Though we marvel at the creative side of evolution, the destructive flip side of that coin often gets less attention. Since its first stirrings, life has been involved in a war of attrition with its environment, “breaking, scraping, drilling, or otherwise changing the solid to the not-so-solid” (p. x). Leave it to palaeontologist Anthony J. Martin to write a witty book that boils over with fascinating studies about one of the more obscure corners of biology: bioerosion.

Life Sculpted: Tales of the Animals, Plants, and Fungi That Drill, Break, and Scrape to Shape the Earth, written by Anthony J. Martin, published by the University of Chicago Press in June 2023 (paperback, 368 pages)

Martin’s speciality is ichnology: the study of animal traces, both modern and fossilised. I have reviewed and enjoyed his two previous popular science books on this topic, Dinosaurs Without Bones (2015) and The Evolution Underground (2017), which were both published by Pegasus Books. Life Sculpted, published by the University of Chicago Press, focuses on a subtopic within ichnology: bioerosion, the process of life eroding hard substances in its environment, and the traces this leaves behind. How about I break this down?

Life Sculpted is divided into chapters dealing with the erosion of rock, shell, wood, and bone. Rock is attacked by a wide array of organisms and Martin describes how cyanobacteria, fungi, lichens, chitons (a group of molluscs), sponges, worms, barnacles, clams, and a host of other species attack rock by scraping, drilling, gouging, and dropping acid. Martin poetically describes it as “a wholesale slaughter of landscape exteriors that reveals illusions of immutability” (p. 25). In the process, they leave behind species-specific patterns of grooves, pits, scratches, and other traces. Martin points out that the cumulative effect is so large that the rock cycle has become as much geology as biology. Vertebrates get in on the action too, as evidenced by what is the most glorious chapter title in this book: “Your Beach Is Made of Parrotfish Poop“. Because, yes, that beautiful white sand found on tropical beaches? That comes out of the behind of parrotfish crunching corals in the process of scraping algae off them. The biological details of this ecosystem—which fish do it and why coral reefs are not harmed by it—are fascinating.

But life equally excels at attacking the living environment. Almost as soon as shells evolved, other invertebrates evolved ways of drilling into them, with trace fossil evidence dating back at least 500 million years. And if not death by drilling, shelled creatures have faced death by crushing from crustaceans, marine reptiles, mantis shrimp, seabirds, and mammals such as otters. Wood similarly was under attack almost as soon as it evolved by insects, later to be joined by (expectedly) woodpeckers and (unexpectedly) dinosaurs munching on rotten wood, possibly for the extra nutrition afforded by its fungi and insects. Wood furthermore has a second life as driftwood, which allows Martin to introduce one of the most amazing fossils: a large log covered by crinoids that I first encountered in Locked in Time. Though they superficially resemble flowers, crinoids are actually echinoderms that spend a large part of their lifecycle attached to substrates. Martin tells the fascinating story of how these crinoid colonies were a temporary phase in life’s history, eliminated by the evolution of wood-boring clams that from then on prematurely sundered these rafts. The evolution of these clams is itself another fascinating rabbit hole to go down, but I will leave that for Martin to tell.

“the cumulative effect [of bioerosion] is so large that the rock cycle has become as much geology as biology.”

Finally, the erosion of bone is an opportunity to dedicate a whole chapter to the wonderfully weird world of whale falls and the worms that feed on them. I briefly encountered these in , but Martin goes into far more detail here. When whale carcasses sink to the bottom of the ocean, they become a miniature ecosystem that lasts for decades, broken down by an ever-shifting cast of scavengers including worms of the genus Osedax that drill into their bones and settle there. Lovingly nicknamed snot or zombie worms, they were only described in 2004. On land, meanwhile, bones are munched on by a diverse cast of organisms looking to supplement their diet with calcium, including surprise appearances by squirrels and assorted herbivorous mammals. Martin goes a bit off-piste here I feel, drifting into a discussion of life’s most powerful biters, including extinct monsters such as Dunkleosteus (an armoured fish), Otodus megalodon (a shark), Deinosuchus (a crocodilian), and Tyrannosaurus rex (a “perenially overexposed diva” (p. 1)). Given this attention to biting it is perhaps surprising there is no mention of dental microwear. Teeth not only erode, but are eroded in turn, though this has been the subject of two popular books not so long ago. A more understandable omission are the traces of wear, disease, and trauma on bones. This is admittedly a huge topic, not all of it is strictly speaking bioerosion, and most work focuses on human remains, falling under the remit of and bioarchaeology.

The biggest bioeroders of them all in terms of volume are probably humans. What started fairly innocently with our ancestors using stone and bone tools has turned into a planet-altering industry. In the process of extracting the resources to make our material world, we drill, scrape, dig, bore, and tunnel like nobody else. The problem is that this is such a massive topic—encompassing basically all of archaeology and economic geology—that it could be a separate book. Martin here merely gestures at it in the final brief chapter, which is not quite a satisfying ending to this book.

Part of the fun in reading Life Sculpted comes from Martin’s humour, though I get the feeling he has toned it down a bit compared to his previous two books. Even so, expect a healthy dose of wit (the boundaries of primitive tectonic plates “supplied both a kitchen and a recipe for primordial soup” (p. 26)), alliterations (mussel muscle), puns (a history of boring boring? Get out!), and the occasional deep cut (how do you calculate the bite force of T. rex when there are no lawyers around?).

“the erosion of bone is an opportunity to dedicate a whole chapter to the wonderfully weird world of whale falls and the worms that feed on them.”

One topic I felt Martin could have emphasized more is the importance of a search image for something. There are behaviours for which we do not yet have trace fossil evidence because we do not know what to look for. This was made explicit in Dinosaurs Without Bones but only hovers in the background here. One example is that we have no trace fossils of lichens because we do not know how to distinguish them from fungi trace fossils or chemical and physical weathering. Similarly, woodpeckers have made holes in trees for over 20 million years, and yet we have not been able to identify pecking traces or nest holes in the fossil record that can be reliably attributed to these birds. Other examples show how we readjusted our search image, such as the dinosaur footprints that turned out to be “potholes” in sediment created by rays that use water jets to uncover buried prey. Another theme that is mentioned in places but not developed further is how climate change will affect bioerosion in the future. Perhaps that would have made a fitting chapter to end the book with.

