An exploration of how the Cryogenian Period, when our planet was covered in ice for millions of years, created today's remarkable biodiversity.
More than half a billion years ago, our world was completely covered by glaciers, a "Snowball Earth" that persisted for millions of years. Incredibly, this unimaginable cold led to the remarkable diversification of life on earth known as the Cambrian explosion. With a geologist's eye and a knack for storytelling, Graham Shields explores when and how such inhospitable conditions enabled animals to evolve, radiate, and diversify into our earliest ancestors.
This journey navigates the wild swings between hot and cold climates, oxygenation and oxygen starvation, biological radiations and extinctions, asking how such instability relates to grander forces that brought our planet to its modern state. Shields guides readers through evidence found in the Australian outback, Mongolia, Scotland, and other locales, revealing how geologists can trace glaciation, the atmosphere, oceans, mountain building, and more through the earth's rocks, providing a comprehensive theory of how life evolved and diversified.
Graham Shields is professor of geology at University College London. He lives in London, UK.
"Born of Ice and Fire is engagingly and fluently written and is an authoritative, detailed overview of a highly complex and interdisciplinary subject."
– Rachel Wood, chair of Carbonate Geoscience, University of Edinburgh
"Graham Shields takes us on a worldwide tour, presenting the latest geological evidence about the Precambrian period and investigating how stark physical conditions like a lack of oxygen and a world covered in ice established the first life on Earth."
– Mike Benton, University of Bristol
"Born of Ice and Fire is a fresh take on the mystery that most vexed Darwin: the seemingly sudden appearance of animal life in Cambrian strata. Graham Shields explores Earth's evolving biogeochemical system and the extreme ice age that ushered in a brave new oxygen-rich world."
– Marcia Bjornerud, author of Timefulness: How Thinking Like a Geologist Can Help Save the World