The Lewisian: Britain's oldest rocks

The Lewisian Complex of North West Scotland contains the first 2,500 million years of Britain's geological history, and this book explores the long journey of discovery in which this history has been gradually deciphered since the end of the 19th century. Geochronological and geochemical techniques have evolved to the point where mafic igneous assemblages can be identified as having oceanic volcanic arc signatures or were the products of intra-continental magmatism, and a complex history covering many separate events of igneous, metamorphic and tectonic activity spanning 2,500 million years of Precambrian time has grown from a stratigraphy composed of three events.

Format: Hardback
Length: 336 pages
Publication date: 24 February 2022
Publisher: Dunedin Academic Press

The geological history of Britain is preserved within the gneisses of the Lewisian Complex in North West Scotland, spanning the first 2,500 million years. This captivating book delves into the long and intricate journey of discovery that has unfolded since the late 19th century, when these rocks were initially investigated in detail. The conventional tools of stratigraphic analysis proved inadequate in unraveling the intricate tapestry of highly deformed and metamorphosed rocks, lacking fossil evidence and discernible sedimentary strata.

This book meticulously charts the evolving sophistication of geochronological and geochemical techniques employed to unravel the complex. The initial breakthrough came with the recognition that a series of intrusive metamorphosed dykes could serve as a valuable tool for separating episodes of deformation and metamorphism that predated the dyke intrusions from those that occurred subsequently.

Geochronological dating methods have undergone a remarkable transformation, evolving from the initial crude potassium-argon and uranium-lead dates in the 1950s to the present-day remarkably accurate lead isotope dates. Geochemical techniques have also advanced to the point where mafic igneous assemblages can be identified with oceanic volcanic arc signatures or as products of intra-continental magmatism. Thus, a stratigraphy initially composed of three events—the Scourian, dyke intrusion, and Laxfordian—has evolved into a comprehensive history encompassing numerous distinct igneous, metamorphic, and tectonic activities spanning 2,500 million years of Precambrian time.

However, much of the extensive literature on the Lewisian Complex is highly specialized and may not be readily accessible to the general reader. This book serves as an endeavor to distill the most significant findings of this research into a more user-friendly format. By exploring the intricate details of the Lewisian Complex's geological history, this book offers valuable insights into the Earth's ancient past and sheds light on the processes that shaped our planet.

Dimension: 260 x 200 (mm)
ISBN-13: 9781780460987