Single-crystal sanidine 40 Ar/ 39 Ar dating revealed at least six new explosive eruption events during the 4.0–3.5 Ma and 3.0–2.5 Ma periods in the eruptive history of the Kožuf-Voras volcanic system located in the central parts of Southeastern Europe. The precise ages helped to redefine the timing and eruptive style of the volcanic system, as the 4.0–2.5 Ma period was previously considered as mainly quiescent, with dominantly lava dome building activity recognized so far. The pyroclastic layers (mainly massive tuff-lapilli tuff and massive lithic breccia) are deposited from phreatomagmatic and subplinian eruptions, and block-and-ash flows in the volcano-sedimentary Mariovo basin, west of the volcanic system. The newly recognized pyroclastic layers could serve as regional marker layers, as neither their ages nor their geochemical and isotopic (bulk and glass) compositions overlap with those previously studied tephra layers, either from the Kožuf-Voras volcanic system or from other volcanic sources (e.g., Aegean arc). Differences in the geochemical and isotopic data imply sequential evacuation of closely emplaced, discrete, melt-dominant bodies during the older period. In contrast, the younger sequence might represent a compositionally zoned single melt body. The latter also represents an explosive-to-effusive transition as the top layer is a block-and-ash flow unit resulting from a dome collapse. • Precise ages helped to redefine the evolution of the Kožuf-Voras volcanic system. • The newly recognized pyroclastic layers could serve as regional marker layers. • At least six explosive eruptions occurred in the 4.0–3.5 Ma and 3.0–2.5 Ma periods. • Data suggests evacuation of discrete, melt-dominant bodies in the older period. • The younger sequence might represent a compositionally zoned, single melt body.

Subduction of serpentinized mantle lithosphere delivers nitrogen (N) into the mantle, but the residency and speciation of N therein remain largely unknown. Serpentine, talc, and chlorite have been proposed as likely hosts in K-poor ultramafic rocks due to the minerals' sheet-like structures and the ability for N to reside in interlayer sites. In this study, we explore whether these three minerals are the primary hosts of N in subduction-related mantle lithosphere and metasomatized hybrid rocks (serpentinites, talc schists, and chlorite schists) by analyzing the N concentrations and isotope compositions of paired whole-rock and phyllosilicate mineral separates. Mineralogy of nine samples and sixteen mineral separates from ultramafic units in Syros, Greece, and Pam Peninsula, New Caledonia, were characterized by petrography and X-ray diffraction (XRD) prior to N analyses. Whole-rock N concentrations are from 25 to 102 μg/g and N-isotopes compositions ( δ 15 N air ) range from −0.2 to +6.9‰, whereas mineral separates contain 8 μg/g to 176 μg/g N with δ 15 N of −1.2 to +7.0‰. These results show that ultramafic rocks and phyllosilicate minerals from subduction zone settings contain 10's to 100's of μg/g of N, and have δ 15 N consistent with mixing with a sedimentary-derived fluid. However, mineral separates show variable N and δ 15 N enrichment or depletion relative to their respective whole-rocks, with most separates containing ≤40% of the whole-rock N and systematically lower δ 15 N values. These data indicate that, for the majority of the samples, a considerable fraction of the N is hosted in minerals or sites within the whole-rock not captured in the mineral separates. We combine textural observations and geochemical correlations to propose that the discrepancy between the whole-rocks and their mineral separates can be explained by heterogeneous N distribution among different generations of phyllosilicate minerals within single samples and/or significant N hosted in other minerals and sites (e.g., accessory phases or interstitial phases). Further investigation is required to distinguish between these possibilities, with implications for N speciation and stability during subduction zone metamorphism from the forearc to depths beneath arcs and beyond. • Rock and mineral N concentrations are from 8 to 172 μg/g and δ 15 N from −1.2 to +7.0‰. • Phyllosilicate minerals alone cannot account for whole-rock N-budget in most cases. • Nitrogen composition of the same phyllosilicate mineral may vary by generation and texture. • Nitrogen may reside in accessory phases, complicating N mobility during subduction. • Significant amounts of N could be subducted in such rocks to deep forearcs and beyond.

