Water, redox, and compositional controls on the crystallization of Rhyacian metaluminous igneous charnockites, Bacajá Domain, SE Amazonian Craton: insights from mineral chemistry and thermodynamic modeling

The garnet amphibolite schist is associated with the gabbroic unit of the Mawat ophiolite, Kurdistan region, Northeast Iraq, in the imbricated zone of the Zagros orogenic belt. Field observation, petrographic study, mineral chemistry, geochemical data, and thermodynamic modeling were used to demonstrate mineral identification, predict the observed stable mineral assemblages, and validate the protolith. The mineral assemblages of prograde are garnet (pyrope-almandine, chlorite (clinochlore), amphibole (grunerite), plagioclase (anorthite), iron oxides while the garnet (almandine-pyrope), chlorite (chamosite), amphibole (cummingtonite), and iron oxide represent retrograde assemblage. The relict pod of metagabbro in the center of the garnet amphibolite schist body consists mainly of plagioclase, amphibole, pyroxene, and iron oxide. Geochemical data reveals that the rock is depleted in SiO2 and CaO and enriched in refractory elements compared to the metagabbro. This may be attributed to the generation of silicic melts by partial melting and producing nearby plagiogranite. The rare earth elements (REE) patterns show that the garnet amphibolite schist is depleted in light rare earth elements (LREE) and gradually enriched in heavy rare earth elements (HREE). Thermodynamic modeling, field observation, combined with petrographic study constrains two metamorphic stages and one possible anticlockwise P-T-t path for garnet amphibolite schist, with increasing pressure and temperature of gabbroic rocks units of Mawat ophiolite. The rocks reached peak metamorphic conditions at more than 800 °C and 8–10 kbar, which partially melted the rock produced prograde resitite and melt. Later, the resitite rock retrograded to the lower stage at temperatures ranging from 620 to 650 °C and pressures ranging from 6.5 to 6.8 kbar. Anticlockwise P-T-t paths suggested based on geochemical and thermodynamic data for garnet amphibolite schist of the Mawat ophiolite. Moreover, the gabbro is considered to be the protolith of garnet amphibolite schist, which have been undergone eclogite facies metamorphism later overprinted by amphibolite facies.

The mechanism of Late Cretaceous crustal thickening and exhumation of the southern Lhasa terrane is critical for understanding the tectonic evolution of the Tibetan Plateau. High-pressure metamorphic rocks from the lower crust are good candidates for addressing this issue. In this study, we focus on Late Cretaceous, high-pressure, garnet-bearing amphibolites from the Nyingchi Complex of the Eastern Himalayan Syntaxis and present an integrated study of geochronology, petrography, mineral chemistry, and thermodynamic modeling. Petrographic data determine three metamorphic stages (M1–M3). The M1 stage is characterized by a peak mineral assemblage of garnet + hornblende + albite + rutile + muscovite + quartz, which is followed by a post-peak (M2) assemblage of garnet + hornblende + plagioclase + epidote + biotite + rutile + quartz. The late retrograde stage (M3) is defined by hornblende + plagioclase symplectites surrounding garnet porphyroblasts. Mineral chemistry, with thermodynamic modeling, constrains the P-T conditions of the M1–M3 stages to 14–19 kbar/660–720 °C, 8–10 kbar/650–660 °C, and <7 kbar/<600 °C, respectively. Metamorphic zircons yield a concordant age at 90 Ma, which indicates the formation of garnet-bearing amphibolites. These results indicate a P-T-t path involving near-isothermal decompression for garnetbearing amphibolites, which suggests that the Nyingchi Complex underwent peak-pressure metamorphism (M1) at 90 Ma, followed by rapid exhumation to the depth of 32–26 km along the subduction channel. Moreover, the garnet-bearing amphibolites are considered to be the product of high-pressure metamorphism of mafic crust at the base of the Gangdese belt. Hence, the crust of the Gangdese belt experienced significant crustal thickening of up to 60 km at 90 Ma.

