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Lunar mare basalts represent melting of mantle material, buoyant ascent in dikes, and eruption onto <20% of the surface. Global mare distribution is distinctly asymmetrical, with a paucity on the farside, plausibly interpreted to be related to thicker farside low‐density crust inhibiting buoyant magma rise to the surface. Challenging this hypothesis is the presence of the huge, ancient farside South Pole‐Aitken (SPA) basin, site of the thinnest crust and deepest depression observed on the Moon. We hypothesize that an oblique impact stripped the farside crust within the SPA basin, permitting early mare basalt emplacement as cryptomaria due to thin/absent crust. However, removal of the SPA thermally insulating megaregolith/crust accelerated lithosphere thickening beneath the basin. This deepening rheological barrier inhibited buoyant rise of mantle diapirs below SPA, resulting in early abatement of mare basalt extrusions compared to the nearside, and retention of the deep, underfilled SPA impact basin observed today. Plain Language Summary: The cause of the observed asymmetry in nearside/farside mare basalt distribution (nearside ∼15% of the surface, farside ∼1%) has been attributed to differences in crustal thickness and the magma buoyancy at the base of the thicker crust, but this single factor is challenged by the presence of the ancient very deep SPA basin (average ∼5 km), significantly underfilled by mare basalts compared to the nearside. We examine the effects of the formation of the giant (∼2,300 km) SPA basin in removing the insulating megaregolith/crust, and show that it could first result in rapid cryptomaria emplacement due to near‐absent crust, accompanied by enhanced heat loss within the basin, and formation of anomalously early thick sub‐SPA lithosphere, inhibiting its mare filling due to a rheological barrier to basaltic magma eruptions, analogous to that which occurs later in lunar history on the lunar nearside. Key Points: The nearside‐farside asymmetry in mare basalt volcanic deposits has been attributed to thicker farside crust inhibiting eruptionChallenging this hypothesis is the very deep, thin‐crust ancient SPA impact basin, significantly underfilled by mare basaltsAfter SPA impact‐removal of insulating crust, sub‐SPA lithosphere thickens anomalously early, inhibiting mare fill following cryptomaria [ABSTRACT FROM AUTHOR]

Diyarbakir province mean rock formation is basaltic due to its location. Basaltic parent rocks release much silt or clay when imposed to chemical or physical weathering. The soils are residual in origin. In other words, they formed in situ where the basaltic parent rocks exist. They were not transported by means of wind or water. In this research, firstly, the properties of Diyarbakir basaltic clays were investigated from literature. After that, one soil sample from Kayapinar vicinity has been taken to laboratory to find index properties. The values from two different locations which are obtained from literature and values which are obtained from laboratory were compared. The results indicated that the three samples from different locations showed roughly the same index properties. As per the results, the clay is high plastic (CH), and it has swelling potential. In this thesis, design parameters of posttensioned slabs on ground under different climatic scenarios were found. The widely used method for slabs on ground under swelling soils is the Post‐Tensioning Institute (PTI) method. In order to use this method, Thornthwaite moisture index is required. This index is used in geotechnical engineering to identify moisture flux boundary conditions for unsaturated soils and depth of active zone for expansive soils. This index has been found using water balance sheet tables for Diyarbakir. So as to find the future moisture index, water balance sheet tables have been formed finding the climate projection data for Turkey in literature. In this way, five moisture index values of Diyarbakir have been found for the current situation and with regard to representative concentration pathway (RCP4.5 and RCP8.5) scenarios for 2050. The parameters for the maximum differential swell (em) and the angular moisture change index (ym) for design procedure according to the PTI method were found for each moisture index. Results showed that the ym and em values increased when the Thornthwaite moisture index is reduced. Also results showed that the slab thickness is increased when moisture index is reduced. Considering the moisture index parameters for future values, Diyarbakir is likely to face arid climates in the future. [ABSTRACT FROM AUTHOR]

S2‐glass fiber reinforced plastics (S2‐GFRP) and basalt fiber reinforced plastics (BFRP) have emerged as crucial materials due to their exceptional mechanical properties, and milling of composite materials plays an important role in achieving desired properties. However, they have proven challenges due to relative inhomogeneity compared with metals, resulting unpredictability in quality of milling operations. The objective of this work is to investigate the effect of cutting parameters, tool geometry and tool surface materials on the surface quality of composites using burrs as a metric. S2‐GFRP and BFRP composites were produced by the vacuum infusion method. Helical and straight flute end mills were manufactured from high‐speed steel (HSS) and carbide rounds, and half of them were coated with titanium nitride using reactive magnetron sputtering technique. Taguchi L18 orthogonal array is used to determine the effect of tool material, tool angle, coating, cutting direction, spindle speed, and feed rate on the machining quality of S2‐GFRPs and BFRPs with respect to burr formations. Milling experiments were conducted under dry conditions and then the burrs were imaged to calculate the total area and length. Statistical analysis was also performed to optimize the machining parameters and tool type for ensuring the structural integrity and performance of the final composite parts. The results showed that the selection of tool material has the most significant impact on the burr area and length of the machined surface. The novel image analysis allows to analyze the extent of the burr size with a desirable operation speed for industrial applications. Highlights: Aerospace grade S2‐Glass (S2‐GFRP) and basalt fiber reinforced plastics (BFRP) were manufactured.Carbide and HSS end mills were fabricated and coated with titanium nitride protective layer.FRPs were machined at various process parameters designed by Taguchi method.Distinctive image processing was firstly used to compute milling induced Burr area and length.Statistical analysis was performed to quantify the contribution of parameters and optimize milling. [ABSTRACT FROM AUTHOR]

Geological samples are inherently multi‐scale. Understanding their bulk physical and chemical properties requires characterization down to the nano‐scale. A powerful technique to study the three‐dimensional microstructure is X‐ray tomography, but it lacks information about the chemistry of samples. To develop a methodology for measuring the multi‐scale 3D microstructure of geological samples, correlative X‐ray micro‐ and nanotomography were performed on two rocks followed by scanning electron microscopy with energy‐dispersive spectroscopy (SEM‐EDS) analysis. The study was performed in five steps: (i) micro X‐ray tomography was performed on rock sample cores, (ii) samples for nanotomography were prepared using laser milling, (iii) nanotomography was performed on the milled sub‐samples, (iv) samples were mounted and polished for SEM analysis and (v) SEM imaging and compositional mapping was performed on micro and nanotomography samples for complimentary information. Correlative study performed on samples of serpentine and basalt revealed multiscale 3D structures involving both solid mineral phases and pore networks. Significant differences in the volume fraction of pores and mineral phases were also observed dependent on the imaging spatial resolution employed. This highlights the necessity for the application of such a multiscale approach for the characterization of complex aggregates such as rocks. Information acquired from the chemical mapping of different phases was also helpful in segmentation of phases that did not exhibit significant contrast in X‐ray imaging. Adoption of the protocol used in this study can be broadly applied to 3D imaging studies being performed at the Advanced Light Source and other user facilities. [ABSTRACT FROM AUTHOR]

Determining subduction‐related processes is crucial for understanding lithological heterogeneity, as substantial quantities of slabs are recycled into the mantle. Molybdenum isotopes are valuable for distinguishing sources materials due to the significant isotope differences between the crust and the mantle. In this study, we systematically investigate Mo isotopes in a suite of well‐characterized continental basalts from Keluo and Halaha‐Chaoer, located in Northeast China. The δ98Mo values of Keluo range from −0.41 to −0.23‰, with an average of −0.34‰, while Halaha‐Chaoer samples ranged from −0.18 to −0.12‰, with an average of −0.15‰. The δ98Mo values of Keluo basalts are lighter than the mean value of fresh oceanic basalts (−0.21‰), whereas those of Halaha‐Chaoer basalts are similar to oceanic basalts. Combined with other geochemical indications (LOI, Ce/Pb, La/Yb and so on), the Mo isotopic variations cannot be attributed to chemical weathering, continental crust contamination or magmatic processes. Instead, the δ98Mo variations in this study are explained by the incorporation of different oceanic crustal materials into the magma sources. Correlations of δ98Mo with Ba/Th, Th/U, 143Nd/144Nd indicated that both sediment and altered oceanic crust have significantly influenced these variations. This study demonstrates the potential of Mo isotopes to distinguish different types of recycled oceanic crust materials. [ABSTRACT FROM AUTHOR]

The Badia Epigraphic Survey (BES) Project was launched in 2015 by Ali Al‐Manaser and Michael C. A. Macdonald and, with two gaps, has been conducting annual surveys in the ḥarra of north‐eastern Jordan ever since. The 2023 survey, like that of 2018, set out to rediscover the cairns at the border between the ḥarra and the ḥamād at which, in the late 1950s, Professor Fred V. Winnett and Gerald Lankester Harding (WH) discovered over 4000 inscriptions. The purpose was to identify the WH cairns by the inscriptions on them, to give them exact locations using Global Positioning System and to photograph all the inscriptions, most of which WH had had to record in hand copies. In the process, numerous inscriptions at other cairns were also recorded, as well as large numbers of modern Arabic inscriptions carved in the 65 years since the WH expedition. This article describes some of the finds made, gives the exact locations of the WH cairns rediscovered and discusses some of the interesting ancient and modern inscriptions and drawings which were found. [ABSTRACT FROM AUTHOR]

Mid‐ocean ridge basalts reflect the mantle's composition and reveal processes from melting to eruption. The Mohns and Knipovich Ridges have ultraslow spreading rates, low magma budgets and erupted lavas indicating various mantle domains. Here, we use geochemistry and isotope systematics of in situ samples from two axial volcanic ridges (AVRs) to study mantle heterogeneity and melt production. By linking chemical variations to high‐resolution bathymetry and age data, we document systematic changes over time in the mantle source of the volcanic sequence. At Mohns Ridge AVR‐M10 (72.3°N), we observed significant variations in chemistry (e.g., (La/Sm)N from 0.7 to 2.9) and isotope systematics in basaltic samples from a small area (∼1 km2), suggesting the emplacement of multiple small‐volume lava flows. Pb isotope variations, for example, 206Pb/204Pb (17.91–18.76), are comparable with the observed range along the entire Mohns and Knipovich Ridges. Temporal constraints document that erupted basalts have changed from highly radiogenic Pb compositions to a more depleted signature within 30 ka. To explain the extreme variations in the erupted lavas at the Mohns Ridge, the mantle would need to be highly heterogeneous in composition with effective melt extraction and limited mixing prior to eruption. We use the highly heterogenous mantle underneath the Mohns Ridge to understand the melt extraction processes and mixing of melts and propose a two‐stage melting model: continuous generation of enriched melts from a deep and fertile source in the first stage, while depleted melts from a shallower and more refractory mantle occur sporadically and simultaneously with the intermittent ascent of diapirs. Key Points: Significant variations in chemistry within a small area suggest the emplacement of multiple small‐volume lava flowsTemporal constraints document that erupted basalts have changed from highly radiogenic Pb compositions to a depleted signature within 30 kaExtreme mantle heterogeneity is recorded in on‐axis lavas when melt extraction is efficient and homogenization in magma chambers is limited [ABSTRACT FROM AUTHOR]

