This dissertation discusses the experimental results designed to constrain the processes of MORB generation. The main focus of this study is to investigate the location and the related processes of the transformation boundary from spinel to garnet peridotite facies at subsolidus conditions, because the presence of garnet in melting residues has significant influence to the conclusion drawn from geochemical/geophysical observations. Using an approach that monitors the rate of reaction progresses, the experimental results confirmed the presence of a region that garnet and spinel coexist in peridotite compositions. The trace element distribution among the product phases (opx and cpx) subsequent to the garnet breakdown reaction is in disequilibrium, due to the differences of diffusivity between major and trace elements. The presence of disequilibrium distribution in nature may be used to infer time scales of geodynamic processes. Diffusion coefficients of A1 in diopside are experimentally determined, and used for modeling the equilibration of major elements in pyroxene during MORB genesis. In summary, this dissertation contributes two major inferences: the location of the transformation boundaries of the gamet-spinel peridotite; the presence of disequilibrium trace elements distribution with equilibrium major elements distribution in mantle pyroxenes.

Volume 39 of Reviews in Mineralogy and Geochemistry about Transformation Processes in Minerals summarises the current state of the art. The selection of transformation processes covered here is by no means comprehensive, but represents a coherent view of some of the most important processes which occur specifically in minerals. Contents: Rigid unit modes in framework structures Strain and elasticity at structural phase transitions in minerals Mesoscopic twin patterns in ferroelastic and co-elastic minerals High-pressure structural phase transitions Order-disorder phase transitions Phase transformations induced by solid solution Magnetic transitions in minerals NMR spectroscopy of phase transitions in minerals Insights into phase transformations from Mössbauer spectroscopy Hard mode spectroscopy of phase transitions Synchrotron studies of phase transformations Radiation-induced amorphization

One of the major developments in Earth Sciences in general, and mineralogy in particular, has been the growth of our understanding of the microscopic behaviour of the complex materials that make up the Earth. This has been made possible by advances in our ability to probe minerals at the atomic level, over a large range of pressure and temperature conditions. New experimental techniques include the use of scanning probe microscopies to investigate mineral surfaces, as well as the use of neutron scattering, nuclear spectroscopies and synchrotron radiation to investigate the bonding and structure of minerals. In addition, there have been major developments in computational methods so that it is now possible to calculate the electronic structure of many rock forming materials. The aim of this volume is to give a coherent survey of the latest developments in experimental and theoretical approaches to the study of microscopic propertie~ and processes in minerals. Chapters in the book cover a number of key themes in the mineral sciences such as the behaviour of minerals at extremes of pressure and temperature, ordering in complex silicates, mechanisms of water incorporation in mantle phases, the importance of reactions occurring at the mineral surface, and the ability of computational methods to provide useful, qualitative information on the bulk and surface properties of minerals. The background to several experimental techniques is covered in some detail with examples of relevance to the issues cited above.

With contributions by numerous experts

Volume 8 of Reviews in Mineralogy treats a Short Course in Kinetics, which brings together the fundamentals needed to explain field observations using kinetic data. It is hoped that this book may serve, not only as a reference for researchers dealing with the rates of geochemical processes, but also as a text in courses on geochemical kinetics. The book is organized with a rough temperature gradient in mind, i.e. low temperature kinetics at the beginning and igneous kinetics at the end. However, the topics in each chapter are general enough that they can be applied often to any geochemical domain: sedimentary, metamorphic or igneous. The theory of kinetics operates at two complementary levels: the phenomenological and the atomistic. The former relies on macroscopic variables (e.g. temperature or concentrations) to describe the rates of reactions or the rates of transport; the latter relates the rates to the basic forces operating between the particular atomic or molecular species of any system. This book deals with both descriptions of the kinetics of geochemical processes.

This book offers a comprehensive exploration of geochemical kinetics--the application of chemical kinetics to geological problems, both theoretical and practical. Geochemical Kinetics balances the basic theories of chemical kinetics with a thorough examination of advanced theories developed by geochemists, such as nonisothermal kinetics and inverse theories, including geochronology (isotopic dating), thermochronology (temperature-time history), and geospeedometry (cooling rates). The first chapter provides an introduction and overview of the whole field at an elementary level, and the subsequent chapters develop theories and applications for homogeneous reactions, mass and heat transfer, heterogeneous reactions, and inverse problems. Most of the book's examples are from high-temperature geochemistry, with a few from astronomy and environmental sciences. Appendixes, homework problems for each major section, and a lengthy reference list are also provided. Readers should have knowledge of basic differential equations, some linear algebra, and thermodynamics at the level of an undergraduate physical chemistry course. Geochemical Kinetics is a valuable resource for anyone interested in the mathematical treatment of geochemical questions.

Volume 69 of Reviews in Mineralogy and Geochemistry covers the fundamental issues of volcanology: At what depths are eruptions triggered, and over what time scales? Where and why do magmas coalesce before ascent? If magmas stagnate for thousands of years, what forces are responsible for initiating final ascent, or the degassing processes that accelerate upward motion? To the extent that we can answer these questions, we move towards formulating tests of mechanistic models of volcanic eruptions (e.g., Wilson, 1980; Slezin, 2003; Scandone et al., 2007), and hypotheses of the tectonic controls on magma transport (e.g., ten Brink and Brocher, 1987; Takada, 1994; Putirka and Busby, 2007). Our goal, in part, is to review how minerals can be used to understand volcanic systems and the processes that shape them; we also hope that this work will spur new and integrated studies of volcanic systems.