Figure 2 - uploaded by Xiaozhi Yang
Content may be subject to copyright.
Unpolarized FTIR spectra of olivine (a), orthopyroxene (b), garnet (c), and clinopyroxene (d) containing dissolved molecular H2. Experimental conditions are given below each spectrum; numbers in parentheses are the thickness (mm) of the polished crystal. The spectra were not normalized to constant thickness, but vertically offset. The two spectra for either the annealed garnet (c) or clinopyroxene (d) were measured on the same recovered crystal after polishing to different thickness.
Source publication
Current models assume that hydrogen was delivered to Earth already in oxidized form as water or OH groups in minerals; similarly, it is generally believed that hydrogen is stored in the present mantle mostly as OH. Here we show by experiments at 2-7 GPa and 1100-1300 °C that, under reducing conditions, molecular hydrogen (H2) has an appreciable sol...
Similar publications
A new (Mg0.5Fe3+0.5)(Si0.5Al3+0.5)O3 LiNbO3-type phase was synthesized at 27 GPa and 2000 K under highly oxidized conditions using an advanced multi-anvil apparatus. Single crystals for this phase are 0.2–0.3 mm in dimension and maroon in color. They crystallize in a noncentrosymmetric structure with space group R3c and lattice parameters of a = b...
Citations
... Notably, investigations conducted in Uzbekistan have linked unusual accumulations of these gasses to regions with heightened fluid conductivity, where hydrogen levels have shown a significant correlation with helium [7]. Furthermore, experimental research, as conducted by Yang et al. [18], has revealed the intriguing solubility of hydrogen in minerals under conditions analogous to those in the Earth's mantle, implying the potential existence of substantial hydrogen reservoirs within the mantle, especially in reducing environments. Moreover, comprehensive research suggests that the upper mantle and extensive regions of the asthenosphere are notably saturated with various metals, implying that the primary fluid within these regions is likely significantly enriched in hydrogen content [7,19]. ...
Natural Hydrogen Gas (H2) is producing a new golden rush worldwide due to its clean energetic features. The potential of natural hydrogen gas (H2) in the southernmost regions of Brazil, specifically Rio Grande do Sul and Santa Catarina, remains largely unexplored. We found free H2 occurrences identified in the intracratonic Mesozoic Paraná Basin, recognized in four formation tests performed in former exploratory wells. The data revealed H2 concentrations ranging from 0.14% to 8.79%, albeit associated with noncommercial volumes of natural gas. These occurrences of H2 exhibit a curious negative correlation with Helium (He), distinguishing it from many Eurasian occurrences associated with mantle sources. The Paraná Basin hosts the largest Brazilian coal reserves and organic-rich rocks. We posit that the hydrogen gas presence can be attributed to the maturation processes affecting mainly Rio Bonito, Taciba, and Ponta Grossa formations in this basin. Also, we identified hydrogen system elements in the rift-type Precambrian Camaquã Basin, which host potential source rocks, reservoirs, and seals. Until now, no H2 measurements have been carried out in this basin. To solve this lack, it is fundamental to execute a systematic sampling survey; it will enable the identification of the potential of H2 deposits in the Southernmost Brazilian region. This work lays the foundations for future research in the region, which is demanded to realize this economic potential.
... «Sketch illustrating the «water» species present in the various phases of the Earth's mantle and crust. * -Olivine, pyroxene, and garnet can incorporate water as H 2 under reduced conditions[Yang et al., 2016], ** -K-feldspat can sometimes include water as H 2 O and NH 4 [Johnson,Rossman, 2004]. ...