A wide range of magnetic field fluctuations in the solar wind have been comprehensively studied over decades, but none of those studies have observed chaotic fluctuations within the solar wind. We present here the observations of chaotic magnetic field fluctuations within the solar wind. In this study we quantify high resolution electron scale magnetic field fluctuations with information theoretic measures (Shannon entropy + Jensen-Shannon complexity). Jensen-Shannon complexity maps of time series data provide a mathematical tool that can characterize fluctuations as stochastic, chaotic, or periodic phenomena. We apply this recently developed tool to characterize the Parker Solar Probe high temporal resolution fluxgate magnetometer magnetic field fluctuations (292.9 samples/s or 3.413 ms per sample) at perihelion. We find that these fluctuations are either chaotic or chaotic with a strong noise component in one or more magnetic field components. Limited statistics of the perihelion periods indicate that at the more distant perihelia (∼0.17 AU) have chaotic fluctuations within just the normal component of the magnetic field and the closer perihelia (∼0.05 AU) display chaotic fluctuations within all three components of the magnetic field. Finally, we find that the chaotic fluctuations appear to be of high dimensionality. · We apply for the first time the Jensen-Shannon complexity technique to Parker Solar Probe fluxgate magnetometer data at perihelion. · High temporal resolution magnetic field fluctuations within 0.17 solar radii can be chaotic or chaotic with a strong noise component. · Chaotic fluctuations were generally observed for frequencies above about 10 Hz up to 293 Hz, above the proton gyrofrequency (1-10 Hz).

Abstract Micrometer-scale Fe (iron)-rich filaments are common in mafic pyroclasts, yet their origin remains debated. These filaments have been variably interpreted as sutured fractures in magma, the product of magma mingling, compositional boundary layers detached from plagioclase crystals, or oxide shells stripped from bubbles. Here, we compare new observations from several case studies with previous results, concluding that shared features point to a common origin of filaments in all eruptions. Key shared features of filaments are as follows: (1) Fe, Mg, and Ca enrichment; (2) variable degree of contortion, sharpness, and Fe oxide microlite content; (3) inclusion of small vesicles and microlite fragments; (4) transition into cracks and broken crystals; (5) connection to sharp concavities of vesicles and pyroclast edges; and (6) separation of regions within pyroclasts with distinct textures. Focused Ion Beam, micron-sized trenches cut perpendicular to the polished section, and X-ray computed microtomography images reveal that the two-dimensional filaments are complex three-dimensional surfaces resulting from magma suturing. These sutures form by fusing of molten, Fe-enriched surfaces, whether exposed crack surfaces within pyroclasts, the surfaces of colliding pyroclasts, or the surfaces of different portions of the same pyroclast folded over itself. During fusing, sutures entrap voids and crystal fragments present on the surfaces. After fusing, sutures evolve by diffusion, crystallization, and viscous deformation. Sutures witness the complex thermal and deformation history of pyroclasts during and after magma fragmentation and act as unique telltales of otherwise invisible processes that affect pyroclast final size, chemical composition, and vesicle and crystal size distributions.

