Gammaridean amphipods are a major component of macrobenthic communities, but information on their distribution and ecology in subtidal habitats of northern Japan is limited. We present the species composition and community structure of benthic amphipods in the subtidal bottoms (5–32 m deep) of Akkeshi Bay, eastern Hokkaido, Japan, and examine whether spatial variability of amphipod assemblage is related to local environmental gradients and biogeographic affinities of the component species. Amphipods were collected at nine sites in 2020 and identified to 40 species consisting of 21 families. Similarity analyses showed that the amphipod community differed among the three habitats: (1) marine soft-bottom substrate, (2) gravelly estuarine substrate, and (3) marine hard-bottom substrate. Distance-based redundancy analysis revealed that variation in the soft-bottom community was related to that of depth and sediment composition. The biogeographic affinities of 15 identified species were categorized as two groups, “Arctic and surroundings” and “Northwestern Pacific,” by similarity analysis with global occurrence records in marine ecoregions. Differences in species composition were related to the biogeographic affinities of the component species, with species grouped as Arctic and surroundings occurring at deeper sites than the Northwestern Pacific species. Changes in community structure along the depth gradient reflected variations in environmental factors, such as temperature, as well as differences in the suitable temperature ranges of the species as determined by their biogeographic history. This study highlights the importance of considering both environmental gradients and macroecological features of component species in interpreting variations in amphipod community structure on the local scale.

Microplastics are found in all oceanic environments and represent a growing concern for researchers and managers of marine environments. A systematic review was carried out to investigate the accumulation of microplastics (MPs) in filter feeders, focusing on the potential relationship between the feeding mechanism and MPs’ accumulation. The accumulation of microplastics was compared among marine benthic filter feeders that use different filtering mechanisms. Rayyan® software was employed to screen the articles, and data extraction was subsequently carried out. The review followed well-structured protocol PRISMA 2020 guidelines to guarantee methodological rigor and minimize biases. Due to the high heterogeneity (Higgins I2 test, I2 > 95%) of data methodologies, a narrative synthesis was used as the output of the review. Most publications report microplastics in mollusks (oysters, mussels, and clams), and bivalves were the group most studied (76.67%). Sponges (91 to 612 items g – 1 DW) and polychaetes (1 to 880 items g–1 WW) had the highest number of MPs. Although it is possible to establish relationships between feeding mechanisms and MPs accumulation, using distinct methodologies makes comparing the results of different studies difficult, leading to an urgent call for standardizing methods for microplastic studies in marine organisms.

Morphological examination of recently collected barnacle specimens confirms the presence of Tesseropora atlantica (Cirripedia, Balanomorpha, Tetraclitidae) along the coastlines of Lanzarote and Fuerteventura, the easternmost islands of the Canary Archipelago. This constitutes the first documented occurrence of T. atlantica in the Canary Islands and establishes a new southern range limit for this relict species in the eastern Atlantic Ocean. Additionally, 16S and COI mitochondrial gene sequences were obtained for the first time for this species, allowing comparisons with related taxa. The study also explores plausible hypotheses concerning the species’ arrival in the Canary Islands.

This study aims to determine the age and growth of Anguilla anguilla from Lake Bafa, Türkiye. A total of 128 samples of European eel were purchased from a small-scale fisherman who caught them in Lake Bafa in November 2016 and 2017, using 34-mm mesh size and 15-m-long fyke nets. The total length (TL) and total weight were measured, and the sex, age, and life stage were identified. The mean TL for females was 54.1 ± 10.1 (36.1–76.2) cm, and for males 43.6 ± 3.7 (35.7–47.8) cm. Yellow and silver eel mean TLs were 48.9 ± 6.6 (35.7–63.7) and 61.9 ± 10.8 (39.9–77.2) cm, respectively, and for pooled data 53.3 ± 10.3 (35.7–77.2) cm. The growth for pooled samples was positive allometric. The age of eels varied from 2 to 9 years. The Von Bertalanffy growth parameters for pooled specimens were determined as L∞ = 71.9 cm, K = 0.25, and t0 = −0.11. The sex ratio (M:F = 1:11.2) was biased in favour of females. It is inferred from this and other studies that eels in Türkiye have comparable length and age distributions in similar habitats.

