You pick up a rock and it”s just a rock. Jan Zalasiewicz picks up a rock and sees a history of the whole Earth. That”s because Zalasiewicz is a geologist, so rocks have more meaning to him than they do to most of us. He has imparted some of his specialized meaning in “The Planet in a Pebble: A Journey Into Earth”s Deep History” (Oxford University Press), one of the most accessible works of geology for the layman available. William Blake rhapsodized on the possibility that one could “see a world in a grain of sand,” but of course he was speaking of the mystical and poetical. He probably would not have gotten much inspiration from Zalasiewicz”s scientific view, but there is inspiration aplenty here for those who want to look at demonstrations of human cleverness. It is quite wonderful that we can make sense of how the Earth came to be and can understand how certain rocks came to have the characteristics they do, since it requires tracing back billions of years. Zalasiewicz does the tracing back, indeed, to the Big Bang and the eventual formation of the Earth right up until the pebble he describes is brought out to be picked up on the beach. The scope of the story is thrilling, and if you can”t picture every step he describes in every chapter (few of us can imagine adequately, for instance, time extending back for such periods), there will always be more astonishments in the next one.

“A pebble of gray slate from a Welsh beach – perhaps from somewhere like Aberystwyth, or Clarach or Borth on the west Wales coast.” Why pick such a source? Simply because Zalasiewicz has had a “career devoted to untangling the intricacies of Welsh slate,” a rock he says is underappreciated and “has often had, alas, the reputation of being wet, grey, and monotonous.” So the choice of pebble might be arbitrary, but we can take for granted that any pebble from anywhere else has someone taking the same tenacious geological stare at it. “In some ways,” writes Zalasiewicz, “the pebble is like one of the newer computer chips, tightly packed with more information than one could ever surmise from gazing on its smooth surface.” It is indeed amazing that so much can be unpacked from this rock, but even the book-length account here makes clear that each of the steps in the rock”s formation have been the subject of countless abstruse papers. Zalasiewicz has written some of those papers, but throughout this work he maintains a casual and chummy tone; it is needed, for trying to understand the stretches of time and the ways we have come to understand them is a challenge.

First things being first, the book starts with the Big Bang, long before there were all the elements that the pebble is made of. (The humble pebble has some of the rarer elements within it, not just copper and lead, but yttrium and niobium which you never think about, as well as gold and silver which you do. It also has more oxygen per mass than the atmosphere has.) Zalasiewicz summarizes the formation of our Sun and the planets around it. Appalling violence characterized not just the Big Bang, but the supernova explosions, and then eventually and locally, earthquakes and volcanic eruptions. There are other periods in which the pebble (or the rock mass wherein it was formed) just waits, shifted in millions of years from one locale to another and infiltrated with ions carried by water into it. It”s a geological story, but there is plenty here to learn about cosmology, astronomy, and chemistry.

Biology is surprisingly important. Zalasiewicz has called on a pebble of Welsh slate because that has been the focus of his studies, and a look at the book”s bibliography reveals another focus: graptolites. There are plankton from the pebble”s time, but far larger, and visible to the naked eye, are weird structures that look like chains of vertebrae, although the varieties are daunting. They were colonies of animals that maybe floated, maybe swam across the Silurian seas. This was about 450 million years ago, after trilobites but long before dinosaurs. According to Zalasiewicz, graptolites don”t get the respect they ought (rather like his underappreciated gray Welsh slate itself), and are certainly dimmer stars in the fossil world than trilobites or dinosaurs. However, they are important enough that the difficulties of extracting them from the rock are worth undergoing; the author himself must have done lots of it, and describes how using a sharp needle, strong magnification, and patience, bit by bit the surrounding rock may be chipped out to leave the graptolite (which, in a process he explains in another chapter, may millions of years later have become filled with crystals of fool”s gold, pyrite). The laborious procedure is worth it because the strange and idiosyncratic forms are one evolutionary group following another. By minute examination, geologists can use them to specify times in million-year chunks, which is an amazing exactitude for so long ago. “Field geology,” Zalasiewicz tells us, “is the ultimate forensic science, the art of the possible, where one combines as much evidence as one can get hold of, with as much ingenuity in analysing it as one can muster – and also with a keen sense of the limitations of one”s deductions.”

Graptolites are thus a chronometer, but they are certainly not the only chronometer described here. Neodymium isotopes tell when the stuff that makes up the pebble was released from the Earth”s mantle, for instance. There are zircon grains, and the decay of radioactive potassium, and many more up until 1945 when all rocks above ground began to be tinged with the leavings of the nuclear age. There is even lichenometry, whereby the exceedingly slow and steady growth of lichen gives a clue about how long the rock on which it is growing has had a surface for its growth. The different chronometers have been calibrated and matched because geologists have to deal with such huge spans of time and “have racked their brains to find as many ways as possible to say what happened when. As racking goes, it has been quite fruitful, all told.” Toward the end of the book, the pebble, inching toward the surface, begins to feel the effects of climate (not seasonal weather, but the broader temperature patterns). It had, before this, drawn any heat it felt from the Earth”s interior. Eventually the external climate would make an impression on it, but it would have been millions of years after that before it felt any seasonal change, and even longer for it to have come to the surface. Once it got there, though, things could change a lot. Split off from its mother rock and washed by tides, it might have lost as much as half its mass in one storm season as it banged around on its neighbors.

Zalasiewicz winds up in a final chapter with a few pages about the pebble”s future, where in a few billion years it will perhaps join all the molecules on Earth as they are swept into the Sun. Maybe bits of it will be exploded out into cosmic dust that become part of a new solar system with new planets. The speculation on the pebble”s fate is similar to the mind-stretching understanding of what it has already been through. It is an astonishing journey, and Zalasiewicz has provided a valuable and detailed account of it, beginning to end.

The Dispatch Editorial Board is made up of publisher Peter Imes, columnist Slim Smith, managing editor Zack Plair and senior newsroom staff.