ALBERT

Description / Table of Contents: The review chapters in this volume were the basis for a short course on molecular modeling theory jointly sponsored by the Geochemical Society (GS) and the Mineralogical Society of America (MSA) May 18-20, 2001 in Roanoke, Virginia which was held prior to the 2001 Goldschmidt Conference in nearby Hot Springs, Virginia. Dr. William C. Luth has had a long and distinguished career in research, education and in the government. He was a leader in experimental petrology and in training graduate students at Stanford University. His efforts at Sandia National Laboratory and at the Department of Energy's headquarters resulted in the initiation and long-term support of many of the cutting edge research projects whose results form the foundations of these short courses. Bill's broad interest in understanding fundamental geochemical processes and their applications to national problems is a continuous thread through both his university and government career. He retired in 1996, but his efforts to foster excellent basic research, and to promote the development of advanced analytical capabilities gave a unique focus to the basic research portfolio in Geosciences at the Department of Energy. He has been, and continues to be, a friend and mentor to many of us. It is appropriate to celebrate his career in education and government service with this series of courses in cutting-edge geochemistry that have particular focus on Department of Energy-related science, at a time when he can still enjoy the recognition of his contributions. Molecular modeling methods have become important tools in many areas of geochemical and mineralogical research. Theoretical methods describing atomistic and molecular-based processes are now commonplace in the geosciences literature and have helped in the interpretation of numerous experimental, spectroscopic, and field observations. Dramatic increases in computer power-involving personal computers, workstations, and massively parallel supercomputers-have helped to increase our knowledge of the fundamental processes in geochemistry and mineralogy. All researchers can now have access to the basic computer hardware and molecular modeling codes needed to evaluate these processes. The purpose of this volume of Reviews in Mineralogy and Geochemistry is to provide the student and professional with a general introduction to molecular modeling methods and a review of various applications of the theory to problems in the geosciences. Molecular mechanics methods that are reviewed include energy minimization, lattice dynamics, Monte Carlo methods, and molecular dynamics. Important concepts of quantum mechanics and electronic structure calculations, including both molecular orbital and density functional theories, are also presented. Applications cover a broad range of mineralogy and geochemistry topics-from atmospheric reactions to fluid-rock interactions to properties of mantle and core phases. Emphasis is placed on the comparison of molecular simulations with experimental data and the synergy that can be generated by using both approaches in tandem. We hope the content of this review volume will help the interested reader to quickly develop an appreciation for the fundamental theories behind the molecular modeling tools and to become aware of the limits in applying these state-of-the-art methods to solve geosciences problems.

Description / Table of Contents: This book has been several years in the making, under the experienced and careful oversight of Ed Grew (University of Maine), who edited (with Larry Anovitz) a similar, even larger volume in 1996: Boron: Mineralogy, Petrology, and Geochemistry (RiMG Vol. 33, reprinted with updates and corrections, 2002). Many of the same reasons for inviting investigators to contribute to a volume on B apply equally to a volume on Be. Like B, Be poses analytical difficulties, and it has been neglected in many studies. However, with recent improvements in analytical technology, interest in Be and its cosmogenic isotopes has increased greatly. Chapter 1 (Grew) is an overview of Be studies in the earth sciences backed by an extensive reference list, and an annotated list of the 110 mineral species reported to contain essential Be as of 2002, together with commentary on their status. A systematic classification of Be minerals based on their crystal structure is presented in Chapter 9 (Hawthorne and Huminicki), while analysis of these minerals by the secondary ion mass spectroscopy is the subject of Chapter 8 (Hervig). Chapter 13 (Franz and Morteani) reviews