By all accounts, this is a book I should utterly adore and I was engaged throughout. Still, I admit I felt ever so slightly underwhelmed after finishing it, though I struggle to put my finger on the why. Perhaps the best way I can explain it is that I feel it lacks a throughline or overarching theme that takes it beyond just a list of the wondrous and bizarre. And I write this while acknowledging that it is exactly the wondrous and the bizarre that propelled me through the book.

Life Sculpted brings together a bewildering array of weird and wonderful creatures and studies from the borderlands between palaeontology and evolutionary biology. Ichnology is already an obscure discipline that few people will have heard of, and bioerosion is a subject that will be on the radar of even fewer people. Leave it to Martin to turn that into an arresting book that is both a smooth and fun read.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Life Sculpted

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

Take a look at the geological time scale^[1]. Thanks to the dinosaurs, we have all heard of the Cretaceous, Jurassic, and Triassic. However, going back in time from the Triassic, the Phanerozoic Eon in which we live today stretches another 289 million years into the past; from the Permian that ended ~252 million years ago, through the Carboniferous, Devonian, Silurian, Ordovician, to the Cambrian that started ~539 million years ago. In The Greywacke, avocational geologist Nick Davidson tells the story of how those geological periods got their names and transports the reader back to the heydays of Victorian geology when three men would make Britain’s rocks the centre of international attention. In so doing, he unlocks for a general audience an episode in the history of geology that was so far consigned to more technical literature.

The Greywacke: How a Priest, a Soldier and a Schoolteacher Uncovered 300 Million Years of History, written by Nick Davidson, published by Profile Books in May 2021 (hardback, 280 pages)

When William Smith produced the first stratigraphical map of England and Wales in 1815, he was not able to further classify the rocks of Wales. A chaotic and incomprehensible jumble of hard-to-trace strata, they were collectively referred to as the titular Greywacke. Given that these rocks might contain the first evidence of life on Earth, they were of great interest to geologists. From 1831 to 1920, three scholars would spend their lifetimes deciphering them.

Davidson dedicates most of his book to the careers and achievements of Adam Sedgwick (1785–1873) and Roderick Murchison (1792–1871). Sedgwick split his time between his clerical duties as a priest and his academic duties as a geology professor in Cambridge. Murchison was a retired soldier with unfulfilled dreams of military glory and a family fortune to burn on his new geology hobby. Both were members of the Geological Society of London and, starting in 1832, decided to collaborate on cracking the identity of the Welsh rocks.

A very brief outline, which Davidson develops in detail over the course of nine chapters, runs something like this. Dividing Wales between them, both men identified a series of rock strata. Sedgwick called his seemingly older series the Cambrian and Murchison called his seemingly younger series the Silurian. The problem that they decided to largely ignore, and that would come back to haunt them, was whether these sequences overlapped in time or were separate. Sedgwick’s career subsequently stalled; doubts, procrastination, poor health, and the workload of clerical and administrative duties all took their toll. Despite encouragement from Murchison and other geologists, he was unable to develop a more sophisticated understanding of the Cambrian rocks, nor identify diagnostic fossils. Murchison, however, became a celebrity, his Silurian system widely adopted. In Devon, together with Sedgwick, he resolved confusion over the presence of younger Carboniferous strata amidst older Silurian rocks by designating the intermediate layer with anomalous fossils as Devonian. In western Russia, he identified the Permian, a new rock layer named after the Russian city of Perm. His book on the geology of Russia won him international accolades and he was basking in the fame and glory he never achieved as a soldier.

“the rocks of Wales, a chaotic and incomprehensible jumble of hard-to-trace strata, were collectively referred to as the Greywacke. […] From 1831 to 1920, three scholars would spend their lifetimes deciphering them.”

As Davidson details, though, Murchison’s fame had some shady sides to it. He rarely acknowledged the geologists and quarrymen who helped him in the field. He glossed over stratigraphical inconsistencies and fossil anomalies. And as he climbed the social ladder, his contemporaries noted in private his increasing arrogance and condescending nature. Younger geologists were quietly suspicious that his sweeping picture was hiding a more nuanced and complex story, but few would openly confront him. Two episodes, told here, illustrate why. By 1852, the souring friendship between Sedgwick and Murchison blew up over the above-mentioned overlap between Cambrian and Silurian strata in Wales that both men were laying claim to. Though new fossil evidence and surveys supported Sedgwick’s Cambrian designation, Murchison brushed those off as a local anomaly and never recanted his Silurian claim. Davidson puts it nicely: “it was clear they were fighting not only over territory, but also over different versions of what they considered the truth” (p. 173). The two men squabbled publicly until their deaths. Something similar happened when Murchison collaborated with a younger James Nicol on the rocks of the Scottish highlands. They also quickly came to different interpretations, with Murchison seeing a smooth succession of strata where Nicol saw a region of upheaval and a large fault line running through Scotland. Murchison would downplay Nicol’s findings and undermine his career, even though later work proved Nicol correct.

The third person in this story, the schoolteacher Charles Lapworth (1842–1920), is not introduced until the penultimate chapter. Working in southern Scotland, he would pioneer the use of graptolites, the microscopic remains of colonial marine animals, as fossil markers. Based on these, he would finally resolve the conflict between Sedgwick and Murchison, showing that the strata both men laid claim to for “their” geological period, were better interpreted as a separate period he called the Ordovician. This part of the book feels all too short. The reason, as Davidson explains, is that Lapworth’s archived notebooks, maps, and letters “still await a biographer to do justice to his quite remarkable achievements” (p. 234)^[2].

“Though written for a general audience, the depth of Davidson’s research stands out and will be appreciated by geologists and science history buffs.”

Many readers will likely have never seen the various rock types that Davidson describes here. Unfortunately, the book contains no colour photos, but Davidson has cleverly included various tables that clearly explain how Sedgwick, Murchison, and Lapworth assigned the various rock strata to geological periods. Also very helpful are Andrey Kurochkin’s simplified sketches of stratigraphical cross-sections. Another facet of this book I appreciated is that Davidson only briefly describes his own visits to many of the locations mentioned here. He never distracts you from the historical narrative by prominently inserting himself.