Primary magmas form by partial melting in the mantle of a terrestrial planet and represent the starting material for building its crust. The compositions of primary magmas are critical for understanding the thermal history of planetary interiors, as they can be used to estimate mantle potential temperatures (TP) and track changes in the conditions of mantle partial melting over time. Here, we introduce PRIMARSMELT, a new member of the PRIMELT software family, calibrated to estimate the composition of Martian primary magmas and their formation conditions. We applied PRIMARSMELT to a comprehensive database of basaltic compositions from Mars. Our results are consistent with their petrology, requiring olivine addition to restore fractionated compositions to their primary parents and olivine subtraction from cumulate rocks. Individual primary magma solutions provide insights into the petrogenesis of specific Martian meteorites, with implications for the near‐primary nature of some primitive meteorites and the relationship between lithologies A and B in meteorite EETA 79001. Taken together, our results suggest nearly constant or potentially increasing mantle potential temperatures throughout the geological history of Mars. The average TP for young shergottite meteorites is ∼1,442 ± 40°C, similar to ambient mantle temperatures inferred from geophysical models. In contrast, older basaltic rocks record potential temperatures as low as ∼1,320 ± 48°C for igneous clasts in meteorites NWA 7034/7533. We suggest that, rather than plume‐related magmatism, shergottite meteorites record ambient mantle temperatures, with the thermal evolution trend possibly resulting from inefficient heat loss, as expected for a planet in stagnant‐lid mode. Plain Language Summary: Primary magmas, formed from the melting of a planet's mantle, are the materials from which the crusts of terrestrial planets are formed. Establishing their composition helps us understand the thermal state of a planet's interior and how it changes over time. We developed PRIMARSMELT, a software tool that estimates primary magmas on Mars using the measured chemical compositions of Martian meteorites and surface rocks. When applied to different Martian samples, PRIMARSMELT produces results that shed light on their origins and relationships. Notably, when combining our results for some suitable samples with their ages, we found that the internal temperature of Mars appears to have remained steady or may even be increasing with time. The primary magmas of young meteorites record temperatures around 1,442°C, while those of older rocks are around 1,320°C. These findings suggest that Mars may not cool efficiently, likely because of its stable outer shell, which does not allow heat to escape as it does on more geologically active planets like Earth, where plate tectonics permits efficient cooling. Key Points: We developed PRIMARSMELT, a new software tool for estimating the composition and conditions of formation of primary magmas on MarsPrimary magma solutions from PRIMARSMELT provide new insights into the formation conditions and petrogenetic history of some Martian rocksOur results from PRIMARSMELT may indicate steady or potentially increasing mantle temperature throughout the geological history of Mars [ABSTRACT FROM AUTHOR]

With growing environmental concerns due to the excessive use of natural river sand in construction, finding sustainable alternatives is crucial. This study explores the potential of basalt waste dust, a by‐product of basalt rock crushing, as a replacement for river sand in one‐part geopolymer mortar. The experimental program is segmented into three series: replacing river sand with basalt waste dust at 25%, 50%, 75%, and 100%; adjusting the activator‐to‐binder ratio as 0.12, 0.15, 0.18, and 0.21; and modifying the aggregate‐to‐binder ratios (1, 1.4, 1.8, and 2.2). Results are discussed using various test results such as fresh property, hardened property, and microstructural property to provide a detailed analysis of mixture properties. Findings in series 1 reveal that replacing 50% of river sand with basalt waste dust optimally enhances the fresh and hardened properties of geopolymer mortar. In series 2, the varying activator‐to‐binder ratio with optimum replacement from series 1, activator‐to‐binder ratio 0.15, was found to be optimal, improving hardened properties. Further opting for this ratio in series 3 and increasing the aggregate‐to‐binder ratio to 2.2 was found to positively impact both the hardened and microstructural properties of one‐part geopolymer mortar. This study demonstrated that basalt waste dust plays a crucial role in these improvements and emphasizes the necessity of optimizing mix proportions to achieve superior performance, establishing basalt waste dust as a viable and sustainable alternative to river sand. [ABSTRACT FROM AUTHOR]

Highlights This work investigates the addition of milled carbon fiber reinforcement and its effect on scratch resistance and mechanical durability for basalt fiber/epoxy composites, assessed under varied loading conditions with the aid of different indenter types according to a factorial design. Composites with MCF content from 0 to 10 wt% were prepared. Scratch behaviors under Vickers and Rockwell indenters were studied for loads of 5, 10, and 15 N. The addition of 10 wt% MCF has resulted in scratch hardness increase from 13.255 N/mm2 up to 47.952 N/mm2, depending on the type of indenter used. Precisely, in conditions of a 5 N load and when a Rockwell‐type indenter was used, a scratch hardness maximum of 47.952 N/mm2 was achieved, while for a Vickers‐type indenter under the same conditions, the maximum value of its equivalent was 23.327 N/mm2. Profilometric and SEM analyses evidence that matrix cracks and surface deformation have been reduced with higher MCF content, at least for the application of lower scratch test loads. The mechanical and surface performances of the basalt fiber composites were found to be considerably improved by the reinforcement with MCF. Scratch resistance for milled carbon fibers increases and peaks at 10 wt% reinforcement. The Rockwell indenter indicates a steady increase in hardness up to 47,952 N/mm2. Peak hardness of 10 wt% is observed under the Vickers indenter for the 5 N load. Higher milled carbon fiber content reduces matrix cracking and surface deformation. There is a clear correlation between scratch performance, milled carbon fiber content, and indenter type. [ABSTRACT FROM AUTHOR]

Translation abstract Durable and sustainable bridge caps made of non‐metallic reinforcement and recycled concreteDue to chloride‐induced corrosion, bridge caps made of steel‐reinforced concrete need to be replaced regularly or more often than planned. As part of a ZIM project funded by the Federal Ministry for Economic Affairs and Climate Action, bridge caps made of non‐metallic basalt fibre reinforcement and recycled concrete were developed to mitigate the weakness of corrosion and to better utilize the materials in terms of the material cycle. To achieve this, bend reinforcement elements made of chloride‐resistant basalt fibre reinforcement and concrete with high frost‐thaw resistance were developed, consisting of up to 100 % recycled aggregate. All sub‐developments were integrated into a holistic approach, and a prototype of a resource‐efficient and durable bridge cap was successfully produced and tested. [ABSTRACT FROM AUTHOR]

The availability of fiber‐reinforced polymers (FRP) as an alternative for conventional steel reinforcement in concrete construction is increasing. To widen the scope of application, for example, in the case of prestressing, and to improve the bond behavior at the bar ends, end anchorages need to be considered. Within this paper, a new short‐length anchor representing a combination between a bond and mechanical anchor is presented using a special inner geometry to increase the load‐bearing capacity due to the mechanical wedge effect, with a bonding length of only 50 mm. Besides giving a short overview of different anchorage systems, the paper focuses on experimental investigations that were performed with mechanical bond anchors with a variation of the inner geometry of the steel anchorage, different FRP bars, and different load transfer media. A numerical investigation completes the study by showing an approach to calculate the presented mechanical bond anchors. It was found that a small thickness of the bonding material is favorable, and a decrease of the bonding length is not necessarily disadvantageous. A tensile failure of the FRP bars was not achieved, although a full exploitation seems promising since a utilization of up to 83% of a basalt FRP bar was reached. [ABSTRACT FROM AUTHOR]

It remains uncertain whether a stagnant slab in the mantle transition zone can affect the asthenospheric mantle beyond its leading edge. To address this question, we investigated Cenozoic alkaline basalts from the Dariganga volcanic field (DVF) in southeastern Mongolia. The DVF is located west of North–South Gravity Lineament (NSGL) in Eastern China, which is spatially coincident with the seismically detected stagnant Pacific slab front. Basalts from the DVF consist of nephelinite, basanite and alkali olivine basalt. These rocks have relatively high Nb/U (average = 58) and Nb/La (>1) ratios and radiogenic Nd–Hf isotopic compositions. They also have high Ca/Al (0.60–1.13), Zn/FeT (13.5–16.5), and FeO/MnO (77–112) ratios as well as low δ26Mg (−0.42‰ to −0.26‰) values, reflecting an asthenospheric mantle source modified by carbonated eclogite‐derived melts. Pb–Nd–Hf isotope characteristics indicate that the carbonated eclogite‐derived melts likely originated from the stagnant Pacific slab. Although Cenozoic basalts from both the east of the NSGL (ENSGL) and DVF domains exhibit light δ26Mg values, basalts from the ENSGL nevertheless have lower δ26Mg values than those in the DVF domain. This suggests a gradual westward decline in the amount of carbonated melts/fluids derived from the stagnant Pacific slab. This variation trend, combined with a more fertile and oxidized asthenospheric mantle toward the ENSGL, indicates that the stagnant slab has affected the mantle and created a compositional aureole beyond its leading edge, which substantially contributed to the formation of the alkaline basalts in the DVF. Plain Language Summary: Subducted slabs can exert a profound influence on overlying mantle domains. However, it remains uncertain whether material from a stagnant subducted slab in the mantle transition zone can influence the mantle domain beyond its leading edge and contribute to the formation of alkaline basalts. This article presents a study on Cenozoic alkaline basalts in SE Mongolia, which lie west of the North–South Gravity Lineament, beyond the leading edge of the stagnant Pacific slab. The Cenozoic alkaline basalts in SE Mongolia are characterized by relatively high Ca/Al, Nb/U and Nb/La ratios. They also show depletion in Pb–Zr–Hf and have radiogenic Nd–Hf and relatively light Mg isotopic compositions, which is consistent with their origination from an asthenospheric mantle source modified by carbonated eclogite‐derived melts. Radiogenic isotopic compositions suggest that the carbonated melts were likely derived from the stagnant Pacific slab. Furthermore, there is a westward decline in signals of carbonated melts/fluids derived from the stagnant Pacific slab. These findings suggest that the stagnant Pacific slab has influenced the mantle domain beyond its front edge, leading to a differential modification of the asthenospheric mantle and the formation of intraplate alkaline basalts in the Dariganga volcanic field. Key Points: The Cenozoic alkaline basalts in Dariganga were sourced from asthenospheric mantle modified by carbonated eclogite‐derived meltsThe carbonated eclogite‐derived melts were derived from the subducted Pacific slab that stagnated in the mantle transitional zoneThe influence of the carbonated melts/fluids waned westward, resulting in a compositional aureole across the North–South Gravity Lineament [ABSTRACT FROM AUTHOR]

The Tarim Craton is an ancient Precambrian continental block, and detailed knowledge of its thermo‐tectonic history is crucial for understanding the early history of continental evolution. Abundant layered mafic rocks, which have commonly been regarded as basalts, occur within the Ediacaran Sugetbrak Formation (Fm.) in the Aksu region of the northwestern Tarim Craton. Clear intrusive features have now been discovered, including mafic rocks truncating Ediacaran sedimentary layers, exhibiting an intrusion‐baked margin where they interact with both the overlying and bottom wall rocks, and displaying a fine‐grained transition zone from their interior to their margins. The new findings demonstrate that these mafic rocks within the Aksu Ediacaran strata were not erupted basalts but instead are intrusive diabase dykes. Therefore, these mafic rocks cannot be used to constrain the timing of the Sugetbrak Fm. in the Aksu area, nor as marker layers for regional stratigraphic correlation. Furthermore, the Ediacaran thermo‐tectonic evolution in this region, deduced from the assumption that the mafic rocks are lavas, needs to be revised. [ABSTRACT FROM AUTHOR]