Views on the origin and evolution of water (the amount and mode of incorporation into crustal and mantle rocks) on Earth are quite diverse. To substantiate them, arguments from various sections of geography, geology, geochemistry, cosmochemistry, and cosmogony are used. A comprehensive analysis allows us to fairly confidently assume that the appearance of water is associated with the final stage of the formation of the planet, which began after the accumulation of 60—90 % of its volume. This period coincided with the entry of water-bearing carbonatites,among other chondrites,into the accretion zone. Having estimated their contribution to the formation of water from different sources, we can compare it with the geological and geophysical data on the Earth’s early history. For this purpose, the author’s idea of the global asthenosphereas a relic of an ancient magmatic ocean, was used. The framework made it possible to estimate the volume of matter from which the emergence of a magma ocean made it possible to extract water. The synthesis of these independent results allows us to state quite confidently that water to fill the ocean was available (in one form or another) throughout the entire studied geological history of the planet. The problem of the ocean itself (a deep-water reservoir with a crust different from the crust of the continents — less powerful and more basic) is considered mainly using the well-known results of B.A. Bluman and E.M. Rudich on the oceans and M.I. Budyko and co-authors on the continents. Their conclusions agree with the schemes of deep processes in the ocean tectonosphere considered by the author. These processes are controlled by a series of geological phenomena and anomalies in geophysical fields.The processes are reduced to heat and mass transfer in the eugeosyncline superimposed on the anomalously basic continental crust and subsequent activation.Thus, a fairly definite picture of the formation of the modern ocean due to the previous development of the Earth’s tectonosphere in the Mesozoic-Cenozoic is emerging.
... Since the drilling industry is not currently capable of reaching the Earth's core or mantle, the characterization of deep-seated sources seems to be a tough and complicated task. Due to this limitation, some researchers have linked the deep-seated sources to the mantle rocks [23][24][25], while others have attributed them to the core rocks. For instance, the natural hydrogen detected in the Kansas region was attributed to mantle rocks [26]. ...
The perspective of natural hydrogen as a clear, carbon-free, and renewable energy source appears very promising. There have been many studies reporting significant concentrations of natural hydrogen in different countries. However, natural hydrogen is being extracted to generate electricity only in Mali. This issue originates from the fact that global attention has not been dedicated yet to the progression and promotion of the natural hydrogen field. Therefore, being in the beginning stage, natural hydrogen science needs further investigation, especially in exploration techniques and exploitation technologies. The main incentive of this work is to analyze the latest advances and challenges pertinent to the natural hydrogen industry. The focus is on elaborating geological origins, ground exposure types, extraction techniques, previous detections of natural hydrogen, exploration methods, and underground hydrogen storage (UHS). Thus, the research strives to shed light on the current status of the natural hydrogen field, chiefly from the geoscience perspective. The data collated in this review can be used as a useful reference for the scientists, engineers, and policymakers involved in this emerging renewable energy source.
... Spektor et al. (12) proposed a direct substitution mechanism of 4H + for Si 4+ with H atoms forming bonds with O atoms in a Si 4+ vacancy. Meanwhile, the physical dissolution of molecular hydrogen (H 2 ) in NAMs has recently been introduced to NAM silicates, which is due to an induced dipole of H 2 molecules interacting with the surrounding crystal matrix (27). The same vibration of OH groups and SiH groups were also observed in vitreous silica, suggesting a chemical dissolution mechanism for H 2 dissociation (28,29) ...
Water in Earth's deep interior is predicted to be hydroxyl (OH-) stored in nominally anhydrous minerals, profoundly modulating both structure and dynamics of Earth's mantle. Here, we use a high-dimensional neuro-network potential and machine learning algorithm to investigate the weight percent water incorporation in stishovite, a main constituent of the subducted oceanic crust. We found that stishovite and water prefer forming medium- to long-range ordered superstructures, featuring one-dimensional (1D) water channels. Synthesizing single crystals of hydrous stishovite, we verified the ordering of OH- groups in the water channels through optical and nuclear magnetic resonance spectroscopy and found an average H-H distance of 2.05(3) Å, confirming simulation results. Upon heating, H atoms were predicted to behave fluid-like inside the channels, leading to an exotic 1D superionic state. Water-bearing stishovite could feature high ionic mobility and strong electrical anisotropy, manifesting as electrical heterogeneity in Earth's mantle.
... As the environment becomes more reducing, the fraction of water in fluids decreases and molecular hydrogen H 2 as well as methane CH 4 become the primary H-species. Recent studies indicate that in the more reduced parts of the mantle, H 2 may not only be present in a free fluid phase, but also as dissolved species in minerals and melts (Hirschmann et al. 2012;Yang et al. 2016). ...
