Clastic Detritus

The post below is my review and the first of two posts devoted to the book ‘Sand: The Neverending Story’ by Michael Welland^. The second post is a Q&A between me and Michael combined with an open Q&A in the comment thread for you to ask questions.

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Pick up a single grain from the beach, look at it through a magnifying glass, and you have embarked on a journey taken by poets, artists, and philosophers — not to mention geologists.
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I have to admit that when I found out there was a popular science book devoted to sand I got really excited. Not only am I geologist, but I am a sedimentary geologist … and not only am I a sedimentary geologist, but I specialize in clastic sediments — a lot of which is sand. So, perhaps it’s not a big surprise that I’m a fan of book all about sand. But, at the same time, because I’m a sand-lover (or an ‘arenophile’ as Welland calls us) I read this book not only for the enjoyment of the narrative but also for additional insights and specific facts about my field of study.

However, this book is not just for the specialist. The subtitle for the edition I have is ‘The Neverending Story’* and the clever narrative that Welland employs throughout much of the book is the journey a grain of sand takes from birth (weathering and liberation of sand-sized particles from rock) through transport, deposition and burial, and, if the geologic situation is right, lithification of those grains into sandstone, and potentially the breakdown of that sandstone back to sand again.

… sand is one of our planet’s most ubiquitous and fundamental materials and is both a medium and a tool for nature’s gigantic and ever-changing sculptures.

This narrative is woven into a book that’s filled with fascinating facts and stories about the role sand has played in both natural and human history. Thus, ‘Sand’ is a great read for anyone interested in the story of one of nature’s most important geologic agents.

Thankfully, Michael Welland, who is himself a geologist, addresses one of the misconceptions about sand in the first few pages of the book — that is, what makes sand sand is the size of the particle, not what it’s made out of.

Our sand grain, newly born, finds itself, together with a motley collection of other detritus, organic and inorganic, as part of a soil, the in situ accumulation from the physical, chemical, and biological processes at work in a particular place. The sand grain is anonymous, waiting for rain and wind to sweep it away on an endless journey, to demonstrate its durability while its weaker companions fall by the wayside. But it is called sand not because of what it is made of or its origins, but because of how big it is.

The first two chapters of ‘Sand’ introduce the basics of this material and discuss some important fundamentals related to the fascinating, and surprising, physics of granular materials (and not just transport but also how this material behaves when mixed, vibrated, dropped, and more).

‘Sand’ then returns the narrative of the journey a grain of sand takes with a series of chapters related to river transport, transport by wind, coastal processes, and finally, export of sand to the deep sea. There is enough fluid dynamics and details of particle transport within these sections to satisfy sedimentologists, yet it is also presented in such a way to be accessible to the non-specialist. In fact, if I were to ever teach a course in clastic sedimentology to novice geologists I would assign these sections of ‘Sand’ as required reading. Welland communicates many of the details within stories about pioneering sedimentologists, especially Ralph Bagnold, and how their research changed the science forever. To me, this is the mark of a successful popular science book — if I wanted straight-up sedimentology I could open a textbook — but, ‘Sand’ discusses these concepts within a story. In this case, a story about nature interwoven with stories about the people who study nature.

I also enjoy Welland’s writing style — some passages almost approach a rhythmic, even poetic style, but the writing manages to stay within a enjoyable and accessible style typical of non-fiction books. I’m not sure if my description is accurate from a literary point-of-view (I’m no expert), but here’s an example from the chapter on deserts:

When sand moves under a gathering desert wind, it seems to take on a life of its own, to become a different form of matter — like a gas, like liquid nitrogen spilling and spreading, following the ground surface. Spraying off the crest of a dune, shimmering in the light, veils of sand race and ripple, spread and vanish, their place continually taken by the next gossamer sheet, dancing, playing, celebrating. Are these jinns, the spirits of the desert? The sight is beautiful and hypnotizing in the evening sun, but if the wind gathers speed, beauty rapidly vanishes as the violence and menace of a sandstorm grows. Suddenly, it seems as if the entire mass of desert sand has sprung from the ground to hurtle with the wind. On the surface, everything is moving, even the largest grains, rolling, tumbling, kicking smaller grains into the rushing current. The sky disappears, and the howl of the wind seems amplified by its cargo of sand. The air is filled with flying sand, unbreathable.

There are many sections of ‘Sand’ that are able to communicate how dynamic and beautiful nature’s processes are. Another theme that is apparent throughout Welland’s writing is the concept of scale — both spatial and temporal — and how sand is so intimately connected with considerations of deep time and countless numbers.

In addition to stories of Earth’s geologic history that are revealed through sand, Welland devotes significant parts of the book to the seemingly countless ways in which sand intersects human civilization. This list is by no means meant to be exhaustive but will give you a flavor of some of the topics discussed in ‘Sand’:

• fundamental materials (building stone, glass, aggregates, etc.)
• the concept of sand as a powerful metaphor in thought and storytelling (e.g., very large numbers and very small things)
• importance of sand for the ecological health and safety of coastal areas
• utility of sand in forensics and crime-fighting
• reservoirs for important (and valuable) fluids
• threat of migrating sand dunes to villages/towns
• sand as an artistic medium —  for drawing, sculpting, painting, writing, and more
• microchips (and, electronics in general)
• how quicksand really works
• and much, much more …

If I had to pick one thing I didn’t like about ‘Sand’ it’s the chapter on the myriad uses of sand in our lives. It is organized as an A to Z list, which, when compared to the other chapters that read more like a story, comes across as encyclopedic and a bit out of place. That said, I don’t have any suggestions for a better way to do it. Sand truly is ubiquitous and its uses are literally everywhere — if the point of the chapter was to emphasize sand’s ubiquity through a comprehensive list then the point is well taken.

The closing chapter of ‘Sand’ addresses the presence and importance of this material beyond the confines of our planet. The fact that the Huygens probe documented sand when it landed on Titan is a poignant testament to how fundamental it is in our universe (nevermind that the sand is made out of hydrocarbon ice — remember, it’s the size that makes it sand).

I highly recommend picking up a copy of ‘Sand’ if you are an Earth scientist of any kind — go ahead and make it a must-read on your 2010 list. For my readers that aren’t Earth scientists but enjoy nature writing at its best, I think you’ll really like this book as well.

Finally, I’ll leave you with one more quote from ‘Sand’ — a quote that offers a clear and succinct answer to the question of why it is important to increase our knowledge of the dynamics and history of a material like sand:

On such details does the character and habitability of our planet depend.

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^ Make sure to check out Michael’s blog Through the Sandglass to read more fascinating stories about sand — some of which are included in the book, but many that are not.

* Michael Welland explains why there are two editions of ‘Sand’ with different subtitles on his blog here.

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UPDATE (2/3/2010): Michael Welland has been awarded The John Burroughs Medal for excellence in natural history writing. This is very well-deserved.