Based on an analysis of the literature on fiber‐reinforced concrete (FRC), especially the development and formation of various types of FRC combined with reactive powder concrete (RPC) in recent years, this paper systematically expounds the research progress, particularly the mechanical properties, of steel fiber RPC, basalt fiber RPC and hybrid fiber RPC. This paper concludes the improvement in the mechanical properties of RPC under common curing methods, elaborates on the influence of steel fiber on the compressive, tensile, and flexural strength of RPC, and outlines the principle of fiber enhancing the mechanical properties of RPC. Additionally, it discusses the research progress in basalt FRC, and further examines the impact of basalt fiber on the mechanical properties of RPC. Referring to the research on single fiber reinforced RPC, the mechanical properties of hybrid fiber RPC are analyzed and summarized; based on the characteristics of steel fiber and basalt fiber, research on steel‐basalt hybrid fiber RPC is proposed. [ABSTRACT FROM AUTHOR]

To investigate the flexural behavior of hybrid reinforced concrete (Hybrid‐RC) beams with Basalt fiber‐reinforced polymer (BFRP) bars and steel bars, this paper designed 14 Hybrid‐RC beams and studied the effect of different reinforcement forms on the flexural behavior of Hybrid‐RC beams. The research results indicated that when ρ≈2.28%$$ \rho \approx 2.28\% $$, an increase in Af/As$$ {A}_{\mathrm{f}}/{A}_{\mathrm{s}} $$ leads to a decrease in the cracking moment, ultimate moment, and ductility of Hybrid‐RC beams, the maximum crack width and deflection will increase. When ρ≈0.86%$$ \rho \approx 0.86\% $$, an increase in Af/As$$ {A}_{\mathrm{f}}/{A}_{\mathrm{s}} $$ will lead to a decrease in the cracking moment, deflection, and ductility of the Hybrid‐RC beams, while the maximum crack width and ultimate moment will increase. In addition, when ρ≤1.87%$$ \rho \le 1.87\% $$, the area of BFRP bars (the area of steel bars remains unchanged) should be changed to improve the flexural behavior of the Hybrid‐RC beams; When ρ>1.87%$$ \rho >1.87\% $$, the Hybrid‐RC beams should change the area of steel bars (the area of BFRP bars remains unchanged) to improve the flexural behavior of the beams. In addition, the ductility index prediction equation for Hybrid (BFRP and steel)‐RC beams was fitted based on the results of the theoretical model research. [ABSTRACT FROM AUTHOR]

The widespread Cenozoic alkaline magmatism within and around the Tibetan Plateau offers a prime opportunity to probe the nature of the mantle at the depths where basalt magmas originate. The close temporal and spatial relationship between volcanism and regional strike‐slip fault systems also helps better understand the geodynamics of outward growth of the plateau in response to the continued India‐Asia convergence. We present a comprehensive study of the deeply sourced alkaline basalts formed along the Kunlun strike‐slip fault with the aim of understanding their petrogenesis and the composition of mantle sources beneath the northeastern Tibetan Plateau. High Nb/U and Ce/Pb ratios and relatively depleted bulk‐rock Sr‐Nd‐Pb isotope compositions corroborate the mantle origin of these alkaline basalts. Homogeneous and low 87Sr/86Sr of clinopyroxene indicates negligible crustal contamination during magmatic evolution. Low δ26Mg in the alkaline basalts and positive correlations with Hf/Sm and Ti/Ti* indicate that the basalts were derived from mantle that was metasomatized by melts derived from sedimentary carbonates during the Paleo‐Tethyan seafloor subduction. Based on 40Ar/39Ar dating results, it appears that the alkaline basaltic magmatism in the northeastern Tibetan Plateau occurred simultaneously with Kunlun strike‐slip faulting. These observations suggest that the India‐Asia convergence must have reactivated ancient subduction plate boundaries and resulted in strike‐slip faulting along these suture zones within and around the Tibetan Plateau. The eruption of low‐volume and deeply rooted alkaline basalts may have been controlled by fractures associated with the strike‐slip fault systems. Plain Language Summary: Small volcanoes that erupted basalt lava with alkaline compositions about 11.5 million years old occur along the northeast margin of the Tibetan Plateau and are close to a major fault system, the Kunlun Fault. Based on their chemical compositions, these basalts were melted from the upper mantle and provide information on the composition of the mantle beneath the plateau. Our chemical, geochronological, and isotopic analyses of the lava indicate that the sub‐plateau mantle was indeed affected by ancient oceanic slab subduction, including subduction of seafloor sediments that resulted in the addition of carbonate‐rich melts to the sub‐plateau mantle, making the mantle more susceptible to melting and more likely to produce alkaline basalt when it did melt. The age of the basalt lava overlaps the age of movement along the Kunlun fault, which suggests that the magma may have been produced from the same tectonic movements that produced the fault and risen through the crust along fractures associated with the fault. Key Points: The light Mg isotopes of the studied alkaline basalts highlight the occurrence of mantle carbonatite metasomatism via Paleo‐Tethyan oceanic slab subductionAlkaline basalts in northeastern Tibetan Plateau erupted coevally with Kunlun strike‐slip faulting that gave rise to mantle upwelling and decompression meltingLithospheric extrusion induced by India‐Asia collision reactivated pre‐existing lithospheric weakness and triggered mantle melting beneath the NE and SE plateau [ABSTRACT FROM AUTHOR]

This study is motivated by the observed variability in trace element isotopic and chemical compositions of primitive (SiO2< ${\mathrm{O}}_{2}< $52 wt %) basalts in southwest North America (SWNA) during the Cenozoic transition from subduction to extension. Specifically, we focus on processes that may explain the enigmatic observation that in some localities, basalts with low Ta/Th, consistent with parental melts in a subduction setting, have εNd ${\varepsilon }_{Nd}$ signatures consistent with continental lithospheric mantle (CLM). In locations with the oldest CLM (Proterozoic and Archean), Cenozoic basalts with low Ta/Th have εNd ${\varepsilon }_{Nd}$ well below zero. We model channelized magma transport through the CLM using simple 1D transport models to explore the extent to which diffusive and reactive mass exchange can modify Nd isotopic compositions via open system melt‐wallrock interactions. For geologically reasonable channel spacings and volume fractions, we quantify the reactive assimilation rates required for incoming melt with a different εNd ${\varepsilon }_{Nd}$ than the wall‐rock to undergo a substantial isotopic shift during ≈ ${\approx} $10 km channelized melt transport. In the presence of grain boundaries, enhanced diffusion between melt‐rich channels and melt‐poor surrounding rock contributes to isotopic equilibration, however this effect is not enough to explain observations; our models suggest a significant contribution from reactive assimilation of wall‐rock. Additionally our models support the idea that the observed covariability in Ta/Th and εNd ${\varepsilon }_{Nd}$ in Cenozoic basalts cannot be attributed to transport alone and must also reflect the transition from subduction‐related to extension‐related parental melts in SWNA. Plain Language Summary: Over the past half century, the abundances and isotopic ratios of trace elements such as Nd in basalts have been widely used to infer aspects of the source region where mantle melting occurs. This assumes that when the mantle melts, trace element characteristics of source rocks are inherited by the generated melts and these are not further modified as melts ascend through the tectonic plate (lithosphere) to be erupted as basalt. We reassess this assumption inspired by enigmatic observations from southwest North America, where basalts that have undergone minimal processing (primitive basalts), show trace element characteristics of both the mantle lithosphere and of the asthenosphere. We use 1D transport models to show that melts moving in channels through the lithosphere may undergo significant trace element changes by interacting with the walls as they ascend, thereby explaining the observations with geologically reasonable scenarios. Key Points: Trace elements in primitive basalts from southwest North America suggest both asthenosphere‐ and lithosphere‐related signaturesOpen system interactions between ascending channelized melts and wallrock may affect the trace element composition of erupted basalts1D transport models quantify the role of diffusion and wallrock assimilation to produce significant Nd isotopic shifts over 10 km of transport [ABSTRACT FROM AUTHOR]

Venus' surface and interior dynamics remain largely unconstrained, due in great part to the major obstacles to exploration imposed by its 470°C, 90 bar surface conditions and its thick, opaque atmosphere. Flyby and orbiter‐based thermal emission data provide opportunities to characterize the surface composition of Venus. However, robust interpretations of such data depend on understanding interactions between the planet's surface basaltic rocks and its caustic carbon dioxide (CO2)‐dominant atmosphere, containing trace amounts of sulfur dioxide (SO2). Several studies, using remote sensing, thermodynamic modeling, and laboratory experiments, have placed constraints on basaltic alteration mineralogy and rates. However, constraints on the effects of SO2‐bearing reactions on basalts with diverse compositions remain incomplete. Here, we present new data from a series of gas‐solid reaction experiments, in which samples of two basalt compositions were reacted in an SO2‐bearing CO2 atmosphere, at relevant Venus temperatures, pressure, and oxygen fugacity. Reacted specimens were analyzed by scanning electron microscopy and scanning transmission electron microscopy using sample cross‐sections produced with focused ion beam milling. Surface alteration products were characterized, and their abundances estimated; subsurface cation concentrations were mapped to show the depth of alteration. We demonstrate that the initial development of reaction products progresses rapidly over the course of 30‐day runs. Alkaline basalt samples are coated by Na‐sulfate (likely thenardite, Na2SO4) and amorphous calcium carbonate (CaCO3) alteration products, and tholeiitic basalt samples are primarily covered by anhydrite (CaSO4), Fe‐oxide (FexOy: likely magnetite, Fe3O4), and other minor phases. These mineralogies differ from previous experiments in CO2‐only atmospheres. Plain Language Summary: Surface features on Venus, such as volcanic landforms, and their ages can be studied to infer the planet's interior properties. Venus' thick, opaque atmosphere and extreme temperature and pressure limit a detailed study of its surface. Fortunately, sensors aboard Venus‐orbiting spacecraft can "see" its surface using select wavelengths of light to provide opportunities to interpret the composition of its surface. However, these interpretations rely on understanding how Venus' atmosphere might chemically interact with the surface and what mineral products may result. This is not yet fully understood despite the results of several prior studies with objectives similar to ours. Here, we share the results from experiments that mimic these chemical reactions. We used rock types such as those known to be on the surface of Venus and subjected them to relevant temperatures and pressure and a blend of two reactive gases, carbon dioxide and sulfur dioxide, to model Venus' atmosphere. After the experiments, we examined the rocks with microscopic instruments that allowed us to characterize chemical changes from their surfaces to their interiors. Our interpretations suggest that these reactions occur rapidly and that the compositions of the mineral coatings produced are dictated by the rocks' slightly different compositions. Key Points: Basalts experimentally altered under Venus P‐T conditions and a CO2–SO2 atmosphere produce reaction products of Ca‐ and Na‐sulfates, and Fe‐oxidesAlteration products and the advancement of alteration were strongly dependent upon the compositions of the solid reactantsThe rates at which basalts altered in a CO2–SO2 atmosphere were greater than rates in a CO2‐only atmosphere [ABSTRACT FROM AUTHOR]