Though written for a general audience, the depth of Davidson’s research stands out and will be appreciated by geologists and science history buffs. He draws on collections of letters and biographies published in the 19th century, archival resources, and unpublished material contributed by other historians. Davidson explicitly acknowledges an intellectual debt to four books. Three of these—Martin Rudwick’s The Great Devonian Controversy (1985), James Secord’s Controversy in Victorian Geology (1986), and David Oldroyd’s The Highlands Controversy (1990)—were published by Princeton and Chicago. Their age means you would have to consult a library or, for bibliophiles such as myself, track down second-hand copies. The fourth influential book, Murchison’s Wanderings in Russia, was published posthumously in 2004 by the British Geological Survey and will not have seen wide circulation. By publishing with a trade publisher, Davidson has effectively unlocked an important piece of science history to a wider audience.

If you want to read beyond the few names that always crop up in the history of geology, such as Charles Lyell or James Hutton, this is a fascinating book on three scholars who left a lasting legacy in the names we still use today.

1. ↑ Surely I am perfectly normal in having a laminated printout of the International Chronostratigraphic Chart within arm’s reach, right? Right?

2. ↑ After this review went live, the Lapworth Museum responded that they are currently cataloguing his archive to make it more widely accessible. You can follow their progress on the museum’s blog.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

The Greywacke

Other recommended books mentioned in this review:

__________________________________________________________________

Say “dinosaurs”, and most people imagine fossilised bones and spectacular museum displays. But body fossils are not the only remains we have with which to reconstruct dinosaur lives. Nor, and this might sound controversial, are they the most important. Or so argues palaeontologist, geologist, and ichnologist Anthony J. Martin. Ichnology is the study of animal traces, whether modern or fossilised. Most traces are ephemeral and disappear within hours or days, but occasionally some are buried and end up in the fossil record. With tongue firmly planted in cheek, and with more puns than you can shake a T. rex thigh bone at, Martin forays into the rich dinosaur trace fossil record: from footprints, burrows, and nests, to teeth marks and fossil faeces. For all the jokes, and despite having been published in 2014, he raises some really interesting points.

Dinosaurs Without Bones: Dinosaur Lives Revealed by Their Trace Fossils, written by Anthony J. Martin, published by Pegasus Books in April 2015 (paperback, 484 pages)

You might indeed ask, why review this book now? Way back in 2018 I reviewed Martin’s 2017 book The Evolution Underground on the evolutionary history of burrowing behaviour and was suitably impressed. I vowed to search out his previous book, though I did not intend to wait this long. Having just reviewed Lomax’s book Locked in Time, now was the right time to make up for that.

Animals of all sorts leave behind traces wherever they go and dinosaurs were no exception. Footprints are probably the first thing to come to mind and a logical place to start. From the US, to Europe, to South America, they have been found on every continent except Antarctica*. Martin discusses how the number of toes and their orientation can reveal what group of dinosaur left the footprint and how their size can be used to estimate its maker’s size. Where multiple footprints form a trackway, their distance can reveal gait and velocity, or whether dinosaurs moved alone or in (family) groups. And with technological advances, we can extract more information from footprints than ever before.

One interesting thing Martin reveals here that I was not aware of, is that most fossil tracks are probably undertracks. That is, the subsurface deformation of the substrate caused by the pressure of the foot. Most tracks likely soon weathered beyond recognition, so unless you find clear skin impressions, the prudent assumption is that you are dealing with undertracks. As he points out: “The decided preservational advantage of this phenomenon is that such tracks were already buried, protecting them from destruction” (p. 33).

“One interesting thing Martin reveals here […] is that most fossil tracks are probably undertracks. That is, the subsurface deformation of the substrate caused by the pressure of the foot […]”

But feet can do much more than just walking and Martin examines trace fossil evidence of dinosaur nests and fossil burrows. Beyond traces made by feet, bones can record tooth marks, though care is needed to distinguish attacks on living animals from post-mortem scavenging. In turn, food leaves tell-tale traces of microwear on a tooth’s surface. More exotic—and controversial—are gastroliths or stomach stones that can act as digestive aids, though likely not all were swallowed on purpose. And then there is that which comes out at the other end. You might have heard of coprolites (fossil dung), and Lomax introduced me to urolites (fossil traces of urination). But what of enterolites (fossil stomach contents) and cololites (fossil intestinal contents)? Or, my favourite, regurgitalites—which is what you think it is.

For some behaviours we do not have clear evidence, while others are highly unlikely to leave traces in the fossil record. But this does segue nicely into one of the most important themes of this book: search image. At several points, Martin encourages readers and researchers alike to ask themselves: what would the traces left by certain behaviours look like? Take sauropod footprints. Given their size you might think they are hard to miss and yet: “In the early days of dinosaur tracking probably more than one paleontologist or geologist walked by their footprints without a second glance, thinking they were some sort of large erosion-caused features. Once these footprints were correlated with the sizes and shapes of sauropod feet […] sauropod tracks magically appeared in the search images of paleontologists worldwide” (p. 22). An important point of reference, and one that Martin profiled for his home turf of Georgia in his previous book, are the traces left by animals alive today, specifically birds. Because, as he reminds you towards the end of the book by shortly recapping the evolution of birds, technically speaking birds are living, flying, feathered dinosaurs.

“[…] one of the most important themes of this book [is] search image. At several points, Martin encourages readers and researchers alike to ask themselves: what would the traces left by certain behaviours look like?”

The other thing to note is Martin’s writing style. All of the above is served up with a healthy dollop of frequently irreverent humour. Some of it borders on dad-jokes though, so let me give you some tasters. He frequently lampoons his own profession: “[…] even dinosaur-track experts have doubts about the identity of some three-toed dinosaur tracks, especially if a rival dinosaur-track expert identified them” (p. 22), and regarding peer review “[…] the scientists who review journal articles are doing it as unpaid volunteers, finding time to perform this important duty in between all of their other tasks such as teaching, grading, research, walking the dog, or (most heinous of all) sleeping” (p. 76). The rear part of a dinosaur “[…] is properly called an ischial callosity, and not the more appealing term “dinosaur butt”” (p. 39). On front teeth: “If a theropod’s potential food item, such as a small ornithopod, was still alive and having issues with a proposal that it should devote its life to feeding a theropod, then the front teeth were the most persuasive tools used by that theropod” (p. 181). And on urolites: “Paleontologists who do such research could be assured of making a big splash with it, while also going against the flow of others’ prejudices. Afterwards, they will be flushed with success, and their colleagues pissed off” (p. 247). If the above made you laugh, you will have a blast with this book. I certainly did.

