustrator, and I’m attaching one here as illustration #1.  (You’d be amazed how little I paid for this work, way back in those immediate post-Sukarno days).  This is one of those cases where a picture is worth a thousand words, but I never got to do a geological report where I could justify using the drawings.  But just imagine a sandstone where every quartz grain was a hopper crystal, how much that would enhance the porosity beyond the theoretical maximum!  Yah, dream on. 

       2) Illustration #2 is of a sand-sized grain of uncertain identity, one from a Kaltim beach.  The characteristic crystal shape and high density (sp gr >3.3) mean that this mineral shouldn’t be that hard to identify, but I was never able to nail it down (and didn’t have too many extra-company resources to consult in Djakarta).  The drawing was done by me.

       3) Now we come to my absolute favorite sand grain, out of what must be the thousands I’ve examined.  Illustration #3 is a sand-sized glass ball, one that came from Samudra Beach in South Java.  This specimen turned up in a heavy mineral study I did to determine the source area of the Cibulakan sandstones---and thus their source direction---to learn where the thicker and coarser portions of these sands might lie.  (I was trying to figure out how to do acreage turnbacks of our undrilled areas.  And just for your geo-interest, the answer was a mixed [north and south] source: our reservoirs have a hypersthene/glassy quartz minor [southern] component plus an abundant zircon/tourmaline/anhedral quartz component that indicates the majority of the grains came from the Sunda Shield.)

        When I began sampling the south Java beaches, I found that the sea had done my heavy mineral separation for me: the swash of the waves had separated the quartz grains from the heavy components (which were overwhelmingly magnetite, occurring in beach sand layers that were pure and as much as 15” thick).  But how, you may wonder, did that help me find this grain?  Well, this grain and many other glass grains were actually of a denser-than-normal glass (> 3.0 specific gravity) which meant that they were mixed in with the magnetite.  Using a magnet, it was easy to separate out the non-magnetic “source fingerprint” minerals---no expensive heavy liquids required!  And in this residue---a tiny fraction of the total amount of beach sand---there were a number of grains of colorless to greenish glass, often in spherical form.  I separated the spherical ones from everything else by rolling them downhill---just tilted our dining room table, sprinkled the grains, caught the round ones in a sheet at the bottom.

       One (and only one that I ever saw) of those grains had a “tail” that was apparently drawn out when the glass was soft---this one is my fave and the one that’s shown in the attached sketch.  I’d like to say that I know the origin of this li’l beauty but all I can do is suggest three possible ways it could have formed:

   1) An eruption from one of Java’s volcanoes?  If found on the “Big Island” of Hawaii, this little ball would probably surprise no one as some very fine glass, including spheres, is erupted there.  But are those glass balls as dense as this one?

   2) A microtektite?  In size and shape, it bears similarities to those, and the Southeast Asia location is right.

   3) A man-made product, from construction of the Samudra Beach hotel  (which sits right behind this beach)?

And though I’ve recently read about glass micro-balls being created by D-Day explosions on Omaha Beach (EARTH magazine, June), I know of no record of ordnance exploding on the south coast of Java.

       So, not knowing anything real about these little balls, I certainly couldn’t say that they helped me in my work.  But as you know more than most, geological fun shows up in many unexpected places.  Studying geology in school, how could I have guessed that it would lead me to rolling sand grains down a table while our Indonesian cook rolled her eyes thinking “What now?”

Your sandy-haired friend, 

Pete

  
[The “hopper” quartz grains from Kalimantan were featured in a post from a couple of years ago, the Lake Toba ones as “a few of my favourite grains,” and Pete’s Bali forams in another Sunday Sand post. Plate 1 from the book - Pete’s samples in a daily pill container – is shown above together with the hopper quartz grains. Thanks, Pete, for all your help and support – and for this post!

Oh, and the sand from the D-Day beaches that Pete refers to – see also my post and article link from the anniversary.]

Guest post: A report from the microscopic front line

As always, a great pleasure for me from this blog is the people who just get in touch out of the blue. Karen Locke first posted a comment on my Sunday Sand post on Bali earlier this year. I was intrigued and followed up with her, discovering to my delight that she is a graduate student scrutinising sand grains in detail – and in earnest. I am always interested in hearing from people whose relationship with sand is professional, hence the “front line” reference in the title; here are folk who are convincing sand grains to tell their stories and for whom the translation of those stories is important. I asked Karen if she would be willing to contribute a guest post, and now here it is – I hope that my readers enjoy this as much as I did, and thanks Karen!