This study looks at how erosive wear affects hybrid composites made by vacuum infusing glass and basalt fibers into an epoxy matrix. The study uses garnet abrasives and a design experiment method to test how resistant these hybrid composites are to erosion at 30°, 60°, and 90° angles of impact. The analysis included three‐dimensional profilometry and scanning electron microscopy. Results show that glass layers enhance erosion resistance, whereas basalt layers increase wear. Key quantitative findings include erosion rates and mass loss, highlighting impingement angle and erosion time as critical factors. At a 30° angle, basalt exhibited more severe wear (erosion rate: 0.8090 mg/g for 20 s) compared to glass (erosion rate: 0.5683 mg/g). Conversely, at 90°, the erosion rate for basalt decreased to 0.3643 mg/g, indicating a decreased sensitivity to this steeper angle. According to the ANOVA, impingement angle and erosion time account for 30.08% and 50.25% of the erosion rate variance, respectively. These findings advance our understanding of material behavior in hybrid composites and emphasize the strategic selection and layering of materials for enhanced durability. This research contributes to developing more sustainable composites, demonstrating natural fibers' potential to improve mechanical properties and erosion resistance. Highlights: Glass layers enhance durability against erosive forces in hybrid composites.Basalt layers accelerate erosion rates, showing a need for strategic layering.Glass fiber reinforcement significantly improves wear performance.Hybrid constructions with glass a top basalt balance flexibility and durability.Emphasizes eco‐friendly advantages of natural materials in composites. [ABSTRACT FROM AUTHOR]

Climate change is one of the most urgent environmental challenges that humanity faces. In addition to the reduction of greenhouse gas emissions, safe and robust carbon dioxide removal (CDR) technologies that capture atmospheric CO2 and ensure long‐term sequestration are required. Among CDR technologies, enhanced silicate weathering (ESW) has been suggested as a promising option. While ESW has been demonstrated to depend strongly on pH, water, and temperature, recent studies suggest that biota may accelerate mineral weathering rates. Bacillus subtilis is a plant growth‐promoting rhizobacterium that can facilitate weathering to obtain mineral nutrients. It is a promising agricultural biofertilizer, as it helps plants acquire nutrients and protects them from environmental stresses. Given that croplands are optimal implementation fields for ESW, any synergy between ESW and B. subtilis can hold great potential for further practice. B. subtilis was reported to enhance weathering under laboratory conditions, but there is a lack of data for soil applications. In a soil‐mesocosm experiment, we examined the effect of B. subtilis on basalt weathering. B. subtilis–basalt interaction stimulated basalt weathering and increased soil extractable Fe. The combined application displayed higher CDR potential compared to basalt‐only application (3.7 vs. 2.3 tons CO2 ha−1) taking solid and liquid cation pools into account. However, the cumulative CO2 efflux decreased by approximately 2 tons CO2 ha−1 with basalt‐only treatment, while the combined application did not affect the CO2 efflux. We found limited mobilization of cations to the liquid phase as most were retained in the soil. Additionally, we found substantial mobilization of basalt‐originated Mg, Fe, and Al to oxide‐ and organic‐bound soil fractions. We, therefore, conclude that basalt addition showed relatively low inorganic CDR potential but a high capacity for SOM stabilization. The outcomes indicated the importance of weathering rate–GHG emission integration and the high potential of SOM stabilization in ESW studies. [ABSTRACT FROM AUTHOR]

The densification mechanisms of silicate melts under high pressure are of key interest in understanding the evolution of the early Earth and its present‐day internal structure. Here, we report Brillouin spectroscopy‐derived transverse acoustic wave velocities VS $\left({V}_{S}\right)$ from a basaltic glass at high pressures up to 163 GPa and ambient temperature to provide insight into pressure‐induced changes in its elasticity and, by extension, its density. We find that the pressure dependence of VS ${V}_{S}$ below 110–140 GPa follows a trend nearly tantamount to those of pyrolite and Fe‐ and (Fe,Al)‐bearing MgSiO3 glasses, indicating that the large compositional differences among these glasses do not exert variable acoustic wave velocity trends. However, at higher pressures we observe a small departure from the VS ${V}_{S}$ profiles of the Al‐poor compositions toward higher acoustic wave velocities to eventually become stiffer. This pressure‐induced steepening in VS ${V}_{S}$ is comparable to that of (Mg, Fe, Al)(Si, Al)O3 glass, and suggests a possible structural change toward a denser state caused by more rapidly changing Al–O coordination in network‐forming Al. Coupled with the high Fe content in basalt, this may render basaltic melt denser than surrounding minerals in the deep lower mantle, and may provide an additional mechanism for the existence of ultralow‐velocity zones. Plain Language Summary: Silicate melts are subject to different densification mechanisms from the counterpart solids. Although less dense at ambient/low pressures and for most of the mantle, it has long been speculated that at high enough pressures a density inversion may take place, where melts may become denser than the corresponding solids. This would have profound implications for the present‐day structure and dynamics of the Earth and its evolution through geological history. We have experimentally measured the sound wave velocities of a basaltic glass, which serves as a laboratory analogue to melt, up to 163 GPa. Through comparison of our sound wave velocity‐pressure profile to other glass compositions we observe a slight deviation in steepness above 110–140 GPa to a potentially stiffer and denser state. This pressure‐induced change may be the result of changes in the Al–O coordination environment. Extrapolated onto expected melt compositions in the lower mantle, which are enriched in both Al and heavy Fe, this may render dense pools of silicate melt gravitationally stable at the bottom of the mantle. Key Points: We have carried out acoustic wave velocity measurements of a basaltic glass up to 163 GPaThe VS‐pressure profile of basalt shows close similarities to other, more depolymerized glasses up to 110–140 GPa, where it becomes steeperThis anomaly is likely induced by changes in Al–O coordination [ABSTRACT FROM AUTHOR]

Recharge to and flow within the Columbia River Basalt Group (CRBG) groundwater flow system of northeastern Oregon were characterized using isotopic, gas, and age‐tracer samples from wells completed in basalt, springs, and stream base flow. Most groundwater samples were late‐Pleistocene to early‐Holocene; median age of well samples was 11,100 years. The relation between mean groundwater age and completed well depth across the eastern portion of the study area was similar despite differences in precipitation, topographic position, incision, thickness of the sedimentary overburden, and CRBG geologic unit. However, the lateral continuity in groundwater age was disrupted across large regional fault zones indicating these structures are substantial impediments to groundwater flow from the high‐precipitation uplands to adjacent lower‐precipitation and lower‐elevation portions of the study area. Recharge rates calculated from the age‐depth relations were <3 mm/yr and independent of the modern precipitation gradient across the study area. The age‐constrained recharge rates to the CRBG groundwater system are considerably smaller than previously published estimates and highlight the uncertainty of prevailing models used to estimate recharge to the CRBG groundwater system across the Columbia Plateau in Oregon and Washington. Age tracer and isotopic evidence indicate recharge to the CRBG groundwater system is an exceedingly slow and localized process. Article impact statement: Recharge to the Columbia River Basalt groundwater system in northeast Oregon is considerably smaller than previously published estimates and models. [ABSTRACT FROM AUTHOR]

The compositional diversity of primitive arc basalts has long inspired questions regarding the drivers of magmatism in subduction zones, including the roles of decompression melting, mantle heterogeneity, and the amount and composition of slab‐derived materials. This contribution presents the volatile (H2O, Cl, and S), major, and trace element compositions of melt inclusions from basaltic magmas erupted at three volcanic centers in the Washington Cascades: Mount St. Helens (two basaltic tephras, 2.0–1.7 ka), Indian Heaven Volcanic Field (two <600 ka basaltic hyaloclastite tuffs), and Glacier Peak (late Pleistocene to Holocene basaltic tephra from Whitechuck and Indian Pass cones). Compositions corrected to be in equilibrium with mantle olivine display variability in Nb and trace element ratios indicative of mantle source variability that impressively spans nearly the entire range of arc magmas globally. All volcanic centers have magmas with H2O and Cl contributions from the downgoing plate that overlap with other Cascade Arc segments. Volatile abundances and trace element ratios support a model of melting of a highly variably mantle wedge driven by a subduction component of variably saline fluid and/or slab partial melt. Magmas from Glacier Peak in northern Washington have unusually high Th/Yb ratios that are similar to Lassen region basalts, indicating possible contributions of "subcreted" metasediments that geophysical data suggest are not present beneath central Oregon and southern Washington. This data set adds to the growing inventory of primitive magma volatile concentrations and provides insight into spatial distributions of mantle heterogeneity and the role of slab components in the petrogenesis of arc magmas. Key Points: The Washington Cascades sub‐arc mantle is remarkably heterogeneousVolatile contributions from the slab are identifiable across different magma types in the WA CascadesSlab fluids of variable salinity and slab partial melts, non‐uniquely, may contribute to subduction components along the entire arc [ABSTRACT FROM AUTHOR]

The link between mantle plumes and the formation of large igneous provinces (LIPs) is well established although the anatomy of these remains equivocal. Recent experimental studies and geophysical data suggest that the mantle plume head is more likely to be irregular and asymmetric, rather than an axisymmetric flattened disk. The Emeishan large igneous province (ELIP) provides a unique opportunity to test this hypothesis. According to robust petrographic, geochronologic, and geochemical evidence from the late Permian basalts in the Sichuan Basin, and in conjunction with a comprehensive compilation of geologic maps and published geochemical data from the ELIP, we identified several giant radial "fingering" structures. Based on the shallow mantle source from the center to margin in the ELIP and relief of the lithosphere‐asthenosphere boundary, we propose a new mantle plume model to explain the evolution of the Emeishan plume periphery, where narrow finger‐like protrusions and plumelets developed outwards from the main body of the plume to the edges of the flattened plume head. Dragged fingers might have been torn apart into some plumelets, which dispersed and were trapped beneath the thinnest lithosphere relief, and eventually erupted to form small‐scale flood basalt in the Outer Zone of the ELIP. Key Points: The spatio‐temporal and geochemical characteristics of the Emeishan basalts in the Sichuan Basin are determinedThe Emeishan large igneous province developed fingering structuresA new model, that is, "fingering, torn apart and plumelets," may interpret the evolution of the mantle plume periphery and surface manifestation of the large igneous province [ABSTRACT FROM AUTHOR]