Dinosaurs Without Bones is great popular science: fascinating, thought-provoking, and told with verve and wit. This is an excellent companion book to Lomax’s Locked in Time and a very nice introduction to trace fossils and ichnology. My only regret is that I waited so long before finally reading it.

* That was true when this book was published in 2014. When I followed up on this, I found one news item claiming the 2016 find of a dinosaur footprint on Antarctica. However, when reading the actual 2019 paper in the open-access journal Polar Research, the authors are a bit more circumspect, attributing this footprint to “a primitive amniote, procolophonid or therapsid“.

Dinosaurs without Bones

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

Where do humanity’s evolutionary roots lie? The answer has long been “in Africa”, but this idea is being challenged from various sides. I previously reviewed Begun’s The Real Planet of the Apes as a warming-up exercise before delving into this book. My conclusion was that its discussion of archaic ape evolution, although proposing that species moved back and forth between Africa and Eurasia, ultimately did not really challenge the Out of Africa hypothesis. Not so Ancient Bones. German palaeontologist Madeleine Böhme, With the help of two co-authors, journalists Rüdiger Braun and Florian Breier, firmly challenges the established narrative in an intriguing book that is as outspoken as it is readable.

Ancient Bones: Unearthing the Astonishing New Story of How We Became Human, written by Madelaine Böhme, Rüdiger Braun, and Florian Breier, published by Greystone Books in September 2020 (hardback, 376 pages)

Ancient Bones was originally published in German in November 2019 as Wie wir Menschen wurden. Less than a year later the good folk at Greystone Books have already published the English translation. The challenge to the Out of Africa narrative is twofold here: criticism by palaeoanthropologists and Böhme’s own discoveries. The latter are the novel part of this book and are told with much verve. Two fossils, in particular, take centre-stage.

First, there is the rediscovery of a tooth and a jawbone christened Graecopithecus freybergi. Originally found in 1944 near Athens, together with other animal fossils, they went missing for decades before Böhme tracks them down, in true Raiders-of-the-Lost-Ark–style, in the catacombs of the Nuremberg congress hall, a location infamous for the Nazi party rallies during World War II. With today’s technology, old fossils hold new value. Careful study of the jawbone with computed tomography scanning showed that the teeth resembled early hominins* more than other great ape fossils. Novel magnetostratigraphic analysis of crystals in sediment trapped inside the animal bones from the same dig allowed the whole lot to be dated to about 7.2 million years ago (mya).

“These two important fossils, Graecopithecus and Danuvius, were present in Europe at a time where conventional wisdom has it that Africa was the epicentre of hominin evolution.”

The second discovery is made by Böhme and collaborators in a southern German clay pit. In a nail-biting race against time—the pit is commercially operated year-round to turn the clay into bricks—they manage to recover much fossil material during three field seasons. This includes a partial skeleton of a new primate species named Danuvius guggenmosi dated to about 11.6 mya. Based on several physical characteristics, Böhme and colleagues argue it, too, resembles early hominins more than known great ape fossils.

So, Graecopithecus and Danuvius, two important fossils, are one part of her argument that there were early hominins in Europe at a period where conventional wisdom has it that Africa was the epicentre of hominin evolution. The second challenge to the Out of Africa hypothesis comes from other palaeoanthropologists. For example, there is criticism of the earliest claimed African hominin, Sahelantropus tchadensis**, with some researchers arguing it is a great ape instead. Then there are several fossils from Asia (the Chinese Homo wushanensis, the Philippine H. luzonensis, and the Indonesian H. floresiensis), plus tools that overlap with the African timeline up to 2.6 mya, contradicting the Out of Africa hypothesis (specifically, the Out of Africa I variant).

“As with deserts, savannah ecosystems were in constant flux and integrated across Africa and Eurasia, a region dubbed Savannahstan by some. Perhaps that was the cradle of humanity.”

This criticism is embedded in plenty of background information that benefits tremendously from excellent infographics by freelance illustrator Nadine Gibler. Some topics covered are the history palaeoanthropological discoveries that, thanks in particular to the Leakey dynasty, shifted in focus from Europe and Asia to Africa from 1924 onwards. There is a recap of the history of archaic ape evolution that Begun told in The Real Planet of the Apes. And there is an overview of the anatomical characters that set apart apes and hominins.

Particularly relevant is the palaeoclimatological and biogeographical story. On the one hand, shrinking and growing deserts throughout northern Africa, the Mediterranean, and Asia provided a barrier to migration. On the other hand, the little known Messinian Salinity Crisis*** saw the Mediterranean Sea dry up about 5.6 mya, allowing migration of fauna between Africa and Eurasia, including a lot of animals we now think of as “typically” African. “Why should early hominins be an exception?” asks Böhme on page 194. As with deserts, savannah ecosystems were in constant flux and integrated across Africa and Eurasia, a region dubbed Savannahstan by some. Perhaps that was the cradle of humanity.

“It is not that the fossils found in Africa are not important, but […] the focus on any one particular continent is too narrow […]”

This material is divided over seventeen reasonably-sized, readable chapters in four parts. Depending on how widely you have read on human evolution, the final two parts of the book will already be familiar to you and feel like filler or will be a tasty sampler of other topics. Böhme changes gear here, introducing two questions. One, what made us human? She briefly discusses the hand, above-mentioned Asian Homo fossils and our wanderlust, long-distance running, Wrangham’s thesis that fire and cooking allowed our brains to grow larger, and the physical and genetic evidence for language (this section is a far cry from Rudolf Botha’s critical evaluation in Neanderthal Language). Two, why are we the last ape standing? Rather than Paul Martin’s Pleistocene overkill hypothesis, she favours the (to me novel) idea that that at least Neanderthals and Denisovans simply merged with us. Ancient DNA has revealed we all carry some of their DNA in us, but we do not all have the same pieces. Puzzle it all together, and an estimated 30% of the Neanderthal genome and up to 90% of the Denisovan genome is retained in the current human population.

Ancient Bones is not afraid to go against the grain and be provocative. Though it will no doubt ruffle feathers, my impression is that Böhme draws on a growing body of convincing evidence and arguments to make her case. It is not that the fossils found in Africa are not important, but Böhme’s conclusion on page 271 that the focus on any one particular continent is too narrow is hard to disagree with in light of everything she presents here. What is undeniable is that her decision to involve three others in the writing process makes this a top-notch example of an engaging book accessible to a broad audience.

