Stable isotope analyses are a relative measurement. The precision is far higher than the accuracy, so that subtle isotopic differences must be made relative to a reference. Modern mass spectrometers can routinely measure the δ18O value of a gas with a precision of 0.01‰. This is 20 times more precise than the accuracy of the 18O/16O ratio of VSMOW (Baertschi 1976). It is for this reason that isotope

Since the first volume of the Reviews in Mineralogy was published in 1974, this series (expanded to Reviews in Mineralogy and Geochemistry in 2000) has grown to an invaluable library comprising 86 volumes on various topics related to mineralogy and geochemistry. Often a volume from that series is given by an advisor to a young graduate student or postdoc as a roadmap when they enter a new research

For many years, it was considered that measurements of the least abundant stable isotope of oxygen, 17O, would not provide any information additional to that obtainable from determinations of the 18O/16O abundance ratio, which, by being a factor of ~5.2 larger than 17O/16O, can be measured more easily. Here, we summarize significant events in the historical development of oxygen stable isotope ratio

We review the O isotope modeling in the atmosphere below 100 km, which is a large and active area of research. Our review will not be exhaustive but instead will highlight some of the key papers on the topic over the past nearly 30 years. We focus our review on modeling the mass-independent fractionation signatures associated with O3 formation and other species that photochemically interact with O3

In this chapter I review some of the knowledge about the oxygen isotope exchange between air O2, rocks, minerals, melts, including some technical products. The rise of free atmospheric molecular oxygen since the great oxygenation event at the Archean–Proterozoic boundary 2.3 Ga ago (Farquhar et al. 2000; Luo et al. 2016) was one of the major events of the Earth environment. The triple oxygen isotope

Variation in both 18O/16O and 17O/16O ratios in natural materials can now be measured with unprecedented precision, with a broad range of potential geochemical applications. In this chapter, equilibrium 18O/16O and 17O/16O fractionation factors are calculated for a selection of minerals and molecules, using first-principles density functional theory models to estimate vibrational frequencies, with

The near-simultaneous discovery of both minor isotopes of oxygen in 1929 was a watershed moment for modern science, to say nothing of its impacts on isotope geochemistry. At the time, oxygen was the international standard for atomic weight, as it had been for over twenty-five years. However, chemists and physicists had grown fond of different definitions: physicists used the weight of the 16O atom

Analyzing classic 18O/16O ratios in solids, liquids and gases has proven useful in almost every branch of earth science. As reviewed in this book, additional 17O analysis generally help to better constrain the underlying fractionation mechanisms providing a more solid basis to quantify geologic processes. Mass independent fractionation (MIF) effects known from meteorites and atmospheric gases (Clayton

This Chapter considers triple oxygen isotope variations and their 4 Gyr temporal evolution in bulk siliciclastic sedimentary rocks and in granites. The δ18O and ∆′17O values provide new insights into weathering in the modern and ancient hydrosphere and coeval crustal petrogenesis. We make use of the known geological events and processes that affect the rock cycle: supercontinent assembly and breakup

The history of the discovery of stable isotopes and later, their influence of chemical and physical phenomena originates in the 19th century with discovery of radioactivity by Becquerel in 1896 (Becquerel 1896a–g). The discovery catalyzed a range of studies in physics to develop an understanding of the nucleus and the properties influencing its stability and instability that give rise to various decay

The analysis of hydrogen (δD) and oxygen (δ18O) isotope ratios of H2O are widely used tools for studies of the hydrological cycle (Friedman 1953; Dansgaard 1954; Gonfiantini 1986; Gat 1996; Araguás-Araguás et al. 2000; Gat et al. 2000) and climate reconstruction (Dansgaard 1964; Johnsen et al. 1989; Petit et al. 1999). Natural variations of δD and δ18O in precipitation are well correlated and fall