Volcanic soils are among the most productive soils in the world as they can accumulate large amounts of organic carbon and nitrogen and have good water storage capacity. They are extensively used worldwide for agriculture, which makes it difficult to study the soil‐landscape dynamics under natural conditions. By working in the Galápagos Islands, a UNESCO World Heritage Site, we aimed to constrain soil development over millennial timescales using empirical data. Our monitoring sites on Santa Cruz Island cover a 10 km long NW‐SE transect with an 8‐fold increase in precipitation and associated vegetation changes. By controlling for age and chemical composition of the basaltic parent material, we investigated the influence of precipitation rates on soil weathering. At the landscape scale, soil weathering degree increased with increasing precipitation, as shown by the spatial patterns in soil depth, pH, mass loss coefficients, chemical index of alteration, chemical depletion fraction, and total reserve in bases. In addition to the climatic effect, rock porosity strongly enhanced basalt weathering. Porosity‐enhanced weathering is particularly important in the humid and perhumid precipitation regimes: soils developed on porous scoriae developed weathering mantles that are ∼10‐fold thicker and have 10‐fold higher mass losses due to weathering compared to soils developed on basalt lava flows. Our results demonstrated that variations in rock pore dimensions and distribution can lead to large variations in basalt weathering rates, particularly in humid and perhumid climates where deep leaching can be facilitated by rock porosity. Plain Language Summary: Tropical volcanic islands are global weathering hotspots. Soil weathering is controlled by climate and lithology, as temperature and precipitation facilitate weathering reactions, solute and nutrient fluxes, and CO2 drawdown. By studying soil‐landscape dynamics along a climosequence in Santa Cruz Island (Galápagos Archipelago), we first explored how precipitation facilitates basalt weathering. Then, we investigated whether rock porosity can further enhance weathering rates. Our data showed that soils are largely composed of atmospheric dust in arid regimes. With increasing precipitation, soil development is increasingly being controlled by in situ soil weathering. Soil weathering rates increased with precipitation, in particular in regions receiving more than 1,000 mm of annual precipitation. We also noted marked differences in soil thickness and degree of weathering between soils developed on basalt lava flows and porous scoriae, with soils developed on scoriae being significantly deeper and more weathered. Key Points: Basalt weathering increases with precipitation while temperature plays a secondary roleSoil weathering depth and rate are higher on porous scoria deposits than on basalt lava flowsPorosity‐enhanced weathering is particularly important in humid and perhumid precipitation regimes [ABSTRACT FROM AUTHOR]

Understanding the coupling between rock permeability, pore pressure, and fluid flow is crucial, as fluids play an important role in the Earth's crustal dynamics. We measured the distribution of fluid pressure during fluid‐flow experiments on two typical crustal lithologies, granite and basalt. Our results demonstrate that the pore‐pressure distribution transitions from a linear to a non‐linear profile as the imposed pore‐pressure gradient is increased (from 2.5 to 60 MPa) across the specimen. This non‐linearity results from the effective pressure dependence of permeability, for which two analytical formulations were considered: an empirical exponential and a new micromechanics‐based model. In both cases, the non‐linearity of pore pressure distribution is predicted. Using a compilation of permeability versus Terzaghi's effective pressure data for granites and basalts, we show that our micromechanics‐based model has the potential to predict the pore pressure distribution over the range of effective pressures expected within the brittle crust. Plain Language Summary: Fluids distributions and fluid migrations play an important role in the Earth's crustal dynamics and how fluids migrate through a rock will depend primarily on permeability. However, the permeability of crustal rocks may exhibit important pressure dependence, because cracks and fractures will increasingly close with increasing tectonic pressure. In this experimental study, we show that the couplings between increasing pressure, crack closure, and permeability reduction may result in non‐linear pore pressure distributions on a rock specimen at the laboratory scale, which confirms for the first time pioneering theoretical and experimental works. Two simple analytical expressions of the pressure dependence of permeability predict this non‐linearity. One empirical expression, most commonly used in the literature, takes the form of an exponential. The second one, a new model, based on crack micromechanics, was developed within this work and shown to outperform the exponential formulation at low Terzaghi's effective pressure. Key Points: Pore pressure was measured locally in rocks exhibiting pressure‐dependent permeabilityWe observed a transition from linear to nonlinear pore pressure distribution with increasing fluid pressure gradientsA new, micromechanics‐based, analytical model was developed for the pressure dependence of permeability in microcracked rocks [ABSTRACT FROM AUTHOR]

The East African Rift System (EARS) provides an opportunity to constrain the relationship between magmatism and plate thinning. During continental rifting, magmatism is often considered a derivative of strain accommodation—as the continental plate thins, decompression melting of the upper mantle occurs. The Turkana Depression preserves among the most extensive Cenozoic magmatic record in the rift. This magmatic record, which comprises distinct basaltic pulses followed by periods of relative magmatic quiescence, is perplexing given the lack of evidence for temporal heterogeneity in the thermo‐chemical state of the upper mantle, the nonexistence of lithospheric delamination related fast‐wave speed anomalies in the upper mantle, and the absence of evidence for sudden, accelerated divergence of Nubia and Somalia. We focus on the Pliocene Gombe Stratoid Series and show how lithospheric thinning may result in pulsed magma generation from a plume‐influenced mantle. By solving the 1D advection‐diffusion equation using rates of plate thinning broadly equivalent to those measured geodetically today we show that despite elevated mantle potential temperature, melt generation may not occur and thereby result in extended intervals of quiescence. By contrast, an increase in the rate of plate thinning can generate magma volumes that are on the order of that estimated for the parental magma of the Gombe Stratoid Series. The coincidence of large‐volume stratiform basalt events within the East African Rift shortly before the development of axial zones of tectonic‐magmatic activity suggests that the plate thinning needed to form these stratiform basalts may herald the onset of the localization of strain. Plain Language Summary: The magmatic record in the Turkana Depression—part of the East African Rift System—is characterized by pulses of basaltic activity that are followed by long periods of relative magmatic quiescence. This is a puzzling observation assuming that these magmas are generated by decompression melting of the upper mantle; there is no obvious changes in the rate of plate motion between Nubia and Somalia. This study presents new geochemical data on the final pulse of basaltic volcanism (during the Pliocene) and interprets these data in the context of a mantle melting model. We find that pulses of basaltic volcanism and intervening periods of quiescence could be simulated using different rates of thinning of the plate. We examine the consequences of a period of enhanced plate thinning in context of melt generation both below and within the plate. Key Points: Pulses of basaltic volcanism and intervening periods of quiescence could be simulated using different rates of thinning of the plate [ABSTRACT FROM AUTHOR]

Three boreholes drilled during the International Ocean Discovery Program (IODP) Expedition 396 have yielded unexpected findings of altered granitic rocks covered by basalt flows, interbedded sediments and glacial mud near the continent‐ocean transition of the mid‐Norwegian margin. U‐Pb and K‐Ar geochronological analyses were conducted on both protolithic and authigenically formed K‐bearing minerals to determine the age of granite crystallisation and subsequent alteration episodes. The granite's crystallisation age based on 104 zircons is 56.3 ± 0.2 Ma, and subsequent exhumation along with alteration/weathering events took place between 54.7 ± 1 and 37.1 ± 1 Ma. This intrusion represents the youngest granite discovered in Norway and intruded at an extremely shallow crustal level before a rapid rift‐to‐drift transition. The shallow emplacement of granitic rock and its fast exhumation before and during the onset of volcanism holds significant implications for the syn‐ and post‐breakup tectonic evolution of volcanic margins. [ABSTRACT FROM AUTHOR]

This case study examines the use of X‐ray fluorescence (XRF) as an effective method for defining distinct chemical compositions of local basalt stone from different sources in the Roman period, even when their quarries have not been identified. It also deals with the archaeological question if public and monumental structures from a village and urban site shared the same stone sources and stonemason's workshops. Ninety‐six samples from the Hippos Territorium, mainly from the polis of Hippos and the village of Majduliyya, were analyzed. XRF was found to be an effective method for defining distinct chemical compositions of local basalt materials from different sources. The distinct composition of the basalt stones between the two sites provided valuable insights into socio‐economic relationships, shedding light on the nature of city–village dynamics in the region. Additionally, it aids in discerning whether diverse basalt sources were utilized in both private and public constructions, as well as installations within a single site. Methodological questions and the application of this method in the archaeological research of basalt‐based architecture are also addressed. [ABSTRACT FROM AUTHOR]

Basalt fiber reinforced polypropylene composites with two initial fiber lengths (3.2 and 6.4 mm) were fabricated using twin‐screw extrusion compounding. In the case of composites with smaller initial fiber length, basalt fibers predominantly served as nucleating agents for polypropylene thereby resulting in an increase in the degree of crystallinity. The addition of polypropylene‐g‐maleic anhydride (PP‐g‐MA) caused the matrix to become amorphous, which was due to the establishment of a fiber–matrix interphase. This behavior was different for the composites with relatively larger initial fiber length especially at higher fiber content. The reduction in fiber length in the composites caused a decrease in crystallinity, as this hindered the ability of the polypropylene matrix to form crystals. Addition of PP‐g‐MA established a fiber–matrix interphase thereby synergistically contributing to the increased matrix amorphousness of the basalt fiber reinforced polypropylene composites with 6.4 mm initial fiber length. Reduced fiber length due to processing also accelerated the thermal degradation of the composites with an initial fiber length of 6.4 mm. However, the reduction in fiber length due to processing resulted in increased fiber orientation, which contributed to the improvement in tensile and flexural properties of the basalt fiber reinforced polypropylene composites with an initial fiber length of 6.4 mm. At 30% fiber content, the tensile strength and modulus of basalt fiber reinforced matrix modified polypropylene composites with 6.4 mm initial fiber length improved by 18% and 13% as compared with the composites with 3.2 mm initial fiber length. [ABSTRACT FROM AUTHOR]

High‐pressure and high‐temperature experiments were conducted to simulate melting of a hybrid cumulate lunar mantle. The experimental results show that intermediate to high‐Ti lunar pyroclastic glasses (>6 wt% TiO2) can be produced by partial melting of lunar cumulates. High‐Ti basalts are generated when the ilmenite/clinopyroxene ratios in the lunar mantle cumulates are between 1/1 and 4/1, depending on the degree of melting. The presence of an urKREEP component in the mantle cumulate strongly influences Al2O3/CaO of the melts. The experiments provide strong evidence for the model that the compositional diversity of lunar basalts is a consequence of a gravitational overturn of the lunar interior after the lunar magma ocean had solidified. Ilmenite/clinopyroxene in the cumulate mantle, which generates high‐Ti melts at partial melting, do not comprise the ratios in ilmenite‐bearing cumulates (IBC), which crystallized after ∼90% solidification of the lunar magma ocean and indicate local accumulation of ilmenite in the overturned lunar mantle. However, to fully match the natural composition of the most primitive lunar samples, secondary processes such as assimilation are still required. Plain Language Summary: The basalt samples, which were returned from the Earth's Moon by astronauts during sample return missions, are chemically different from terrestrial basalts. Whilst terrestrial basalts usually contain less than 1 wt% of TiO2, the lunar rocks can contain more than >6 wt% of TiO2. The origin of these extraordinarily high TiO2 contents has long been debated, and hence we conducted experiments at high pressures and temperatures to simulate melting of a heterogeneous lunar mantle. Our experimental results imply that the lunar high‐Ti basalts can be produced by melting of a heterogeneous lunar mantle that contains high amounts of Ti‐rich minerals, such as ilmenite or similar Fe and Ti‐rich oxides, and silicate minerals, such as olivine, orthopyroxene, and clinopyroxenes. Our results support the hypothesis that the stratification of the lunar mantle after it had solidified was not preserved, suggesting a high dgree of heterogeneity within the mantle. Besides Ti, other major elements of our melts do not completely match the natural samples. This can be accounted for by interaction with the host rocks during the ascent of the magmas. Key Points: High‐Ti lunar basalts can be produced experimentally by a simple melting process of a hybrid lunar cumulate mantle with nonmodal ilmenite/clinopyroxeneThe entire chemical spectrum of most primitive lunar basalts requires additional processes such as reactive ascent and assimilationThe process of partially melting a heterogeneous lunar mantle also yields melts with similarities to low‐Ti, high‐Al lunar mare basalts [ABSTRACT FROM AUTHOR]

