Geomagnetic field reversals are relatively common events, occurring 4-5 times/Myr over the last 10 Ma. However, there are two well-documented periods, called superchrons, when no reversal occurred for >30 Myr in the Cretaceous and Permo-Carboniferous. A third superchron has been proposed in the Ordovician when the field was in a reversed polarity state. Here, we report high-resolution, Middle to Late Ordovician magnetostratigraphic data from carbonate rocks spanning 471 to 454 Ma collected in the Siljan district, central Sweden. The Siljan record correlates well with Ordovician sequences from Baltoscandia, Siberia and Poland. In Siljan, a flip from reversed to normal polarity at 466.1 +/- 0.9 Ma clearly identifies the termination of the Ordovician Reversed Superchron (ORS), thereby constraining its duration to 13.9 +/- 2.2 Myr. To evaluate the statistical significance of this interval, we compiled a geomagnetic polarity timescale spanning the last 493 Myr and analyzed chron length distributions using a robust interquartile range method. The ORS is a clear statistical outlier that exceeds a critical 6.8 Myr threshold, corroborating its classification as a bona fide superchron. Our chron length analyses support the view that superchrons represent rare, stable dynamo regimes, rather than merely the tail of a continuous reversal rate distribution.

The human brain contains magnetic iron oxide nanoparticles in the form of magnetite (Fe3O4); however, the origin and physiological implications of these crystals remain debated. Due to their low concentrations in brain tissue (∼1-20 ng g-1), the identification and characterization of individual magnetic particles require nanometer-scale spatial resolution over large scan volumes. In contrast to conventional electron microscopy techniques that have field of views typically on micron scales, the Quantum Diamond Microscope (QDM), based on wide-field nitrogen-vacancy center imaging, can generate magnetic field maps over areas of several square millimeters while detecting nanoscale particles. Moreover, the QDM can directly quantify the strength and direction of the particles' magnetic moments. Operating the QDM in a high-sensitivity mode, coupled with long acquisition times, enabled the detection of magnetic moments as small as 3 × 10-17 Am2, corresponding to a magnetite particle diameter of approximately 50 nm, in maps covering 1.40 × 2.25 mm2. This is the highest magnetic moment sensitivity of wide-field magnetic microscopy >1 mm2 to date. In addition, collecting repeat, but slightly offset magnetic field maps resulted in the unique ability to distinguish sources within a sample from contamination and artifacts. By applying this technique to tissue, we demonstrate the detection of magnetic dipole-generating sources in human and rodent brain samples with the QDM. Detected particles span a size range of 60-135 nm, consistent with the larger end of magnetite particle sizes found by electron microscopy. These are the first direct magnetic observations of magnetite nanoparticles in brain tissue using quantum sensing techniques.

Abstract Anisotropy of magnetic remanence (AMR) holds promise for quantifying relative paleointensity values from sedimentary rocks. A proof of concept was established for applied fields that exceeded the intensity of the geomagnetic field. Under Earth‐like fields, large uncertainties necessitate the development of a new approach to improve the estimation of the anisotropy tensor. To this aim, we designed a numeral method that demonstrated the applicability and resolution needed to optimize the experimental protocol. Following this, we implemented a 30‐position procedure for AMR measurements and compared the numerical and experimental data with a typically used, 12‐position procedure. Redeposition experiments with sediments rich in single domain magnetite were carried out in fields with intensities of 0, 10, 50 and 100 μT; 25 individual samples were redeposited and measured at each field condition. The 30‐position protocol better facilitates the isolation and resolution of the field‐aligned prolate fabric (<3% of the total) from the oblate sedimentary fabric, and more so when applying tensor subtraction of the fabric obtained in a null field. Together with the high‐resolution protocol and tensor subtraction method, we demonstrate that an anisotropy‐based paleointensity deviates <10% relative to classical remanence based relative paleointensity in Earth‐like fields ranging from 10 to 100 μT. Using a synthetic subtraction method, we show that remanence‐based anisotropy precisely tracks the paleofield direction in rocks hosting detrital remanences, which is important when viscous or isothermal overprinting dominates the paleomagnetic vector.

