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Book Review: The Planet In A Pebble

A sculptor once said to me, “Science is a discipline followed with passion. Art is a passion followed with discipline.” In The Planet In A Pebble: A Journey Into Earth’s Deep History, Jan Zalasiewicz describes well how geology and its pursuit is simultaneously both discipline and passion. From the origin of its parts in the Big Bang and earth’s own cataclysmic birth to its subterranean assembly, from its exhumation in a plate tectonic act to ultimate disintegration many millions of years from now, the book follows the life of a pebble of Welsh slate. Along this arduous journey with the pebble, the reader is introduced to the fundamentals of geology as well as the tools and practices of the trade.

A pebble of Welsh slate. One will never consider such a rock sample drab, lowly or boring again on learning its contents and history, which is the makeup and story of the earth itself. The book begins with the creation of our solar system and immediately relates geology to the first principles of science – that an implicit understanding of these is required, that geology is not an “ism” in isolation but a synthesis of fundamental sciences in the study of this ball of physics, chemistry and biology on which we live. Pebble also directly imparts an understanding of and respect for time, that key geological ingredient.

Landscapes are transient. This is a concept that does not come easily to us. In our brief lifetimes we see the Earth’s landmasses as things of massive permanence, the bedrock of passing civilizations. And yet even in these human lifetimes we can see masses of rock debris piled up beneath mountain crags – and, as we walk nearby, hear the fall of new scree fragments, dislodged from rock faces by wind and water … Multiply such changes by the vastness of geological time, and there is plenty of time to change the face of a continent.

Zalasiewicz appears to be a paleontologist and geochronologist primarily, obvious from the tender explanations of the biochemistry of deep sea life, fossil preservation and rock dating techniques. One cannot get over clever phrases like  “cathedral-like vaults” when describing clay mineral formation at a molecular level, “atomic wallflowers” in the U-Pb dating of detrital zircons and the “baroque complexity” of well-preserved graptolites. The only complaint I have about the book, then, is that while it jumps with the ease and intellectual curiosity between concepts required of such an investigation, it does not spend equal amounts of time on those concepts. Case in point: The word “graptolite” shows up approximately 60 times in the book, while “lithosphere” and “palaeomagnetism” appear not even once. Zalasiewicz loves graptolites, we get it.

The book has its excessively-detailed Tolkien moments, but it is that same passion and dedication which propelled me through Pebble and its beautiful take on a deeply-buried mudstone’s oil window – “not only did that pebble yield up its own few drops of oil, but it also allowed through it many more such droplets that travelled up from the strata below, on their way towards the surface.” And following that the transformation of that mudstone into the metamorphic rock slate, in a majestic act of mountain-building known as the Caledonian/Acadian orogeny.

No scientist should be without a sense of humility and humor. In his generous use of terms like “reasonable,” “estimate,” “conundrum” and “working model,” Zalasiewicz sends the message clearly that geological analysis is a forensic science – an investigation using all currently-available tools and theories – and the only thing we know is that there is a lot more to know.

Out there, somewhere, will be the Rosetta Stone of the chitinozoans … waiting to be released. Someone will find it, and realize what it is … Then, there will be brief fanfare among palaeontologists, and celebrations and the concoction of a purple-prosed press release. And the next day, palaeontologists (one or two with slight hangovers) will get back to work, for there is much more work to do out there, and many more mysteries to be solved.

Admittedly, it is hard to review an earth science book without an eye to science education and literacy. Given that an introductory geology class is the only science class many students take at the university level, I offer that this book with more illustrations (and scale bars on existing illustrations) would serve as an excellent textbook, thanks in large part to its readability, with more formal classroom learning following along with its chapters. I can guarantee that many a budding geologist will emerge from its pages, the amazing tale of this lowly pebble no more.

There is a pleasure in the pathless woods,
There is a rapture on the lonely shore,
There is society where none intrudes,
By the deep sea, and music in its roar.

The Dark, Blue Sea by Lord George Gordon Byron


Disclosure: Oxford University Press gave me a copy of the book for review purposes. No other form of compensation was received.

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