This study investigates the mechanical characteristics of basalt fiber/epoxy polymer composites (BPC) inspired by nature's higher‐order designs especially helicoidal structures found in fish scales. The present work includes the experimental analysis of 20‐layered bioinspired BPC composites in single helicoidal ([90/80/70/60/50/40/30/20/10/0]s), and double helicoidal ([130/40/120/30/110/20/100/10/90/0]s) layups. The hand layup technique, followed by the vacuum bagging method, is used to fabricate composite laminates. The layup design significantly influenced the mechanical properties of both helicoidal structures with different stacking sequences, including load capacity, deformation, energy absorption, and fracture modes. Interestingly, failure mechanisms demonstrated both bending and twisting (attributed to specific ply orientation, resulting in a twisting effect) occurring majorly under flexural loading, leading to improved energy absorption. The flexural strength of single helicoidal laminate was observed to be 28.8% higher than double helicoidal laminate design. On the other hand, the double helicoidal laminate showed 46.8% and 19.4% higher interlaminar shear strength (ILSS) and impact resistance properties, respectively, compared to the single helicoidal laminate design. Therefore, this comparative experimental analysis of both stacking structures provides insights into potential changes in conventional stacking sequences and enhances understanding of mechanical responses in bioinspired composites. Highlights: Mechanical characterization of bioinspired helicoidal laminates is done.The flexural strength of single helicoidal laminates is 28.8% higher than double helicoidal laminates.Double helicoidal laminates showed better interlaminar shear strength and energy absorption. [ABSTRACT FROM AUTHOR]

Basalt fiber (BF)‐reinforced thermoplastic polymers (TPs) show great potential by leveraging their recyclability. Sizing agents are crucial in optimizing BF quality and aiding polymer impregnation during production. However, the absence of established guidelines for sizing agents tailored to thermoplastic BFs persists. This study investigates the effects of sizing agent ingredients on the mechanical and surface properties of BFs under industrial conditions. The Taguchi method was used to formulate nine BF sizing agents, predominantly incorporating polypropylene (PP) emulsion, epoxy or polyurethane emulsion, silane coupling agents (SCAs), and additives. Our investigation extends to evaluating the tensile strength, surface roughness, and wetting characteristics of individual BFs. Results indicate that a heightened PP concentration enhances BF adhesion to TPs but concurrently reduces BF tensile strength. Furthermore, using SCA, specifically dodecyltrimethoxysilane, leads to a remarkable enhancement of approximately 20% in BF tensile strength and an impressive 40% in BF adhesion to TPs. This study unravels sizing agent intricacies, illuminating their nuanced interplay with the work of adhesion rooted in fiber and polymer surface energy. Our work offers innovative solutions to optimize BF‐reinforced thermoplastic polymers. Highlights: Investigating thermoplastic sizing agent formulations for basalt fibers (BFs)Guiding formulation of BF sizing agents with the Taguchi Method.Predicting contact angles between BFs and commonly used thermoplastic polymers.PP emulsions favor BF‐thermoplastic polymer adhesion but not BF tensile strength. [ABSTRACT FROM AUTHOR]

To expand the applications of hybrid fiber composites in structural engineering applications, it is essential to study their fatigue behavior. The tensile and fatigue performance of unidirectional hybrid basalt/glass epoxy composites made with vacuum‐assisted resin infusion molding are investigated in this research. The sequencing influence on tensile properties was assessed using the two configurations of basalt/glass fiber epoxy hybrid fiber composites, namely GBBBG and BGBGB, having nearly equal volume fractions. According to the test results, hybrid fiber composites showed a positive hybrid effect on their tensile strength. Both hybrid layups showed higher tensile strengths (3.5% to 10.5%) than GFRPs and BFRPs. The GBBBG laminate has slightly higher fatigue resistance than BGBGB laminate under tension–tension (T–T) fatigue. Scanning electron microscopy (SEM) images verify the fatigue failure modes, which include fiber, matrix cracking, delamination, and debonding. The DMA analysis showed the lower adhesion efficiency of hybrid fiber composites, signifying lower damping properties. Highlights: The basalt/glass fiber hybrid fiber composites were fabricated using VARIM.The static and fatigue properties of basalt/glass fiber hybrid fiber composites were studied.The stiffness degradation and hysteresis were calculated for the composites tested.The DMA was performed, and Tg, storage modulus, and adhesion efficiency factor were calculated. [ABSTRACT FROM AUTHOR]

Meteoroid impacts produce different types of fractures and damage zones beneath impact craters. The 3D geometry of these features reflects the trajectory and energetics of an impact event. In this study, we mapped the impact damage zone beneath the 1.88‐km‐diameter Lonar crater, emplaced in Deccan basalts, using Ambient Noise Tomography (ANT). A network of 23 broadband seismic stations in and around the crater yielded a 1.2 km deep 3D shear wave velocity (VS) image covering ∼7 km by ∼5 km area. It revealed ∼500–900‐m‐thick heterogeneous target basalt flows, underlain by an undulating Archean granite‐gneiss basement. A substantial reduction in VS is observed beneath the crater. The original crater floor was found at a depth of 400 m below the crater rim, which is filled by impact breccia and lake sediments. Beneath the original floor, we found an oval‐shaped, asymmetric 200‐m‐thick lensoidal low‐velocity layer with a tongue‐like feature beneath the southwestern ejecta blanket. The damage zone is inferred to have formed as a result of oblique impact, in which the projectile arrived from northeast to southwest direction. The VS reduction in the low‐velocity layer was used to calculate the amount of impact damage in it. The oblique impact produced a more elevated southwestern crater rim. Impact‐related near‐surface fracture zones up to a radial distance of >1 km beneath the ejecta blanket were also found. We suggest that impact damage beneath impact craters on Earth and other planetary bodies may be imaged using ANT. Plain Language Summary: Impact craters are ubiquitous on planetary surfaces. The impact produces both surface and sub‐surface changes, including fracturing and damage beneath the crater floor. The 3D geometry of the damage zone depends on the impact angle and velocity. While vertical impacts generate symmetric damage zones beneath the craters, oblique impacts produce asymmetrical damage zones with greater damage in the downrange direction. Field geological mapping provides limited information about these features, while the Ambient Noise Tomography (ANT) brings out a complete shape and size of the damage zone in the sub‐surface. The shear wave velocity image also provides the characteristics of target rocks within and outside the impact crater. In this work, we carried out the ANT study of Lonar crater, emplaced in Deccan basalts in India, using a network of 23 broadband seismometers. This study revealed a ∼500–900‐m‐thick heterogeneous basaltic target underlain by an Archean granite‐gneiss basement, and an asymmetric damage zone beneath ∼400‐m‐deep original crater floor because of southwest directed oblique impact. We quantified the amount of impact damage beneath the original crater floor. The ANT can be used for imaging damage zones beneath impact craters on Earth and other solid planetary bodies, thus providing more insight into impactor trajectories. Key Points: Ambient noise tomography reveals a 500–900 m thick heterogeneous basaltic target underlain by Archean granite basement beneath Lonar craterAn asymmetric damage zone is found beneath the 400 m deep original crater floor filled by impact breccia and lake sedimentsAsymmetric topography and impact damage zone geometry are consistent with a southwest‐ward oblique impact trajectory [ABSTRACT FROM AUTHOR]

The subaerial exposure of the modern continental crust through time remains intensely debated, with estimates of the first exposure ranging from the late Archean to the Neoproterozoic. To constrain when and how much of the continental crust was exposed subaerially during Earth's history, we trained a supervised machine learning model on the compositions of modern subaerial and submerged basalts. Then, we applied this well‐trained model to a refined worldwide data set of basaltic compositions and calculated the mean proportions of basalts erupted subaerially since 3.8 billion years ago (Ga). Our results suggest that ∼20% of the basalts were exposed subaerially in the early Archean, which may have driven the synthesis of biopolymers crucial to the origins and evolution of life. The proportion of subaerial basalts increased markedly during two stages between the late Archean and the Paleoproterozoic before reaching the present‐day level no earlier than ∼1.8 Ga. Plain Language Summary: Although land only covers about 30% of Earth's surface, it plays a crucial role in our planet's ecosystem by interacting with the ocean and atmosphere. Scientists are still debating when and how much land was above sea level throughout history. In our study, we used a machine learning technique to analyze the chemical compositions of basalts and classified rocks that formed on land and under water. We then used this program to study rocks from different times in Earth's history and estimate how much land was above the oceans over time. We found that about 15%–30% of the continents were above the oceans about 3.8 to 2.8 billion years ago (Ga). This may have helped life evolve by creating molecules essential for living things. The amount of land above water increased significantly during two periods between 2.8 and 1.8 Ga and reached today's level no earlier than 1.8 Ga. Key Points: Improve the geochemical data quality of global basaltic rocksMachine learning can effectively classify subaerially and subaqueously erupted basaltsThe subaerial proportion of basalts may reach present‐day level at about 1.8 billion years ago to a maximum [ABSTRACT FROM AUTHOR]

Inspired by the strong adhesion of mussels, basalt fibers (BFs) were modified with polydopamine and then composited with nylon 6. The effect of polydopamine content on the interfacial interactions and mechanical properties of the composites was investigated. In addition, silica nanoparticles were grown on the surface of polydopamine‐modified BFs to investigate the synergistic effect. The study revealed that the mechanical properties of the composites based on polydopamine‐modified BF were gradually enhanced with the increase of the dopamine coverage concentration, and gradually decreased after reaching the peak. 0.5 g/L concentration of dopamine solution modified BFs showed the best enhancement effect on nylon 6, and its tensile strength could reach 133.1 MPa, which was 28.5% higher than that of the unmodified composites. The tensile strength of the composites modified with both dopamine and silica nanoparticles reached 157 MPa, which was 51.7% higher than that of the unmodified composites. In addition, scanning electron microscope images of fracture sections confirmed the strong interfacial interaction between BF and PA6. Highlights: The surface roughness of BF was increased by nano‐SiO2.Hydrogen bonding was formed between PDA and PA6.Physical interlock was formed between nano‐SiO2 and PA6.Tensile strength increased by 51.7% with both nano‐SiO2 and PDA.Stronger interfacial interaction leads to higher thermal stability. [ABSTRACT FROM AUTHOR]