*Hominins are a taxonomical grouping encompassing humans, chimpanzees, and bonobos, plus their extinct ancestors.

**There is a remarkable personal attack here on Sahelanthropus‘s discoverer who has withheld a thighbone from scrutiny by the wider scientific community for close to two decades pending his own investigations. It could answer whether Sahelanthropus was bipedal or not. When two scientists wanted to present our understanding so far at a meeting their application was rejected. “Could it be that Michel Brunet, one of the icons of French science, Knight of the Légion d’honneur, recipient of the Ordre national du Merité, did not want to be challenged?” (p. 128), is one of the things Böhme asks pointedly. Now, it is not that there are no big egos in science, because there are, but to publicly shame a colleague in a book for a general audience felt, to me, unnecessary. It would have been sufficient to write, as she does here, that his choice is unfortunate and holds back scientific progress.

***The Messinian Salinity Crisis is a fascinating geological event that cries out for a popular treatment. Though some books mention it, as far as I am aware, there has not been a book dedicated to it since 1983, even though our knowledge on it has increased tremendously.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Ancient Bones

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

We all have a pretty good idea of what a volcanic eruption looks like, but they are only the surface expression of a much larger and longer underground process that is hidden from view. The internal workings of a volcano, its plumbing if you will, are studied by the relatively new scientific discipline of volcanotectonics. Icelandic volcanologist Agust Gudmundsson has been researching and teaching this topic for two decades and here delivers the field’s first textbook. In preparation, I beefed up my knowledge base by first reviewing a introductory volcanology textbook, but it almost was not necessary—Volcanotectonics turned out to be exceptionally instructive and accessible.

Volcanotectonics: Understanding the Structure, Deformation and Dynamics of Volcanoes, written by Agust Gudmundsson, published by Cambridge University Press in April 2020 (hardback, 586 pages)

As an academic field, volcanotectonics draws on the disciplines of structural geology, tectonics, geophysics, and, more generally, classical physics, specifically rock-, fracture-, and fluid mechanics. In the field, it draws on studies of rock outcrops, geodesy (the study of the shape of the earth and its gravitational field, here specifically the monitoring of ground deformation), and, importantly, seismology (the study of earthquakes). Additionally, there is a healthy dollop of modelling involved. That is quite the list. Plus, the book is a hefty tome of almost 600 pages. Feeling intimidated already? No need.

There are five underground structures that you will become intimately familiar with reading this book, all of them made of magma: chambers, reservoirs, dikes, sheets, and sills. The first two are, as the names imply, the underground storage parts. Reservoirs are large and deep-seated (typically 10–25 km below ground), chambers are smaller and more shallow (commonly 1–5 km below ground). The second three are the parts connecting reservoirs, chambers, and the volcanoes at the surface. Gudmundsson here uses the word dike to encompass both vertical dikes and inclined sheets. Both of these cut across rock layers. Sills, on the other hand, do not: they form where magma meets a rock layer it cannot penetrate and then spreads out laterally, parallel to it. Sills are thus emplaced horizontally, or close to it.

“Very roughly, it looks something like this: volcanoes are fed by either shallow magma chambers that are fed by deeper and larger reservoirs, or sometimes directly by reservoirs, through a complex, branching network of dikes, sheets, and sills. “

Having explained the basic anatomy, Gudmundsson proceeds with important physics concepts such as stress, strain, and elasticity, including various laws and constants to do with mechanics. It also offers one of the clearest explanations I have seen for when and why to use different modelling approaches, in this case analytical, numerical, and analogue ones. The mathematical details are purposefully kept relatively brief, with readers referred to the technical literature and books such as Rock Fractures in Geological Processes and Modeling Volcanic Processes for more details.

All this setup is a necessary warming-up exercise to understand volcanotectonic processes. Very roughly, it looks something like this: volcanoes are fed by either shallow magma chambers that are fed by deeper and larger reservoirs, or sometimes directly by reservoirs, through a complex, branching network of dikes, sheets, and sills. Many of these are dead ends: dikes can become deflected into sills if they hit rock layers they cannot penetrate and stop there (or, with luck continue upwards again if they hit on weak spots), or they can run out of steam, reaching equal pressure with their surroundings and end up as arrested dikes. Those that make it to the surface are called feeder-dikes and result in volcanic eruptions.

Gudmundsson argues that chambers originate from the rapid (geologically speaking) emplacement of sills. As long as new dikes from the reservoir at the crust–mantle boundary feed more magma into the growing sill before it cools down and solidifies, it has a chance to develop into a magma chamber, passing through an intermediate stage called a laccolith. The shape these chambers take is rarely a perfect sphere, more often a flat ellipsoid. All this subterranean movement, meanwhile, is frequently accompanied by small, local earthquakes occurring in swarms, and small but measurable ground deformation, both of which are important for monitoring and forecasting eruptions.

“What makes the book all the more convincing and attractive is that it relies on more than just theory, calculations, and modelling exercises. Gudmundsson adds results from field studies on recent eruptions and fossil volcanoes worldwide and includes numerous photos.”

For magma to force its way through the surrounding rock requires sufficient pressure to overcome local tensile strain and stress. Interestingly, the process is analogous to the artificial hydraulic fracturing, or fracking, for shale oil and gas, which has allowed the testing and confirming of ideas. Large sections of the book go into the calculations and equations you need to quantify how much pressure is needed, how this is affected by local stress and strain, and how modelling assumptions make a difference. Simplifying assumptions of a homogeneous and isotropic (i.e. uniform in all orientations) rock crust make for easy calculations but sometimes unrealistic results. In reality, our subterranean world is not quite like that: Earth’s crust is heterogeneous and anisotropic, with many layers stacked on top of each other, stiff ones alternating with softer ones. Dedicated chapters explore what this means for the often erratic paths that dikes follow as magma moves through the crust, and for the size of eruptions. Gudmundsson also outlines how particularly catastrophic eruptions (for instance Tambora, Krakatoa, and Toba) resulted from caldera collapses. Here, various dikes join up to form a ring-fault that isolates a block of rock that can subside into the magma chamber, squeezing it largely empty in the process. A final chapter applies the material to forecasting and (possibly maybe) prevention of eruptions.