Mesoproterozoic suturing of Archean crustal blocks in western peninsular India: Implications for India–Madagascar correlations

Strain localization within shear zones may partially erase the rock fabric and the metamorphic assemblage(s) that had developed before the mylonitic event. In poly‐deformed basements, the loss of information on pre‐kinematic phases of mylonites hinders large‐scale correlations based on tectono‐metamorphic data. In this study, devoted to a relict unit of Variscan basement reworked within the nappe stack of the Northern Apennines (Italy), we investigate the possibility to reconstruct a complete pressure (P)–temperature (T)–deformation (D) path of mylonitic micaschist and amphibolite by integrating microstructural analysis, mineral chemistry and thermodynamic modelling. The micaschist is characterized by a mylonitic fabric with fine‐grained K‐white mica and chlorite enveloping mica‐fishes, quartz, and garnet pseudomorphs. Potassic white mica shows Mg‐rich cores and Mg‐poor rims. The amphibolite contains green amphibole+plagioclase+garnet+quartz+ilmenite defining S1 with a superposed mylonitic fabric localized in decimetre‐ to centimetre‐scale shear zones. Garnet is surrounded by an amphibole+plagioclase corona. Phase diagram calculations provide P–T constraints that are linked to the reconstructed metamorphic‐deformational stages. For the first time an early high‐P stage at >11 kbar and 510°C was constrained, followed by a temperature peak at 550–590°C and 9–10 kbar and a retrograde stage (<475°C, <7 kbar), during which ductile shear zones developed. The inferred clockwise P–T–D path was most likely related to crustal thickening by continent‐continent collision during the Variscan orogeny. A comparison of this P–T–D path with those of other Variscan basement occurrences in the Northern Apennines revealed significant differences. Conversely, a correlation between the tectono‐metamorphic evolution of the Variscan basement at Cerreto pass, NE Sardinia and Ligurian Alps was established.

A well‐preserved remnant of the middle crust of the former Adriatic passive margin is exposed in the Southern Alps (Italy). The Dervio–Olgiasca Zone is located south of the Insubric Line along the northern part of Como Lake and, because of the lack of Alpine overprint, provides favourable conditions to investigate the pre‐Alpine (rift‐related) history. We reconstruct the P–T–t–d evolution of the Adria middle crust through petrological (petrography, mineral chemistry, thermobarometry and thermodynamic modelling) and geochronological (Lu/Hf in garnet and U–Pb in monazite) data from pegmatites and host micaschists. These data allow reconstruction of a complex tectono‐thermal evolution of the future proximal Adriatic margin at the onset of Alpine rifting. The amphibolite‐facies Carboniferous metamorphic basement (7.6–10 kbar and 610–660°C at 318–312 Ma) was affected by pervasive extensional deformation (5.1–7.6 kbar and 580–660°C) in the Middle‐ to Late‐Permian (257.5 ± 3.8 Ma). Pegmatite intruded at 249.8 ± 1.1 Ma in an extensional phase that re‐equilibrated rocks of the basement at 3.5–4.5 kbar and 560–600°C. During the Middle‐ to Late‐Triassic (241–235 Ma), the basement experienced static thermal recrystallization (T = 689 ± 41°C and ~5.0 kbar). This Late‐Anisian to Early‐Carnian thermal event was simultaneous with the emersion of carbonate platforms, volcanism and ore deposition in the future proximal Adriatic margin. The subsequent cooling of the middle crust was synchronous with large‐scale extensional detachments developed in the upper crust (e.g., the Lugano‐Val Grande Fault), which controlled the formation of the Monte Generoso Basin. This study reveals that the local post‐Carboniferous thinning and heating events recorded in the Adriatic middle crust were interconnected to other processes occurring at different crustal levels that were, in turn, induced by crustal stretching in the early stages of the Alpine rifting.

Metamorphic evolution of the Sa’al–Zaghra Complex in Sinai: Evidence for Mesoproterozoic Rodinia break-up?