Sulfate is the most abundant electron acceptor in the ocean today. A large fraction of the buried organic matter in marine sediments is re-mineralized through microbial sulfate reduction (MSR) during which the sulfate is reduced to H2S (Jørgensen 1982; Kasten and Jørgensen 2000). The H2S can be re-oxidized to sulfate or buried as pyrite in sediments (Jørgensen 1977). The burial of pyrite ultimately

The usefulness of triple isotope studies of natural systems is contingent on the existence of resolvable differences in mass-dependent fractionation exponents θ [where θ = ln(17/16α)/ln(18/16α)] among processes that are prevalent in the system(s) of interest, or on the existence of resolvable non-mass-dependent fractionation in the system. Both such contingencies are satisfied in continental hydroclimate

The field of stable isotope geochemistry began with the recognition that the oxygen isotope composition of ancient carbonates could be used as a paleothermometer (Urey 1947; Urey et al. 1951). As stated by Urey (1947), “Accurate determinations of the Ol8 content of carbonate rocks could be used to determine the temperature at which they were formed”. This concept was based on the temperature dependence

The surface temperature of a planet is one of the key parameters that define its potential habitablity. On Earth, the temperature regime sustained by the seawater column provided one of the necessary conditions for the evolution and prosperity of life. Ancient marine chemical sediments such as cherts and carbonates offer an opportunity to reconstruct the seawater temperature throughout geologic history

Reactive transport modeling is a process-based approach that accounts for advection, diffusion, dispersion and a multitude of biogeochemical reactions. The occurrence of these reactions, by nature, tends to affect the properties of porous media in many ways (Tenthorey and Gerald 2006). If these alteration reactions are significant, then feedback mechanisms could occur that influence the flow of groundwater

Biogeochemical processes are of tremendous importance for determining the fate of many organic and inorganic compounds in the subsurface. Most global elemental cycles involve biogeochemical transformation, and the recycling of carbon and nutrients relies almost exclusively on biogeochemical processes. In particular, the majority of natural organic compounds are biogeochemically reactive, but also a

Nanoporous media consist of homogeneous or heterogeneous porous material in which a significant part of the pore size distribution lies in the nanometer range. Clayey rocks, sediments or soils are natural nanoporous media, and cementitious materials, the most widely used industrial materials in the world, are also nanoporous materials. Nanoporous materials also include compounds present at the interface

A watershed (also drainage basin, river basin, or catchment) is defined as “… the area that topographically appears to contribute all the water that passes through a specified cross section of a stream (the outlet)” (Dingman 2015). In this chapter, I choose to use the term “watershed” as it is a broadly used one; it should be understood more as small watersheds or catchments. Watersheds are the fundamental

Power generation plays an important role in global warming (Audoly et al. 2018) and although the use of nuclear power in the energetic mix can be seen as sustainable (Brook et al. 2014; Knapp and Pevec 2018), nuclear energy is debated in many countries (Meserve 2004; Cici et al. 2012). Over 50 years of nuclear energy and the use of radioactive material in nuclear research and in industrial, medical

Upon injection into a reservoir, CO2 migrates and interacts with the host rock and pore water (Benson et al. 2005, 2012). Supercritical or gaseous CO2 dissolves in the pore aqueous solution as a function of the pressure, temperature, and salinity conditions. This process changes the local chemistry; in that it significantly decreases the pH and promotes geochemical reactions such as the dissolution

This chapter addresses the use of multicomponent reactive transport modeling (MCRTM) in an attempt to understand and quantify the interaction between acid water and rocks or Portland cement (mortar, concrete) during and after the injection of CO2 in deep aquifers (geological CO2 storage) and in the treatment of acid mine drainage (AMD). Anthropogenic acidification of water occurs in the two cases (Gunter

Of the 92 elements naturally present on modern Earth, only 21 are monotopic. The remainder are composed of multiple isotopes, many of which are either stable or decay over such extraordinarily long timescales that they may be considered effectively stable for appropriate applications. These isotopes of a given element are distinguished by the number of neutrons within their nucleus, resulting in subtle