To help meet emission standards, hydrogen sulfide (H2S) from geothermal production may be injected back into the subsurface, where basalt offers, in theory, the capacity to mineralize H2S into pyrite. Ensuring the viability of this pollution mitigation technology requires information on how much H2S is mineralized, at what rate and where. To date, monitoring efforts of field‐scale H2S reinjection have mostly occurred via mass balance calculations, typically capturing less than 5% of the injected fluid. While these studies, along with laboratory experiments and geochemical models, conclude effective H2S mineralization, their extrapolation to quantify mineralization and its persistence over time leads to considerable uncertainty. Here, a geophysical methodology, using time‐domain induced polarization (TDIP) logging in two of the injection wells (NN3 and NN4), is developed as a complementary tool to follow the fate of H2S re‐injected at Nesjavellir geothermal site (Iceland). Results show a strong chargeability increase at +40 days, interpreted as precipitation of up to 2 vol.% based on laboratory relationships. A uniform increase is observed along NN4, whereas it is localized below 450 m in NN3. Changes are more pronounced with larger electrode spacing, indicating that pyrite precipitation takes place away from the wells. Furthermore, a chargeability decrease is observed at later monitoring rounds in both wells, suggesting that pyrite is either passivated or re‐dissolved after precipitating. These results highlight that a sequence of overlapping reactive processes (pyrite precipitation, passivation, pore clogging and possibly pyrite re‐dissolution) results from H2S injection and that TDIP monitoring is sensitive to this sequence. Plain Language Summary: High‐temperature geothermal production is responsible for air pollution due to hydrogen sulfide (H2S) present in the magmatic fluid. To help meet emission standards, H2S may be injected back into the subsurface, where basalt offers the capacity to transform H2S into pyrite. Transformation into an immobile mineral prevents further transport into the atmosphere, sea, surface streams, or lakes. However, ensuring the viability of this pollution mitigation technology requires information such as how much H2S is mineralized, at what rate and where, which are highly uncertain due to the heterogeneity and inaccessibility of subsurface processes. Here, a geophysical monitoring methodology is developed and tested during the re‐injection of H2S at Nesjavellir geothermal site in south‐west Iceland. According to laboratory studies, pyrite precipitation is expected to increase the electrical capacitance, "chargeability," of the subsurface. Using the so‐called time‐domain induced‐polarization (TDIP) method embedded in a wireline logging tool, the chargeability of a 2 m‐wide cylinder around the injection wells is measured with high spatial‐resolution before and during H2S injection. A strong chargeability increase at +40 days indicates that up to 2% pyrite is formed. A subsequent decrease at later rounds raises questions on whether pyrite is re‐dissolved or passivated by other secondary minerals. Key Points: H2S reinjection in basalt and mineralization into pyrite was monitored using TDIP logging in two of the injection wellsChargeability increases observed at +40 days (first monitoring round) correspond to 1%–2% pyrite precipitation with great spatial variabilitySubsequent monitoring rounds show a decrease in chargeability, suggesting that pyrite is either passivated or re‐dissolved [ABSTRACT FROM AUTHOR]

As part of the Synergetic Utilisation of CO2$_2$ storage Coupled with geothermal EnErgy Deployment project, investigating CO2$_2$ reinjection with different seismic methods, both passive and active seismic surveys have been conducted at the geothermal power plant at Hellisheiði, Iceland. During the 2021 survey, two geophone lines recorded noise for a week. We process the passive‐source data with seismic interferometry to image the subsurface structure around the CarbFix2 reinjection reservoir. To improve image quality, we perform an illumination analysis to select only noise panels dominated by body‐wave energy. The results show that most noise panels are dominated by air‐wave energy arriving from the direction of the power plant. We use panels with a near‐vertical incidence to create a zero‐offset image and a larger selection of body‐wave‐dominated panels to create virtual common‐shot gathers. We process the gathers with a simple reflection seismology processing workflow to obtain stacked images. The zero‐offset images show a relatively lower signal‐to‐noise ratio and only horizontal reflectors. The stacked images show slightly dipping reflectors and possibly lateral amplitude variations around the expected injection region. This could indicate a region of interest for future research into the reinjection reservoir. [ABSTRACT FROM AUTHOR]

Ocean island basalts (OIBs) are generated by mantle plumes, with their geochemistry controlled by a combination of source composition, temperature, and thickness of overlying lithosphere. For example, OIBs erupting onto thicker, older oceanic lithosphere are expected to exhibit signatures indicative of higher average melting pressures. Here, we quantitatively investigate this relationship using a global data set of Neogene and younger OIB compositions. Local lithospheric thicknesses are estimated using theoretical plate‐cooling models and Bayes factors are applied to identify trends. Our findings provide compelling evidence for a correlation between OIB geochemistry and lithospheric thickness, with some variables (SiO2, Al2O3, FeO, Lu) showing linear trends that can be attributed to increasing average melting pressure, whereas others (CaO, La, λ0, and λ1) require a bi‐linear fit with a change in gradient at ∼55 km. Observed variations in highly incompatible elements are consistent with degrees of melting that decrease with increasing lithospheric thickness, as expected. Nevertheless, at thicknesses beyond ∼55 km, the implied degree of melting does not decrease as rapidly as is suggested by theoretical expectations. This observation is robust across different lithospheric thickness estimates, including those derived from seismic constraints. We infer that at thicknesses exceeding ∼55 km, weak plumes fail to effectively thin overlying lithosphere and/or produce insufficient melt to erupt. This is supported by independent estimates of plume buoyancy flux, indicating that OIB magmatism on older lithosphere may be biased toward hotter plumes. In addition, we find evidence for a "memory effect" of incomplete homogenization of melts during their ascent. Plain Language Summary: Most of Earth's volcanoes occur at tectonic plate boundaries, but some emerge within plate interiors in so‐called intra‐plate settings. These volcanoes are believed to mark the surface expression of mantle plumes: hot, buoyant columns that rise from the core‐mantle‐boundary toward the surface. As they rise, lower pressures near the surface facilitate melting. However, the lithosphere—Earth's rigid outermost shell—limits plume ascent, and therefore controls the final (lowest) melting pressure of mantle plumes (the "lid effect"). Here, we collate and analyze a global geochemical data set of oceanic island basalts—the products of plume melting—to test this hypothesis. Using a range of diagnostics and a novel probabilistic analytical approach, we find that some geochemical parameters either linearly increase or decrease with lithospheric thickness, whereas other trends exhibit abrupt changes. We propose potential explanations for these patterns, focusing on factors such as the degree of melting (which is sensitive to temperature and pressure) and variations in mantle mineralogy at different depths. Notably, we suggest that there is a higher chance of observing volcanism above hotter plumes in regions of thicker lithosphere and identify a "memory effect", whereby their geochemistry to some extent preserves information from the initial melting process. Key Points: We quantify the relationship between lithospheric thickness and ocean island basalt geochemistry: the so‐called lid effectObserved trends are controlled by pressure‐related changes in the degree of melting, mineral assemblage, and spinel‐garnet phase transitionMagmatism beneath older lithosphere may be biased toward hotter plumes that more effectively thin and penetrate overlying lithosphere [ABSTRACT FROM AUTHOR]

In this study, we developed composites with a poly(lactic acid) matrix and reinforced with basalt fiber, carbon‐based nanoparticles (carbon nanotube [CNT] and expanded graphene [GNP]), and both basalt fiber and nanoparticles (hybrid composites). The composites were produced by extrusion, and then tensile specimens were injection molded from the composites. The hybrid composites exhibited enhanced mechanical properties. The reinforcing materials increased crystallinity; this was more pronounced for hybrid composites. We experienced significant increase in the glass transition temperature, which proves the better interaction between the reinforcing and the matrix phases. Dynamic mechanical thermal analysis showed that the nanoparticles increased the storage modulus both alone and in combination with basalt fibers. Furthermore, the basalt fiber‐reinforced composites and hybrids exhibited significant modulus above the glass transition temperature. Based on scanning electron microscopy images of the fracture surfaces, we concluded that adding basalt fibers during compounding resulted in better dispersion of the nanoparticles. Highlights: Poly(lactic acid) (PLA) reinforced with basalt fiber has good strength properties.Graphene hybrid exhibits notable tensile modulus improvement in hybrids.Graphene and carbon nanotubes are crystalline nucleating agents for PLA.Enhanced nanoparticle distribution was discovered for hybrid composites.The glass transition temperature of PLA increases with reinforcement. [ABSTRACT FROM AUTHOR]

Subduction processes play a pivotal role in facilitating material exchange between the crust and mantle, contributing to the growth of continents. However, the onset and evolution of subduction remain hotly debated. Here, we developed a high‐dimensional machine learning (ML) model to use multiple compositional data (e.g., Nb/La, Nb, Ti, Nb/U, Pb/Nd, and Nb/Th) to distinguish arc‐type from non‐arc basalts worldwide, then applied this well‐trained ML model to identify and delineate the secular occurrence of Archean arc‐type basalts. Our findings indicate that basaltic arc magmatism can be traced back to only a few early Archean cratons. A noticeable increase in the prevalence of arc‐type basalts during the Mesoarchean and Neoarchean suggests the synchronous formation of Archean subduction across different cratons. This observation hints at transitioning from the predominantly stagnant geodynamic regime to the early, more mobile tectonic regime. Plain Language Summary: Deep beneath the Earth's surface, subduction moves material from the crust to the mantle, generating magma and igneous activity. This process is crucial for building the continental crust. Despite its importance, how the subduction process evolved over billions of years remains debated. To better understand when and where subduction began, we trained a machine learning model to distinguish between arc (subduction‐related) and non‐arc (not subduction‐related) basalts to recognize the chemical "fingerprints" of subduction in these rocks. By applying the same model to ancient basalts, we could trace basaltic arc‐like magmatism back to several Archean eon cratons, known as cratons, early in Earth's history (during the Archean Eon). The number of arc‐type basalts increased during the Mesoarchean and late Archean, suggesting that subduction expanded to different regions for about 700 million years. The transition suggests a significant shift in how the Earth's crust moved and changed, from a primarily steady state to a more mobile tectonics as observed today. Our study sheds new light on the ancient history of our planet and helps us understand how the Earth's crust has evolved over billions of years. Key Points: Machine learning can accurately distinguish between arc and non‐arc basalts worldwideSubduction‐related basaltic magmatism may have produced on several cratons during the early ArcheanSubduction‐related processes may have started in cratons worldwide during the late Archean [ABSTRACT FROM AUTHOR]

In this research, basalt fiber reinforced plastic (BFRP) rebars reinforced tunneling segment (BRRTS) technique was developed. All the BFRP rebars were designed, pre‐cured according to the reinforcement design and the reinforcement drawing of steel rebars reinforced concrete tunneling segments (SRRTSs). Two criteria, the equal reinforcement ratio criterion (ERRC) and the half stiffness principle (HSP), were applied to design the BRRTs. Bending experiments were performed to reveal the deformation, damage and load carrying capacity of the BRRTSs. With flexural‐shearing coupling failure mode, the BRRTS has longer elastoplastic deformation and comparable (ERRC) or much greater (HSP) load carrying capacity compared with traditional SRRTS, indicating that the BRRTS can replace the SRRTS in some cases. Highlights: BFRP rebars reinforced tunneling segment was designed, constructed, and tested.BFRP rebars reinforced tunneling segment has long ductile deformation.BFRP rebars reinforced tunneling segment has higher load‐bearing capacity.Utilization efficiency of BFRP rebars varies from 0.565 to 0.646. [ABSTRACT FROM AUTHOR]

