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Summary: A 65-million-year-old Murder Mystery
Review: This is the story of the discovery of why the dinosaurs -- and so many other creatures -- went extinct at the end of the Cretaceous period, 65 million years ago. Walter Alvarez was a young geologist who discovered an "iridium anomaly" in a deposit at the Cretaceous/Tertiary boundary that strongly suggested that an extraterrestrial event of massive effect had happened then. He was joined by his father, Luis Alvarez, a physicist at Berkeley, in the pursuit of the significance of this finding. It seems hard to believe, but most geologists were reluctant to posit anything like a meteor strike as being a significant factor in Earth's history, preferring to explain everything by invoking gradual processes.Yet it became clear early on that something big had happened, and various candidates were mooted, such as a nearby supernova, or a companion star to the sun periodically throwing comet orbits out of whack. This book is the story of how geologists, chemists, physicists and others over more than a decade closed in on the solution -- a massive impact in the Yucatan Penninsula whose after-effects shrouded the Earth in darkness for many months -- starting with that original discovery back in 1977. This is a reasonably lightweight account, but with enough details to give the reader a good idea of the technical problems without descending into jargon. When you are done you don't really know much more geology than when you started, but you might wish you had become a geologist, because the field trips sure seem like a lot of fun.
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