The field of reactive transport lies at the intersection of several disciplines in the Earth and Environmental sciences, including hydrology, geochemistry, biology and geology. The processes in natural and engineered media that are the focus of study of these disciplines take place over a wide range of spatial and temporal scales. Specifically, geological media are characterized by their physical and

The interplay between mixing and reactive processes plays a pivotal role in a range of biogeochemical processes controlling the transport, transformation and turnover of chemical elements (McClain et al. 2003; Dentz et al. 2011; Valocchi et al. 2018). The study of these processes is of primary importance in many scientific disciplines and technical applications, including fluid mechanics, geochemistry

The development of reactive transport soared during the 1990's, driven by the necessity to demonstrate the long-term efficiency of radioactive waste repositories (Bildstein et al. 2019; Claret, 2019; Cama et al. 2019, both this volume). The approach, based on a rigorous description of processes and their coupling, provides a basis of confidence to bridge the gap in time and space between knowledge

Reactive transport in the Earth and Environmental Sciences is at a crossroads today. The discipline has reached a level of maturity well beyond what could be demonstrated even 15 years ago. This is shown now by the successes with which complex and in many cases coupled behavior have been described in a number of natural Earth environments, ranging from corroding storage tanks leaking radioactive Cs

Fractures are ubiquitous and important features in the Earth subsurface (Berkowitz 2002; Pyrak-Nolte et al. 2015). They are created as a result of rock failure when the critical stress (i.e., fracture toughness) is exceeded, or in the case of subcritical crack growth, when cracks propagate under stress conditions below fracture toughness, facilitated by chemical reactions (Atkinson 1984). The necessary

Chemical weathering, or the breakdown of rock to form regolith, occurs within an interface between the highly dynamic atmosphere and the comparably quiescent bedrock boundary known as the Critical Zone (Amundson et al. 2007; Anderson et al. 2007). The Critical Zone hosts a complex biosphere that redistributes water and nutrients while injecting carbon into the regolith as gas, dissolved compounds and

The vadose zone (often called the unsaturated zone) is commonly defined as the geologic media spanning from the land surface to the groundwater table of the first unconfined aquifer (Stephens 2018). The vadose zone is known to play a critical role within the biosphere: (1) as a storage medium to supply water to the plants and atmosphere, and (2) as a controlling agent in the transmission of recharging

Soil organic matter (SOM) represents the single largest actively cycling reservoir of terrestrial organic carbon, accounting for more than three times as much carbon as that present in the atmosphere or terrestrial vegetation (Schmidt et al. 2011; Lehmann and Kleber 2015). SOM is vulnerable to decomposition to either CO2 or CH4, which can increase atmospheric greenhouse gas concentrations (GHGs) and

Open system behavior is predicated on a fundamental relationship between the timescale over which mass is transported and the timescale over which it is chemically transformed. This relationship describes the basis for the multidisciplinary field of reactive transport. In the 20 years since publication of RiMG volume 34: Reactive Transport in Porous Media, reactive transport principles have expanded

High temperature gas–solid reactions interactions are ubiquitous in and on the Earth and other planetary bodies (Fig. 1). In these natural systems, gases are elusive. Like a hurricane’s wind that leaves a path of destruction but no trace of wind after the event, the gas that initiated a gas–solid reaction may be conspicuously absent. Because gases effectively escape from geologic systems, gas–solid

It has been 23 years (as we type) since Carroll and Holloway published the “Volatiles in Magmas” MSA volume (Carroll and Holloway 1994). The 1994 volume dealt with how to safely sample high-temperature gases and analytical methods for volatiles in glasses, which included secondary ion mass spectroscopy and vibrational spectroscopy. Since that time, some things have changed, and some have remained the