Chalcedony forms across a wide area in eastern Iran, particularly in the Sarbisheh district near Birjand city, with notable occurrences in the Qazdez-Bahamarz region. Here, cryptocrystalline quartz is found in hydrothermal veins and veinlets within volcanic rocks hosted by carbonate and intermediate igneous formations. Chalcedony samples of various colours—black, purple, green, blue, lavender, grey, lemon yellow and white—were analysed using diverse techniques. These chalcedony samples display fibrous and granular textures, comprising microcrystalline quartz, cryptocrystalline moganite, and opal-CT and opal-C interlayers. Elements that affect the colouration of chalcedony include iron (producing red and yellow tones), chromium (green), manganese (black, blue and grey patterns), nickel (purple) and copper (also purple). Altered carbonate host rocks are enriched in Fe, Cu, Zn and Cd, with Al and Mn depletion. Stable isotope analyses show δ18O values in agates range from +14.9‰ to +25.5‰, whereas δ18O and δ13C values in carbonate minerals and chalcedony range from +14.1‰ to +24.8‰ and –5.7‰ to +0.7‰, indicating agate formation from mantle-derived hydrothermal fluids mixed with meteoric waters. Raman spectroscopy detected moganite, α-quartz, goethite, aragonite and illite in agate interlayers. Analyses by field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) revealed minerals of Fe, Cr, Ni, Ti and Sn. X-ray diffraction confirmed chalcedony, moganite and opal-CT, whereas EPR spectroscopy showed strong magnetic backgrounds from goethite and silicon-vacancy centres formed by radioactive decay of U, Th and their byproducts.

Ranunculite is a rare supergene hydrated aluminium uranyl phosphate reliably reported only from the type locality – the Kobokobo pegmatite in the Sud-Kivu province, Democratic Republic of Congo; its structure has remained unknown until now. Based on 3D electron diffraction data, ranunculite is monoclinic, with a C-centred unit cell: a = 11.1812(7) Å, b = 17.9281(5) Å, c = 17.91548(16) Å, β = 98.350(4)°, and V = 3553.2(2) Å3 (Z = 4). The structure (C2/c) was refined kinematically to R1 = 0.4114 for 1697 unique observed reflections. The structure of ranunculite is based upon infinite uranyl-phosphate sheets of novel topology. The two-dimensional representation of the structural unit consists of hexagons (occupied by U6+), pentagons (occupied by U6+), squares (occupied by Al3+) and triangles (occupied by P5+). Those sheets are stacked perpendicular to c; the interplanar distance is ~9.5 Å. They result from the clusters of edge-sharing uranyl hexagonal and pentagonal bipyramids linked by Al-octahedra and PO4 tetrahedra. The decoration of the sheets is unique but somewhat resembles the arrangement (of U-clusters, squares and triangles) observed in bijvoetite and lepersonnite topologies; the ring symbol is 61514232. In the interlayer, there are two Al3+-hosting sites (one [6]- and [5]-coordinated; the pyramidal one is only partially occupied), as well as isolated H2O groups. There is an extensive network of hydrogen bonds; adjacent sheets are either held by hydrogen bonds only or by tetramers of Al-polyhedra when occupied (through shared O19). This arrangement most probably causes a poor crystallinity of ranunculite (which gives rise to stacking faults observed in the powder diffraction data).

Carbonatites are complex rocks yet globally significant hosts of critical mineral resources. Mitigating exploration risk demands robust understanding of their geodynamic setting, which hinges on constraining the timing, duration and nature of associated magmatic and fluid–rock processes. We present multi-method geochronology and isotope geochemistry for the recently discovered Luni and Crean mineralized (Nb, REE, P) carbonatites of the Aileron Province, central Australia. We integrate data from multiple mineral-isotope-pairs: U–Pb and Lu–Hf in zircon, Rb–Sr in biotite and Sr, Lu–Hf, Sm–Nd and (U–Th)/He in apatite. Combined petrological and isotopic evidence resolves distinct geological events over >500 Myr. Zircon U–Pb and biotite Rb–Sr dates range from 831 ± 3 Ma to 796 ± 9 Ma. The oldest dates from less altered minerals reflect primary crystallization, and younger dates relate to pervasive hydrothermal alteration. Radiogenic isotopes (Sr–Nd–Hf) imply a moderately depleted mantle source with negligible recycled sedimentary components in the primary carbonatite magma. Our findings correlate carbonatite magmatism in the Aileron Province at ∼830–820 Ma with the onset of Rodinia Supercontinent breakup, during widespread rift-related extension and mantle-derived magmatism across Australia. Post-emplacement, Lu–Hf apatite dates from 722 ± 17 Ma to 653 ± 22 Ma suggest protracted alteration, whereas apatite (U–Th)/He data indicate exhumation at ∼250 Ma. Carbonatite emplacement probably exploited pre-existing transcrustal corridors during Tonian extension. These zones of structural weakness likely facilitated ascent of volatile-rich, mantle-derived melts to mid–shallow crustal depths, highlighting how regional geodynamics govern the localization and preservation of mineralized carbonatites.

