The Interpretation Of Igneous Rocks

Our aim in writing this book is to try to show how igneous rocks can be persuaded to reveal some ofthe secrets of their origins. The data of igneous rocks consist of field relations, texture, mineralogy, and geochemistry. Additionally, experimental petrology tells us how igneous systems might be expected to behave. Working on this material we attempt to show how hypotheses concerning the origins and evolution of magmas are proposed and tested, and thus illuminate the interesting and fundamental problems of petrogenesis. The book assumes a modest knowledge of basic petro graphy, mineralogy, classification, and regional igneous geology. It has a role complementary to various established texts, several of which are descriptively good and give wide coverage and evaluation of petrogenetic ideas in various degrees of detail. Existing texts do not on the whole, however, deal with methodology, though this is one of the more important aspects of the subject. At first sight it may appear that the current work is a guidebook for the prospective research worker and thus has little relevance for the non-specialist student of geology. We hope this will prove to be far from the case. The methodological approach has an inherent interest because it can provide the reader with problems he can solve for himself, and as an almost incidental consequence he will acquire a satisfying understanding.

This book is for geoscience students taking introductory or intermediate-level courses in igneous petrology, to help develop key skills (and confidence) in identifying igneous minerals, interpreting and allocating appropriate names to unknown rocks presented to them. The book thus serves, uniquely, both as a conventional course text and as a practical laboratory manual. Following an introduction reviewing igneous nomenclature, each chapter addresses a specific compositional category of magmatic rocks, covering definition, mineralogy, eruption/ emplacement processes, textures and crystallization processes, geotectonic distribution, geochemistry, and aspects of magma genesis. One chapter is devoted to phase equilibrium experiments and magma evolution; another introduces pyroclastic volcanology. Each chapter concludes with exercises, with the answers being provided at the end of the book. Appendices provide a summary of techniques and optical data for microscope mineral identification, an introduction to petrographic calculations, a glossary of petrological terms, and a list of symbols and units. The book is richly illustrated with line drawings, monochrome pictures and colour plates. Additional resources for this book can be found at: http://www.wiley.com/go/gill/igneous.

Decades of field and microscope studies, and more recent quantitative geochemical analyses have resulted in a vast, and sometimes overwhelming, array of nomenclature and terminology associated with igneous rocks. This book presents a complete classification of igneous rocks based on all the recommendations of the International Union of Geological Sciences (IUGS) Subcommission on the Systematics of Igneous Rocks. The glossary of igneous terms has been fully updated since the first edition and now includes 1637 entries, of which 316 are recommended by the Subcommission. Incorporating a comprehensive bibliography of source references for all the terms included in the glossary, this book is an indispensable reference guide for all geologists studying igneous rocks, either in the field or the laboratory. It presents a standardised and widely accepted naming scheme that will allow geologists to interpret terminology in the primary literature and provide formal names for rock samples based on petrographic analyses. It is also supported by a website with downloadable code for chemical classifications.

Rock microstructures provide clues for the interpretation of rock history. A good understanding of the physical or structural relationships of minerals and rocks is essential for making the most of more detailed chemical and isotopic analyses of minerals. Ron Vernon discusses the basic processes responsible for the wide variety of microstructures in igneous, sedimentary, metamorphic and deformed rocks, using high-quality colour illustrations. He discusses potential complications of interpretation, emphasizing pitfalls, and focussing on the latest techniques and approaches. Opaque minerals (sulphides and oxides) are referred to where appropriate. The comprehensive list of relevant references will be useful for advanced students wishing to delve more deeply into problems of rock microstructure. Senior undergraduate and graduate students of mineralogy, petrology and structural geology will find this book essential reading, and it will also be of interest to students of materials science.