Immiscibility between water and hydrogen-rich fluids may be responsible for the formation of super-reduced mineral assemblages and for the early oxidation of Earth´s upper mantle. In the current study, we present new data on the critical curve in the H2-H2O system to 1400 ℃ and 4 GPa. We utilized a synthetic fluid inclusion method to trap fluids at high P–T conditions within quartz and olivine crystals. Experiments were performed in a piston-cylinder type apparatus, employing a double-capsule technique. The inner capsule contained the crystal and fluids of interest, while the outer served as oxygen fugacity buffer, maintaining f(O2) at the iron-wüstite (Fe-FeO) equilibrium. Our results suggest that below ~ 2.5 GPa, the critical curve has a mostly linear slope of 200 ℃/GPa, while at more elevated pressure it becomes significantly steeper (400 ℃/GPa). This implies that in most of the modern, reduced upper mantle, water and hydrogen are immiscible, while localized heating events, such as rising plumes, may close the miscibility gap. The steep increase of the critical curve at high pressure observed in this study implies that even for very hot geotherms in the early Archean or the late Hadean, H2-H2O immiscibility likely occurred in the deeper parts of the upper mantle, thus making a plausible case for rapid H2 loss as a mechanism of early mantle oxidation. To constrain the geochemical fingerprint of this process, we performed a series of element partitioning experiments to unravel how the H2-H2O unmixing may affect element transfer. Noble gases such as Xe as well as methane are preferentially incorporated in the hydrogen-rich phase, with a XeH2O/XeH2 ratio of ~ 8. This partitioning pattern may, for example, explain the underabundance of Xe isotopes produced by fission of Pu in the mantle. These Xe isotopes may have been removed by a primordial H2-H2O unmixing event during the early stages of planetary evolution.
... Furthermore, another school of thought argues that hydrogen is produced from the mantle of the earth's core, especially under reducing conditions. In one such study, Yang et al. [54] observed the presence of hydrogen in minerals under reducing conditions. Also, the analysis of the earth minerals such as diamond existing at equivalent depths in which deep-seated hydrogen has been previously reported shows hydrogen presence [55]. ...
The quest for natural or white hydrogen exploration and production emanates from the growing interest in clean, carbon-free hydrogen energy. Countries all over the world are beginning to formulate legislation to promote hydrogen production as a way of combating global warming occasioned by climate change. Currently, all avenues for producing hydrogen are either very expensive or environmentally unsustainable. White hydrogen in commercial accumulations might produce cheaper and more environmentally sustainable hydrogen energy, thus providing a viable alternative to other forms of renewable energy. Despite its potential to become the cheapest hydrogen source, published literature on its occurrence, sources, accumulation, generation processes, and recovery methods are scarce. Consequently, little is known regarding white hydrogen sources, accumulation, and extraction. This study reviewed the various sources and forms in which white hydrogen can exist in nature. The various processes by which white hydrogen is produced and extracted have also been presented. This work aimed to offer new perspectives and direction for future research on white hydrogen exploration and production. Furthermore, the current challenges of white hydrogen exploration and production, and its future outlook, were also presented.
... ΔG( P,T,X Fe )~ΔG * ( P,T) + X Fe ΔG * ( P,T) ′ + 高阶项 Withers and Hirschmann, 2008;Gaetani et al. , 2014;Yang, 2016;Blanchard et al. , 2017;Fei and Katsura, 2020;Liu and Yang, 2020;Druzhbin et al. , 2021;Zhang et al. , 2022) Yang et al. , 2016) ( Hirschmann et al. , 2005) Stixrude and Lithgow-Bertelloni, 2011;PerpleX, Connolly, 1990) , Dong 等 ( 2021 Mierdel et al. , 2007;Litasov et al. , 2011) , Meade et al. , 1994;Bolfan-Casanova et al. , 2000;Murakami et al. , 2002;Litasov et al. , 2003;Inoue et al. , 2010;Fu et al. , 2019;Liu et al. , 2021 ...
