The first 2,500 million years of the geological history of Britain are stored in the gneisses of the Lewisian Complex of NW Scotland. Graham Park explores the long journey of discovery in which this history was gradually deciphered and the controversies and arguments in the scientific community over the past two centuries that arose in this period.

Developments in Petrology, 6: Trondhjemites, Dacites, and Related Rocks focuses on the geology, geochemistry, and petrology of several kinds of trondhjemites, dacites, and genetically related rocks. The selection first elaborates on the definition, environment, and hypotheses of origin of trondhjemite; a review of the mineralogy and chemistry of tertiary-recent dacitic, latitic, rhyolitic, and related salic volcanic rocks; and some trace elements in trondhjemites and their implications to magma genesis and paleotectonic setting. Discussions focus on tectonic environments and trace element patterns, selection and reliability of trace elements, interrelationships between mineralogy and chemistry, and regional variations of dacitic and rhyolitic magmas. The publication then tackles strontium isotope geochemistry of late Archean to late Cretaceous tonalites and trondhjemites; Archean gray gneisses and the origin of the continental crust in West Greenland; and metamorphic development of early Archean tonalitic and trondhjemitic gneisses in Saglek Area, Labrador. The book examines the petrology, geochemistry, and origin of the Sparta quartz dioritetrondhjemite complex; reconnaissance geochemistry of Devonian island-arc volcanic and intrusive rocks in West Shasta District, California; and origin of the Twillingate trondhjemite in North-Central Newfoundland. The selection is highly recommended for geologists and geochemists wanting to explore trondhjemites, dacites, and genetically related rocks.

Basic magmatic rocks make up approximately three-quarters of the crust ofthe present day Earth. Because we can observe and study the volcanic products of present day tectonic regimes comprehensively, we can shed light on ancient tectono-magmatic provinces, and thereby deduce the petrogenesis and evolution of the oldest basic rocks. This is the primary objective of this book. The book was conceived in order to provide a comprehensive review of the basic rocks produced during the first half of the Precambrian, i.e. the Archaean and early Proterozoic, to about 1.8 Ga years ago. Two major questions are addressed. First, what basic magmas were generated during the early Precambrian: were these magmas globally uniform, and to what extent were prevailing tectonic controls and compo sitions analogous to those of the present day? Clearly, this can be answered only by bringing together fundamental information about all relevant basic magmatic events. Second, is there any systematic temporal variation in the nature of basic suites, and what implications might such variations have on our interpretations of early Earth history? Are there important differences between early Archaean, late Archaean, Proterozoic and modern basic magmatic suites? The book uses two approaches to address these questions. Early chapters examine the fundamental characteristics of these basic rocks, whilst later chapters assess regional distribution and development by providing an overview of each major early Precambrian craton.

This book is for undergraduates, postgraduates and research workers who wish to gain an insight into present ideas and speculations on the origin of granite batholiths. It is a summary of the proceedings of a one-day meeting of the Geochemistry Group of the Mineralogical Society held at the University of liverpool on the 2nd May 1979, entitled The Origin of Granite Batholiths: Geochemical Evidence. It was felt that relevant new geochemical and isotopic data with associated field and petrological observations would be helpful in clarifying the main issues connected with the origin of granitic rocks. The speakers who participated contri buted a wealth of data and ideas to the problem, based on many years' experience of granitic rocks in various parts of the world. The popularity of the meeting indicated that a summary of the talks might be welcomed by a wider audience; hence this book. For reasons of length and cost, authors have been limited to presenting only the essential results necessary to develop their arguments and ideas. The comprehensive reference list will, however, assist those who wish to pursue specific aspects in greater detail. Inevitably, the cost and speed of publication may have resulted in some errors and inconsistencies which would not have occurred in a book produced over a longer time-span, but the editors hope that the rapid and up-to-date publication will offset this. The controversy over the origin of granite is as old as the science of geology.