Sand in Thin Sections

Thanks to Michael for allowing me to guest-post. I suppose I should start with a little bit about myself: I’m an older MS grad student at San José State University in San José, California, USA. I’m just finishing up a thesis on the composition and provenance of sands extracted from wells drilled in the Santa Clara Valley, where San José is located.

The Santa Clara Valley has had a violent history. It’s surrounded by mountains that were raised (and are still being raised) by thrust and strike-slip faults. The mountains are made of a fascinating array of different types of rocks. The valley itself is filled with sediment from the mountains, and is subsiding under its own weight, as valleys do. By studying sand from various depths in the wells, I get a picture of how the sediment changed over time, and I’m finding clues to the paleoevolution of this valley over the last 800 thousand years or so. I’m asking questions like, did the streams always flow the same way? What was the composition of the rocks that ran down the middle of the valley but have eroded away, and does that tell me about how they might have moved in the past? And the big question, which I can’t answer but can provide a few more clues about is: how did the faults around the valley move to create the changes I see in the sands, and what does that imply about what they might do in the future?

But that’s a thesis; what I really want to talk about today is how I studied the sand. By studying the sand, my goal was to identify the composition of the sand grains. I wanted to know what kind of rock each one came from. Now, sand grains are tiny things. Even under a microscope, it can be deucedly hard to identify them. So I chose to make thin sections, and study the sand under a petrographic microscope.

Thin sections are created by gluing a 0.03 mm slice of rock (or in this case, a slice of sand set in epoxy) to a glass slide. In such a thin slice, most minerals are translucent or transparent. Yes, you can see through solid rock if it’s thin enough. Thin sections are made to be viewed with a petrographic (polarizing) microscope, because lots of minerals have interesting properties when viewed with polarized light – properties that can help identify them. Rocks are made of minerals, and the first step in identifying a rock is identifying its minerals.

The petrographic microscope has a polarized light source that shines through from beneath the slide, rather than illuminating it from above. Why polarized light? Many visual properties of minerals change as you rotate them over polarized light, and it’s the change with rotation that makes them significant. Color is one interesting property; many minerals rotate through two or three colors, while other minerals are steadfastly one color or colorless throughout the rotation. Another interesting property is relief (how tall a mineral crystal appears relative to the ones around it). Yes, the minerals can appear to be different heights, even though the slice is uniformly thick, and the apparent relief can change as you rotate the slide.

Playing with a petrographic microscope messes with your sense of reality. J

Other very important diagnostic properties of minerals in thin section are cleavage and growth habit. Cleavage is the way a crystal breaks internally; some minerals break at very specific angles, while others do not. Habit is how a single mineral tends to grow, or how multiple crystals of a mineral aggregate together. Long and skinny or squared off, aggregating in sheaves or long strings or just growing along side one another – there are lots of possibilities, and often they’re very diagnostic.

Then there’s another critical, and very cool, tool on a petrographic scope. Between the slide and the eyepiece, these scopes have a second, or upper, polarizer that polarizes perpendicular to the one on the light source. This polarizer slides in and out. Now, polarizers cause light waves to move in a plane. So with the upper polarizer out, you’re looking at your slide illuminated by plane light. Putting the upper polarizer in, or crossing the polars, means you’re now looking at the light that came through your slide in one plane, and attempting to look at it in a perpendicular plane. But that generally doesn’t work. Light in one plane can’t get through a polarizer perpendicular to it. Try taking two pairs of polarizing sunglasses and holding the lenses perpendicular to one another; the result will just be black. So looking at your thin section with crossed polars, what you should see is black nothing – unless the minerals themselves perturb the initial polarization. Which of course is what some of them do.