experimental studies of systems involving Be. Chapter 2 (Shearer) reviews the behavior of Be in the Solar System, with an emphasis on meteorites, the Moon and Mars, and the implications of this behavior for the evolution of the solar system. Chapter 3 (Ryan) is an overview of the terrestrial geochemistry of Be, and Chapter 7 (Vesely, Norton, Skrivan, Majer, Krám, Navrátil, and Kaste) discusses the contamination of the environment by this anthropogenic toxin. The cosmogenic isotopes Be-7 and Be-10 have found increasing applications in the Earth sciences. Chapter 4 (Bierman, Caffee, Davis, Marsella, Pavich, Colgan and Mickelson) reports use of the longer lived Be-10 to assess erosion rates and other surficial processes, while Chapter 5 (Morris, Gosse, Brachfeld and Tera) considers how this isotope can yield independent temporal records of geomagnetic field variations for comparison with records obtained by measuring natural remnant magnetization, be a chemical tracer for processes in convergent margins, and can date events in Cenozoic tectonics. Chapter 6 (Kaste, Norton and Hess) reviews applications of the shorter lived isotope Be-7 in environmental studies. Beryllium is a lithophile element concentrated in the residual phases of magmatic systems. Residual phases include acidic plutonic and volcanic rocks, whose geochemistry and evolution are covered, respectively, in Chapters 11 (London and Evensen) and 14 (Barton and Young), while granitic pegmatites, which are well-known for their remarkable, if localized, Be enrichments and a wide variety of Be mineral assemblages, are reviewed in Chapter 10 (Cerny). Not all Be concentrations have obvious magmatic affinities; for example, one class of emerald deposits results from Be being introduced by heated brines (Chapters 13; 14). Pelitic rocks are an important reservoir of Be in the Earth's crust and their metamorphism plays a critical role in recycling of Be in subduction zones (Chapter 3), eventually, anatectic processes complete the cycle, providing a source of Be for granitic rocks (Chapters 11 and 12).

Description / Table of Contents: Earth is a water planet. Oceans of liquid water dominate the surface processes of the planet. On the surface, water controls weathering as well as transport and deposition of sediments. Liquid water is necessary for life. In the interior, water fluxes melting and controls the solid-state viscosity of the convecting mantle and so controls volcanism and tectonics. Oceans cover more than 70% of the surface but make up only about 0.025% of the planet's mass. Hydrogen is the most abundant element in the cosmos, but in the bulk Earth, it is one of the most poorly constrained chemical compositional variables. Almost all of the nominally anhydrous minerals that compose the Earth's crust and mantle can incorporate measurable amounts of hydrogen. Because these are minerals that contain oxygen as the principal anion, the major incorporation mechanism is as hydroxyl, OH-, and the chemical component is equivalent to water, H2O. Although the hydrogen proton can be considered a monovalent cation, it does not occupy same structural position as a typical cation in a mineral structure, but rather forms a hydrogen bond with the oxygens on the edge of the coordination polyhedron. The amount incorporated is thus quite sensitive to pressure and the amount of H that can be incorporated in these phases generally increases with pressure and sometimes with temperature. Hydrogen solubility in nominally anhydrous minerals is thus much more sensitive to temperature and pressure than that of other elements. Because the mass of rock in the mantle is so large relative to ocean mass, the amount that is incorporated the nominally anhydrous phases of the interior may constitute the largest reservoir of water in the planet. Understanding the behavior and chemistry of hydrogen in minerals at the atomic scale is thus central to understanding the geology of the planet. There have been significant recent advances in the detection, measurement, and location of H in the nominally anhydrous silicate and oxide minerals that compose the planet. There have also been advances in experimental methods for measurement of H diffusion and the effects of H on the phase boundaries and physical properties whereby the presence of H in the interior may be inferred from seismic or other geophysical studies. It is the objective of this volume to consolidate these advances with reviews of recent research in the geochemistry and mineral physics of hydrogen in the principal mineral phases of the Earth's crust and mantle.