There are obviously many more subtleties and complexities to it than this brief sketch, and I learned an incredible amount, suggesting that some of the unknowns Ellen Prager highlighted in her book Dangerous Earth are being filled in. What makes the book all the more convincing and attractive is that it relies on more than just theory, calculations, and modelling exercises. Gudmundsson adds results from field studies on recent eruptions and fossil volcanoes worldwide and includes numerous photos. Dikes and solidified chambers, now called plutons, come to the surface over the long stretch of time due to erosion, while quarries and road-cuts offer another window into the underground.

“The real selling points of Volcanotectonics are its superb structure and accessibility. […] earth science students […] can pick this up without trepidation”

The real selling points of Volcanotectonics are its superb structure and accessibility. Clearly formulated aims start each chapter, while summaries and lists of all the symbols used end each one. Student exercises are accompanied by worked examples that go through equations stepwise and explain symbols and units. Some degree of repetition and cross-referencing between chapters ensures important concepts are reiterated. Mathematical operators you are unlikely to have seen before are extensively introduced. And jargon is consistently and repeatedly explained. For example, the fact that strike- and dip-dimensions of dikes correspond (roughly) with their horizontal and vertical dimensions. By constantly repeating this, I noticed that halfway through the book I had absorbed their meaning. Repetition works. Arguably the only thing that students might miss is a glossary.

The result is that even someone like myself (a biologist interested in geology), whose reading on the subject is limited to an undergraduate geology textbook and introductory graduate texts on structural geology and volcanology, never felt out of my depth. Volcanotectonics should be a hit with earth science students and they can pick this up without trepidation—Gudmundsson’s many years as a teacher shine through. Significant questions and challenges remain, for example regarding submarine volcanism near mid-ocean ridges, but Volcanotectonics brings together a vast body of work and represents a significant advancement in our understanding.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Volcanotectonics

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

Volcanoes are some of the most awe-inspiring natural spectacles on our planet. There is much more to them, though, than the stereotypical image of a conical fire-spitting mountain, and I have been keen to learn more. As I searched for serious introductory books on volcanology, this was one title that kept coming up. But wait, why is a biologist reviewing geology textbooks?

Volcanoes, written by the late Peter Francis and Clive Oppenheimer, published by Oxford University Press in December 2003 (paperback, 521 pages)

A short preamble seems in place. My choice to study biology went at the expense of geology, although the latter topic continued to fascinate me. Two decades later, my job exposes me to many fascinating-sounding but advanced-level earth science books. I have since started to make inroads into this field for the sheer joy of expanding my knowledge. And thus I found myself eyeing up the new book Volcanotectonics. Yet, as I recently rediscovered, there is still a gap between having covered the essentials of geology and diving headlong into an advanced topic. Hoping to bridge that gap, I turned to Francis & Oppenheimer’s Volcanoes.

The first edition of this book was published in 1993 and authored by volcanology professor Peter Francis. When he passed away in 1999, his former PhD student Clive Oppenheimer, now a professor of volcanology in his own right, took it upon him to revise the text and bring it up to date for this second edition, published in 2003. Francis’s desire was to write a book to be read rather than consulted. Volcanoes is thus less of a textbook than you might think: there are no chapter summaries or student exercises. What you will find is a logical flow of chapters detailing the inner workings of volcanoes, glued together by the fascinating stories of past eruptions and, occasionally, Francis’s trademark humour, lampooning the field of volcanology.

“Volcanoes is […] less of a textbook than you might think: there are no chapter summaries or student exercises. What you will find is a logical flow of chapters detailing the inner workings of volcanoes, glued together by the fascinating stories of past eruptions […]”

Volcanoes starts with very primordial questions. Where do the heat and the rocks that drive volcanism come from? This introduces you to planetary formation and the radioactive decay of isotopes. In case you were expecting to start with plate tectonics, that is the next subject to be tackled. This explains the difference between volcanoes at plate margins where the oceanic crust is either formed or destroyed, and the minority occurring far from margins, such as the volcanic islands of Hawai’i.

Chapters four to twelve form, to my mind, the nuts-and-bolts section of this book, going into all the glorious and gory details of an eruption from beginning to end. This covers everything from formation and movement of magma; different eruption styles; types of lava; eruption columns and the deposits of ash and pyroclastic rocks they leave behind; pyroclastic density currents, debris avalanches, and mudflows or lahars—and their deposits; the different landscape forms left after eruptions, including types of volcanoes and how they erode, and the landscape depressions known as calderas; super-eruptions; and, finally, the common but hard-to-observe phenomenon of underwater volcanism.

The last four chapters cover closely allied topics: volcanoes in the solar system; the effects of recent eruptions on climate and the palaeoclimatological evidence of older ones; and, new to this edition, two chapters on monitoring of volcanoes, and assessing and managing the risks they pose.

“I was fascinated by some of the technicalities. For example by […] the physics behind eruption columns and the interplay with the wind, and how to deduce eruption intensity from them […]”

Two aspects, I thought, make this book very enjoyable to read. First, it broaches subjects without overwhelming you. When it talks of magma, it mentions the physics of gas bubble formation and growth (vesiculation), and the flow of liquid rock (rheology) without smothering you in detail. It will list different eruption styles (Hawaiian, Strombolian, Vulcanian, Plinian, etc.) and lavas (andesitic, dacitic, rhyolitic, etc.) while highlighting the arbitrary nature of such classifications, as these things exist on a continuum. And where formulas are given, for instance in the chapter on eruption columns, it is to demonstrate principles rather than go deep into the mathematics. If you are so inclined, each chapter comes with recommended sources and literature references for further research.

The authors explain terminology as they go, supported by many photos and diagrams. I would have liked a glossary—lacking that, I occasionally had to grab my dictionary to jog my mind. Even so, I was fascinated by some of the technicalities. For example by the distinction between central vent and large-scale fissure eruptions. By the underground movement of magma and intrusion of dikes. By the physics behind eruption columns and the interplay with the wind, and how to deduce eruption intensity from them. By the detective work that uses palaeoenvironmental records such as tree rings, and the extent and thickness of deposits to reconstruct eruptions for which there is no eyewitness testimony. Or by what makes pyroclastic density currents so terrifyingly destructive.

