Judging by the title of this book, you might expect it to talk of 25 remarkable kinds of rocks and minerals. But in the preface, geologist and palaeontologist Donald R. Prothero makes clear that his book looks as much at famous outcrops and geological phenomena. Bringing together 25 readable and short chapters, he gives a wide-ranging tour through the history of geology, celebrating the many researchers who contributed to this discipline.
At first blush, you might think this book is part of the ongoing craze of spiritual mindfulness books. But let me refrain from snarky comments. Geologist Marcia Bjornerud does indeed want to instil a sense of mindfulness about deep time, but one that is, pardon the pun, grounded in geology. In her opinion, most of us lack an awareness of durations of important chapters in our planet’s history and of rates of change of many natural processes. As a consequence, we fail to see just how rapidly we are altering our planet. In one of the first paragraphs she eloquently writes:
“Like inexperienced but overconfident drivers, we accelerate into landscapes and ecosystems with no sense of their long-established traffic patterns, and then react with surprise and indignation when we face the penalties for ignoring natural laws”.
And with that, she had me hooked.
This book is an example of what happens when you go down rabbit holes. I have been reading several books on the subject of palaeontology and geology lately, and I know that the face of the earth has shifted over the hundreds of millions of years of deep history covered in these books. But where were all the continents at different times? Many will have seen the iconic maps of the supercontinent Pangaea. But I want to know more. What happened in between? And before? As Nield tells in Supercontinent: 10 Billion Years in the Life of Our Planet, Pangaea was only one of several such supercontinents in Earth’s history. But I want to know more still. Where exactly were the continents located? And how did they move? Several accessible books have provided snapshots of iconic moments, such as the formation of the Himalayas (Mike Searle’s Colliding Continents: A Geological Exploration of the Himalaya, Karakoram, & Tibet) or the disappearance of the Tethys ocean (Dorrik Stow’s Vanished Ocean: How Tethys Reshaped the World). But I want to know more! This technical reference work contains lots of fantastic palaeogeographical maps that answered all my questions.
If you have used a compass, you will know our planet has a magnetic North and South pole. You might even be aware that the geographical and magnetic poles are not exactly in the same location. The magnetic poles have a tendency to wander with time. They can even swap places, and we have evidence of a long history of such geomagnetic reversals in the rock record. But how does this happen? And what would the consequences be if this happened today? Earth’s magnetic field offers protection against radiation from outer space, primarily from the sun, so if this field weakens or changes, what will happen to us and our electrical infrastructure? Join science journalist Alanna Mitchell as she explores this topic and delves into the history of electromagnetism.