This book is designed to be used as an introduction to geochemistry by undergraduate and graduate chemistry and geology students as well as by those from other sciences. It summarizes the significant facts and ideas concerning the chemistry of the earth and synthesizes these data into an account of the physical and chemical evolution ol the earth. The aim of the book is to explore an intlresting, complex, and changing subject. An attempt has !'een made to cover the entire field of geochemistry. However, not alI subjects have been coveredwith equal detail becauseto properly cover the facts and theories would require a volume far too long to be suitably used as a text. Some areas of geochemical interest such as phase diagrams and ore deposits have been adopted by other courses in thc geology curriculum. and thermodynamics, a key to understanding geochemical processes, requires the depth of presentation given in physical chemistry courses. <...>

The second edition of Principles of Igneous and Metamorphic Petrology follows the same general approach as the first edition. The book is designed to introduce igneous and metamorphic petrology to those who have completed introductory college-level courses in physics, chemistry, and calculus. Its emphasis is on principles and understanding rather than on facts and memorization. With this approach, it is hoped that students will not only gain a sound understanding of petrology but will develop skills that can be applied to the analysis of problems in many other fields of Earth Science. <...>

Igneous petrology was to some extent essentially a descriptive science until about 1960. The results were mainly obtained from field work, major element analyses, and microscopical studies. During the 1960's two simultaneous developments took place, plate tectonics became generally accepted, and the generation of magmas could now be related to the geodynamic features like convection cells and subduction zones. The other new feature was the development of new analytical apparatus which allowed high accuracy analyses of trace elements and isotopes. In addition it became possible to do experimental studies at pressures up to 100 kbar. <...>

Metamorphism refers lo Ihe inineni logical and structural alteration of rock к in Karth's crust, and excludes alteration at or just beneath ihe surface, such as weathering and early diagencsis. However, diagenetic changes grade into mctamorphic changes in burial meuimorphism. In face* metamor-phism may occur in several geological environments, because assemblages react to changes in temperature (T), pressure (iJ) and activities of mobile chemical components, regardless ol the geological processes responsible for the changes. For example, identical or very similar assemblages can be formed by (1) deuleric alteration in an igneous intrusion 12) wall-rock alteration around a hydro! hernia) orebody. (3) low-tempe rat lire alteration around an igneous intrusion, (4) burial metamorphism of sedimentary/volcanic successions and (5) alteration, both local and regional, in geothermal areas (Vernon. 1976f.