Zalasiewicz - The planet in a pebble: a journey into Earths deep history

THE PLANET IN A PEBBLE

A Journey into Earths Deep History

JAN ZALASIEWICZ

Great Clarendon Street, Oxford ox2 6DP
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Jan Zalasiewicz 2010

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First published 2010

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ISBN 978-0-19-956970-0

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To my colleagues who pursue the secrets of Welsh slate;
the stories in this book belong, naturally, to them.

This book began its life in a conversation with that nonpareil editor at OUP, Latha Menon, and she then delicately helped guide the resultant narrative into its current shape. Others at OUP, including Emma Marchant and Kate Farquhar-Thomson have also contributed to various stages of this book, and it has been a pleasure to work with them. Tim Colman, Jane Evans, Sarah Gabbott, Ryszard Kryza, Alex Mack, Stewart Molyneux, Melanie Leng, Derek Raine, Adrian Rushton, Andy Saunders, Sarah Sherlock, Thijs Vandenbroucke, and Dick Waters have readily and considerably improved sections of this book (thanks also to Tim Colman, Sarah Gabbott, Ryszard Kryza, Rob Wilson and Thijs Vandenbroucke for supplying or helping with illustrations): to them many thanks (though errors of omission or commission in this narrative are mine alone).

Beyond that, most of this pebble book forms a kind of summationan interim summation, naturallyof work that I have been involved with, more or less tangentially, in the large part of my career devoted to untangling the intricacies of Welsh slate. In this, there is a large cast of colleagues near and far to who I owe much thanks, for educating me in this most under-appreciated type of rock (that has often had, alas, the reputation of being wet, grey, and monotonous). Much of this took place while I was working with the British Geological Survey, mapping the hills of central Wales. First of all, there were the field geologists I worked withDick Cave, Dick Waters, Jerry Davies, Dave Wilson, Chris Fletcher, Dave Schofield, Tony Reedman, John Aspden, and others besides. It is hard to overstate the value of the skill and expertise that they built up as they worked year after year on long field seasons, in all weathers. The insights they developed to these difficult, perplexing rocks form, it seems to me (as someone who had a ringside seat), a true classic of British geology.

Key parts have been played too by Jane Evans and Tony Milodowski on the rare earth mysteries and much else besides; Sarah Sherlock on the subtleties of rock-bound argon; Dick Merriman and Bryn Roberts on the clay minerals and micas; Keith Ball and Melanie Leng on the chemistry of these rocks; and Alex Page, deciphering both ancient life and climate from them. There is the fossil world too, that almost infinite jungle of vanished life, traversed sure-footedly by the likes of Adrian Rushton, Dennis White, Mark Williams, Barrie Rickards, David Loydell, Steve Tunnicliff, Mike Howe, Stewart Molyneaux, Phil Wilby, and Hugh Barron. Since I joined the University of Leicester, I have kept in touch with this kind of geology, mostly vicariously, as it has been pursued by such as Sarah Gabbott, Mike Branney, Mike Norry, John Hudson, Steve Temperley, Dick Aldridge, David Siveter, Andrea Snelling, Anna Chopey-Jones, Anne-Marie Fiddy, Lindsey Taylor, Bob Ganis, and Thijs Vandenbroucke. Other colleagues more widely within the Welsh orbit have included Nigel Woodcock, Denis Bates, Richard Fortey, Robin Cocks, Howard Armstrong, Derek Siveter and all those associated with those nigh-legendary (if tiny) institutions, the LRG (the Ludlow Research Group) and BIG G (the British and Irish Graptolite Group), and more lately the Welsh Basin Group. And, going back to my own ancient history, John Norton and then Harry Whittington played key roles in starting me on this path.

To these and to yet others I am truly in debt: most of the stories in the following pages belong toand hence the book is dedicated tothese people.

Pebbles and rocks, though, go back a long way in my life. My parents and sister patiently toleratedindeed supported and encouragedmy early excavation of such things, despite the large volume of rock that I insisted on carrying into a small house. More recently, my wife Kasia and son Mateusz have borne the brunt of the time stolen to fashion and refashion the words in these pages (not to mention the long weeks and months when I have been in the field amid the Welsh hills). To these also I am eternally grateful.