Description / Table of Contents: Fluids rich in water, carbon and sulfur species and a variety of dissolved salts are a ubiquitous transport medium for heat and matter in the Earth’s interior. Fluid transport through the upper mantle and crust controls the origin of magmatism above subduction zones and results in natural risks of explosive volcanism. Fluids passing through rocks affect the chemical and heat budget of the global oceans, and can be utilized as a source of geothermal energy on land. Fluid transport is a key to the formation and the practical utilization of natural resources, from the origin of hydrothermal mineral deposits, through the exploitation of gaseous and liquid hydrocarbons as sources of energy and essential raw materials, to the subsurface storage of waste materials such as CO2. Different sources of fluids and variable paths of recycling volatile components from the hydrosphere and atmosphere through the solid interior of the Earth lead to a broad range of fluid compositions, from aqueous liquids and gases through water-rich silicate or salt melts to carbon-rich endmember compositions. Different rock regimes in the crust and mantle generate characteristic ranges of fluid composition, which depending on pressure, temperature and composition are miscible to greatly variable degrees. For example, aqueous liquids and vapors are increasingly miscible at elevated pressure and temperature. The degree of this miscibility is, however, greatly influenced by the presence of additional carbonic or salt components. A wide range of fluid–fluid interactions results from this partial miscibility of crustal fluids. Vastly different chemical and physical properties of variably miscible fluids, combined with fluid flow from one pressure – temperature regime to another, therefore have major consequences for the chemical and physical evolution of the crust and mantle. Several recent textbooks and review articles have addressed the role and diverse aspects of fluids in crustal processes. However, immiscibility of fluids and the associated phenomena of m ultiphase fluid flow are generally dealt with only in subsections with respect to specific environments and aspects of fluid mediated processes. This volume of Reviews in Mineralogy and Geochemistry attempts to fill this gap and to explicitly focus on the role that co-existing fluids play in the diverse geologic environments. It brings together the previously somewhat detached literature on fluid–fluid interactions in continental, volcanic, submarine and subduction zone environments. It emphasizes that fluid mixing and unmixing are widespread processes that may occur in all geologic environments of the entire crust and upper mantle. Despite different P-T conditions, the fundamental processes are analogous in the different settings.

Description / Table of Contents: Over 25 years ago, Volume 9 of Reviews in Mineralogy: Amphiboles and Other Hydrous Pyriboles seemed to contain all that was possible to know about this group of fascinating minerals. The subsequent twenty-five years have shown that this assessment was wrong: Nature was keeping a lot in reserve, and has since revealed considerable new complexity in the constitution and behavior of amphiboles. Some of the advances in knowledge have been due to the use of new experimental techniques, some have been due to the investigation of hitherto neglected rock-types, and some have been due to the development of new ideas. The identification and systematic investigation of variable LLE (Light Lithophile Elements), particularly Li and H, led to the identification of several new amphibole species and the recognition that variable Li and H play an important role in chemical variations in amphiboles from both igneous and metamorphic parageneses. In turn, this work drove the development of microbeam SIMS to analyze LLE in amphiboles. Detailed mineralogical work on metasyenites showed hitherto unexpected solid-solution between Na and Li at the M(4) site in monoclinic amphiboles, a discovery that has upset the current scheme of amphibole classification and nomenclature and initiated new efforts in this direction. Systematic and well-planned synthesis of amphiboles, combined with careful spectroscopy, has greatly furthered our understanding of cation and anion order in amphiboles. The use of bond-valence theory to predict patterns of SRO (Short-Range Order) in amphiboles, and use of these predictions to understand the infrared spectra of well-characterized synthetic-amphibole solid-solutions, has shown that SRO is a major feature of the amphibole structure, and has resulted in major advances in our understanding of SRO in minerals. There has been significant progress relating changes in amphibole composition and cation ordering to petrogenetic conditions and trace-element behavior. Work on the nature of fibrous amphiboles and their toxicity and persistence in living organisms has emphasized the importance of accurate mineralogical characterization in environmental and health-related problems. The current volume has taken a different approach from previous volumes concerned with major groups of rock-forming minerals. Some of the contents have previously been organized by the investigative technique or groups of similar techniques: crystal-structure refinement, spectroscopy, TEM etc. Here, we have taken an approach that focuses on aspects of amphiboles rather than experimental techniques: crystal chemistry, new compositions, long-range order, short-range order etc., and all experimental results germane to these topics are discussed in each chapter. The intent of this approach is to focus on amphiboles, and to emphasize that many techniques are necessary to fully understand each aspect of the amphiboles and their behavior in both natural and industrial processes.

