Peralkaline granites and pegmatites are a prime repository of REE and HFSE, critical raw materials. Although it is accepted that magmatic processes are fundamental in concentrating these metals, the role of hydrothermal fluids in concentrating and fractionating these elements remains unclear. This paper investigates the global reproducibility of the magmatic-hydrothermal evolution of alkaline silica-saturated

Accurate geochemical models of magmatic processes require an understanding of crystal-melt partitioning of trace elements. Many major igneous processes at different tectonic environments in Earth occur in the presence of garnet as a residual phase. Since the pioneering crystal lattice-strain model, several attempts have been made to quantify garnet-melt partitioning coefficients over a wide range of

Slow-slip events frequently occur, but regular earthquakes are much less active on the H2O fluid-rich subduction interface at depths of ~ 40 km. The characteristic duration for silent earthquakes, which are categorized as the great slow-slip events, is more than five orders of magnitude longer than that for regular earthquakes. Such phenomena are often attributed to the slippage of the softer part

Thermodynamic modeling is an important technique to simulate the evolution of metamorphic rocks, particularly the poorly preserved prograde metamorphic reactions. The development of new thermodynamic modeling techniques and availability of updated thermodynamic databases and activity–composition (a–X) relations, call for an evaluation of best practices for modeling pressure–temperature (P–T) paths

Diffusion profiles in olivine crystals from the final mafic eruption products of the compositionally zoned Laacher See tephra deposit were measured to identify recharge and eruption-triggering events prior to the eruption of the Laacher See volcano (12.9 kyr). These products represent the hybrids of mixing between phonolite and intruding basanite at the bottom of the reservoir, which is likely related

Supercritical fluids in rock–H2O systems have been proposed to be important agents of mass transfer in subduction zone environments. New experimental studies were conducted on the simple model granite system NaAlSi3O8 (Ab)–H2O in order to investigate phase relations and to develop the thermodynamic mixing properties between aqueous fluid (a.k.a. vapor, V) and silicate melt (a.k.a. liquid, L) at pressures

Coexistence of baddeleyite and zircon is rarely documented in metacarbonate rocks and poorly understood. In this study, metamorphic baddeleyite and zircon were recognized in marbles from the Tongbai orogen, central China. We carried out high spatial resolution analysis of trace element geochemistry and U‒Pb‒Lu‒Hf‒O isotope systematics for the zircon and baddeleyite. SIMS (Secondary Ion Mass Spectroscopy)

Translating burial and exhumation histories from the petrological and geochronological record of high-pressure assemblages in subduction channels is key to understanding subduction channel processes. Convective return flow, either serpentinite or sediment hosted, has been suggested as a potential mechanism to retrieve rocks from significant depths and exhume them. Numerical modelling predicts that

Carbonatite compositions resulting from melting of magnesian calcite + olivine + clinopyroxene were experimentally determined in the system CaO–MgO–SiO2–CO2–H2O as a function of temperature and bulk H2O contents at 1.0 and 1.5 GPa. The melting reaction and melt compositions were found to be highly sensitive to H-loss or -gain during experiments. We hence designed a new hydrogen-trap technique, which

Ba zonation patterns in sanidine phenocrysts from mafic and intermediate phonolite and crystal-rich cumulates from the Laacher See volcano (12.9 ka) in western Germany document diffusion times suggestive of periodic recharge events throughout the magma reservoir’s entire lifespan of ~ 24 ky. Phenocrysts analysed from samples that formed late at the base of the compositionally zoned magma reservoir

The 156–138 Ma Chidliak kimberlites on the Eastern Hall peninsula (EHP) of Baffin Island entrained mantle xenoliths interpreted to have been a part of the Archean North Atlantic Craton (NAC) lithospheric mantle. We studied 19 Chidliak eclogite xenoliths that comprise 10 bimineralic, 5 rutile-bearing, 3 orthopyroxene-bearing and 1 kyanite-bearing eclogites. We report major and trace element compositions

Magma mixing and contamination are among the dominant processes in the building of the isotopic diversity of granite rocks. Felsic microgranular enclaves (FMEs) are remnants of magma mixing and they often carry xenocrysts that also record contamination and assimilation in crystallization fronts disrupted during replenishment events. In addition to isotopic changes, contamination may alter the redox