The Đurđevac Sands constitute a wide area of small-scale dune relief in the Podravina (NE Croatia), located along the central part of the southern Drava River valley. Even though it has been the subject of earlier investigations, the timing and characteristics of aeolian activity and pedogenesis remain unclear. In this study, field investigations and laboratory methods are combined to gather information on past aeolian systems in the southern part of the Pannonian Basin. The results indicate that weak soil formation during the Bølling-Allerød interstadial stabilized the dunes after the first episode of aeolian activity that took place since ca. 18 ka. The source material for dune building is thought to be fluvial sand from the Drava River, which was blown from exposed terraces. During the Younger Dryas and/or Early Holocene, a new phase of aeolian activity is recorded, with material showing stronger evidence of weathering compared to the underlying aeolian material. Finally, during the Mid and/or Late Holocene, dunes were overbuilt once again with fresh unweathered sand. In general, these new findings obtained from the Đurđevac Sands area correlate rather well with other regions in the Pannonian Basin, in terms of the timing and characteristics of soil formation and aeolian activity.

The petrographic and geochemical characterisation of the diagenetic calcite and dolomite associated with carbonate-hosted ore deposits can contribute to a better understanding of mineralisation mechanisms. The lower Carnian Breno Formation and Calcare Metallifero Bergamasco in the Dossena area (Gorno mining district, Lombardy Basin, Southern Alps) are two shallow marine carbonate lithostratigraphic units hosting Alpine-type Pb-Zn-F-Ba ores. Several interpretations have been proposed for the genesis of mineralisation in these Triassic carbonates: syngenetic from submarine exhalations linked to the Ladinian–Carnian volcanism; or Alpine-type syngenetic to epigenetic in burial settings by hydrothermal fluids, during Early–Middle Jurassic rifting. Recent studies propose that ores formed in shallow burial settings (tens to few hundreds of metres), precipitated from hydrothermal fluids related to Triassic magmatism, prior to the Early Jurassic rifting.

Petrographic analysis, δ18O data, REEYN normalised patterns, calculated element ratios and lanthanum, cerium and europium normalised anomalies suggest precipitation of the saddle dolomite and calcite cements, filling-fractures preceding and post-dating the mineralisation, from low temperature (<200°C) hydrothermal fluids. The geochemistry of these fluids was influenced by seawater and burial basinal brines. REEYN patterns and Y/Ho ratios suggest the interaction of these fluids with Permian and Ladinian–Carnian siliciclastic and volcaniclastic deposits and/or with the Variscan metamorphic basement, which are possible sources for metals.

The identified paragenesis supports a hydrothermal epigenetic origin for the mineralisation, at burial depths not shallower than 300 m. In fact, pre-mineralisation fractures filled by saddle dolomite and calcite cements cross-cut voids occluded by burial sparite cements and stylolites in an already lithified host rock, affected by burial compaction and pressure solution.

These conclusions may contribute to the understanding of other global occurrences of carbonate-hosted Pb-Zn mineralisation, providing new insights into complex dolomite and calcite paragenesis preceding and following the ore formation.

As international exploration of the Meso-Neoproterozoic continues, these layers have become a key target for deep oil and gas field exploration. The Ordos Basin exhibits considerable sedimentary thicknesses within the Meso-Neoproterozoic. However, significant hydrocarbon discoveries have not been forthcoming, primarily due to the complex tectonic evolution. This paper focuses on the southern Ordos Basin, utilizing logging-seismic calibration to interpret seismic data and elucidate Meso-Neoproterozoic tectonic features. By comparing ancient and modern tectonic patterns, based on palaeotectonic maps retrieved through the impression method and combining these with tectonic evolution profiles, the study clarifies the history of tectonic modification. Under the control of two fracture systems – basin-controlling fractures at the margin and trough-controlling fractures – the Changchengian exhibits two categories (single-fault and double-fault) and five sub-categories of fault depression combinations. The study highlights significant differences between ancient and modern tectonics in the Meso-Neoproterozoic, which are attributed to various tectonic stages, including the trough-uplift depositional differentiation stage during the early rift-late depression of the Changchengian, the basin-margin subsidence stage of the southwestern depression of the Jixianian, the uplift and denudation stage of the Sinian basin’s main body and the four-stage tectonic remodelling stage of differential uplift-subsidence in the Palaeoproterozoic. This study employs the ancient-present tectonic pattern as a point of departure, thereby enhancing the theoretical understanding of deep-seated tectonics in the Ordos Basin. It offers novel insights into the exploration of Meso-Neoproterozoic gas reservoirs from a tectonic remodelling perspective.