Calcite is prone to chemical and microstructural modifications, especially after having been strained at high stresses and strain rates, as during hypervelocity impact events. These modifications include precipitation from pore fluid as well as replacement of strained volumes by recrystallization. In calcite aggregates of a metagranite breccia of the Ries Bunte Breccia, shocked calcite is partly replaced by new, undeformed grains. This breccia indicates shock conditions of 10-20 GPa by the presence of planar deformation features in quartz of the metagranite. Shocked calcite shows grain orientation spread (GOS) angles of 3-10 degrees and contains e-, f-, and r- twins, as well as a- and f-type lamellae. In contrast, the new coarse calcite grains, which are hundreds of mu m in diameter, have low GOS angles (<1 degrees), and do not contain twins. Calcite aggregates have a chemical zonation (varying Mnn+ content), which is independent of new grains, suggestive of fast transformation. We propose that the new grains originate from sites of high crystal-plastic strain and grew by grain boundary migration driven by the reduction in strain energy, replacing previously strained grains at low stresses, that is, static recrystallization. Heating experiments on shocked calcite confirm the strain control on static recrystallization.

Magnetotaxis has evolved independently numerous times in bacteria, whereby genetically controlled biomineralization of nano-crystalline magnets results in swimming along Earth's magnetic field lines. Compared to magnetotactic bacteria (MTB), evolutionary mechanisms of magnetotaxis as a trait in eukaryotes remain poorly understood. Here, we report a magnetotactic ciliate, Tropidoatractus magnetotacticus sp. nov., that acquires magnetotaxis via syntrophy. T. magnetotacticus exhibits magnetotaxis due to the magnetic moment of internal ferrimagnetic magnetite (Fe3O4) nanoparticles forming ellipsoidal "necklace-shaped" parallel chains. Electron microscopy revealed T. magnetotacticus hosts numerous internal rod-shaped bacteria containing these magnetosome chains. Consistent with this, a genomic population of MTB (Thermodesulfobacteriota) in magnetically sorted T. magnetotacticus cells was found that encoded and expressed a magnetosome gene cluster responsible for magnetosome Fe3O4 biomineralization closely related to that of the ectosymbiont "Candidatus Desulfarcum epimagneticum." T. magnetotacticus also housed a second genomic population affiliated with the endosymbiotic methanogen Methanoregula. Metatranscriptomes of sorted T. magnetotacticus cells show eukaryotic hydrogenosomal Fe-hydrogenase gene expression, and expression of genes encoding proteins in an electron transport chain indicative of H2-producing mitochondria-related organelles. Active gene expression of energy metabolism pathways indicates a tripartite syntrophic network whereby anaerobic fermentation products from T. magnetotacticus are consumed by two syntrophic partners: MTB producing the magnetosome chains and hydrogenotrophic methanogens. Our findings show how magnetotaxis can emerge as a trait in eukaryotes via syntrophic cooperation.

Paleomagnetism relies4 on stable remanent magnetizations held in rocks to reconstruct the ancient geomagnetic field direction and intensity. However, rocks may carry secondary overprints that obscure or completely destroy the original signal. To study the stability of the magnetic vector(s), laboratories routinely apply static alternating field demagnetization along three orthogonal axes (AFD₃), which is fast, non-destructive, and easy to automate. Here, we present a multiparticle model that shows AFD₃ can deviate the natural remanent magnetization (NRM). Deviations can be avoided when fulfilling two conditions: (i) the NRM was acquired in a weak field where magnetization intensity varies linearly with field strength, and (ii) the sample is magnetically isotropic. The first condition is generally satisfied for rocks holding thermal or detrital remanent magnetizations, but not those affected by an isothermal remanence (e.g., lightning), even though AFD₃ is often used to remove them. In rocks with an anisotropic particle orientation distribution, stepwise AFD₃ progressively removes different coercivity subpopulations as a function of grain orientation so the effective remanence anisotropy of the surviving carriers changes during demagnetization. The anisotropy-driven deflection therefore evolves with AF step, producing curvilinear demagnetization trajectories. Our theoretical results argue for caution when applying AFD₃ to anisotropic samples or those with isothermal overprints. Undesired NRM rotation can be avoided by tumble demagnetization or mitigated by increasing the number of alternating field axis orientations.