The geochemistry of biotite crystals from thirty fertile and barren Silurian–Devonian granitoids of New Brunswick, Canada, was studied in situ using electron microprobe and laser ablation inductively coupled plasma-mass spectrometry to investigate the suitability of biotite geochemistry as a diagnostic fertility index among these intrusions. The Fe2+/(Fe2+ + Mg2+) ratio of biotite varies as a function

To investigate the petrogenesis of cyclic units in layered intrusions, we examined chromitite, dunite, poikilitic harzburgite and bronzitite from the Ultramafic Zone of the Stillwater Complex and measured stable isotopes of Li and O in their major minerals. The Li isotopes in olivine range from 4 to 26‰ in δ7Li with uniform Li contents of 1–3 ppm, whereas orthopyroxene and clinopyroxene have Li contents

To better investigate the behavior of titanium (Ti) isotopes during magmatic processes, we report high-precision Ti isotope compositions for 60 terrestrial igneous rocks from different geological settings worldwide. Based on their major element compositions and petrographic descriptions, these samples can be subdivided into two groups: Fe-Ti oxide unsaturated and Fe-Ti oxide saturated. The Fe-Ti oxide

Understanding the timing and duration of metamorphism is fundamental to correctly interpreting the geodynamic evolution of orogenic events. Metamorphic constraints are still ambiguous in the Khondalite Belt, North China Craton, so Paleoproterozoic orogenic processes remain unclear. Here, we investigate a suite of high-grade rocks from the Dongpo locality in the Daqingshan Terrane by integrating zircon

Even though platinum group elements (PGE) solubilities are measured relative to pure metals, the PGE are assumed to dissolve as oxide complexes in silicate melts. PGE-oxide phases are, however, not known in magmatic rocks; in many cases PGE are associated with discrete magmatic phases (alloys, arsenides, bismuthotellurides, antimonides and sulfides). Here, we determine the concentrations of Pt, Pd

Iron oxidation state and environment in magmas affect their phase diagram and their properties, including viscosity and density, which determine magma mobility and eruptive potential. In turn, magma composition, pressure, temperature and oxygen fugacity affect iron oxidation state and coordination, potentially leading to complex feedbacks associated with magma ascent, degassing and eruption. While

In situ LA-ICP-MS U–Pb geochronology has been performed on apatite and zircon within thermally recrystallized clast-laden and clast-poor impact melt rocks from the Brent impact structure. A total of 377 laser analyses on 120 impact melt-grown (n = 9) and impact-recrystallized zircon grains (n = 111) were obtained, from which a concordia age of 452.8 ± 2.7 Ma (MSWD 0.57, n = 11), and a weighted average

The Fe–Mg and Fe–Mn interdiffusion coefficients for ilmenite have been determined as a function of temperature and crystallographic orientation. Diffusion annealing experiments were conducted at 1.5 GPa between 800 and 1100 \(^{\circ }\hbox {C}\). For Fe–Mg interdiffusion, each diffusion couple consisted of an ilmenite polycrystal and an oriented single crystal of geikielite. The activation energy

Garnet is one of the most robust and ubiquitous minerals that record element zoning during crustal metamorphism. In addition to major elements, zoning in trace elements can provide a wealth of information to document the changing conditions of garnet growth and modification. However, mapping trace elements at low concentrations, over large areas and with high resolution has remained a major challenge

Pegmatites often exhibit regional as well as internal zonation. In this study, we use major and trace element and Li–B isotopic composition of muscovite and tourmaline from internally zoned and un-zoned S-type pegmatites and their host granites to characterize the geochemical and isotopic fractionation associated with their formation. The internally zoned pegmatites comprise three distinct textural

Zircon microcrystals are found in many planetary crustal rocks and nanoscale research on grains from well-characterized impact environments on Earth provide a baseline for reconstructing extreme shock and thermal histories elsewhere. However, using zircon to date large impact events can be challenging given that shock-related isotopic re-setting of U–Pb ratios, when measured at micrometre scale, is