Minerals are crystalline in structure. Some have very regular, simple structures; others have elaborate arrangements. When light goes through a mineral, it can’t simply go through the atoms in the crystal, it has to run down channels between the rows and columns, if you will. Now, when the crystal structure of a mineral is simple and rectangular, it takes the light the same amount of time to run down a row as up a column, and the light comes out the other side of the crystal together. This is called an isotropic mineral, and it really does turn completely black when the polars are crossed. But when light hits a more elaborately-organized crystal structure, it can actually take more time to move through the crystal in one direction than in another. When this light comes out of the crystal, the difference in the outgoing waves produces light that’s not in the original plane, and so it gets through the upper polarizer. This effect is called birefringence, and can be extremely diagnostic.

Finally, birefringence gives me one last property I can use to identify minerals: extinction. As the slide is rotated, the birefringence effectively fades from bright to dark and then brightens again; when a birefringent mineral goes dark, it’s said to be extinct. Different minerals with similar birefringence go extinct at different angles to their growth habits, so angle of extinction is another identification tool.

So, now I have color, relief, cleavage, and habit in plane light, and birefringence and extinction in crossed polars. There are other mineral properties one can look at using the petrographic scope, but these are generally the ones I used to identify the minerals in the sand grains – at least, those mineral grains that were big enough to see. Some mineral grains were so tiny that even under a 40x power lens I couldn’t make them out. But that’s helpful in its own way, because identifying minerals is just one step on the road to my original goal: identifying rocks.

Rocks aren’t just random aggregates of minerals, they’ve got recognizable textures. It’s the combination of identifiable minerals and texture that identifies the rock. And now that I can talk about the rocks, I can show you some pictures. They’re all taken with a digital camera built into a petrographic scope. They’re all pictures of sand grains that are between 250 and 425 micrometers in size.

These are photos of a grain of argillite, a metamorphosed siltstone. The picture on the left is taken in plane light, and the picture on the right is taken with crossed polars. (The blue cast to the crossed polars picture is an artifact of the camera; under the microscope it’s much more grayscale.) Argillite consists of tiny grains of silt (mostly quartz or feldspar) in a brown mudstone matrix. The bright white crystal in the middle on the left is black on the right; in this case, that’s an example of extinction. Note that what seem to be whole crystals in the left picture don’t look whole on the right. That’s because in the process of metamorphosis, they’ve been recrystallized; one larger crystal has become many small ones, each with its own different angle of extinction. The next pair of pictures show that more clearly.

 
These photos are of two quartz sand grains. They’re not quite 100% quartz; the dark markings on them in the plane light photo (left) suggest they have some small amount of some opaque, probably metallic, mineral attached to them. Though it’s cracked, the upper grain is more-or-less a single crystal of quartz. You can tell that because the whole grain has the same birefringence in the crossed-polars photograph (right). The lower grain doesn’t look that much different from the upper grain in plane light, but crossing the polars reveals it is now composed of many smaller quartz crystals, each having its own angle of extinction. Again, this is recrystallization under metamorphosis. Under metamorphic pressure, the crystal, in many different areas at once, tends to reorganize into the tightest structure it can manage, creating many smaller crystals out of one larger one. Note that because quartz grains tend to be on the boxy side with irregular edges, extinction can’t be compared with growth habit to identify the mineral. I can’t show it in the picture, but quartz has a very unusual extinction habit that makes it trivially easy to identify: as the slide turns and the crystal goes dark, the color change proceeds in a wave across the crystal.

For something very different, here’s a pair of pictures of a metavolcanic sand grain:

A metavolcanic is a metamorphosed rock that was once lava. Lava is a very, very fine-grained rock, and even under the petrographic microscope it’s hard to make out the grains; it’s called a groundmass. But during metamorphosis, some of the tiny grains will organize into crystals. The long, skinny crystals in this grain are mostly feldspars; the stuff between them is still pretty much groundmass. Feldspars don’t necessarily grow long and thin, but they seem to do so during metamorphosis of volcanic rocks.

Finally, here are photos of my favorite rock, serpentinite. Alas, still photos can’t do it justice.

 
[For an early report on the project Karen's research has contributed to, see http://pubs.usgs.gov/sir/2004/5250/; for resources on microscopic petrography and the spectacular appearances of minerals in thin section, see http://serc.carleton.edu/NAGTWorkshops/mineralogy/optical_mineralogy_petrography.html and J.M. Derochette’s superbly illustrated site.]