Description / Table of Contents: Medical Mineralogy and Geochemistry is an emergent, highly interdisciplinary field of study. The disciplines of mineralogy and geochemistry are integral components of cross-disciplinary investigations that aim to understand the interactions between geomaterials and humans as well as the normal and pathological formation of inorganic solid precipitates in vivo. Research strategies and methods include but are not limited to: stability and solubility studies of earth materials and biomaterials in biofluids or their proxies (i.e., equilibrium thermodynamic studies), kinetic studies of pertinent reactions under conditions relevant to the human body, molecular modeling studies, and geospatial and statistical studies aimed at evaluating environmental factors as causes for activating certain chronic diseases in genetically predisposed individuals or populations. Despite its importance, the area of Medical Mineralogy and Geochemistry has received limited attention by scientists, administrators, and the public. The objectives of this volume are to highlight some of the existing research opportunities and challenges, and to invigorate exchange of ideas between mineralogists and geochemists working on medical problems and medical scientists working on problems involving geomaterials and biominerals. Examples presented in this volume (Table of contents below) include the effects of inhaled dust particles in the lung (Huang et al. 2006; Schoonen et al. 2006), biomineralization of bones and teeth (Glimcher et al. 2006), the formation of kidney-stones, the calcification of arteries, the speciation exposure pathways and pathological effects of heavy metal contaminants (Reeder et al. 2006; Plumlee et al. 2006), the transport and fate of prions and pathological viruses in the environment (Schramm et al. 2006), the possible environmental-genetic link in the occurrence of neurodegenerative diseases (Perl and Moalem 2006), the design of biocompatible, bioactive ceramics for use as orthopaedic and dental implants and related tissue engineering applications (Cerruti and Sahai 2006) and the use of oxide-encapsulated living cells for the development of biosensors (Livage and Coradin 2006).

Description / Table of Contents: This volume presents an extended review of the topics conveyed in a short course on Geothermal Fluid Thermodynamics held prior to the 23rd Annual V.M. Goldschmidt Conference in Florence, Italy (August 24–25, 2013). Geothermal fluids in the broadest sense span large variations in composition and cover wide ranges of temperature and pressure. Their composition may also be dynamic and change in space and time on both short and long time scales. In addition, physiochemical properties of fluids such as density, viscosity, compressibility and heat capacity determine the transfer of heat and mass by geothermal systems, whereas, in turn, the physical properties of the fluids are affected by their chemical properties. Quantitative models of the transient spatial and temporal evolution of geochemical fluid processes are, therefore, very demanding with respect to the accuracy and broad range of applicability of thermodynamic databases and thermodynamic models (or equations of state) that describe the various datasets as a function of temperature, pressure, and composition. The application of thermodynamic calculations is, therefore, a central part of geochemical studies of very diverse processes ranging from the aqueous geochemistry of near surface geothermal features including chemosynthesis and thermal biological activity, through the utilization of crustal reservoirs for CO2 sequestration and engineered geothermal systems to the formation of magmatic-hydrothermal ore deposits and, even deeper, to the de-volatilization of subducted oceanic crust and the transfer of subduction fluids and trace elements into the mantle wedge. Application of thermodynamics to understand geothermal fluid chemistry and transport requires essentially three parts: first, equations of state to describe the physiochemical system; second, a geochemical model involving minerals and fluid species; and, third, values for various thermodynamic parameters from which the thermodynamic and chemical model can be derived. The two biggest current hurdles for comprehensive geochemical modeling of geothermal systems are …

Description / Table of Contents: 'Building materials' as a generic term encompasses steel, aluminum, copper and a range of metal alloys, glass and glaze, particulate materials like sand, gravel, or crushed rock, and natural stone of sedimentary, igneous or metamorphic origin. Each of these materials sees a wide range of applications, from structural/bearing via functional to merely ornamental and decorative. The wide range of 'building materials' application is achieved through an equally wide range of processing, from use 'as is' (e.g., stacking boulders to make a retaining wall), through simple re-dimensioning and fitting (e.g., splitting and sizing of roofing slate) to purification and complex treatment in multi-stage processing (e.g., glass, Portland cement clinker, concreting). The use of building materials, their applications and processing has changed considerably with the development of civilization and technology. Consequently, comprehensive coverage of building materials, applications, processing and history would require multiple volumes. This volume contains a selection of papers on the applied mineralogy of cement and concrete, by far the most popular modern building material by volume, with an annual production exceeding 9 billion cubic meters, and steadily growing. Not even all 'concrete' topics can be covered by a single volume, but an interesting assortment was finally obtained. The seven chapters deal with mineralogy and chemistry of (alumina) clinker production and hydration (Pöllmann), alternative raw clinkering materials to reduce CO2 emission (Justnes), assessment of clinker constituents by optical and electron microscopy (Stutzman), industrial assessment of raw materials, cement and concrete using X-ray methods in different applications (Meier et al.), in situ investigation of clinker and cement hydration based on quantitative crystallographic phase analysis (Aranda et al.), characterization and properties of supplementary cementitious materials (SCMs) to improve cement and concrete properties (Snellings et al.), and deleterious alkali-aggregate reaction (AAR) in concrete (Broekmans).