Arc lower crust plays a critical role in processing mantle-derived basaltic melts into the intermediate continental crust, yet can only be studied indirectly or in exposed arc sections. Compared with the relatively well-studied oceanic arc sections (e.g., Kohistan and Talkeetna), the composition and formation mechanisms of continental arc lower crust remain less clear. Here we present a geochronological

The supracrustal metamorphic rocks of the Dora-Maira Massif, western Alps, have been intensively studied. Certain ultra-high-pressure lithologies contain coesite and nearly end-member composition pyrope, Mg3Al2Si3O12, making this locality petrologically and mineralogically unique. Structural OH-, loosely termed “water”, in pyrope crystals of different composition has been investigated numerous times

Interactions between carbonated ultramafic silicate magmas and the continental lithospheric mantle results in the formation of dunite—a ubiquitous xenolith type in kimberlites and aillikites. However, whether this process dominantly occurs in the mantle source region or by subsequent interactions between lithospheric mantle fragments and transporting silica-undersaturated magmas during ascent remains

Zircon is widely used to date metamorphic processes, particularly due to slow cation diffusion under crustal conditions. Here, we present laser-ablation depth profiling data that demonstrate rapid U diffusion in partially altered, high-pressure zircon. The zircons are hosted in metagabbros that underwent eclogite-facies (~ 550 °C, ~ 2.6 GPa) recrystallization during subduction of the Monviso meta-ophiolite

The occurrence of post-subduction magmatism in continental collision zones is a ubiquitous feature of plate tectonics, but its relation with geodynamic processes remains enigmatic. The nature of mantle sources in these settings, and their interaction with subduction-related components, are difficult to constrain using bulk rocks when magmas are subject to mixing and assimilation within the crust. Here

The compositional zoning styles of natural crystals produced during magma intrusion can be used to investigate the structure of magmatic plumbing systems and its relation to expressions of volcanic unrest (seismic, deformation, volatiles). However, magma intrusion is a progressive, dynamic process and yields non-monotonic heterogeneities in physio-chemical variables such as complex spatial variations

We measured the electrical conductivity of tremolite over a range of pressures (1.0, 1.5, and 2.0 GPa) and temperatures (648–1373 K). At temperatures lower than 1173 K, the electrical conductivity of tremolite was ~ 0.001 S/m, but once the dehydroxylation reaction took place at 1173 K, we observed a significant increase in the electrical conductivity. The electrical conductivity continued to increase

Observations in the S-type granites (s.l.) of the Wilson’s Promontory batholith demonstrate that one type of schlieren in granitic rocks represent accumulations of mainly mafic magmatic minerals, with internal layering formed through pulsed magma flow. Loss of interstitial magmatic liquid played, at most, a minor role in shaping the preserved compositions of the schlieren; filter pressing was not involved

A geochemical study was undertaken on basaltic lava flows intercalated with Oligocene to Miocene strata in the Sabzevar region, northern Iran, to examine their petrogenesis in a regional tectonic framework. The lavas are either aphyric or have phenocrysts and micro-phenocrysts of olivine and, to a lesser extent, clinopyroxene. Geochemically, the lavas are silica-undersaturated alkali basalts characterized

Kimberlites are pipe-like igneous bodies, consisting of a pyroclastic crater and diatreme, commonly underlain by coherent root-zone rocks, and with associated dyke/sill complexes. The processes that control the different modes of coherent kimberlite emplacement remain uncertain. In addition, late evolution of kimberlite melts during emplacement into the upper crust remains poorly constrained. Therefore

Garnet is a nominally anhydrous mineral that can incorporate several hundreds of ppm H2O in the form of OH groups, where H+ substitutes for cations in the garnet structure. To understand the effect of such small amounts of H2O on the physical and chemical properties of garnet, it is essential to determine where and how the OH groups are incorporated into the mineral structure. We investigated correlations

The Taupo Volcanic Center [TVC; Taupo Volcanic Zone (TVZ), New Zealand] is home to the two most recent silicic caldera-forming eruptions in the TVZ—the giant (530 km3 DRE) Oruanui supereruption and the large (35 km3 DRE) Taupo eruption. This offers a unique opportunity to investigate similarities and differences between large and supersized volumes of rhyolitic magma at the TVC and more generally.