Strange and wonderful designs

 
Just what exactly is going on here? There is, as far as I know, no answer to that question – and that simply adds to the sense of wonder, of mystery. I first used this image in Sand, as an illustration of the intricate and unfathomable artistry of nature and sand; it came from Martyn Gorman who has the good fortune to live close to  a wild stretch of dunes on Scotland’s east coast. His photographs are spectacular, and showcased on his site, where he writes that:

I am fortunate to live within sight of the fabulous Sands of Forvie on the northeast coast of Aberdeenshire in Scotland; a complex of mobile sand dunes and beaches of great beauty and scientific interest. I never cease to be fascinated by the constantly changing forms and patterns to be seen in the sand and by the plants and animals that live there.

This particular photo was taken in 2006; recently he wrote to me with the words “They have returned!” and attached this image:

So this is clearly not a one-off phenomenon: something is going on, a conspiracy of sand and physics - and maybe a little chemistry - that inevitably results in these complex and compelling sculptures. But I can only repeat the question – what exactly is going on here? Isn’t it wonderful?

 

{Images copyright, and reproduced with thanks with the permission of, Martyn Gorman; make sure you visit his site.]

Guest post: It Sorts, They Gather, We Collect

Now for something completely different. Longtime visitors to this blog may remember Richard Bready's evocative poem "Times of Sand" from 3 August 2009; many of you will have noticed his erudite comments on various posts — very often a learning experience for me as I follow in the directions his encyclopaedic knowledge points to. I've been pestering him to write another guest post for quite a while and he has finally succumbed to the pressure, inspired by Kate Clover's remarks on sand collecting.

So, without further ado, the return of the polymath whose multiple interests conveniently happen to include geology and sand:

It Sorts, They Gather, We Collect

A biscuit tin filled with dirt: poorly sorted alluvial sand and clay, red with iron oxidized by the Triassic atmosphere. How did an object so undistinguished enter the collection of a museum in Baltimore, Maryland, USA? Answer: this dirt was gathered at the spot, also in Baltimore, where Babe Ruth first stood to bat as a professional baseball player. And the museum occupies Ruth’s birthplace.

“Why do people collect?” asks Kate Clover. Association provides one reason; this dirt matters to people because it once bore a hero. A bottle of grains gathered on a Hawaiian beach holds the time spent there, a stopped sandglass. The souvenir urge is so strong that Petrified Forest National Park in Arizona prohibits all removals, however small, while local superstition warns that illegal petrified wood brings bad luck. Fortunately, sand is typically plentiful.

Further association, with other similar items, brings a change in status. Your bottle of sand, my bottle of sand, are souvenirs; together, they form a collection and invite others to join. We can discuss them, note similarities and differences, offer them for exchange. We can try to understand what we have picked up. So we become collectors.

Virginia Woolf wrote a story, Solid Objects, about a man who abandons a promising political career to seek stones, broken bits of china, lumps of glass. He does not know why he seeks them so obsessively, or even what he seeks until he finds it. All he knows is that each new treasure embodies its own kind of beauty, making the quest worthwhile. He is an artist, but he is not a collector.

The true collector values objects but swears by categories. Satisfaction requires the objects to belong to a pre-existing classification. Do not expect the specialist in hand-blown pre-Prohibition whisky bottles[1] to thank you for any other empty. Some collectors possess only memories and lists: birds seen in the back yard, seen from the car, seen on television. Lists mark the true collector.

Except to artists and innocents, information defines the collectible’s value. Consider Antiques Roadshow: “What you have here is not just a tattered piece of cloth but a cockade worn at the coronation of Queen Victoria”—yes, I am making this up—“and so worth buckets of money.” Though Woolf’s treasure hunter would not have the shabby thing in his rooms. Collectors in a new category know that the value of their holdings, and the prices of new acquisitions, will shoot up as soon as someone publishes a book or creates a Web site explaining and classifying these objects.[2]

Children of collectors, my brothers and I spent more time in shops than we enjoyed. To amuse ourselves, we would study some randomly chosen piece, wait until the proprietor was near us, pretend not to notice, then murmur, “I wonder if they know?” And leave the shop.

Pursuit of possessions, pursuit of information, bring the collector together with the scholar, and both with the obsessive. Is there a better portrait of the collector who needs one item to complete his set than “the monomaniac old man,” Captain Ahab? “His delirious but still methodical scheme” to find Moby-Dick leads him to chart “all tides and currents” until he can predict the migratory patterns of whales around the world.