Nominally anhydrous minerals (NAMs) are the primary carriers of water in rocky planet mantles. Therefore, studying water solubilities of major NAMs in the mantle can help us estimate the water storage capacities of rocky planet mantles and indirectly constrain the actual water contents of their interiors. By using data science methods such as statistics and statistical learning algorithms, in this paper, current modeling studies on the mantle water storage capacities of Earth, Mars, and exoplanets have been introduced and summarized. Firstly, the thermodynamic model for mantle water storage capacity has been reviewed. Then, based on the two case studies on Earth and Mars, how to translate atomic-scale experimental data of water solubility and their measurement errors into planetary-scale models of mantle water storage capacity has been explored by using robust regression, Monte Carlo methods, and bootstrap aggregation algorithms. Thirdly, how the large sample data from the exoplanet observational campaigns can help us understand the statistical properties of the mantle water storage capacities of rocky exoplanets has been introduced. Finally, the application limitations of data science methods in mineral physics research have been discussed, and how to better combine statistics and statistical algorithms with mineral physics data research has been prospected.
... Except for pore water at forearc depths and fluid inclusions (molecular H 2 O) in minerals, water in the subducting crust at greater depths (~80-300 km) is mainly present as structural hydroxyl in either hydrous or nominally anhydrous minerals (NAMs) (e.g., Bolfan-Casanova, 2005;Xia et al., 2005;Saffer and Tobin, 2011;Wang et al., 2018;Wu and Wang, 2018;Liu et al., 2021). Although H 2 can exist in mantle minerals (Yang et al., 2016;Moine et al., 2020), it is significant only at very high pressure and highly reducing conditions (Yang et al., 2016;Zhang et al., 2022). The subducting slab itself is rather oxidizing for depths above 300 km (McCammon, 2005), meaning that H 2 is unlikely a common species in subduction-exhumed eclogites. ...
... Except for pore water at forearc depths and fluid inclusions (molecular H 2 O) in minerals, water in the subducting crust at greater depths (~80-300 km) is mainly present as structural hydroxyl in either hydrous or nominally anhydrous minerals (NAMs) (e.g., Bolfan-Casanova, 2005;Xia et al., 2005;Saffer and Tobin, 2011;Wang et al., 2018;Wu and Wang, 2018;Liu et al., 2021). Although H 2 can exist in mantle minerals (Yang et al., 2016;Moine et al., 2020), it is significant only at very high pressure and highly reducing conditions (Yang et al., 2016;Zhang et al., 2022). The subducting slab itself is rather oxidizing for depths above 300 km (McCammon, 2005), meaning that H 2 is unlikely a common species in subduction-exhumed eclogites. ...
... Trace amounts of hydroxyl groups in mantle minerals can significantly affect their physical and chemical properties, such as elastic wave velocity, electrical conductivity, thermal conductivity, viscosity, diffusion, and melting, and element distribution behavior (Hirth and Kohlstedt, 1996;Asimow and Langmuir, 2003;Bercovici and Karato, 2003;Huang et al., 2005;Wang et al., 2006;Mao et al., 2008;Yang et al., 2011;Yang, 2012;Zhang et al., 2019;Zhang et al., 2021aZhang et al., , 2021b. On the contrary, only the studies of Yang et al. (2016) and Moine et al. (2020) discussed the presence of molecular hydrogen in mantle minerals. ...
... The Raman peaks in silicate glass and diamond from the mantle provide evidence for the presence of molecular hydrogen (Wopenka and Pasteris, 1987;Chen et al., 1994). The presence of molecular hydrogen in mantle minerals was initially proposed and experimentally tested by Yang et al. (2016). Fourier-transform infrared (FTIR) shows that molecular hydrogen has an appreciable solubility in the interstitial positions of olivine, orthopyroxene, clinopyroxene, and garnet, suggesting the migration pattern of nebular molecular hydrogen during the accretion of the Earth and the presence of significant amounts of molecular hydrogen in lower mantle minerals . ...
... Therefore, we can speculate that the molecular hydrogen adsorption on the surface of forsterite in the upper mantle (0-410 km) is physisorption. Similarly, Yang et al. (2016) showed that molecular hydrogen is actually physically dissolved in the crystal lattice. The isosteric heat of adsorption can also characterize the strength of the interaction between the adsorbate molecules and the adsorbent framework in the course of adsorption; higher isosteric heat corresponds to stronger interaction. ...