We developed a model to predict nucleation delay of olivine, plagioclase, and clinopyroxene in basaltic melts, and alkali feldspar and quartz in felsic melts. The model, based upon classical nucleation theory, was improved by applying modifications inspired by diffuse interface theory. The theoretical calculations were compared to results available in the literature (basalts) and from new experiments

In a paper published in 1920, Bowen conceived of a situation where forces acting on a crystalline mesh could extract the liquid phase from the solid, and in doing so cause variations in chemistry distinct from the purely gravitational effects of fractional crystallisation. His paper was a call-to-arms to explore the role of deformation as a cause of variation in igneous rocks, but was never followed-up

The impact of fluorine on phase relations and clinopyroxene–melt element partitioning has been explored experimentally to better understand the effect of this halogen on the residual enrichment of the REE and HFSE during crystallisation of alkaline and peralkaline magmas. Clinopyroxene was grown from three \(\hbox {H}_2\hbox {O}\)-saturated synthetic glasses of tephriphonolite-to-phonolite composition

The original version of this article contained a mistake.

Trace element partitioning between minerals and liquids provides crucial constraints on igneous processes. We quantified trace element concentrations in clinopyroxene (Cpx) phenocrysts and their phonolite melt inclusions from the 2007–08 eruption of Oldoinyo Lengai (Tanzania), and report Cpx-melt partition coefficients (D) and corresponding partitioning equations for rare earth elements (REE) and high

In the version of the article originally published

Lattice diffusion coefficients and partition coefficients have been determined for Li, Mg, Al, Sc, Ti, Cr, V, Mn, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, In, Lu, Hf, Ta and U in single crystals of natural magnetite as a function of oxygen fugacity (fO2) at 1150 °C and 1 bar by equilibration with a synthetic silicate melt reservoir. Most experiments were run for twelve hours, which was sufficient to generate

Silicic volcanoes are increasingly understood to be underlain by crystal-rich and vertically extensive magma reservoirs within which disequilibrium is widespread. Observations from ignimbrite deposits demonstrate that silicic magma reservoirs are often compartmentalised and compositionally stratified. However, it is currently unclear whether the small (i.e., < 0.1 km3 dense rock equivalent) eruptions

We experimentally investigated changes to the titanium concentrations of quartz-rich rocks caused by grain-boundary migration. Synthesis experiments were performed to make high-Ti quartz starting materials for usage in recrystallization experiments. We isothermally recrystallized quartz starting material in separate experiments at 10–25 kbar to reduce the solubility of Ti in quartz. Microstructural

The Half Dome Granodiorite in Yosemite National Park, California, contains multiple crosscutting generations of high-silica dikes that vary in texture but share the distinctive trace element characteristics of fine-grained aplite dikes of the region (e.g., low Y and middle REE). Dikes of the youngest generation are typical fine-grained, sugary aplites with sharp planar contacts, whereas progressively

Aqueous fluids produced by dehydration of the downgoing slab facilitate chemical exchange in subduction zones, but the efficiency of fluid-mediated redox transfer as a mechanism to deliver oxidized material from the slab to the sub-arc mantle remains hotly debated. Here we report the first direct measurements of the oxidation state of experimentally produced slab fluids using in situ redox sensors

We conducted in situ geochemical (major-, trace-element and Nd isotope compositions) analyses on apatite, together with whole-rock geochemistry from gabbro, granodiorite and granite in the Cretaceous Pingtan intrusive complex (SE China), aiming to investigate the roles of magmatic evolution and post-crystallization hydrothermal activity during its formation. Regardless of limited range in initial Nd

The Phalaborwa world-class phosphate deposit (South Africa) is hosted by a Paleoproterozoic alkaline complex mainly composed of phoscorite, carbonatite, pyroxenitic rocks, and subordinate fenite. In addition, syenite and trachyte occur in numerous satellite bodies. New petrological and in-situ geochemical data along with O and Sr isotope data obtained on apatite demonstrate that apatite is in the principal

Primary carbonates in kimberlites are the main CO2 carriers in kimberlites and thus can be used to constrain the original carbon and oxygen-isotope composition of kimberlite melts and their deep mantle sources. However, the contribution of syn- and post-emplacement processes to the modification of the C–O-isotope composition of kimberlites is yet to be fully constrained. This study aims to shed new