Context . Roughly half of Sun-like stars have at least one stellar companion, whereas it is widely assumed that most known exoplanets orbit single stars, largely due to observational biases. However, astrometric surveys, direct imaging, and speckle interferometry are steadily increasing the number of confirmed exoplanets in binaries. A stellar companion introduces additional effects, such as circumstellar disk truncation and gravitational perturbations, which can strongly impact planet formation. While global planet formation models (e.g., Bern model) have been broadly applied to single stars, modeling S-type binaries requires key modifications to capture these effects. Aims . This study extends the Bern model by incorporating the gravitational influence of a stellar companion into its N -body integrator, allowing us to quantify how this perturbation affects planetary formation and final system architecture across a range of binary configurations. By comparing binary and single-star systems under identical initial conditions, we can assess the specific impact of binary-induced dynamics. Methods . We modified the Bern model’s N -body integrator to include secondary star perturbations and ran three sets of simulations: (i) a grid of in situ single-embryo cases to quantify gravitational effects; (ii) formation simulations with and without migration to compare outcomes with single-star analogs; and (iii) multi-embryo runs to evaluate impacts on multi-planetary systems. Results . Planets forming beyond half the host star’s Hill radius are much more likely to become unbound (i.e., in about six out of seven cases), especially in systems with high binary eccentricity. Even within stable zones, growth is suppressed by both reduced material availability (due to disk truncation) and increased eccentricity from stellar perturbations. Multi-embryo simulations have shown that these perturbations tend to reshape architectures even in dynamically stable regions. Conclusions . Both disk truncation and stellar perturbations must be included to model planet formation in S-type binaries accurately. Neglecting either one will end up misrepresenting planetary growth and survival. Finally, population synthesis studies will be key in making statistical comparisons with observed systems.

Abstract With microbes critical for ocean ecological and biogeochemical processes, we need to understand their abundance and diversity distributions. While traditional amplicon sequencing provides only relative abundance data, and the strongly preferred absolute abundances can be determined from samples spiked with internal standards, few oceanographic studies with absolute abundances exist. However, many have flow cytometry (FCM) data that should allow us to retrospectively “anchor” the relative abundances into absolute abundances. We tested this hypothesis with data from the 29th Atlantic Meridional Transect (AMT) cruise where we had FCM of Synechococcus and Prochlorococcus, amplicons corrected with internal standards, and absolute cell count estimates from single copy recA and radA metagenomics. Anchoring the AMT29 amplicon data with Synechococcus FCM (used because phycoerythrin in Synechococcus is reliably detected by FCM in surface waters) yielded results strongly correlated with amplicon data corrected with internal standards (Pearson’s r = 0.94, slope = 0.73), FCM (r = 0.80, slope = 0.43), and recA-based genome counts (Pearson’s r = 0.94, slope = 0.62). Seeing this method worked reasonably well, we then generated estimates of absolute rRNA gene abundances from the Global rRNA Universal Metabarcoding of Plankton (GRUMP) transects that had FCM data (Pacific ~65N to ~40S). These FCM-anchored gene copy estimates also showed strong correlations to FCM data (i.e., anchor with Synechococcus and predict Prochlorococcus), with r values ranging from 0.48–0.86. While the results are clearly only reasonable estimates, we believe the approach has the potential to significantly enhance the value of amplicon data which have accompanying FCM data.

Binary stars are as common as single stars. The number of detected planets orbiting binaries is rapidly increasing thanks to the synergy between transit surveys, Gaia, and high-resolution direct-imaging campaigns. However, global planet formation models around binary stars are still underdeveloped, which limits the theoretical understanding of planets orbiting binary star systems. We introduce the PAIRS project, which aims to build a global planet formation model for planets in binaries and to produce a planet population synthesis to statistically compare theory and observations. In this first paper, we present the adaptation of the circumstellar disc to simulate the formation of S-type planets. The presence of a secondary star tidally truncates and heats the outer part of the circumprimary disc (and vice versa for the circumsecondary disc), limiting the material to form planets. We implemented and quantified this effect for a range of binary parameters by adapting the Bern Model of planet formation in its pebble-based form and for in situ planet growth. We find that disc truncation has a strong impact on reducing the pebble supply for core growth and steadily suppresses planet formation for binary separations below 160 a when all the formed planets more massive than Mars are considered. Moreover, S-type planets tend to form close to the central star with respect to the binary separation and disc truncation radius. Our newly developed model will be the basis of future S-type planet population synthesis studies.