In this study, we investigated the morphological and mechanical properties of hybrid composites with a polyamide 6 (PA6) matrix and reinforced with basalt fibers (BFs) and halloysite nanotubes (HNTs). The presence of reinforcing materials fundamentally changed the behavior of the molecules, which was morphologically manifested in the change in the ratio of the rigid and the mobile amorphous phase. The x‐ray diffraction and transmission electron microscopic images showed the crystal nucleating effect of the halloysite nanotubes. Based on these, we concluded that around the basalt fibers, an interphase is formed, while around the nanoparticles, a two‐layer interphase is created, the inner layer of which is semicrystalline, while the outer layer is rigid amorphous (RA). The nanoparticles are surrounded by a semicrystalline interphase, which is surrounded by an RA interphase. This overlaps with the interphase of the basalt fibers, therefore the halloysite nanotubes can effectively help the stress transfer from the matrix to the basalt fibers. The mechanical properties of the samples also reflected this: the hybrid composites had a significantly higher tensile modulus, tensile strength, and an unchanged elongation at break compared to the composite reinforced with only basalt fiber. Highlights: Environmentally friendly polyamide 6 matrix hybrid composites were prepared.Uniform distribution of halloysite nanotubes was achieved.Enhanced mechanical properties were observed for hybrid composites.Halloysite nanotubes aid stress transfer from matrix to basalt fibers.Halloysite nanotubes act as crystalline nucleating agents. [ABSTRACT FROM AUTHOR]

Detachment faults at slow‐ and ultraslow‐spreading mid‐ocean ridges are essential for lithosphere‐hydrosphere interactions. However, their coupling with subseafloor hydrothermal circulation is poorly understood. Here, we investigated shallow hydrothermal fluid circulations in the active Dragon Horn detachment fault system of the Southwest Indian Ridge using combined near‐bottom magnetic anomaly data and rock magnetic analyses. We observed enhanced magnetic anomalies related to the high magnetization of basaltic country rocks and highly serpentinized (>80%) peridotite, whereas the hydrothermally altered basalts and sulfide deposits had weak magnetization and reduced magnetic anomalies. Therefore, the low‐magnetization zone was interpreted as a proxy for the hydrothermal fluid channel. The spatial distribution of the low‐magnetization zone revealed that the inactive Suye field expanded more than 500 m in diameter horizontally and ∼100 m vertically, and the active Longqi hydrothermal field had a >1 km fluid channel, both centered around the detachment fault fracture zone. Our results establish a robust link between detachment faulting and shallow hydrothermal circulation in which the detachment fault system provides critical fluid paths. Therefore, detachment tectonics are important elements for evolving seafloor hydrothermal fields along the Southwest Indian Ridge and possibly other slow‐ and ultraslow‐spreading mid‐ocean ridges globally. Plain Language Summary: The detachment faults of slow‐ and ultraslow‐spreading mid‐ocean ridges are geological structures motivated by seafloor spreading. Intermitted movements of detachment faults exhume deep oceanic crust or mantle rocks and provide pathways for seafloor hydrothermal systems. The magnetic properties of rocks in seafloor detachment fault systems are sensitive to hydrothermal fluids and can be used to study fluid circulation within seafloor detachment fault systems. Using magnetic methods, we found that magnetic minerals in fresh basalt and highly serpentinized peridotite created positive magnetic anomalies, whereas the absence of magnetic minerals in hydrothermally altered basalts and sulfides decreased the magnetic anomalies. As represented by the low‐magnetization zones, the shallow hydrothermal fluid channels sit on the detachment fault, highlighting the close relationship between detachment tectonics and the evolution of seafloor hydrothermal systems. We conclude that the detachment fault system primarily controls the formation of black‐smoker chimneys along the magma‐poor mid‐ocean ridges. Key Points: Altered basalt and sulfide deposits attenuated the magnetic anomaly of the normal‐polarity zone in the Dragon Horn areaSerpentinized peridotite (>80%) produced significant positive magnetic anomalies in the Dragon Horn areaDetachment faulting controls the formation of fluid channels for hydrothermal circulation [ABSTRACT FROM AUTHOR]

The Golan Heights plateau in northern Israel is underlaid by volcanic rocks ranging in age from ~5.5 to 0.1 Ma. Throughout the Golan Heights, these rocks are covered by shallow soils that rarely exceed 0.5 m in depth. The soils are generally assumed to form a chronosequence, in which their ages correspond to those of the basalts they cover. Such age correspondence would imply that the soils have been slowly accumulating over hundreds of thousands to a few million years, suggesting a generally stable system. The ages of these soils and their temporal correlation to the basalts, however, have never been determined or tested. Here, we present age constraints for the soils of the Golan Heights. Soils were surveyed and sampled with their corresponding basalt bedrock. Mass balance calculations based on conservative immobile elements, coupled with 36Cl-based basalt denudation rates, suggest that the soil ages are decoupled from the ages of the underlying basalts, and represent up to a few thousand years of soil production, at most. This time frame is orders of magnitude shorter than the basalt age, challenging the prevalent assumption that the soils form a chronosequence. Our findings strongly suggest that erosion is a significant factor controlling soil formation and accumulation on the plateau, despite the generally flat morphology of the Golan Heights. The erosion is associated with tectonic activity along the Dead Sea transform, with the development of the Kinarot and Hula valleys, and with the consequential development of drainage systems of various sizes on the plateau. Throughout the Golan Heights, the timing of volcanic activity in relation to the development of the valleys and drainage systems also appears to strongly affect soil development and accumulation. [ABSTRACT FROM AUTHOR]

The purpose of this study is to present a novel method for producing mechanically strong epoxy composite laminates of different compositions, reinforced with basalt fabric and reduced graphene oxide flakes. The laminates are prepared with basalt fabric, which is subjected to low‐temperature plasma treatment. This approach is aimed to enhance the adhesion of fabric to resin filled with reduced graphene oxide flakes. Physical properties, adhesion, and mechanical properties of the obtained materials are determined. Based on the experiments, it is found that the tensile strength is improved by 6–21% after using reduced graphene oxide filler, 9–23% after plasma treatment, and up to 27% using the combination of plasma and reduced graphene. It is found that the highest improvement of tensile strength is obtained for epoxy composite with 0.5 wt% graphene‐based filler and 3 min basalt fiber plasma treatment with 25 W plasma power. [ABSTRACT FROM AUTHOR]

In the central area of the South Pole‐Aitken (SPA) basin, an intermediate albedo, mafic compositional anomaly (SPA Compositional Anomaly, SPACA) has been documented by previous studies, but its origin remains uncertain. We conducted an investigation of stratigraphic units defined based on morphology and composition and their relative ages, and placed these in the context of basin topography and the observed sequence of geological events, all helping to distinguish between SPACA origins from: (a) SPA impact melt, (b) volcanism induced by the SPA event and (c) lunar cryptomaria. We conclude that SPACA represents extensive traditional cryptomare deposits overlying the SPA impact melt. We interpret the basin center to be filled with cryptomare deposits at least one km thick (>1 × 105 km3 in volume) with ages not younger than Early Imbrian. We attribute the relatively high albedo of SPACA to lateral mixing of ejecta from nearby highlands craters and basins, and conclude that the cryptomaria basalts are likely to be very similar to basalts on the nearside. Our findings imply a 0.5%–1.8% increase in the total volume of global lunar mare and cryptomare deposits. These results show that mare volcanism was common only in areas of thinnest crust on the lunar farside, a factor important in understanding lunar nearside‐farside asymmetries. Despite this significant increase in total cryptomare volume in the SPA basin center, SPA remains underfilled relative to nearside mascon basins. Return of mare basalts from the SPA region by Chang'E‐6 will help determine potential mantle source region differences and petrogenetic pathways. Plain Language Summary: On the enigmatic farside of the Moon, a huge impact basin called SPA basin occupies an immense area (∼2,500 km diameter). Previous spectroscopic investigations identified four compositional zones across SPA, and the central one shows a distinctive high‐Ca pyroxene anomaly, designated the "South Pole‐Aitken compositional anomaly" (SPACA). SPACA has a higher albedo compared to typical maria but lower than lunar highlands and has a paucity of impact craters relative to other SPA units. Previous studies concluded that SPACA is either associated with (1) the SPA impact melt sheet or (2) subsequent volcanic resurfacing events of a special composition induced by the SPA impact. Our reassessment favors the hypothesis that SPACA represents cryptomaria erupted into the basin center during a period of higher impact flux, resulting in lateral dusting of the dark mare surfaces by highland material, thereby raising their albedos. Consequently, the SPACA is similar to other lunar basins in that cryptomaria were deposited in the basin center, followed by maria when the impact flux declined and lateral dusting was minimal. Our SPA cryptomare volume estimates represent a 0.5%–1.8% increase in the total volume of global lunar mare and cryptomare deposits, but SPA remains underfilled relative to nearside giant basins. Key Points: The central South‐Pole Aitken basin compositional anomaly is formed of cryptomare deposits rather than a differentiated impact melt sheetSouth‐Pole Aitken basin resembles other lunar basins having mare/cryptomare infilling the center, adding 0.5%–1.8% to the global basalt inventoryCrustal thickness variations may account for the concentration of farside maria in the South‐Pole Aitken basin, yet it remains underfilled [ABSTRACT FROM AUTHOR]

In this study, the behavior of composite material produced using basalt, a natural fabric, under ballistic and Charpy impact loads was investigated. The damage resistance of target plates under ballistic loads is an important design parameter in the structures that will be exposed to these loads. Cross‐ply fiber‐reinforced composite plates were produced with different numbers of layers. The composite specimens are produced using the vacuum infusion method, cross‐ply laminated with 3, 6, 9, and 12 layers ([0/90]3, [0/90]6, [0/90]9, and [0/90]12). Carbon/Epoxy specimens were also produced in identical sequences to be used as comparison material. The study aimed to understand the absorbed energy under ballistic loads and the required energy level under the Charpy impact loads of Basalt/Epoxy composite specimens with different thicknesses. Ballistic loads are applied to the specimens using a test set‐up including the sample holder mechanism and a firing system. Charpy impact tests were conducted using a standard test machine. According to the results, for 12‐layer specimens, the residual velocity difference between Basalt/Epoxy and Carbon/Epoxy is approximately 1.5 times. For the Basalt/Epoxy plate, increasing number of layers from 3 to 12 increases the amount of energy absorbed approximately 13 times. Although this increase is approximately 19 times for the Carbon/epoxy plate, when Basalt/Epoxy and Carbon/Epoxy plates are compared, Basalt/Epoxy absorbs more energy for all layer numbers. For the Charpy impact cases, it has been observed that Basalt/Epoxy absorbs approximately 34% more energy for flat wise impact and approximately 24% more energy for edgewise impact. Highlights: The behavior of composite material produced using basalt, a natural fabric.Cross‐ply fiber‐reinforced composite plates.Effect of different number of layers considered.The damage resistance of target plates under ballistic loads.Comparison of basalt and carbon‐reinforced composites. [ABSTRACT FROM AUTHOR]