The rise of the Yellowstone plume coincided with a shift from orogenic collapse of the Cordillera to Basin and Range extension in the northern Rocky Mountains, yet its impact on regional uplift, sediment dispersal, and drainage patterns remains largely unexplored. Here, we present rock magnetic analyses from eight Oligo-Miocene sedimentary sections in southwestern Montana. Using two complementary datasets, we identify a sharp increase in magnetic mineral concentration immediately after the early Miocene unconformity [~20 million years ago (Ma)], concurrent with a shift in detrital zircon ages, indicating a major provenance shift. We identify bimodal volcanism of the Columbia River Basalt Group as the dominant Miocene source, requiring that the early Miocene Continental Divide lay ~400 kilometers west of its present position. This reorganization, driven by Yellowstone plume–induced uplift, persisted until at least 10 Ma. Our study provides geologically based, temporal, and spatial constraints on dynamic topography previously only estimated from modeling.

Magnetic anisotropy plays a central role in many petrofabric and paleomagnetic studies. Anisotropy is typically represented by a second-order symmetric tensor that reflects the combined contributions from mineral populations with differing grain sizes, orientation distributions and particle scale anisotropies. Thus, the quality of geologically significant information obtained from magnetic anisotropy data depends on our ability to disentangle the complexity of these coexisting fabrics. In this study, we present a least-squares technique that can be employed in combination with additional geological or other supporting evidence to separate measured anisotropy tensors into independent contributions with distinct physical meaning. The analysis is readily adaptable and widely applicable to interpreting composite hybrid magnetic anisotropies, like those which arise from tectonic forces. Here, we revisit published deposition experiments and anisotropy of anhysteretic remanence (AARM) measurements to demonstrate the usefulness of the tensor decomposition approach. Remanence anisotropy measurements are decomposed into idealized tensorial sub-components originating from the preferred alignment of particles parallel to the magnetic field (field-aligned fabric) and within the bedding plane (sedimentary fabric). The least-squares decomposition isolates the field-aligned fabric by subtracting the sedimentary-compaction fabric. After subtraction of the sedimentary fabric, quantitative paleofield strength and direction can be directly inferred from the field-aligned subfabric.

Abstract We investigated the paleogeography of Baltica via a paleomagnetic study of 471‐454 Ma limestones from the Siljan (Sweden) impact structure. Stepwise thermal demagnetization isolated a well‐defined magnetization component that unblocks up to the Curie temperature of magnetite and passes fold and reversal tests, indicative of a primary magnetization. Paleolatitude data show that Baltica experienced an initial stationary phase at approximately 55°S from 471 to 467 Ma, followed by a rapid northward drift (∼35 cm/yr) after 467 Ma. This motion slowed to ∼15 cm/yr at ∼463 Ma until 454 Ma when Baltica reached 33°S. A notable correlation was found between Baltica's latitude and the relative proportion of magnetite and hematite in the carbonates; they are relatively hematite rich at 55°S and magnetite rich by 33°S. Our results provide a high‐precision model how Baltica moved in the Ordovician with potential environmental implications regarding the oxidation state of the ocean at that time.

The early Miocene unconformity (EMU) formed during a transition in the tectonic regime of western North America that coincided with faunal diversification. The Railroad Canyon section in the northern Rocky Mountains provides a complete geologic record around this event. Our new magnetostratigraphic study in combination with published U-Pb ages from intercalated ash places the end of the EMU at similar to 20.1 Ma with a duration of up to 1.5 Myr. The EMU is marked by an abrupt change in rock colour, an increase in magnetite concentration, and a decrease in calcite abundance. Average sedimentation rates are similar above and below the EMU, as are climate proxies; therefore, the changes in mineralogy likely reflect a reorganisation in sediment source. Drainage network reorganisation seemingly contributed to this, possibly related to a change in tectonic regime, such as the onset of Basin and Range extension and/or arrival of the Yellowstone plume.

