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Reviews / Shetland’s geological journey explained

150610 Shetland geology

David Malcolm has already produced three very fine editions of A Photographic Guide to Shetland’s Wildflowers. Now he has teamed up with Shetland Amenity Trust geology officer Robina Barton to produce a comprehensive illustrated guide to the geology of Shetland, James Mackenzie writes.

Geology is a science that possibly many people have trouble coming to grips with, as the timescales involved are so huge. Even when events like the recent earthquakes in Nepal remind us that the vast Himalayan mountain range is the result of the ongoing collision of two continents, it’s still hard to comprehend how long ago and where these movements began and what immense forces are involved.

Shetland is quite unique in that it presents to the geologist evidence of “an incredible geological journey”, as the authors put it and explain to us. And they are to be congratulated for making that evidence so accessible to the layperson.

The book follows the conventional classification of rocks into the three major types: igneous (extrusive or volcanic, and intrusive), metamorphic, and sedimentary. Each section provides a brief history, and ample and excellent photographs of the different rocks, their formations and the minerals that are contained within them, in various locations in Shetland.

All the photographs have explanatory captions, which make what we are looking at easy to understand.

It is fascinating to realise that exposed rocks such as conglomerates and sandstones were formed by giant rivers and lakes and that Shetland was once part of a desert south of the equator; and that these exposures that we now see are the result of glaciation and erosion.

A further section describes the Shetland Ophiolite – an ancient oceanic floor – which forms parts of Unst and Fetlar, and which in the former was the origin of the Keen of Hamar and its unique flora.

The book concludes with short chapters on the uses humans have made of rock (and still do make) in Shetland, and on some miscellaneous rocks, and their colouration by weathering, minerals and vegetation. These are followed by a very useful glossary of terms.

There are also maps illustrating the geology of Shetland and places of special geological interest, and aptly – as the book is a guide and can be used in the field – a nine page identification chart where readers and explorers can note what they discover.

The fact that Shetland has been designated as a Global Geopark, recognised by UNESCO, is credit to the work that has been done in publicising geology in both the public and private sectors in Shetland.

There has also been a worldwide growing realisation that geological processes underpin both biodiversity and human social development – indeed the relatively new term ‘geodiversity’ is now often heard or seen.

As this book’s introduction emphasises: “Our bird life, wild flowers, human settlements and activity are all intricately bound up with the rocks around us and the soil beneath our feet!”

This book will ensure that local and visitor interest in geology will spread and grow, and it is to be hoped that, at national and local level, Shetland’s Geopark status will be given the recognition and support it so richly deserves.

A Photographic Guide to Shetland’s Geology – David Malcolm & Robina R. Barton (Shetland Times Ltd., 2015)