The Americano do Brasil and Mangabal complexes belong to a cluster of Neoproterozoic mafic–ultramafic intrusions in the southern Goiás Magmatic Arc in Brazil. Both complexes were highly deformed and metamorphosed under amphibolite facies, leaving few igneous relict domains. We have documented the mineralogy and texture of the poorly exposed rocks of the Americano do Brasil and Mangabal complexes. We use diverse analytical methods, encompassing petrography, mineral chemistry, geochemistry and thermodynamic modelling, with the principal objective of elucidating the intricacies of secondary alteration processes and offering insights into the complex metamorphic history of the complexes. The rocks of both complexes show intense amphibolitization associated with the most highly metamorphosed rocks. The construction of pseudosections suggests a temperature between 670 and 710°C and pressure up to 7.5 kbar at amphibolite facies conditions. In some amphibolite samples, we note unusual minerals such as kyanite, sillimanite, muscovite, silvialite (a sulfate-rich member of calcic scapolite) and/or anhydrite. We attribute some unusual assemblages to open system behaviour during metamorphism, probably related to metasomatism surrounding diorite veins that are inferred to have released fluids rich in CO 2 , Ca and SO 3 . However, this open system behaviour and fluid circulation do not seem to favour Ni–Cu mineralization.

Our understanding of the nature of crustal formation in the Eoarchean is limited by the scarcity and poor preservation of the oldest rocks and variable and imperfect preservation of protolith magmatic signatures. These limitations hamper our ability to place quantitative constraints on thermomechanical models for early crustal genesis and hence on the operative geodynamic regimes at that time. The recently discovered ca. 3.75 Ga Ukaliq supracrustal enclave (northern Québec) is mainly composed of variably deformed and compositionally diverse serpentinized ultramafic rocks and amphibolitized mafic schists whose metamorphic peak, inferred from phase equilibria modeling, was below 720 °C. Inferred protoliths to the Ukaliq ultramafic rocks include cumulative dunites, pyroxenites, and gabbros, whereas the mafic rocks were probably picrites, basalts, and basaltic andesites. The bulk-rock and mineral chemistry documents the partial preservation of cumulative pyroxenes and probably amphiboles and demonstrates the occurrence of a clinopyroxene-dominated, tholeiitic suite and an orthopyroxene-dominated, boninite-like suite. Together with the presence of negative μ142Nd anomalies in the boninitic basalts, two liquid lines of descent are inferred: (i) a damp tholeiitic sequence resulting from the fractionation of a basaltic liquid produced by mantle decompression; and (ii) a boninitic suite documenting the evolution of an initially primitive basaltic andesite liquid produced by flux melting. Petrographic observations, thermodynamic modeling, bulk-rock and mineral chemistry, and 142Nd isotopic compositions identify the Ukaliq supracrustal belt as the remnant of an Eoarchean arc crust produced by the recycling of Hadean crust in a similar way as modern-style subduction.

Based on the deep-water high temperature and high pressure LS25 gas field in the Nanhai Reservoir, through the design of heterogeneous formations and the design of water control experimental schemes, physical simulation experiments of different gas reservoir water control processes have been completed, focusing on evaluating the variable density compound water control technology based on continuous packers. In terms of the adaptability of deep-water gas reservoirs, on this basis, combined with the experiment-mine scale conversion method, a water-controlled exploitation plan for deep water high-temperature and high-pressure gas reservoirs is given. The experimental results show that: (1) Under elastic production conditions, the water body of the bottom water in the gas reservoir rises in a “progressive” manner in the initial stage, and generally develops in a “cone progression” in the middle and late stages. (2) There are obvious differences in the effects of various water control processes. A single continuous sealing body has no obvious effect on bottom water control during the gas production period of a gas well, and a single variable density screen process has no obvious effect on water control in the early stage of gas well production. The effect is good, but the risk of water channeling cannot be avoided after the gas well breaks through. The experimental effect of the variable density composite water control process based on the continuous packer is good, and the bottom water coning effect has changed to a certain extent. The experiments show that the water-free gas production period of the composite water control process is 13.7 years, the total gas production time is extended to 15.8 years, the total gas production after water control is as high as 12.37×108m3, and the recovery rate of gas wells is 9.2%, which is higher than that of elastic production. The research results aim to establish an optimal water control development model for high temperature and high-pressure deep water gas reservoirs and provide a good technical support for rational and scientific research on water control in horizontal wells of offshore deep water gas reservoirs.