The central portion of the 2019 +/- 2 Ma Vredefort (South Africa) impact structure comprises a 40-50 km diameter central uplift of Archean basement rocks surrounded by a 15-20 km wide collar of late Archaean to early Proterozoic Witwatersrand Supergroup sedimentary and volcanic rocks. The collar is characterized by a ring of strongly negative (up to -5 500 nT) aeromagnetic anomalies surrounding much of the structure where the strata dip steeply to overturned. To better understand the origin of this magnetic feature, we undertook a ground survey along 20 transects (340 km) in the Vredefort structure using a three-axis fluxgate magnetometer mounted on a mountain bicycle. Upward continuation of our profiles to 150 m matches the aeromagnetic data in shape and amplitude. From the bicycle measurements, we pinpointed the rocks responsible for the extremely negative anomalies. Field observations and microfabric analyses of the rocks from six outcrops substantiated that the magnetic signal correlates with 10-100 m thick metamorphosed banded iron formations (BIFs) at the base of the supergroup as the main producer of the anomalies. Paleomagnetic samples collected from the rocks at the surface that produce the most intense anomalies (up to -22 000 nT) have extremely high natural remanent magnetization intensities (up to >1000 Am-1) likely arising from lightning strikes. Stepwise demagnetization and rock magnetic experiments establish a new protocol to distinguish samples that escaped remagnetization from lightning and possess the established 2.02 Ga paleodirection at Vredefort. From a suite of thermoremanent magnetization (TRM) experiments, the best estimate for the paleofield intensity at the time of impact was 52 mu T, corresponding to an average remanence of 32.5 Am-1. The results of the TRM experiments together with the paleodirection enabled us to successfully model the prominent negative anomalies in the metasediments only when accounting for the post-impact orientation of the BIFs. We interpret the strongly negative magnetic anomalies in the collar region as being formed directly after crater exhumation and uplift of the rocks. This interpretation implies that Bushveld-related metamorphism at 2.06 Ga created the up to mm-sized magnetite and garnet crystals in the BIFs, which resided at temperatures higher than the Curie temperature of magnetite (580 degrees C) until the impact rapidly brought the BIFs close to the surface, where magnetite cooled to acquire a thermal remanence in the 2.02 Ga field.

Aggregates of ilmenite with varying amounts of rutile, ferropseudobrookite, and pseudorutile in suevites from the Ries impact structure have been analyzed by light microscopy, analytical scanning electron microscopy, electron microprobe analysis, and Raman spectroscopy to constrain their formation conditions. The tens to hundreds of micrometer aggregates comprise isometric ilmenite grains up to 15 mu m in diameter that form a foam structure (i.e., smoothly curved grain boundaries and 120 degrees angles at triple junctions). Grains with foam structure show no internal misorientations, indicating a post-impact formation. In contrast, ilmenite grains with internal misorientation occurring in the core of the aggregates are interpreted as shocked remnant ilmenite originating from the target gneisses. They can contain twin lamellae that share a common {1120} plane with the host, and the c-axis is oriented at an angle of 109 degrees to that of the host. Similarly, the new grains with foam structure display up to three orientation domains, sharing one common {1120} plane for each pair of domains and c-axes at angles of 109 degrees and 99 degrees, respectively. This systematic orientation relationship likely reflects a cubic supersymmetry resulting from the transformation of the initial ilmenite upon shock (>16 GPa) to a transient perovskite-type high-pressure phase (liuite), subsequent retrograde transformation to the polymorph wangdaodeite, and then back-transformation to ilmenite. Whereas, the new grains with foam structure formed from complete transformation, the twin domains in the shocked ilmenite are interpreted to represent only partial transformation. Ferropseudobrookite occurs mostly near the rim of the aggregates. An intergrowth of ferropseudobrookite, ilmenite, and rutile, as well as magnetite or rarely armalcolite occurs at contact with the (devitrified) matrix. The presence of ferropseudobrookite indicates high temperature (>1140 degrees C) and reducing conditions. The surrounding matrix provided Mg2+ to form the ferropseudobrookite-armalcolite solid solution. Rutile can occur within the aggregates and/or along the ilmenite boundaries; it is interpreted to have formed together with iron during the decomposition of ilmenite at lower temperatures (850-1050 degrees C). We suggest magnetite in the rims formed by electrochemical gradients driven by the presence of a reducing agent, where Fe2+ within ilmenite diffused toward the rim. Subsequent cooling under oxidizing conditions led to the formation of magnetite from the iron-enriched rim as well as pseudorutile around ilmenite grains. Our study demonstrates that the specific crystallographic relationships of ilmenite grains with foam structure indicate a back-transformation from high (shock) pressures >16 GPa; moreover, the presence of associated Fe-Ti-oxides helps indicate local temperature and oxygen fugacity conditions.

