The first ichthyosaurian specimens discovered from the Upper Triassic of the Russian Arctic (Kotelny Island, New Siberian Islands) are described herein. They include the remains of large- to small-bodied ichthyosaurians originating from six stratigraphic levels spanning the lower Carnian to middle Norian. The material is mostly represented by isolated vertebrae and ribs, which are not possible to accurately diagnose, but also includes specimens comprising associated vertebrae and a fragmentary skeleton that preserves cranial remains (parabasisphenoid, fragmentary quadrate, partial mandible and hyoids). Based on vertebral and rib morphology, we identify the specimens as representatives of the following taxonomic groups: large-bodied shastasaurids, medium-sized indeterminate ichthyosaurians with a single rib facet in the presacral centra, and small euichthyosaurians with double rib facets present throughout the presacral vertebrae that likely represent toretocnemids and/or basal parvipelvians. In addition, the cranial and mandibular remains preserved in one of the specimens, ZIN PH 5/250, were studied using micro-computed tomography. Its mandible is highly similar to that of toretocnemids, whereas the parabasisphenoid demonstrates a peculiar combination of both plesiomorphic and derived character states, providing the first detailed data on this cranial element in a Late Triassic ichthyosaurian. Furthermore, the specimen also demonstrates a distinctive condition of rib articulation in the anteriormost presacral (cervical) vertebrae, which together with other features allows for the erection of a new taxon – Auroroborealia incognita gen. et sp. nov. Although the phylogenetic position of this taxon is uncertain due to its fragmentary nature, its anatomy, indicating toretocnemid or parvipelvian affinities, further supports the previously hypothesised sister-group relationships between these two clades. The morphology of the parabasisphenoid and vertebral column of the new taxon is discussed in broader contexts of the patterns of evolution of these skeletal regions in ichthyosaurs.

This study presents an appraisal of the Middle Eocene–Quaternary Dugong Supersequence of the Eucla Basin, offshore southern Australia. It combines details of the rock record with seismic-stratigraphical information, and the resulting stratigraphic framework provides constraints on the nature of the late post-breakup development of the southern Australian continental margin. It is well established that the onshore-to-mid-shelf succession comprises a predominantly aggrading-to-prograding unconformity-bounded succession of carbonate platform deposits; however, our analysis of the outer shelf–upper slope section challenges the widely held view that this shelf-margin wedge represents a distally steepened prograding carbonate ramp primarily modulated by global eustasy. Instead, our results show that the Middle Eocene–Quaternary succession is punctuated by a series of unconformities that reflect a persistent tectonic instability and differential vertical movements throughout the late post-breakup period, the genesis of which is most closely related to tectonic events. Moreover, the upper slope clinoform succession was constructed and shaped predominantly by alongslope processes, and four different contourite drift types are recognised based on their seismic-stratigraphic expression: elongate mounded drift (Quaternary); infill drift (Pliocene); plastered drift (Oligocene); and separated drift (Middle–Upper Eocene). The Quaternary drift – herein termed the ‘Eyre Terrace Drift’ – is a spectacular basin-scale deposit, over 500 m thick and traced for up to 200 km along the upper slope Eyre Terrace. Upslope-migrating sediment waves are associated with this drift. Key sedimentary attributes consistent with a contourite origin include fine-grained sediment, multi-scale gradational bed contacts and pervasive bioturbation. There is also evidence of episodic downslope mass-movement processes ranging from the large-scale Late Neogene Slide, which extends downslope for 15–20 km, to sporadic slumped beds and turbidites recovered in boreholes. The interaction of alongslope and downslope processes indicates a more dynamic sedimentary setting than previously assumed along the outer margin of the Eucla Basin.

The development of non-toxic and inexpensive materials for arsenic removal is required due to water sources being polluted by arsenic in many countries around the world. The main aim of this study was to characterise the capacity and behaviour of Mg/Fe layered double hydroxides/biochar [Magnesium/Iron-Layered Double Hydroxide (Mg/Fe-LDH)] composite for arsenate adsorption from solution. Apple tree pruning residues were used to produce biochar at 500 °C under oxygen-limited atmosphere. Mg/Fe-LDH-biochar was synthesised using a spontaneous in situ co-precipitation method. Batch experiments were used for the assessment of the kinetics, isotherms, and the effects of initial solution pH (4, 6, 8, and 10), ionic strength (0.01, 0.1, and 0.2 mol L−1), and co-occurring anions (carbonate and phosphate) on the arsenate removal. Scanning electron microscope images showed Mg/Fe-LDH were loaded on the biochar porous structure, and X-ray diffraction analysis affirmed the presence of crystalline LDH minerals in Mg/Fe-LDH-biochar. Surface modification of biochar by Mg/Fe-LDH increased the maximum arsenate adsorption capacity (3.6 mg g−1) ten times compared to unmodified biochar (0.35 mg g−1). Arsenate removal capacity increased from 4.2 % to 54.2 % with modification of biochar by Mg/Fe-based LDH. Kinetic studies indicated that >90 % of Mg/Fe-LDH-biochar arsenate adsorption from a starting concentration of 10 mg L−1 occurred in the first 120 min. Pseudo-second order and Langmuir models described well the kinetics and isotherm of arsenate adsorption by biochar and Mg/Fe-LDH-biochar. Mg/Fe-LDH-biochar showed maximum arsenate removal capacity at pH 6. Increasing solution ionic strength and the presence of phosphate and carbonate anions suppressed arsenate removal by Mg/Fe-LDH-biochar. In summary, surface modification of biochar using Mg/Fe-LDH produced a potentially more cost-effective, locally available, reusable, and non-toxic arsenic adsorbent for decontamination of surface- and groundwater.