Description / Table of Contents: In high-temperature geochemistry and cosmochemistry, highly siderophile and strongly chalophile elements can be defined as strongly preferring metal or sulfide, respectively, relative to silicate or oxide phases. The highly siderophile elements (HSE) comprise Re, Os, Ir, Ru, Pt, Rh, Pd, and Au and are defined by their extreme partitioning (〉104) into the metallic phase, but will also strongly partition into sulfide phases, in the absence of metal. The HSE are highly refractory, as indicated by their high melting and condensation temperatures and were therefore concentrated in early accreted nebular materials. Within the HSE are the platinum-group elements (PGE), which include the six elements lying in the d-block of the periodic table (groups 8, 9, and 10, periods 5 and 6), i.e., Os, Ir, Ru, Pt, Rh and Pd. These six elements tend to exist in the metallic state, or bond with chalcogens (S, Se, Te) or pnictogens (P, As, Sb, Bi). Rhenium and Au do not necessarily behave as coherently as the PGE, due to their differing electronegativity and oxidation states. For these reasons, a clear definition between the discussion of the PGE and the HSE (PGE, Re and Au) exists in the literature, especially in economic geology, industrial, or bio-medical studies. The strongly chalcophile elements can be considered to include S, Se, and Te. These three elements are distinguished from other chalcophile elements, such as Cd or Pb, because, like the HSE, they are all in very low abundances in the bulk silicate Earth. By contrast with the HSE, S, Se, and Te all have far lower melting and condensation temperatures, classifying them as highly volatile elements. Moreover, these elements are not equally distributed within chondrite meteorite groups. Since their initial distribution in the Solar nebula, planetary formation and differentiation process have led to large fractionations of the HSE and strongly chalcophile elements, producing a range of absolute and relative inter-element fractionations. The chemical properties of the HSE, that set them apart from any other elements in the periodic table, have made them geochemical tracers par excellence. As tracers of key processes, the HSE have found application in virtually all areas of the physical Earth sciences. These elements have been used to inform on the nucleosynthetic sources and formation of the Solar System, planetary differentiation, late accretion addition of elements to planets, core-formation and possible core-mantle interaction, crust-mantle partitioning, volcanic processes and outgassing, formation of magmatic, hydrothermal and epithermal ore deposits, ocean circulation, climate-related events, weathering, and biogeochemical cycling. More recently, studies of strongly chalcophile elements are finding a similar range of applications. Their utility lies in the fact that these elements will behave as siderophile or strongly chalcophile elements under reducing conditions, but will also behave as lithophile or atmophile elements under oxidizing conditions, as experienced at the present day Earth’s surface. A key aspect of the HSE is that three long-lived, geologically useful decay systems exist with the HSE as parent (107Pd–107Ag), or parent–daughter isotopes (187Re–187Os and 190Pt–186Os). This volume is dedicated to some of the processes that can be investigated at high-temperatures in planets using the HSE and strongly chalcophile elements. While this volume is not dedicated to the practical applications of the HSE and strongly chalcophile elements, it would be remiss not to briefly discuss the importance of these elements in society. All of these elements have found important societal use, from the application of Au as a valued commodity in early societies, through to the present-day; the importance of S and Se in biological processes; the discovery and implementation of Pt, Pd, and subsequently other PGE to catalytic oxidation, and the importance of the anti-cancer drug cisplatin (cis-[Pt(NH3)2Cl2]) to anti-tumour treatments. The use of the PGE, most especially Pt, Pd and Rh, in the automotive industry to generate harmless gases has caused some potential collateral effects; the possible environmental