AbstractHow and when sedimentary rocks record Earth's magnetic field is complex. Most studies assume a time‐progressive lock‐in mechanism during sediment deposition called depositional remanent magnetization (DRM). However, magnetic minerals can also form in situ, recording a chemical remanent magnetization (CRM) that is discontinuous in time. Disentangling the two mechanisms represents a major hurdle, and differences in their recording efficiencies remain unexplored. Here, our theoretical solutions demonstrate that CRM intensities exceed DRM by a factor of six when acquired in the same magnetic field. Novel experiments growing greigite (Fe3S4) in sediments and subsequent redeposition under identical magnetic field conditions confirm the predicted difference in recording efficiency. Thus, if left unrecognized, CRM leads to overestimated paleointensity and deserves more attention when interpreting Earth's magnetic history from sedimentary records. Recognition of fundamental differences between CRM and DRM characteristics provide a way forward to distinguish the recording mechanisms through routine laboratory protocols.

This paper addresses one of the critical questions of scientific inquiry: How do we know when a given data set is representative of the phenomenon being examined? For paleomagnetists, the question is often whether a particular dataset sufficiently averaged paleosecular variation (PSV). To this aim, we updated an existing PSV dataset that now comprises 2441 site mean directions from 94 individual studies (PSV10-24). Minimal filtering for data quality resulted in 1619 sites from 90 publications. Fitting PSV10-24 with three newly defined parameters as well as two existing ones form the basis of a Giant Gaussian Process field model (THG24) consistent with the data. Drawing directions from THG24 yields directional distributions predicted for a given latitude allowing a comparison between empirical distributions and the cumulative distribution function generated by the model. This tests whether the observed data adequately averaged out PSV according to THG24. Sedimentary datasets that may have experienced inclination shallowing can be corrected using an (un)flattening factor that yields directions satisfying THG24 in a newly-defined, four-parameter space. This approach builds on the Elongation-Inclination (E/I) method of Tauxe and Kent (2004), so the approach introduced here is called SVEI. We show examples of the use of SVEI and explain how to use this newly developed python code that is publicly available in the PmagPy GitHub repository.

In the Aumühle quarry of the Ries impact structure, moderately shocked clasts from the Variscan basement occur sandwiched between overlying suevite and components derived from the Mesozoic sedimentary cover of the underlying Bunte Breccia without distinct shock effects. We analyzed the clasts by optical microscopy, scanning electron microscopy (SEM/EDS/EBSD), and Raman spectroscopy to unravel their emplacement relation to the overlying suevite and the sediment-rock clasts of the Bunte Breccia. Clasts sizes range up to few decimeters and are embedded in a fine-grained lithic matrix; no impact-melt fragments are observed. Amphibolite clasts contain maskelynite with few lamellar remnants of feldspar, indicating shock pressures of 28–34 GPa. Amphiboles have cleavage fractures and ( 1 01) mechanical twins suggesting differential stresses > 400 MPa. Felsic gneiss components have optically isotropic SiO2 indicative of shock pressures ≈35 GPa. Metagranite cataclasite clasts contain shocked calcite aggregates and quartz with a high density of fine rhombohedral planar deformation features indicating shock pressures ≈20 GPa. The moderately shocked basement clasts originate from deeper levels of the transient cavity and lower radial distance to the center of the structure compared to the sediment-rock clasts. Both were ballistically ejected during crater excavation. In accordance with palaeo- and rock magnetic data, they were mixed during turbulent deposition at the top of the Bunte Breccia before the emplacement of suevite. The high amount of basement clasts below suevite and on top of the underlying Bunte Breccia is consistent with the commonly reported inverse stratigraphy in the Ries impact structure.

The Ries impact structure (Germany) contains well-preserved ejecta deposits consisting of melt-free lithic breccia (Bunte Breccia) overlain by suevite. To test their emplacement conditions, we investigated the magnetic properties and microstructures of 26 polymict breccia clasts and a stratigraphic profile from the clasts into the suevite at the Aum & uuml;hle quarry. Remanent magnetization directions of the Bunte Breccia clasts fall into two groups: those whose directions mostly lie parallel to the reversed field during impact carried mostly by magnetite, and those whose directions vary widely among each clast carried by titanohematite. Basement clasts containing titanohematite acquired a chemical remanent magnetization (CRM) during the ejection process and then rotated during turbulent deposition. Clasts of sedimentary rocks grew magnetite after turbulent deposition, with CRM directions lying parallel to the paleofield. Suevite holds a thermal remanent magnetization carried by magnetite, except for similar to 12 cm from the contact with the Bunte Breccia, where hematite concentrations increase due to hydrothermal alteration. These observations lead us to propose a three-stage model of (a) turbulent deposition of the melt-free breccia with clast rotation <580 degrees C, (b) deposition of the overlying suevite, which acted as a semi-permeable barrier that confined hot (<300 degrees C) oxidizing fluids to the permeable breccia zone, and (c) prolonged hydrothermal activity producing further alteration which ended before the next geomagnetic reversal. Basement outcrops have significantly different magnetic properties than the Bunte Breccia basement clasts with similar lithology. Two basement blocks situated near the inner ring may have been thermally overprinted up to 550 degrees C.