Unlike accumulators, collectors love arranging their collections. Their need to classify, to create and fulfill taxonomies—shouldn’t we speak of OCO, Obsessive Compulsive Order?—may display in dramatic ways a quality central to intelligence, even to life itself: improbability.

You could gather newspapers by keeping them every day, but the sense of accomplishment would be limited. Copies of successful books are not hard to obtain.[3] The comic strip Doonesbury depicts a wealthy rock musician collecting stamps: “Send me Belgium. Yes, everything.” The collector’s categories make acquisitions more rare and more thrilling. The collector’s triumphs are black swans, white whales—singular events among a widely distributed average. (As mathematicians say, one person’s mean is another’s Poisson distribution.)

The study of probability began in questions posed by 17^th-century gamblers, who presumably knew like gamblers today the psychology of intermittent reward on an unpredictable schedule: it’s hard to quit. Reporting Catherine Winstanley’s experiment to recreate gambling behavior in animals, the writer notes:

Reward systems in humans and other animals evolve to help us learn how and where to get and maintain access to primary rewards like food, shelter and sex. "When we gamble, that network is hijacked by that extraneous -- that is, non-essential -- reward," Winstanley said. "Then all of our behaviours become focused on attaining that [gambling rush or win] rather than on the things that help us to survive."

Research into human learning suggests that intermittent rewards fuel behaviours that are harder to extinguish than predictable rewards. Since you never know when the next reward is coming, it could be the very next card that brings the rush of reward. Or it could be the time after that.

As Dorothy Parker lamented, “Some men, some men, cannot pass a book shop.” Because any book shop might contain an autographed copy of Poe’s Tamerlane (not a successful book, fewer than 30 copies known to exist, only two signed)—or that long-sought, not-on-the-Internet, needed-to-complete-the-set volume of Tintin. Or it could be the book shop after that.[4]

Evolving as hunter/gatherers, humans grew steadily better at finding and recognizing their quarry. They grew better at remembering where and when to look for what they needed. At the peak of natural selection, a collector can recognize a single unique flower in a field. Or note, as collector Charles Darwin did, special features in the beaks of finches.

The foraging hominid, the lepidopterist, the professional gambler, needs to be more than a good noticer. “You got to know when to hold ‘em, know when to fold ‘em, know when to walk away, and know when to run.” Survival, fame, and big money depend on pattern recognition, pattern exceptions.

Intelligence orders experience. It selects, and thinks of Nature as doing the same. Intelligence gathers (intelligent has a possible source in Latin interligare, tie together); it separates (or in intellegere, to judge between things). Intelligence recollects: Robert Trivers, Steven Pinker, and others suggest that social animals need to recognize each other readily so that they know who in their gatherings is likely to help them, and who will try to cheat.[5] The word category comes from agora, the Greek marketplace, linked to Greek verbs meaning “to speak in public” and “to gather.” Social animals exchange goods and ideas.

Life orders matter. As if they were Maxwell’s Demons, foraminifera selectively gather the glass sheets and flakes they use as integument. Researchers are grateful: “They effectively concentrated the glass samples for us!” Organisms combat entropy’s jumble with genetic information and physical form, “evade the decay to equilibrium” by “continually sucking orderliness” from the environment (Schrödinger, What Is Life). Ilya Prigogine argues that recognition of self-organizing entitities and systems, acting beyond determinism, is a fundamental advance in our concepts of biological and physical science.

Many physical processes do yield surprisingly orderly results. Sorting, for example. “Sand, like all granular materials, dislikes being mixed and will find endless ways of sorting itself out into its components.” Self-organization, for example.  “Systems displaying this behaviour exist on the boundary between stability and instability, order and chaos, . . . definitely not characterised by randomness.” Saltation, for example. “Why did [dunes] absorb nourishment and continue to grow instead of allowing the sand to spread out evenly over the desert as finer dust grains do?” Ralph Bagnold’s question explicitly likens the organized to the organic. In the other direction, D’Arcy Wentworth Thompson collects a myriad of organisms to display “the mechanical phenomena which are profoundly associated with Life, and inseparable from our understanding of Growth and Form.”