impact and human health-risks from available PGE in the environment. An entire volume can (and should!) equally be written on the utility of the HSE and strongly chalcophile elements during low-temperature geochemistry. In this volume, a number of key areas are reviewed in the use of the HSE and strongly chalcophile elements to investigate fundamental processes in high-temperature geochemistry and cosmochemistry. It is divided into five parts. The first part of the volume concerns measurements and experiments. Chapter 1, by Brenan et al. (2016), provides an comprehensive overview of experimental constraints applied to understanding HSE partitioning under a range of conditions, including: liquid metal–solid metal; metal– silicate; silicate–melt; monosulfide solid solution (MSS)–sulfide melt; sulfide melt–silicate melt; silicate melt–aqueous fluid–vapor. Chapter 2, by Meisel and Horan (2016) provides a summary of analytical methods, issues specifically associated with measurement of the HSE, and a review of important reference materials. The second part of the volume concerns the cosmochemical importance of the HSE and strongly chalcophile elements. In their assessment of nucleosynthetic isotopic variations of siderophile and chalcophile elements in Solar System materials, Yokoyama and Walker (2016, Chapter 3) discuss some of the fundamentals of stellar nucleosynthesis, the evidence for nucleosynthetic anomalies in pre-Solar grains, bulk meteorites and individual components of chondrites, ultimately providing a synthesis on the different information afforded by nucleosynthetic anomalies of Ru, Mo, Os, and other siderophile and chalcophile elements. Chapter 4 concerns the HSE in terrestrial bodies, including the Earth, Moon, Mars and asteroidal bodies for which we have materials as meteorites. Day et al. (2016) provide a summary of HSE abundance and 187Os/188Os variations in the range of materials available and a synthesis of initial Solar System composition, evidence for late accretion, and estimates of current planetary mantle composition. The third part of the volume concerns our understanding of the Earth’s mantle from direct study of mantle materials. In Chapter 5, Aulbach et al. (2016) discuss the importance and challenges associated with understanding HSE in the cratonic mantle, providing new HSE alloy solubility modelling for melt extraction at pressures, temperatures, fO2 and fS2 pertaining to conditions of cratonic mantle lithosphere formation. Luguet and Reisberg (2016) provide similar constraints on non-cratonic mantle in Chapter 6, emphasizing the importance of combined geochemical and petrological approaches to fully understand the histories of mantle peridotites. The information derived from studies of Alpine peridotites, obducted ophiolites and oceanic abyssal peridotites are reviewed in Chapter 7 by Becker and Dale (2016). The fourth part of the volume focusses on important minerals present in the mantle and crust. Chapter 8 provides a broad overview of mantle chalcophiles. In this chapter, Lorand et al. (2016) emphasise that chalcophile and siderophile elements are important tracers that can be strongly affected by host minerals as a function of sulfur-saturation, redox conditions, pressure, temperature, fugacity of sulfur, and silicate melt compositions. Along a similar theme in Chapter 9, O’Driscoll and Gonzalez-Jimenez (2016) provide an overview of platinum-group minerals (PGM), pointing out that, where present PGM dominate the HSE budget of silicate rocks. Finally in this section, Harvey et al. (2016) examine the importance of Re–Os–Pb isotope dating methods of sulfides for improving our understanding of mantle processes (Chapter 10). The fifth and final part of the volume considers the important of the HSE for studying volcanic and magmatic processes. In Chapter 11, Gannoun et al. (2016) provide a synthesis of the most abundant forms of volcanism currently operating on Earth, including mid-ocean ridge basalts, volcanism unassociated with plate boundaries, and subduction zone magmatism. The volume is completed in Chapter 12 by Barnes and Ripley (2016), by an appraisal of the obvious importance of magmatic HSE ore formation in Earth’s crust.

