Earth is a complex, dynamic system governed by the chemical, physical, and mechanical properties of its component minerals. From the crust through the deep mantle and into core, minerals experience extreme pressures and temperatures, resulting in phase transformations and variations in properties. These alterations influence seismic wave propagation, mechanical strength, viscosity, electrical and thermal conductivities, as well as the cycling of key elements such as carbon, water, and oxygen, thereby influencing mantle dynamics, subduction processes, and core dynamics. Thus, understanding the physicochemical properties of minerals in Earth's interior is crucial for interpreting Earth’s structure, dynamic behavior, and evolutionary processes.
This special issue of Geoscience Frontiers includes 14 pioneering studies examining various aspects of mineral behavior in Earth's deep interior through experiments and computational approaches. These studies reveal the properties of several critical minerals under extreme pressure and temperature conditions, advancing our comprehension of Earth’s internal processes like subduction dynamics, deep carbon and water cycles, and core dynamics. Additionally, these findings hold broader implications for planetary science, allowing us to draw parallels between Earth's evolution and that of other rocky planets. The articles are categorized into three primary themes: (1) the elasticity and seismic properties of minerals, (2) phase transitions and reactions of minerals, and (3) the influence of light elements on mineral properties.
Elasticity and seismic properties of minerals. Several studies in this issue focus on mineral elasticity and its implications for interpreting seismic data.
Yang et al. (2025) examine the elasticity of Fe-bearing post-perovskite under D'' layer conditions near the core-mantle boundary. This study provides crucial constraints on interpreting seismic anomalies in this region, refining models of the lowermost mantle. Similarly,
Ma et al. (2025) investigate the seismic properties of epidote, a hydrous mineral, by measuring its compressional and shear wave velocities at high pressure, shedding light on the blueschist-to-eclogite transition's velocity structure. The study by
Liu et al. (2025a) analyze the wave velocities and anisotropy of rocks from the Qinling Orogenic Belt, providing insights into low-velocity zones and tectonic processes. Additionally,
Song et al. (2025) explore forsterite’s behavior at extreme pressures, offering insights into the mineral's sound velocity along Hugoniot curve. This is essential for interpreting seismic wave data in both Earth's mantle and larger exoplanets. Together, these studies improve the interpretation of seismic data observed in Earth’s mantle, which in turn enhances our understanding of Earth's interior structure and the processes occurring at depth.
Phase transitions and reactions of minerals. Phase transitions and chemical reactions of minerals and fluids under high pressure–temperature conditions are essential for understanding the physicochemical changes occurring in subduction zones and mantle. The study by
Sun et al. (2025a) investigates carbonate interactions with siliceous fluid under varying oxygen fugacity, underscoring the role of redox conditions in generating carbon-rich fluids in shallow subduction zones.
Zeng et al. (2025) examine antigorite (a serpentine mineral) dehydration and its impact on water migration in subduction zones. Their findings indicate that the water release from antigorite notably contributes to the formation of low-velocity zones, influencing water transport into the deep Earth. Furthermore,
Sun et al. (2025b) extend the exploration of hydrous minerals in their study, which analyzes brucite's stability under mantle conditions, suggesting that brucite may carry water to depths greater than previously thought. Similarly, the paper by
Guo et al. (2025) investigate the role of siderite (FeCO
3) in deep carbon cycling, revealing that water interactions facilitate CO
2 release in the upper mantle, with potential implications for volcanic activity. Meanwhile,
Zhang et al. (2025) examine the spin-state transitions of siderite using Raman spectroscopy and electrical conductivity measurements. This study reveals changes in siderite’s physical properties under extreme pressure and temperature conditions, shedding light on its role in mantle carbon cycling and storage.
Zhao et al. (2025) investigate cation disorder in ringwoodite (a high-pressure phase of Mg
2SiO
4) and propose a mechanism for seismic velocity variations at the 560 km depth, contributing to our understanding of mantle transition zones. These studies collectively provide valuable data to refine models of element cycling and the physical processes governing subduction, mantle dynamics, and deep-Earth chemistry.
Influence of light elements on mineral properties. Light elements (H, O, C, He, P, Si, S, etc.) are distributed throughout Earth’s crust to its core, where their storage and cycling significantly impact the dynamics of Earth’s interior. Investigating the behavior of materials containing these light elements under extreme conditions is crucial for understanding the deep interiors of Earth and other planetary bodies. In this category,
Huang et al. (2025) examine helium diffusion in aragonite, a carbonate mineral, which is critical for understanding the storage of helium within Earth’s deep mantle. Additionally,
Liu et al. (2025b) investigate the diffusion behaviors of molecular hydrogen in olivine under extreme pressure–temperature conditions, providing foundational data to model hydrogen migration within Earth's mantle. Approximately 3%–10% of Earth’s iron core is composed of light elements, altering its physical properties and dynamics.
Xie et al. (2025) explore how the presence of light elements such as oxygen can influence the core’s physical properties and its interactions with the mantle, offering new insights into the composition of the core and its role in generating Earth's magnetic field.
Xu et al. (2025) calculate the viscosities of hexagonal close-packed (hcp) iron alloyed containing light elements, providing key data for understanding the rheology of Earth’s inner core. The study contributes to our knowledge of core dynamics, particularly the anisotropy observed in seismic wave propagation through the inner core. These studies advance our understanding of light-elements-bearing minerals under the high-pressure conditions, providing valuable data for modeling the Earth’s deep interior and their evolutionary processes.
Overall, the research presented in this special issue demonstrates the vital role of mineral physics in advancing our understanding of Earth’s deep interior and planetary science. By investigating elasticity, phase transitions, and the thermodynamic properties of key minerals, these studies offer critical insights into dynamic processes that shape Earth’s mantle, core, and subduction zones. Together, these papers illustrate the interdisciplinary nature of modern geosciences, where experimental techniques, theoretical simulations, and seismic data interpretation converge to provide a comprehensive understanding of Earth’s interior. The insights presented here extend beyond Earth, fostering an improved comprehension of the processes governing the evolution of planetary interiors.
Acknowledgements
We sincerely acknowledge the contributors of this special issue and to the referees for their valuable comments. We are especially grateful to Prof. M. Santosh and Dr. Lily Wang for providing this opportunity and their editorial support. We extend our gratitude to the excutive committee of the Ninth Meeting, From Atom to Earth, held in 2023 in Dujiangyan, Chengdu, China. This special issue originated from discussions at the meeting, supported by Sichuan University, Innovation Academy for Precision Measurement Science and Technology of the Chinese Academy of Sciences, and Yanshan University. This work was made possible by the financial support from the National Natural Science Foundation of China (Grant Nos. 42325203, 42422201, 42394114).
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