Paleomagnetic records of middle Neoproterozoic (820 to 780 Ma) rocks display high amplitude directional variations that lead to large discrepancies in paleogeographic reconstructions. Hypotheses to explain these data include rapid true polar wander (TPW), a geomagnetic field geometry that deviates from a predominantly axial dipole field, a hyper-reversing field (>10 reversals/Ma), and/or undiagnosed remagnetization. To test these hypotheses, we collected 1,057 oriented cores over a 85 m stratigraphic succession in the Laoshanya Formation (Yangjiaping, Hunan, China). High precision U-Pb dating of two intercalated tuff layers constrain the age of the sediments between 809 and 804 Ma. Thermal demagnetization isolates three magnetization components residing in hematite which are not time-progressive but conflated throughout the section. All samples possess a north and downward directed component in geographic coordinates at temperatures up to 660 degrees C that is ascribed to a Cretaceous overprint. Two components isolated above 660 degrees C reveal distinct directional clusters: one is interpreted as a depositional remanence, while the other appears to be the result of a mid-Paleozoic (460 to 420 Ma) remagnetization, which is likely widespread throughout South China. The high-temperature directions are subtly dependent on lithology; microscopic and rock magnetic analyses identify multiple generations of hematite that vary in concentration and distinguish the magnetization components. A comparison with other middle Neoproterozoic paleomagnetic studies in the region indicates that the sudden changes in paleomagnetic directions, used elsewhere to support the rapid TPW hypothesis (ca. 805 Ma), are better explained by mixtures of primary and remagnetized components, and/or vertical axis rotations. Plain Language Summary Paleomagnetic directions recorded in 820 to 780 million year old rocks from South China exhibit large amplitude changes that vary rapidly, which have been interpreted to indicate extraordinarily fast motion of Earth's crust and mantle, up to 90 degrees within a 5 million year span, with respect to the spin axis of the core. This hypothetical phenomenon, called rapid true polar wander (TPW), could be responsible for dramatic global environmental change at that time. To test this theory, we collected over 1,000 samples from a well exposed section where the incongruous directions are found. Our measurements suggest that some of the rocks acquired a new magnetic signal during a pervasive remagnetization event in South China around 440 million years ago, long after original deposition of the rocks. New hematite growth has a demagnetization spectrum that partially overlaps or completely obscures the original magnetic signal, which was previously unrecognized. This implies that rapid TPW is likely an artifact of magnetic overprinting in ancient rocks from South China. Our results suggest that South China was in a relatively stable position at high latitudes 809 to 804 million years ago. We find no evidence to support exceptionally fast continental drift or an abnormal geomagnetic field geometry during that time.

Explosivity in erupting volcanoes is controlled by the degassing dynamics and the viscosity of the ascending magma in the conduit. Magma crystallisation enhances both heterogeneous bubble nucleation and increases in magma bulk viscosity. Nanolite crystallisation has been suggested to enhance such processes too, but in a noticeably higher extent. Yet the precise causes of the resultant strong viscosity increase remain unclear. Here we report experimental results for rapid nanolite crystallisation in natural silicic magma and the extent of the subsequent viscosity increase. Nanolite-free and nanolite-bearing rhyolite magmas were subjected to heat treatments, where magmas crystallised or re-crystallised oxide nanolites depending on their initial state, showing an increase of one order of magnitude as oxide nanolites formed. We thus demonstrate that oxide nanolites crystallisation increases magma bulk viscosity mainly by increasing the viscosity of its melt phase due to the chemical extraction of iron, whereas the physical effect of particle suspension is minor, almost negligible. Importantly, we further observe that this increase is sufficient for driving magma fragmentation depending on magma degassing and ascent dynamics.