In my own pursuit, order makes rhyming formal verse more interesting to me than free verse. Formal or free, the language of poetry is highly organized and highly improbable. Consider: Zipf’s Law states that real-life word usage frequency follows a power law distribution.[6] Rare words are very rare. Among the most popular poems in English, however, the word darkling, elsewhere as scarce as an American robin surrounded by British twitchers, is practically standard.[7]

Poems and novels, dramas and stories and movies, organize experience and give it the appearance of pattern--or sometimes the self-conscious irony of disorder, pattern denied.[8] Popular fiction, sold by category, delivers payoff in recognition: disease diagnosed, crime solved, case closed, neat and tidy. “Now produce your explanation, and pray make it improbable,” wrote Wilde. He collected blue and white china, a carefully sorted clay[9] colored with cobalt.

(This is the first piece Richard Bready has written specifically for a blog since he retired.)

---

[1] My father. These are now in the Maryland Hall of Records.

[2] I am not making this up. As reported in Private Eye Number 1285.

[3] “The book jackets often are as expensive as the books themselves, conveying the idea of pristine purity--which of course means sterility as far as the cognitive content of the book is concerned, because the less read it is, the more valuable it becomes to collectors,” observes economist Michael Hudson.

[4] Woolf expresses this fixation:

...the determination to possess objects that even surpassed these tormented the young man. He devoted himself more and more resolutely to the search. If he had not been consumed by ambition and convinced that one day some newly-discovered rubbish heap would reward him, the disappointments he had suffered, let alone the fatigue and derision, would have made him give up the pursuit. Provided with a bag and a long stick fitted with an adaptable hook, he ransacked all deposits of earth; raked beneath matted tangles of scrub; searched all alleys and spaces between walls where he had learned to expect to find objects of this kind thrown away. As his standard became higher and his taste more severe the disappointments were innumerable, but always some gleam of hope, some piece of china or glass curiously marked or broken lured him on.

[5] Joanna Lumley, writing in Punch:

I am sometimes asked to officiate at charity jumble sales...I warn them with quiet insistence that I will not be making a speech...once when I did attempt a few words...I saw at the far end of the hall a stout, tweed-coated woman had jumped the gun and was negotiating in whispers over the price of a Coalport tureen. So now, barely pausing by the microphone to shout, “Good afternoon it’s open,” I hurl myself, elbows out, into the crowd of human locusts.

[6] Benford’s law describes a similar distribution of digits in “real-life” numerical data.

[7] Thomas Hardy’s “The Darkling Thrush” might have been written to contrast life’s self-actuating force and the entropic heat death of the universe—but probably not.

[8] Or the yet more self-conscious irony of pattern excessively fulfilled, as when Tom Stoppard’s Rosenkrantz and Guildenstern Are Dead opens with coin flips producing ninety-two consecutive heads.

[9] To quote Samuel Parkes (and share his hope):

The tribute which an elegant modern poet [Erasmus Darwin, grandfather of Charles] has paid to the peculiar industry and genius of this very eminent man [porcelain manufacturer Josiah Wedgwood] is so just, and at the same time so beautiful, that, I do hope, no reader of taste will blame me for its insertion.

Gnomes ! as you now dissect with hammers fine 
The granite rock, the noduled flint calcine ; 
Grind with strong arm the circling chertz (sic) betwixt 
Your pure Kaolins and Petuntzes mixt ; 
O'er each red saggar's burning cave preside, 
The keen-eyed fire nymphs blazing by your side.  
And pleased on Wedgwood ray your partial smile,  
A new Etruria decks Britannia's isle.

Wilde’s china was doubtless Chinese, however, not from Wedgwood’s Etruria factory.

Guest post: A Museum with Sands

Finally, a voice other than mine again: this from Kate Clover, Gallery Manager at the Science Museum of Minnesota:

A Museum with Sands

There is a collection of vials with sands on exhibit at the Science Museum of Minnesota in St. Paul. The collection includes sands from around the world that has been donated by staff and visitors and friends and brought into the museum in baggies, chip bags, pop bottles, mint tins, medicine vials, and cigarette wrappers. The sands have been collected from lakes, rivers, seas, oceans, deserts, dunes beaches, quarries, backyard sandboxes and playgrounds—green sand, red, black, white, and generic brown sands. From the ABC of countries: Argentina, Bulgaria, Canada, Denmark, Ecuador, Fiji, Greece . . . and every state in the US—nearly 1000 samples and ever growing!