Gas–solid reactions result in changes in solid structure and composition including the formation of surface layers or thin films (Delmelle et al. 2018, this volume; Henley and Seward 2018, this volume; King et al. 2018, this volume; Palm et al 2018, this volume; Renggli and King 2018, this volume), dissolution-reprecipitation processes resulting in zoning or porosity and mineral replacement (Altree-Williams

Sulfur dioxide (SO2(g)) is an important gas species in most common volcanic settings on Earth including subduction zones (Shinohara 2013). The relative abundances of SO2(g) may vary at a volcano over time with the highest rates of SO2(g) emissions occurring during eruptive degassing and lesser amounts emitted continuously during quiescent degassing, resulting in a large total amount of SO2(g) integrated

Major and trace elements in igneous and metamorphic rocks are commonly used to infer their petrogenesis (e.g., Carmichael et al. 1974; Wilson 1989; Pearce and Parkinson 1993). To date, our understanding of element transport is informed by diffusion data (e.g., Zhang 2010; Spandler and O’Neill 2010) and partitioning measurements that quantify the fractionation of an element between a mineral and a melt

The common manifestation of an explosive volcanic eruption is the emission of a hot mixture of solid fragments and expanding magmatic gases, referred to as the eruption plume, into the atmosphere (Fig. 1, Sparks et al. 1997; Carey and Bursik 2015). Ash (the rock particles less than two millimeters across) usually dominates the plume’s solid load, whereas water vapor followed by CO2 and lesser amounts

Arc volcanoes are most commonly defined in terms of their magmatic and eruptive histories but the sustained flux of high temperature reactive gases through them, at all stages of their eruptive cycles, equally defines them as large scale, gas phase, chemical reactors (Fig. 1). Inside them, reactive mass transfer occurs continuously as magmatic vapor, released from crystallizing silicate melt at lithostatic

Gas–solid reactions on solar system bodies occur in the vicinity of their surfaces and in their interiors where gases are liberated through magma degassing or thermal devolatilization. The reactions are driven by chemical disequilibria created by exogenic (erosion, impacts) and endogenic processes (tectonics, magmatism) that change the composition of gas–solid systems and/or alter temperature and pressure

Despite its importance in geological sciences, our understanding of interactions between gas and condensed phases (comprising solids and liquids) remains clouded by the fact that, often, only indirect evidence remains for their occurrence. This arises from the tendency for the vapor phase to escape from the condensed phase with which it interacts, owing to its much lower density and thus greater volume

Evaporation and condensation of crystalline or amorphous materials at high temperature are the fundamental processes at low pressure in circumstellar environments such as protoplanetary disks and outflows around evolved stars and supernovae, where liquid is basically unstable. Condensation or evaporation of various dust species in a multi-elemental system causes elemental and/or isotopic fractionation

Chemical reactions involving both solid and gas species are pervasive not only in the natural world, but also in engineered systems. Many common, large-scale industrial processes involve chemical reactions and physical phenomena that occur at a gas–solid interface. The industrial scale production of chemical commodities, oil refining, metallurgy, minerals processing, pulp and paper production, food

Throughout the Earth’s crust from magmatic/volcanic to lower temperature hydrothermal environments, low density aqueous fluids play a fundamental role in its chemical evolution. These gas-like fluids contain a periodic table of elements but their molecular chemistry has been little studied. Even the gas-phase molecular chemistry of the solvent itself, steam or low density supercritical water, is poorly

Geochemistry was dominated by thermodynamic theory for much of its first century of existence (Anderson and Crerar 1993; Nordstrum 2006). Interest in high temperature igneous and metamorphic processes combined with the presumption of long time periods that are available for geochemical reactions justified the assumption of equilibrium thermodynamics. Consequently, geochemists were interested in reactants

Gas mixtures play a crucial role in distributing elements between different parts of Earth and planet-forming systems over a range of settings and temperatures. Despite the fundamental role of gases in geochemical cycles and their prevalence both in the crust and the early solar system, we are unaware of any reviews on this topic. This volume arose from an interest in promoting further research into