The second aspect that makes Volcanoes very readable is that this is not a theoretical treatise with hypothetical scenarios. Explanations are given by means of real-world examples of past eruptions. Four classic ones are introduced early on (Vesuvius, Krakatau, Mount Pelée, and Mount St. Helens), but plenty of others are recounted throughout. This includes those familiar from popular accounts (e.g. Tambora, Laki, and Toba), technical books (e.g. Pinatubo and the Soufrière Hills volcano), and those only known to volcanologists and victims (e.g. El Chichón and Nevado del Ruiz). You will learn as much about these eruptions as about what we learned from them.

“Having read the book cover to cover, there remains one important question that is difficult for me to answer. Given its publication date, how up to date is it? And is it time for a new edition?”

Having read the book cover to cover, there remains one important question that is difficult for me to answer. Given its publication date, how up to date is it? And is it time for a new edition? Technological advances and new space missions have revealed much more about extraterrestrial volcanoes—this book was published before the Opportunity and Curiosity rovers started trundling over the surface of Mars, for example. But what about volcanism here on earth? Recent eruptions have probably taught us new lessons (2010 tongue-twister Eyjafjallajökull no doubt revealing more about ash clouds), but not being a student of earth sciences, this is a hard question for me to answer. The only other more recent book I could think of was The Encyclopedia of Volcanoes, published in a second edition in 2015. But at over 1400 pages this can hardly be called an introductory textbook.

I decided to contact Clive Oppenheimer who kindly replied that there have not been any paradigmatic shifts in volcanology since then, but he did mention, in addition, the 2010 Merapi eruption, and highlighted new technology such as synchrotron radiation sources for fine-scale chemical analysis of volcanic rocks. Additionally, he pointed out Volcanoes: Global Perspectives (2022) as a recent textbook. And a third edition? It is not yet in the making, though he hopes to get around to it when time allows.

So, in sum, if you are looking for a good introductory volcanology textbook, I found this one both enjoyable and accessible. I came away feeling I understood much more about volcanoes. Bring on Volcanotectonics.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Volcanoes (2nd edition)

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

“Origins: How The Earth Made Us“, written by Lewis Dartnell, published in Europe by The Bodley Head (a Vintage imprint) in January 2019 (hardback, 346 pages)

Dartnell takes as his starting point the evolution of Homo sapiens in East Africa. He subscribes to Maslin’s ideas for where and when we evolved, outlined in The Cradle of Humanity: How the Changing Landscape of Africa Made Us So Smart. The gist of his argument was that it was a combination of plate tectonics and climate. The geography of the African rift valley and pulses of climate variability interrupting longer periods of stability led to regional lakes rapidly appearing and disappearing. This unstable environment favoured adaptability and intelligence. Dartnell similarly gives a revealing geological explanation reaching back 55 million years for how the most recent ice age came about and how it has impacted human dispersal around the world.

Now, it is easy to accuse a popular science book like this of glossing over subtleties for the sake of a good story. I therefore appreciated that Dartnell clearly signposts there are frequent disagreements on the details of the story of human evolution, and that not all evidence points in the same direction: his narrative represents the consensus view. He is nuanced enough to point out what that may seem rapid and purposeful – humanity’s global migration starting 60,000 years ago – was, in fact, a matter of trial and error. I liked his suggestion that there may have been earlier attempts at migrating out of Africa, or developing agricultural civilizations, that simply fizzled out before taking off. Similarly, when he brings up the effects of the Toba eruption on early humans (see my review of When Humans Nearly Vanished: The Catastrophic Explosion of the Toba Volcano), he immediately flags this up as controversial. All this gave me a good feeling about the balance Dartnell is trying to strike between presenting a captivating narrative while sticking to the facts and how best to interpret them.

“there may have been earlier attempts at migrating out of Africa, or developing agricultural civilizations, that simply fizzled out before taking off.”

From this point forward, the remainder of the book deals with the last 10,000 years of human civilization, making excursions into deep time explanations where needed. For readers of Diamond’s Guns, Germs and Steel: A Short History of Everybody for the Last 13,000 Years this is perhaps more familiar territory as he discusses the rise of agriculture (see also my review of Against the Grain: A Deep History of the Earliest States for some nuanced counterpoints to the standard narrative) and livestock husbandry. Here he reaches back into deep time to explain why Eurasia ended up with so many more domesticable species compared to the Americas, and why the orientation of the continents made the spread of agriculture easy in Eurasia (which is oriented East-West), but hard in the Americas (which is oriented North-South).

With agriculture came trade and Dartnell chronicles the establishment of the first maritime and overland trade routes, leaning heavily on overview works such as The Sea and Civilization: A Maritime History of the World and The Silk Roads: A New History of the World. His interest is in how these were shaped by the geography of the seas (the shape of coastlines, the existence of naval bottlenecks) and the land (the ruggedness of the terrain, microclimates). And he explores how our subsequent maritime Age of Exploration, when Western nations started colonising countries around the globe, depended on, and was shaped by, the planetary patterns of ocean and air currents, in turn shaped by where plate tectonics has parked the continents currently.

In the same vein, he spends two chapters exploring the deep origin of the materials we use to build and construct with (whether architecture or objects and tools), how they are formed, how they have ended up distributed over the world the way they have, and how that has played into the fortunes of civilizations and nations. He talks of rocks and metals and does an excellent job explaining our current dependence on rare earth elements and platinum group metals.

“90% of the coal we have used since the Industrial Revolution was formed during the Carboniferous […] if that had not happened, would the Industrial Revolution have taken off?”

He is concerned about our continued appetite for these resources. His arguments got me thinking, and I wonder whether we might be reaching a hard limit. When our increasingly advanced machinery and electronics depend on almost all the elements in the periodic table, where do you go from there? These materials are – if not always rare – hard to obtain, and there are often no suitable replacements. When you depend on finite resources like that, and things like renewable energy technology and computers cannot function without, can we continue to science and engineer our way out of our problems? I get the feeling this is rarely thought or talked about when considering the future. Similarly, he convinces that transitions throughout our history have acted as a ratchet, allowing us to expand and increase our population to a point where there is no turning back (or at least not without drastically decreasing the size of our global population) – we would not be able to feed, clothe, and shelter this number of people anymore with yesterday’s technologies.