Controls on the chemistry of minerals in late-stage veins and implications for exploration vectoring tools for mineral deposits: An example from the Marathon Cu-Pd deposit, Ontario, Canada

Reassessing the PT conditions of Neoproterozoic collisional metamorphism and partial melting in southernmost Brazil

Chemical thermodynamic models of solvent and solute activities predict the equilibrium behavior of aqueous solutions. However, these models are semi-empirical. They represent micro-scale ion and solvent behaviors controlling the macroscopic properties using small numbers of parameters whose values are obtained by fitting to activities and other partial derivatives of the Gibbs energy measured for the bulk solutions. We have conducted atomistic simulations of aqueous electrolyte solutions (MgCl2 and CaCl2) to determine the parameters of thermodynamic hydration models. We have implemented a cooperative hydration model to categorize the water molecules in electrolyte solutions into different subpopulations. The value of the electrolyte-specific parameter, k, was determined from the ion-affected subpopulation with the lowest absolute value of the free energy of removing the water molecule. The other equilibrium constant parameter, K1, associated with the first degree of hydration, was computed from the free energy of hydration of hydrated clusters. The hydration number, h, was determined from a reorientation dynamic analysis of the water subpopulations compared to bulk-like behavior. The reparameterized models [R. H. Stokes and R. H. Robinson, J. Solution Chem. 2, 173 (1973) and Balomenos et al., Fluid Phase Equilib. 243, 29 (2006)] using the computed values of the parameters lead to the osmotic coefficients of MgCl2 solutions that are consistent with measurements. Such an approach removes the dependence on the availability of experimental data and could lead to aqueous thermodynamic models capable of estimating the values of solute and solvent activities as well as thermal and volumetric properties for a wide range of compositions and concentrations.

In the advancement of bottom water reservoir development, water breakthrough poses a significant challenge to the productivity of oil and gas wells, underscoring the paramount importance of effective water control strategies. Given the intricate nature of the factors leading to reservoir water breakthrough, a one-size-fits-all approach to water management is non-existent. Rather, tailored water control techniques are necessary to address the diverse causes of this phenomenon. This paper delves into the evolution and application of water control technologies, particularly focusing on the prevalent horizontal well water control methodologies. Horizontal well variable density water control, segmented water control, double horizontal well oil recovery water control, along with advanced solutions such as ICD (Inflow Control Device), ICV (Inflow Control Valve), AICD (Autonomous Inflow Control Device), and AICV (Autonomous Inflow Control Valve) water control systems are comprehensively introduced. Furthermore, center-controlled, mechanical plugging, and chemical plugging water control technologies are also examined in depth, accompanied by a thorough analysis of their respective strengths, limitations, and adaptability to various scenarios. By keeping abreast of both domestic and international trends in horizontal well water control, the future trajectory of this field is forecasted. Emerging as key technologies are novel composite water control systems, dual-purpose water control and sand prevention techniques, and intelligent water control solutions. These advancements promise to revolutionize the management of water breakthrough in bottom water reservoirs, enhancing oil and gas recovery efficiency and sustainability.