 

This case showcases a small number of the sands on exhibit at the museum. Stereo microscopes are used for viewing sands. Photograph by Kate Clover

The sand collection is displayed in the museum’s Collectors’ Corner, a trading post where visitors of all ages can trade their found objects from nature for other things —rocks, shells, skulls, bones, insects, and yes—sands. Traders are awarded points for their objects and their knowledge, and then they can use their earned points to “purchase” other things. It’s a successful program. The program encourages people to engage in science in their homes, parks and in their travels and to dig a little deeper to broaden their knowledge of the world. The program engages learners at their own level and encourages life-long, life-wide and life-deep learning. http://www.smm.org/visit/collectorscorner/

In addition to trading sands, visitors can use stereo microscopes to examine sands and view poster-size photographs of sands magnified 225 times. The photos by Dr. Gary Greenberg (www.sandgrains.com) illustrate the stunning beauty and intricate nature of sea urchin spines, glass sponge spicules, shells and forams as well as colorful mineral grains. Visitors stand in awe in front of the photographs and comment about the diversity of colors, textures and mineral or biological grains. At the display of vials, they seek to locate their hometown beaches and favorite beach vacation destinations. Foreign visitors look for sands from their home countries.

 

Dr. Gary Greenberg’s photograph of sand on display in the Collections Gallery at the Science Museum of Minnesota. Photograph by Kate Clover

Gallery manager Kate began to assemble the sand display from her personal collection in December 1999. Initially, museum staff expressed skepticism about the sand display idea, but today, it’s a visitor favorite within the museum. Everyone has some experience with sand, and looking at sand under a microscope offers a new way to explore and understand a region’s geology or marine ecology.

Why do people collect? I believe our inquisitive nature is behind our impulse to collect objects. In collecting, we try to make sense of the rocks, shells or sands and their place in the geological or biological history of the earth. Maybe this learning doesn’t happen at first, but the more one collects, the more one sees the variables and begins to ask questions: why? where? how? Our goal at the museum’s trading post is to encourage learning and to instill a value to the scientific significance of the things kids collect. Science is about observing; it’s fun, exciting and engaging. The objects in our collections teach.

Heavy mineral sand from Lake Winnibigoshish, Minnesota

Mention Lake Winnibigoshish, more commonly known as Lake Winnie, to Minnesotans and you’re likely to hear fishing tales of northern pike, walleye, bass and muskellunge—not sand.

This stunning photograph of sand grains from Lake Winnibigoshish in north-central Minnesota shows the vivid, exquisite beauty that sand grains can show when viewed under the microscope.  Many of these grains are garnets, miniature gems!

 

Sand from Lake Winnebigoshish, Minesota. Photograph by Dr. Gary Greenberg. Used with permission.

These sand grains originated billions of years ago in the rocks of northern Minnesota and Canada. After as many as a million years and multiple cycles of weathering and transportation, the rocks have broken down into rounded grains like we see in this photograph. This sand was most probably collected from a dark swath on the beach where the action of the waves naturally concentrates denser minerals like garnet and magnetite.

Grains in this Sand

•  Garnets:  This sample includes both pink and orange garnets.

•  Quartz: Quartz grains in this sample are colorless to cloudy white, rounded and polished.

•  Magnetite, Ilmenite, and Hematite: These iron minerals appear opaque and range from black to red.  Along with hornblende (which also appears black), these minerals make up nearly half the sand grains.

•  Epidote: The pistachio-green grains are epidote.

•  Diopside:  The dark glassy green grains are diopside.

• Zircon: The faceted bluish grain near three o’clock is likely a zircon.

The Rock Hard Café features an eclectic menu.

There’s some whimsy at the Collectors’ Corner too. Check out platters of food at the Rock Hard Café where spilled ice water is depicted with calcite rhombohedrons and a sheet of mica, azurite nodules are blue berries, and green olivine sand is guacamole served with ribbed cockle shell chips. There’s more sand in the spice rack too: yellow sand “curry,” red sand “paprika,” white sands “salt”, black sand “pepper,” generic brown sand “cumin.” Next time you’re in town, check out our Rock Hard Café!