Description / Table of Contents: The pore scale is readily recognizable to geochemists, and yet in the past it has not received a great deal of attention as a distinct scale or environment that is associated with its own set of questions and challenges. Is the pore scale merely an environment in which smaller scale (molecular) processes aggregate, or are there emergent phenomena unique to this scale? Is it simply a finer-grained version of the “continuum” scale that is addressed in larger-scale models and interpretations? We would argue that the scale is important because it accounts for the pore architecture within which such diverse processes as multi-mineral reaction networks, microbial community interaction, and transport play out, giving rise to new geochemical behavior that might not be understood or predicted by considering smaller or larger scales alone. Fortunately, the last few years have seen a marked increase in the interest in pore-scale geochemical and mineralogical topics, making a Reviews in Mineralogy and Geochemistry volume on the subject timely. The volume had its origins in a special theme session at the 2015 Goldschmidt Conference, Prague, Czech Republic, August 16-21, 2015, where at least some of the contributors to this volume gave presentations. From the diversity of pore-scale topics in the session that spanned the range from multi-scale characterization to modeling, it became clear that the time was right for a volume that would summarize the state of the science. Based in part on the evidence in the chapters included here, we would argue that the convergence of state of the art microscopic characterization and high performance pore scale reactive transport modeling has made it possible to address a number of long-standing questions and enigmas in the Earth and Environmental Sciences. Among these is the so-called “laboratory-field discrepancy” in geochemical reaction rates, which may be traceable in part to the failure to consider porescale geochemical issues that include chemical and physical heterogeneity, suppression of precipitation in nanopores, and transport limitations to and from reactive mineral surfaces. This RiMG volume includes contributions that review experimental, characterization, and modeling advances in our understanding of pore-scale geochemical processes. The volume begins with chapters authored or co-authored by two of the éminences grises in the field of pore-scale geochemistry and mineralogy, two who have made what is perhaps the strongest case that the pore-scale is distinct and requires special consideration in geochemistry. The chapter by Andrew Putnis gives a high level overview of how the pore-scale architecture of natural porous media impacts geochemical processes, and how porosity evolves as a result of these. The chapter makes the first mention of what is an important theme in this volume, namely the modification of thermodynamics and kinetics in small pores. In a chapter authored by Røyne and Jamtveit, the authors investigate the effects of mineral precipitation on porosity and permeability modification of rock. Their principal focus is on the case where porosity reduction results in fracturing of the rock, in the absence of which the reactions will be suppressed due to the lack of pore space. The next chapter by Emmanuel, Anovitz, and Day-Stirrat addresses chemo-mechanical processes and how they affect porosity evolution in geological media. The next chapter by Anovitz and Cole provides a comprehensive review of the approaches for characterizing and analyzing porosity in porous media. Small angle neutron scattering (SANS) plays prominently as a technique in this chapter. Stack presents a review of what is known about mineral precipitation in pores and how this may differ from precipitation in bulk solution. Liu, Liu, Kerisit, and Zachara focus on porescale process coupling and the determination of effective (or upscaled) surface reaction rates in heterogeneous subsurface materials. Micro-continuum modeling approaches are investigated by Steefel, Beckingham, and Landrot, where the case is made that these may provide a useful tool where the computationally more expensive pore and pore network models are not feasible. The next chapter by Noiriel pursues the focus on characterization techniques with a review of X-ray microtomography (especially synchrotron-based) and how it can be used to investigate dynamic geochemical and physical processes in porous media. Tournassat and Steefel focus on a special class of micro-continuum models that include an explicit treatment of electrostatic effects, which are particularly important in the case of clays or clay-rich rock. Navarre-Sitchler, Brantley, and Rother present an overview of our current understanding of how porosity increases as a result of chemical weathering in silicate rocks, bringing to bear a range of characterization and modeling approaches that build toward a more quantitative description of the process. In the next chapter, Druhan, Brown, and Huber demonstrate how isotopic gradients across fluid–mineral boundaries can develop and how they provide insight into pore-scale processes. Yoon, Kang, and Valocchi provide a comprehensive review of lattice Boltzmann modeling techniques for pore-scale processes. Mehmani and Balhoff summarize mesoscale and hybrid models for flow and transport at the pore scale, including a discussion of the important class of models referred to as “pore network” that typically can operate at a larger scale than is possible with the true pore-scale models. Molins addresses the problem of how to represent interfaces (solid–fluid) at the pore scale using direct numerical simulation.