Finally, he gives a quick tour of energy (see also Energy and Civilization: A History) and how we transitioned from muscle power to wind and water power and then fossil fuels, taking the reader through the age of coal, the steam engine and then oil. Here, too, he is specifically interested in how these resources were formed and why they are found where they are found. From reviewing Energy: A Human History and Carboniferous Giants and Mass Extinction: The Late Paleozoic Ice Age World I was already familiar with the fact that 90% of the coal we have used since the Industrial Revolution was formed during the Carboniferous, some 360-300 million years ago (leading Dartnell to ask the same question as Rhodes in the former book: what if that had not happened, would the Industrial Revolution still have taken off?) But Dartnell provides a lucid geological explanation to the question why so much coal was formed then. And it turns out there was a similar period in which the vast majority of the world’s oil reserves were formed, again for a good geological reason.

In his book The Equations of Life: The Hidden Rules Shaping Evolution, Charles Cockell wrote that physics is life’s silent commander, setting hard limits on what evolution can and cannot do. I would argue that Dartnell here similarly convinces that geology is history’s silent commander. Very accessible and full of interesting ideas, Origins is a worthy contender in the saturated market of big history and environmental history books. Depending on how much you have read on this topic, not everything here will be novel, but I do think that with its deep time and geology perspectives, Dartnell goes a few steps beyond most books.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Origins paperback, hardback, ebook or audiobook

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

“Structural Geology“, written by Haakon Fossen, published by Cambridge University Press in March 2016 (hardback, 510 pages)

If you know how to read them, whole landforms, individual rocky outcrops, and even slices of a rock examined under a microscope can reveal a detailed story of how they have formed. Rock deformation, then, is what the subdiscipline of structural geology is all about (this excludes structures produced by sedimentation or magmatic processes, though, once produced, these can later be deformed). The first edition of this book was published in 2010, but Fossen has not rested on his laurels. Incorporating feedback from readers, and adding an online module with animations, the second edition of this advanced-level textbook followed in 2016. The book is specifically intended for use in coursework and includes chapter summaries and review questions. But, as I found out, the book can also be tackled outside of a classroom setting.

Fossen starts off with four chapters on the basics of strain (changes in length or volume of rocks) and stress (how the forces involved acted). These are probably the most technical, introducing basic matrix algebra and the graphical methods geologists have developed to analyse strain and stress and represent these three-dimensional processes on paper in a graph or diagram. Rheology, the mechanical properties of materials and how they flow under pressure and temperature, is one other basic cornerstone that is introduced.

Fossen then breaks down his approach following the two main forms of deformation. Near the surface rocks behave in a brittle fashion, breaking and shattering as the Earth moves, and Fossen here discusses fractures, joints, veins and faults. At depth, under high pressure and temperature, rocks are more plastic and deform slowly by flowing. A short introduction to the basics of crystallography is needed here, after which Fossen treats structures such as folds, foliations, lineations, boudins, and shear zones. This catalogue of structures is then placed in the context of tectonics, explaining how these show up when plates collide, separate, or move past each other. Salt in rock form behaves rather differently from most other rocks, so Fossen dedicates one chapter to salt tectonics (for a fuller treatment see Salt Tectonics: Principles and Practice). Finally, he looks at restoration: how can you infer what rocks looked like before deformation?

“fascinated by photos of folded rocks that look like so many layered cakes that had an accident in a bakery [this book] seemed like a good starting point to deepen my knowledge further.”

The above paragraph is full of jargon, but don’t let that faze you. Read through Structural Geology, and the terminology gradually will be demystified (even though I found it useful to have a copy of the Oxford Dictionary of Geology & Earth Sciences at hand). Before long I found myself casually reading about fracture mechanisms in the brittle regime and realising that these words meant something to me. The glossary helps, but it is especially the huge number of photos and diagrams that clarify much. Trying to describe movements and dynamic processes with words and static pictures will only get you so far, though. This is where the online module shines, as it contains a huge number of Flash animations. I can try to describe in words how a listric fault moves, or how boudins form, or I can show you (click on the camera icon to start the animation).

Structural Geology is more than just a technical catalogue of deformation processes, though. Obviously, there is the obligatory nod to the practical relevance of this knowledge for structural engineers and the fossil fuel and mining industries. What I found far more fascinating is what this book reveals about structural geology as a field of knowledge.

First, Fossen stresses how important it is to make field observations. Geologists can do small-scale experiments with plasticine or putty, or they can artificially deform rocks and minerals under high pressure and temperature over the course of days or weeks. Similarly, there are plenty of options for simulations and numerical models. But all these are replete with simplifications and assumptions, such as idealised homogeneous materials. As in other disciplines, it is the only way to get to grips with the data. But how realistic are these experiments and our models, especially given the extremely long time scales over which rock deformation plays out? Fossen reiterates throughout how important it is we continue to check this against real-world situations.

Second – and as an evolutionary biologist I can appreciate this – structural geology is a historical and descriptive discipline. We look at (essentially) static structures that result from long and slow processes and we try to figure out what happened.

Third, each chapter introduces one kind of rock deformation, but in the field you are usually looking at rocks that underwent several deformations, either simultaneously or sequentially. Figuring out what happened and in what order can be a challenge.

Especially points two and three explain how we can have competing models for observations, and why geologists disagree amongst each other which is the correct explanation for the formation of observed geological structures.

“[…] trying to describe movements and dynamic processes with words and static pictures will only get you so far – this is where the online module shines.”

The last thing I want to remark on are the production values – it’s a beautiful book! Big, heavy, and with a sturdy binding, it is absolutely chock-a-block with full-colour photos and illustrations. And it comes at a very reasonable price, suggesting that the poor binding and high price of an undergraduate textbook like Essentials of Geology are unnecessary.

Not being a geologist by training, it is hard to make hyperbolic claims about this book being the best. I have not read other books on this topic and am not familiar with the literature. I also have not used this book in the setting of coursework or field excursions. What I can say is that, even if some of the technical details might have gone over my head, Structural Geology does a tremendous job at explaining the subject, even to someone with a limited background in geology. The book has received rave reviews elsewhere and it is easy to see why – high production values, a well-structured and well-written text, and a supplementary online module with useful animations make this book a solid choice if you need to or want to read up on this topic.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Structural Geology (2nd edition) hardback or ebook

Other recommended books mentioned in this review: