ABSTRACT This study investigates the micro‐pore structure characteristics and genesis of low‐resistivity reservoirs in the Wufeng and Longmaxi Formation of the Sichuan Basin. A comprehensive analytical approach—combining core analysis, gas adsorption, high‐pressure mercury intrusion, and X‐ray photoelectron spectroscopy (XPS) was employed to systematically characterize the pore structure of low‐resistivity shale reservoirs and their relationship with electrical resistivity. The results reveal that low‐resistivity shale reservoirs typically exhibit smaller pore volume and specific surface area, along with a higher degree of organic matter graphitization. This organic matter graphitization process significantly reduces the rock's resistivity. Pore structure evolution is governed by both compaction and tectonic deformation, leading to macropore reduction and meso‐/micropore redistribution. Morphological transformations in organic matter pores—including pore collapse and wall contact—further facilitate electron migration and contribute to resistivity decline. By analyzing microstructural features of the Wufeng–Longmaxi shale, this study highlights the dominant influence of organic matter maturity, graphitization, and pore structure dynamics on resistivity, offering a theoretical framework for understanding the genesis and guiding exploration of low‐resistivity shale gas reservoirs.

The Longshou Shan area is located on the northeastern margin of the Tibetan Plateau in northwest China. The study area is located where the sinistral Altyn Tagh and Haiyuan Faults overlap and the Qilian Shan thrust fault systems in the northeastern Kunlun–Qaidam Block converge. This region experiences frequent seismic events, including large-magnitude earthquakes, which are significant indicators of ongoing tectonic deformation and stress accumulation in the Earth’s crust. The seismicity of Longshou Shan is not only a consequence of its tectonic setting but also a key factor in understanding the seismic hazard posed to the surrounding areas. The tectonic activity within the Longshou Shan region of NW China is a focus of our geomorphological research due to its significance in understanding the complex interactions between tectonic forces and surface processes. Situated on the northeastern edge of the Tibetan Plateau and along the eastward trace of the Altyn Tagh Fault, Longshou Shan is crucial for investigating the plateau’s northward expansion. This study leverages ALOS-based digital elevation models (DEMs) and geomorphic indices to evaluate the tectonic activity in the area, employing various indices such as mountain front sinuosity, valley floor width-to-height ratio, hypsometric curves, asymmetry factors, basin shape indices, and channel steepness index to provide a comprehensive tectonomorphological analysis. Our results indicate intense tectonic activity on both sides of Longshou Shan, making it a highly hazardous seismic area. We also highlight the importance of thrust faults and related crustal shortening in the formation and expansion of the plateau.

Advanced Spaceborne InSAR for Monitoring Tectonic and Anthropogenic Ground Deformation in the Seismically Sensitive Almaty Region, Kazakhstan

Anatexis is a key process linking deep crustal metamorphism, tectonic deformation, and magmatic activity in orogenic systems. Understanding continental arc crustal metamorphism and anatexis is crucial for comprehending crustal differentiation and reworking. The North Wulan metamorphic complex, located along the northern margin of the Qinghai-Tibet Plateau, northern Tibet, contains a rock sequence that outcrops from deep to shallow crustal levels of a continental arc. In this paper, we present systematic studies on different types of migmatite in the North Wulan metamorphic complex to constrain the pressure-temperature-time conditions of metamorphism and partial melting within the deep crust of continental magmatic arcs. The biotite-amphibole gneiss formed through the remelting of preexisting Cambrian arc rocks, whereas the felsic gneiss originated from the partial melting of the Paleoproterozoic basement within the arc crust. Zircon U-Pb geochronology reveals that the igneous protoliths of the biotite-amphibole gneiss crystallized at 503−500 Ma. U-Pb data and Hf isotopic data from zircons indicate that these Cambrian arc rocks and the Paleoproterozoic basement underwent contemporaneous metamorphism and anatexis at 465−458 Ma. Based on both petrographic and geochemical evidence, the leucosomes in the migmatites formed from water-fluxed melting. Petrographic analysis shows diffuse boundaries between the leucosome and gneiss, along with an absence of anhydrous peritectic minerals in the leucosomes. Geochemical analysis supports this conclusion, with data showing specific correlations in element ratios (Rb/Sr versus Sr, Rb/Sr versus Ba, Ta versus Nb, and U versus Th). Phase equilibrium modeling indicates that partial melting of Cambrian arc rocks and felsic gneiss occurred under water-saturated conditions (with 1.48 wt% and 1.74 wt% H2O, respectively). The zircon Eu/Eu* data reveal that the switch from compression to extension occurred at ca. 480 Ma. As previous studies have concluded, we suggest that asthenosphere upwelling through thinned lithospheric mantle introduced high heat flow into the lower crust due to the rollback of the subducted oceanic plate. This caused water-fluxed melting in low-pressure/high-temperature granulite facies and the reworking of the continental arc crust during the subduction of the Qaidam oceanic slab in the early Paleozoic.

The complexity of geological structures significantly impacts both mining production efficiency and operational safety, making its quantitative assessment a core issue in ensuring coal’s safe production and coalbed methane development. Focusing on the Wugou Coal Mine in Anhui Province, which exhibits multi-phase tectonic superposition, modification, and relatively complex structural characteristics, this study integrates stereographic projection analysis, fractal theory, and multiple structural curvature methods to quantitatively characterize structural types and evaluate complexity. The results show that the Wugou Coal Mine has undergone four main stages of tectonic deformation since the formation of the coal seam. The superposition and modification of tectonic events of different periods and properties have led to a complex structural pattern. The fractal dimension effectively characterizes the development degree and distribution density of faults. Structural curvature not only intuitively reflects the deformation extent of fold bending and fault separation, but also provides valuable insights into the structural types, structural positions, and the characteristics of superimposed folds. By combining the strengths of fractal analysis and curvature characterization, a fractal-curvature integrated evaluation model was developed to assess structural complexity. This model facilitates a high-resolution quantitative evaluation, delineating the geological structures of the Wugou Coal Mine into zones of extremely complex, complex, moderately complex, and simple structures. The findings not only provide accurate geological guidance for mine design and hazard prevention but also offer a quantitative evaluation methodology for the optimal selection of favorable areas for coalbed methane development.

The gravity changes images of different spatiotemporal scales in the region were obtained using gravity data in the Northeastern Tibetan Plateau from 2018 to 2024. By combining regional tectonic distribution and dynamic environmental, we conducted an in-depth analysis of the dynamic relationship between gravitational spatiotemporal dynamic changes and the incubation processes of the 2022 Menyuan MS 6.9 earthquake and the 2023 Jishishan MS 6.2 earthquake. The following conclusions were reached: (1) The spatial distribution of the gravitational field in the study area is closely related to the fault zones of the two earthquakes, reflecting that the fault zones underwent tectonic activity or deformation that caused changes in surface gravity during the earthquake incubation period. (2) The reverse change of gravity may be a precursor phenomenon to earthquakes, and gravity evolution images shows that both the Menyuan earthquake and the Jishishan earthquake occurred during the periods of reverse change of gravity. (3) The gravity changes gradient zone and the center of the four-quadrant are the transition region of material conversion, where the difference movement of material increase and decrease is strong, which is prone to produce shear stress and rupture, thus inducing earthquakes, and the 2022 Menyuan earthquake and the 2023 Jishishan earthquake both occurred on the high-gradient zone. (4) The significant gravity changes before and after the Menyuan earthquake and the gravity changes before the Jishishan earthquake reflect a strong correlation with deep material structural movements, which may indicate that the occurrence of the Menyuan earthquake may have influenced the occurrence of the Jishishan earthquake. Before the earthquakes, the China Earthquake Administration made mid-term predictions for Menyuan and Jishishan based on changes in the gravity field. The occurrence of these two earthquakes strongly supporting the unique role of mobile gravity field data in determining the location of strong earthquakes.

The quantitative analysis of drainage landscapes utilizing digital elevation models (DEMs) has been widely adopted to effectively investigate structural development and evolution. However, the orientation of tectonic forces often exhibits intricate patterns and undergoes dynamic changes, leading to the superimposition of tectonic deformation and the emergence of complex structural styles. The response of drainage networks to these complex processes has been rarely documented. The Weiyuan anticline in the SW Sichuan Basin, China, serves as a case study to evaluate its applicability. Derived topographic metrics and geomorphological features indicate that deep tectonic deformation with an asymmetric uplift pattern results in contrasting tectonic activity on its flanks. The currently observed triangular distribution of anomalously high geomorphological indices in the central and northern regions suggests the presence of superimposed deformation. It is probable that the Weiyuan anticline has experienced two stages of tectonic shortening: an initial SE-directed basinward propagation of deformation from the Longmen Shan, followed by an east–west-directed shortening owing to the eastward extrusion of the Tibetan Plateau. Observed drainage patterns reveal that the current landscapes are undergoing transient adjustments. Quantitative morphotectonic analysis is proposed as a reliable and effective method for unravelling the complex history of structural superimposition.

Abstract. An analysis of 542 moment tensor focal mechanisms across the Iberian Peninsula was conducted to infer active tectonic deformation and stress regimes. This study employed a suite of complementary methodologies, including focal mechanism classification (FMC) of the rupture type, composed focal mechanisms based on the average seismic moment tensor, rotation angle between tensor estimates, right dihedra composed focal mechanisms, slip model analysis to determine the strain conditions, and classical stress inversion methodology. Based on the slip model results and considering the tectonic constraints of Cenozoic deformation in Iberia, the study region was subdivided into several tectonically coherent zones, where the different methods were applied independently to ensure robust regional interpretations. The results indicate that thrust faulting stress regimes are active in the Gorringe–Horseshoe (GH) area and the easternmost Tell Atlas. In the south, most of the zones are transpressive, as is the southwestern corner of Iberia, south of Lisbon. The exception is the Granada Basin (GB), which exhibits a nearly radial normal faulting stress regime. Normal faulting stresses are dominant in the Pyrenees and the Mediterranean rim, north of the Betic Mountains. In the central part of the Pyrenees, the maximum horizontal extension is oriented perpendicular to the mountain range, indicating that local stresses related to post-orogenic collapse or isostatic rebound dominate over regional ones. The maximum horizontal compression along the Eurasia–Africa plate limit is consistently oriented around N154° E, except in some parts of the Betics that are probably influenced by a remnant effect of the Alboran Slab. In the Central Ranges and offshore Atlantic, the maximum horizontal compression is slightly rotated anticlockwise to N140° E.

The study of faults in seismic gap areas is essential for assessing the potential for future seismic activity and developing strategies to mitigate its impact. In this research, we employed a combination of geomorphological analysis, aerophotogrammetry, high-resolution topography, and soil analysis to estimate the age of tectonically exposed fault surfaces in a seismic gap area. Our focus was on the Piano delle Rose Fault in the northern Calabria region, (southern Italy), which is a significant regional tectonic structure associated with seismic hazards. We conducted a field survey to carry out structural and pedological observations and collect soil samples from the fault surface. These samples were analyzed to estimate the fault’s age based on their features and degree of pedogenic development. Additionally, we used high-resolution topography and aerophotogrammetry to create a detailed 3D model of the fault surface, allowing us to identify features such as fault scarps and offsets. Our results indicate recent activity on the fault surface, suggesting that the Piano delle Rose Fault may pose a significant seismic hazard. Soil analysis suggests that the onset of the fault surface is relatively young, estimated in an interval time from 450,000 to ~ 300,000 years old. Considering these age constraints, the long-term slip rates are estimated to range between ~0.12 mm/yr and ~0.33 mm/yr, which are values comparable with those of many other well-known active faults of the Apennines extensional belt. Analyses of key fault exposures document cumulative displacements up to 21 m. These values yield long-term slip rates ranging from ~0.2 mm/yr (100,000 years) to ~1.0 mm/yr (~20,000 years LGM), indicating persistent Late Quaternary activity. A second exposure records ~0.6 m of displacement in very young soils, confirming surface faulting during recent times and suggesting that the fault is potentially capable of generating ground-rupturing earthquakes. High-resolution topography and aerophotogrammetry analyses show evidence of ongoing tectonic deformation, indicating that the area is susceptible to future seismic activity and corresponding risk. Our study highlights the importance of integrating multiple techniques for examining fault surfaces in seismic gap areas. By combining geomorphological analysis, aerophotogrammetry, high-resolution topography, and soil analysis, we gain a comprehensive understanding of the structure and behavior of faults. This approach can help assess the potential for future seismic activity and develop strategies for mitigating its impact.

Danxia landform, recognized for its steep cliffs and red coloration, has drawn significant scientific attention. While Chinese Danxia Landforms are UNESCO World Heritage Sites, their genesis and evolution, particularly in less-explored regions, remain under study. The southern Sichuan Basin, one of China's three largest Danxia outcrop areas, offers a unique case study due to its distinct geological setting and limited research. This study investigates the genesis of Danxia landforms in the southern Sichuan Basin using a multi-faceted approach. Field observations documented geomorphological characteristics and stratigraphy of the Danxia formations. Tectonic analysis, using regional structural data and fault mapping, assessed the impact of tectonic uplift and deformation. The findings suggest that the genesis of Danxia landforms in the southern Sichuan Basin is driven by four factors: (1) thick, well-bedded red sandstones and conglomerates; (2) regional tectonic structures, such as faults and folds; (3) episodic tectonic uplift, creating topographic relief and fluvial incision; and (4) the combined effects of weathering, erosion, and gravity shaping the cliffs. The analysis challenges the prevailing southeast-to-northwest evolutionary model for Chinese Danxia, as the southern Sichuan Basin follows a distinct developmental trajectory, influenced by regional tectonic settings and external forces. This study shows that Danxia genesis is a complex interaction of lithological, tectonic, and geomorphic processes. The findings highlight regional variability and underscore the importance of considering regional tectonic context and external forces in understanding Danxia evolution across China. This research deepens understanding of Danxia genesis and provides insights for conserving these globally significant landscapes.

This research confirms that Blega Subdistrict, located in the southern part of Madura Island, is a structurally complex region within the Rembang Anticlinorium that requires detailed geological assessment due to its hazard potential and strategic land use. Through GIS-based integration of DEMNAS, Landsat 8, Sentinel-2A, geological maps, and field validation, the study identified asymmetrical folds trending S71°E and S75°E, with anticline limbs dipping at 30–40% on the southern flank and 25–35% on the northern flank, as well as four inactive faults oriented perpendicular to the fold axes. These structures, though no longer tectonically active, remain zones of weakness that affect slope morphology, groundwater infiltration, and mechanical stability. The results also show clear morphological contrasts, with the northern sector dominated by slopes exceeding 25% and locally reaching 55%, where slope instability, shallow landslides, and soil creep are most likely to occur, while the southeastern plains with slopes of 0–2% are prone to subsidence related to karst dissolution processes. This dual hazard scenario highlights that the geohazard potential in Blega is controlled not only by tectonic deformation but also by carbonate weathering and karstification, making it essential to consider geological structures and slope conditions in land use planning. The novelty of this work lies in providing a localized, quantitative characterization of structural patterns and hazard zones at the subdistrict scale, which has not been previously documented for Madura Island. By linking structural geology with slope analysis and land use, the study offers a practical foundation for risk-sensitive planning, disaster mitigation, and sustainable regional development in Bangkalan Regency.

Abstract The India‐Asia collision generated the high topography of the northeastern Tibetan Plateau; yet the timing of its uplift remains debated. Reconstructing the deformation and uplift history of the Qilian Shan (northeastern margin of plateau) is therefore crucial for understanding the region's growth patterns and tectonic processes of the plateau. The well‐exposed, continuous Cenozoic sedimentary record in this area provides a detailed archive of the evolution of these active orogenic belts. This study presents new magnetostratigraphic data from the Baiyanghe section in the Jiuxi basin to constrain the timing of deformation and growth of the Qilian Shan. Our results date the depositional age of the Baiyanghe formation to ∼30–21.8 Ma (early Oligocene to early Miocene). Integrated stratigraphic analysis, paleocurrent data, and provenance results indicate that the Jiuquan basin likely initiated as a foreland basin and began receiving sediments from the Central Qilian Shan by the early Oligocene (∼30 Ma). Synthesizing these findings with prior research, we propose that the Qilian Shan has undergone three phases of tectonic deformation since the early Oligocene: initial uplift in the early Oligocene, northward propagation in the early Miocene, and intense uplift with outward expansion during the middle to late Miocene. Collectively, these findings elucidate the northward expansion of the Tibetan Plateau since the Oligocene.

Abstract Located in eastern South America, Uruguay has been considered tectonically inactive since rifting in the Late Cretaceous. Here, we use a high‐resolution digital elevation model and field observations to investigate the presence of recent tectonic activity in the Basaltic Plateau, northwest Uruguay. Based on topographic, drainage network and field‐based data, we identify evidence for long‐lasting, and potentially Quaternary tectonic deformation, including fault breccia, scarps, and offset channels, suggesting strike‐slip and normal faulting. The orientation and spatial pattern of this deformation aligns closely with inherited structures, particularly Proterozoic and Mesozoic fault zones. Our results suggest that reactivation of ancient basement structures has localized recent deformation, highlighting the importance of tectonic inheritance in controlling deformation in intraplate regions, considered otherwise tectonically “inactive.” The detection of subtle, recent deformation in Uruguay is only possible because of high‐resolution topographic data, underscoring the role of modern remote sensing tools in assessing tectonic activity in presumed stable regions. Lastly, this study highlights the need to reassess intraplate landscapes for signs of recent deformation, particularly in regions underlain by major basement structures that may act as zones of weakness, facilitating deformation even under low differential stress.

The Lancangjiang fault zone (LCJFZ) is a major crustal-scale fault system that traverses the Sichuan-Tibet traffic corridor. Determining its late Quaternary activity is thus crucial for assessing seismic hazards and guiding the planning of this critical infrastructure. However, there is no clear evidence as to whether the fault zone has been active since the late Quaternary. Although recent studies have suggested that the Lancangjiang fault (LCJF), a main branch of the LCJFZ, offsets Holocene sediments near the Jitang and Quzika sites and is therefore active, the supporting evidence remains inconclusive. In this paper, we carried out detailed field investigation along the Quzika-Jitang segment, building on previous work. Combined with radiocarbon dating, we reassessed the late Quaternary activity of the LCJF. Our new results reveal that the nearly SN-trending segment of the LCJF (F1) shows no sign of late Quaternary activity. In contrast, the NE-trending branch fault of the LCJF (F2), located near Quzika Township, has faulted the late Quaternary strata and may exhibit Holocene activity. Further analysis suggests that the LCJFZ is no longer the main structure regulating regional tectonic deformation. Instead, secondary strike-slip faults, such as fault F2 and the Yangda-Yaxu fault (YYF), cut through or intersect the LCJFZ, and exhibit obvious late Quaternary activity. Thus, we speculate that the NE-trending F2 and WNW-trending YYF are both probably the most active structures around the LCJFZ today. These observations indicate that the main structures absorbing and regulating regional strain energy have changed from nearly SN-trending LCJFZ to several secondary WNW- and NE-trending faults, which means that tectonic transformation and fault neogenesis have occurred around the LCJFZ.

Sorowako and surrounding areas are geologically influenced by Sulawesi’s microcontinent movement, which has produced several geological phenomena. Morphometry is one of the parameter that can reveal geological condition of particular area. Morphometric analysis of water catchment area in Sorowako and surrounding areas using Bifurcation Ratio (Rb) and Drainage Density (Dd) can provide comprehensive information on level of deformation in Sorowako region. Analysis result of Bifurcation Ratio Index (Rb) on water catchment area reveals that Rb<3 value is dominant and equally spread in Sorowako region, it varies from 0.094 to 2.888. However in several place the value of Bifurcation Ratio (Rb) index is more than 5 (Rb>5) with varies from 5.142 to 10.250. Drainage Density (Dd) value ranges from 0.907 to 8.422 with an average value is 4.125 describes impact of erosion and tectonic on Sorowako region. Based on morphometric analysis of two parameters, Sorowako and surroundings area have been heavily impacted by tectonic activity on Sulawesi island. In western, eastern and northern regions on water catchment area, level of deformation tends to be higher compared to southern region. This can be seen on analysis result of water catchment area 43, water catchment area 196, and water catchment area 302 that have relatively larger number of stream orders, and also have Bifurcation Ratio’s value less than three (Rb<3). Information of tectonic deformation level on Sorowako region through morphometric analysis is important to further use as a basis for water catchment area management planning, so that it can identify areas prone to geological disasters. This fairly high level of tectonic deformation also believed to be a controlling factor for nickel grade contained in Sorowako and surrounding areas which allow supergene enrichment to occurs in rocks.

Abstract Southeast Tibet, a key region for the southeastward extrusion of the Tibetan Plateau, remains debated in terms of its tectonic deformation in response to the ongoing collision between the Indian and Eurasian plates. In this study, we applied shear‐wave splitting analysis of core‐refracted phases recorded by a newly deployed dense seismic array and six permanent stations to delineate crustal and mantle deformation processes. The observed fast polarization directions are predominantly aligned NNW–SSE, while the splitting delay times vary across four sub‐blocks. The anisotropy pattern suggests a dominantly asthenospheric origin, consistent with southeastward‐directed mantle flow associated with the extrusion of the Tibetan lithosphere. The splitting delay times are relatively larger near major faults and tectonic boundaries compared to areas farther away, and the fast polarization directions beneath these structures exhibit a moderate rotation toward the fault strike, indicating that such tectonic discontinuities contribute to observable azimuthal anisotropy.

ABSTRACT The Terrestrial Reference Frame (TRF) is essential for solid Earth research, including geodesy and geodynamics, providing a unified spatiotemporal datum. With the continuous expansion of global GNSS infrastructure and data, significant progress has been made in refining TRF and models of crustal plate motion and tectonic deformation. This study provides a global velocity field and a plate motion model through three decades of Global Navigation Satellite System (GNSS) data and nonlinear TRF refinement. Key contributions include: (1) the Integrated and Improved Time Series Analysis (IITSA) model, achieving horizontal fitting precision of 3 mm and vertical precision of 6 mm for three-decade GNSS time series; (2) the Global GNSS Velocity Model 2020 (GGVM2020), with RMS values of 0.12, 0.11, and 0.26 mm/yr in the north, east, and up directions, providing new insights into the crustal movements of Antarctica and North America; (3) the Global Interpolation Velocity Model 2020 (GIVM2020), offering a global horizontal velocity grid (3°×3°) with interpolation accuracy better than 3 mm/yr, enabling velocity estimation for any site globally; and (4) the Global Plate Motion Model 2020 (GPMM2020), which improves the accuracy of Euler motion parameters for the 14 major tectonic plates, achieving precision better than 3 mm/yr. In conclusion, the study’s results, including the global GNSS velocity field and plate motion model, enhance the reliability and application of terrestrial reference frame products.

ABSTRACT This study investigates the effects of tectonic deformation and oxygen concentration on the thermodynamic characteristics of coking coal during oxidation and combustion using thermogravimetric analysis. Three groups of tectonic coking coal samples were analyzed for characteristic temperatures, mass changes, exothermic behavior, and kinetic parameters. Results show that tectonic deformation reduces the maximum mass temperature and ignition point by 2.5–4.5°C and 4.5–5.7°C, respectively. Oxygen uptake-induced weight gain and pyrolysis/combustion activation energy decreased by 3.36%–7.92% and 12.07%–25.57%, respectively, increasing spontaneous combustion tendency. Under low oxygen conditions, oxidation-thermal reactions exhibit hysteresis, with activation energy shifting from a third-order to a second-order model, and heat release decreasing with oxygen concentration. Reducing oxygen levels can suppress spontaneous combustion, but low oxygen also promotes a transition from oxidation decomposition and gas-phase combustion to prolonged solid-phase combustion, which is harder to extinguish. This research provides critical insights into the heightened reactivity of tectonic coking coal and strategies for mitigating spontaneous combustion risks in tectonically active mining areas, supporting ecological protection and fire prevention efforts.

Surface and subsurface deformation analysis of Sarajeh Gas field and adjacent areas: Implications of tectonic deformation on gas reservoir characteristics

The subduction of seamounts greatly affects arc volcanism, earthquakes, and tectonic deformation of the overriding plate, but the role of seamounts during bending and hydration of the incoming plate at subduction zones is poorly understood. We present seismic tomographic results along three profiles from the Middle America Trench offshore northern Costa Rica. The crustal and upper mantle P-wave velocities decrease toward the trench, with the onset of velocity reduction at ∼70 km from the trench axis, indicating bend-faulting, alteration, and hydration of the incoming plate. The most prominent low-velocity anomaly of 7.6−7.8 km/s in the upper mantle occurs beneath a seamount at the outer rise, indicating enhanced hydration with ∼2.4 wt% water content, compared to ∼1.1−1.2 wt% in the subducting plate away from the seamount. Near the seamount, extremely low heat flow (<10 mW/m2) supports vigorous hydrothermal recharge of seawater. Our results reveal that subducting seamounts efficiently increase the permeability of the oceanic crust prior to subduction, facilitate the transport of seawater into the mantle, exert control on widespread serpentinization, and potentially promote water recycling back into Earth’s interior.