<p>The project, PYROKINE, aims at developing new modeling approaches adapted to one of the most promising thermochemical processes, fast pyrolysis, applied to the conversion of contaminated lignocellulosic biomass. The fast pyrolysis converts solid biomass into volatiles and a limited amount of char. The volatiles are then rapidly quenched resulting in a high yield of bio-oil, 70-75wt% of the starting material on a dry basis. The liquified biomass can be further upgraded catalytically or blended to produce new advanced biofuels. In addition to the yield, the product distribution determines their quality, and this is critically dependent on biomass type and its temperature-time history. In the present study, we propose to establish a dynamic model adaptable to the conversion of different biomass types under various pyrolysis regimes according to two research programs.</p><p>The first program consists of integrating coupled chemical kinetics into heat and mass transfer models for biomass fast pyrolysis. So far, the coupled kinetic model combining the Friedman isoconversional method with a Distributed Activated Energy Model (DAEM) has been developed and validated with a set of experimental data obtained under slow heating conditions. The apparent activation energy, Eα, one of the kinetic parameters that describes the overall reactivity of the feedstock, has been plotted versus the extent of conversion, α, to assess the chemical complexity of the reaction. For example, the lignin was found to degrade into two successive stages from 174 to 280kJ/mol between 0.05<α<0.60 and up to 322kJ/mol until α=0.85. Two kinetic parameter datasets were derived and used as inputs for the double-Gaussian DAEM that successfully fitted experimental curves. This chemical kinetic model will be combined with heat and mass transport models according to the type of thermal regimes.</p><p>The second program focuses on the thermodynamic and kinetic modeling of the intermediate liquid compound in the presence of metallic species. This liquid appears in the early stages of the fast pyrolysis and results from the softening of biomass. Its physico-chemical characteristics are the origin of the multiphasic nature of the biomass fast pyrolysis. A preliminary study has allowed the development of a thermodynamic model and headspace coupled to gas chromatographic methods to predict the vapor-liquid equilibrium for model liquid mixtures. The system studied was a closed system with air and a solution mixture of five components (acetic acid, hydroxyacetone, phenol, furfural, and methanol) near its boiling point, 90°C, and under atmospheric pressure. To predict the thermophysical parameters of the solution, the Soave-Redlich-Kwong (SRK) equation of state coupled with Modified Huron-Vidal (MHV2) mixing rules incorporating the UNIversal Functionnal Activity Coefficient (UNIFAC) model was implemented. Concentration measurements in vapor and liquid phases were compared to vapor-liquid equilibrium data. A quantitative agreement between simulated and measured concentrations in the liquid phase was achieved with this combined state-predictive model of the SRK-MHV2-UNIFAC model, confirming that it accounts well for the nonidealities. This thermodynamic model will need to be coupled with a chemical kinetic model in the presence of inorganics to reveal the role of those contaminants on the chemistry.</p>

This study presents improved chemical, thermodynamic and Pitzer activity models for the system Tc(iv)–Na+–K+–Ca2+–Mg2+–H+–Cl−–OH−–H2O(l) in the context of the German Thermodynamic Reference Database (THEREDA, https://www.thereda.de). The work is based on (i) the previous THEREDA release No. 10 for Technetium in 2016, (ii) the data selection in the second update book of the Nuclear Energy Agency-Thermochemical Database (NEA-TDB) project and (iii) available new solubility studies in dilute to concentrated NaCl, KCl, CaCl2 and MgCl2 solutions. Updated chemical and thermodynamic models are evaluated to include the hydrolysis species Tc2O32+, TcO(OH)2(aq), TcO(OH)3−, Ca3[TcO(OH)5]3+ and Mg3[TcO(OH)5]3+. The model provides a new hydrolysis constant for TcO(OH)3− and new Pitzer activity coefficient for the interactions between TcO(OH)3− and Na+/K+. The updated model properly describes Tc(iv) solubility data in binary NaCl, KCl, CaCl2 and MgCl2 salt systems, as well as in selected mixed solutions (ternary, quaternary, quinary). The incorporation of the updated model in thermodynamic databases represents an important tool for source term estimations and speciation calculations of Tc(iv) under a variety of geochemical conditions of relevance in the context of nuclear waste disposal, with focus on high ionic strength conditions.