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Geopedia: A Brief Compendium of Geologic Curiosities

5 December 2023

Have you ever wondered why a pseudotachylyte is called a ‘pseudo’-tachylyte or why a zircon is called a zircon? Maybe, yes. But have you ever thought about how many complicated geological words exist and what their corresponding geological, historical, or cultural stories are? Perhaps not. Geopedia by Marcia Bjornerud is the answer to those curious questions. This compendium of geological words details stories of remarkable places, strange incidents, misconceptions, and, even, dramatic plot twists. 

The entries are like an anthology, with unique storylines consisting of different plots with a common factor: Earth science. The entries are categorised alphabetically and based on the word’s language of origin, geographical location (such as Asia or New Zealand), biographical reference (such as Darwin, Lyell, or Wadati), and category (such as fossils, metamorphism, landforms, groundwater, or geological age). A simplified geological timescale is also provided for reference. Each entry is explained in detail with background stories using commanding words. Both the stories and words are a treat to read. 

As an example, there is the story of the Tully monster. Though very small in size, this unusual and scary looking fossil was named after its monstrous look and fossil collector, Francis Tully, who discovered it in 1955. It is still a debate whether Tully monster was an invertebrate or a vertebrate. We also learn about namakier, a Farsi word for “mountain of salt”, which describes a body of salt that can move and flow over land as fast as a few inches per year, much like a glacier. The Zagros range, Iran, is one of the only examples where namakiers exist. 

This compact book is well written and full of wit. There are some illustrations by Haley Hagerman to support the text, which are so simple, engaging, and entertaining that it leaves us wanting more. To quote the author, “our society is a geological illiterate society” and by reading this book either alphabetically or by browsing through the entries, one can gain knowledge on Earth system science and its coevolution with life over billions of years. 

Overall, this is a one-of-a-kind book that aims to educate as well as entertain the Earth science community or “Earthlings”, as the author refers to geologists. Considering its simplicity and the storytelling ability of the author, I recommend this book for everyone, be it school children, graduate students, or the general public. 

Reviewed by R. Arun Prasath 



BY: Marcia Bjornerud (2022). Princeton Academic Press. 200 pp. (hbk) 

ISBN: 9780691212579 

PRICE: £10.99 https://press.princeton.edu