Proximal and distal garnets from skarns at Jiaduobule, Tibet, are used to demonstrate how variation in the fluid composition and parameters such as salinity, pH, fO2, and \({\text{X}}_{{\rm CO}_{2}}\) will impact on rare earth element (REE) distribution in garnets, and also to constrain skarn evolution across the orefield from proximal (Fe mineralization) to distal (Cu mineralization). These garnets

The intense explosive and effusive volcanic activity of the last 1000 years at La Fossa volcano (Vulcano Island, Italy) was characterized by the eruption of magmas ranging in composition from latites to trachytes and rhyolites, as well as K-rich trachytes. Evidence of syn-eruptive mixing among these magmas is frequently observed in the form of magmatic enclaves and bands in lava flows and pyroclastic

We report the results of kinetic experiments of graphitization at various pressures (0.5–8.0 GPa) and durations (1 s to 24 h) at 1200 °C. The natural carbonaceous material in sedimentary rocks from the Shimanto accretionary complex and the Hidaka metamorphic belt, Japan, underwent systematic changes in crystallinity and morphology with increasing pressure. To assess the pressure dependence of graphitization

Lamproites and kimberlites are natural probes of the subcontinental lithospheric mantle providing insights into the Earth’s continental lithosphere. Whole-rock major-, trace-element and Sr–Nd–Pb isotopic compositions of the Paleozoic (~ 253 Ma) lamproite dikes from the Baifen zone of the Zhenyuan area in southeastern Guizhou Province (in the southern Yangtze Block, South China) are presented. The Baifen

The 1370 Ma Gifford Creek Carbonatite Complex (GCCC) comprises a diverse suite of alkaline dyke and sill complexes that cover an area of ~ 250 km2 in the Gascoyne Province, Western Australia. Most carbonatite types are interpreted to be related products of fractional crystallisation, with calcite carbonatites representing cumulate rocks and dolomite carbonatites representing crystallised products of

Despite the natural abundance of pyrite and marcasite and their intergrowth, and a wealth of information they can provide on the physical–chemical conditions of mineral deposits, a complete mechanistic and kinetic study on the phase transformation from the thermodynamically metastable polymorph marcasite to the stable polymorph pyrite is yet to be made. This limits the application of marcasite as an

Small-volume proximal-summit eruptions, sometimes with only little precursors, are common at Piton de la Fournaise (La Reunion Island, France). Their eruptive style ranges from Hawaiian to Strombolian, but their eruptive mechanisms are still not completely understood. To gain insight, we combined syn-eruptive field work, textural and geochemical measurements on the short-lived eruption of July 2015

Abstract The petrology, mineral major and trace-element concentrations, and garnet oxygen isotopic composition of low-MgO (11–16 wt%) eclogites from the Obnazhennaya kimberlite, Siberian craton, are used to infer their petrogenesis. These eclogites contain two types of compositionally distinct garnet: granular coarse garnet, and garnet exsolution (lamellae and fine-grained garnet) in clinopyroxene

Abstract Supersaturation Nucleation and Growth of Plagioclase (SNGPlag) is a numerical model that predicts the nucleation and growth of plagioclase crystals in a decompressing magma as a function of time. The model is written in Matlab, but is available as a standalone compiled program. SNGPlag uses the MELTS webservice to determine equilibrium plagioclase mode, for a user-defined magma composition

Abstract Understanding the impact of magmatic plumbing systems on explosive volcanic activity is important for hazard management. This study describes phase equilibria experiments using a high-silica andesite (HSA; SiO2 = 62.5 wt%) from the 2006 eruption of Augustine Volcano, Alaska. Experiments were conducted under H2O saturated conditions, \(f_{{0_{2} }}\) = RRO (Re–ReO2 or ~ Ni–NiO + 2), at pressures

Abstract The ascent of hydrous magma prior to volcanic eruptions is largely driven by the formation of H2O vesicles and their subsequent growth upon further decompression. Porosity controls buoyancy as well as vesicle coalescence and percolation, and is important when identifying the differences between equilibrium or disequilibrium degassing from textural analysis of eruptive products. Decompression