Recent experimental studies have already discussed the existence of molecular hydrogen in mantle minerals. Here, we investigate the adsorption behavior of molecular hydrogen in forsterite with 0–15 Å intercrystalline pore at 0–519 MPa and 300–1800 K by using the Grand Canonical Monte Carlo (GCMC) method. Molecular hydrogen fills the interstitial positions of nonporous forsterite in an adsorbed state, whereas the filling of intercrystalline pore includes the adsorbed and free states. The adsorption of molecular hydrogen on the crystal surface of forsterite intercrystalline pore belongs to physisorption. The interaction between the adsorbate molecular hydrogen and the adsorbent forsterite framework weakens with pressure and strengthens with temperature, which is a crucial factor, and intercrystalline pore size. The adsorption capacity of molecular hydrogen in the intercrystalline pore of forsterite increases with pressure and intercrystalline pore size and decreases with temperature. By contrast, the adsorption capacity of molecular hydrogen in nonporous forsterite is controlled by pressure above 1200 K. Variations in intercrystalline pore size above 5 Å have a negligible effect on the capacity of adsorbed state molecular hydrogen at a given temperature and pressure. The adsorption of molecular hydrogen on different crystal faces of forsterite is anisotropic, with stronger adsorption on (001) and (100) than on (010) crystal faces. The adsorption capacity of molecular hydrogen in the intercrystalline pore decreases with the increase in oxygen fugacity at a given pressure, temperature, or intercrystalline pore sizes. The significant amount of molecular hydrogen stored in forsterite can provide a rich material basis for the short-term seismic precursor anomaly of hydrogen concentration and the formation of water through the reaction of silica with molecular hydrogen in the mantle.
... There are several forms of water in the deep Earth's interior: (1) hydroxyl groups (OH -) inside the lattice structures of hydrous minerals (DHMS), or defects in nominally anhydrous minerals (e. g., Smyth et al., 2006Smyth et al., , 2004Bell and Rosman, 1992); (2) H 2 O molecules around the boundaries of particles, or inside the bulk defects (e.g., Kawamoto et al., 2013;Zheng, 2009;Su et al., 2002); (3) H 2 O or OHin fluids and melts (e.g., Germán et al., 2015;Ni et al., 2013;Zhang and Stolper, 1991); (4) molecular H 2 in the minerals in the deep mantle (Moine et al., 2020;Yang et al., 2016); (5) forming superionic iron alloys in the Earth's inner core (He et al., 2022). Among the existing forms mentioned above, the OHgroups in the crystal structures of minerals have been extensively studied for their impact on the physical and chemical properties of minerals, such as thermal-elasticity, electrical conductivity, melting behavior, rheological strength, phase transitions, element partitioning, isotopic fractionation, and so on. ...
Water in the deep Earth’s interior has important and profound impacts on the geodynamical properties at high-temperature (T) and high-pressure (P) conditions. A series of dense hydrous Mg-silicate (DHMS) phases are generated from dehydration of serpentines in subduction slabs below the lithosphere, including phase A, chondrodite, clinohumite, phase E, superhydrous phase B and phase D. On the other hand, olivine and its high-P polymorphs of wadsleyite and ringwoodite are dominant nominally anhydrous minerals (NAMs) in the upper mantle and transition zone, which could contain significant amount of water in the forms of hydroxyl group (OH−) defects. The water solubilities in wadsleyite and ringwoodite are up to about 3 weight percent (wt.%), making the transition zone a most important layer for water storage in the mantle. Hydration can significantly affect the pressure-volume-temperature equations of state (P-V-T EOSs) for the DHMS and NAM phases, including the thermal expansivities and isothermal bulk moduli. In this work, we collected the reported datasets for the DHMS and NAM phases, and reconstruct internally consistent EOSs. Next, we further evaluated the thermodynamic Grüneisen parameters, which are fundamental for constraining the temperature distribution in an isentropic process, such as mantle convection. The adiabatic temperature profiles are computed for these minerals in the geological settings of normal mantle and subduction zone, and our calculation indicates that temperature is the dominant factor in determining the gradient of a geotherm, rather than the mineralogical composition.