 
This Lake Superior beach shows streaks of heavy minerals, including magnetite and garnet. The pebbles are dark basalt and reddish rhyolite. Photograph by Kate Clover

 

[Kate and I began our virtual conversation after I had posted a Sunday Sand piece on Easter Island. She sent me a photo from her collection of a very different sand from the island – clearly volcanic fragments from the rocks that the island is built from. I discovered that she runs this great program at Minnesota’s Science Museum and asked if she would write a guest post, which she did – many thanks, Kate! And please note that Through the Sandglass would be delighted to host other guests – the more the merrier, so don’t hesitate to get in touch.]

Christchurch liquefaction - an eyewitness story

When an earthquake strikes, the normal, and reassuring, sense of terra firma vanishes instantly. This is caused by not one, but often two, potentially devastating impacts of the earthquake: the shaking itself and, if the subsurface is unconsolidated and water-logged sand, liquefaction. I have written about this phenomenon, the complete loss of strength and support for the foundations of buildings, before, in the context of the Loma Prieta and Haiti earthquakes. And now, through one of those odd series of connections that occur far less rarely than one expects, I have received a very personal account of liquefaction associated with the recent Christchurch earthquake.

I’m working in Jakarta at the moment, and recently got together with an old geologist friend whom I hadn’t seen in a long time. As the catching-up conversation hurtled from one topic to another, it turned out that, until not long ago, he had lived in Christchurch, and that a mutual colleague still does  - and has experienced major liquefaction events in both the earthquake of last year and this latest, tragic, one. Specifically, sand volcanoes had erupted on his property in both earthquakes. This, of course, led me to exclaim (for once, that word seems quite appropriate) that this topic was of some considerable interest to me, and I have now been in touch with my erstwhile-colleague in Christchurch. The account and the photographs that he has sent me are extraordinary, and he has kindly (given how much else of somewhat greater importance he has on his mind right now) allowed me to reproduce them here.

Admirably, he ran a brewery in Christchurch – I say “ran” because it was only a couple of blocks away from the collapsed building that tragically trapped so many people. Here’s how he described the event:

I was in the brewery weighing out hops. The building is still standing, though we have sustained some structural damage, parapet walls down and large cracks in the walls (not to mention all the fallen bottles and barrels and broken glass) was all that I could see before we evacuated the area. All the customers and staff were uninjured though it was terrifying and the mess that I glimpsed before I left is much much worse than last time.

In a later email he describes how he has had to make his staff redundant and has “No idea when if ever we will be allowed back into the CBD.” The Central Business District (CBD) remains cordoned off.

As for the liquefaction and sand volcanoes at his home, the effects are incredible:

 
He commented that

It seems churlish in a way to moan about the state of our garden while people are still being pulled from the rubble, but ironically just this last weekend Lisa's parents finished cleaning up the last of the sand from the September earthquake and now it is all back in EXACTLY the same places. Another 100 tons or so to remove! Our wooden house has survived well again, although I am sure it must have sunk and bent a bit more, but we can still live in it.

Aftershocks continue to shake the house as I write this email. I still have dust and bits of masonry in my hair!

“Another 100 tons or so”! But then, when you look at the extent of the eruptions, this seems like a possible underestimate. Here are a couple of photos of the last clean-up, followed by more of the current mess.

 

I wrote to my old colleague that “While I deeply regret the spontaneous deposition of tons of my favourite material yet again in your garden, your photos are fascinating” – I hope readers will agree. I guess that geologists must be phlegmatic about natural processes impacting their lives, but this would push me (and most certainly my wife) to the limit. So thanks, Martin, and very best wishes for re-building (and re-clearing).

 

[See a compelling video of liquefaction in a wheelbarrow as the results of arenaceous volcanicity are cleaned up in Christchurch; Chris Rowan at Highly Allochthonous has a kept an excellent series of posts on the earthquake updated, here and here. See also an excellent and graphic summary of Christchurch liquefaction as a pdf by the local government, and New Zealand Sciblogs have a description of the process and of sand “boils.”. The New Scientist has a good summary of New Zealand tectonics. As for what might conceivably be done to reduce the effects of liquefaction, see my post on the remarkable skills of bacillus pasteurii.