• 100 years of deep-sea tubeworms in the collections of the Natural History Museum, London

      Sherlock, E; Neal, L; Glover, AG (2014-12-18)
      Despite having being discovered relatively recently, the Siboglinidae family of poly- chaetes have a controversial taxonomic history. They are predominantly deep sea tube- dwelling worms, often referred to simply as ‘tubeworms’ that include the magnificent me- tre-long Riftia pachyptila from hydrothermal vents, the recently discovered ‘bone-eating’ Osedax and a diverse range of other thin, tube-dwelling species. For a long time they were considered to be in a completely separate Phylum, the Pogonophora, but with the discovery of a segmented posterior and then conclusive DNA evidence, they were re- stored to the Phylum Annelida. In this project curation and research teams have com- bined to enhance the Museum’s collection. This has been facilitated through targeted donation requests, comprehensive digitisation, a location move to the rightful taxonomic place and teaming up with global database initiatives to promote the collection.
    • Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Cnidaria

      Dahlgren, T; Wiklund, H; Rabone, M; Amon, D; Ikebe, C; Watling, L; Smith, C; Glover, AG (2016-06-30)
    • Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca

      Wiklund, H; Taylor, JD; Dahlgren, TG; Todt, C; Ikebe, C; Rabone, M; Glover, AG (2017-10-10)
    • Accumulation and Dissolution of Magnetite Crystals in a Magnetically Responsive Ciliate

      Monteil, CL; Menguy, N; Prévéral, S; Warren, A; Pignol, D; Lefèvre, CT; Kelly, RM (American Society of Microbiology, 2018-02-09)
      Magnetotactic bacteria (MTB) represent a group of microorganisms that are widespread in aquatic habitats and thrive at the oxic-anoxic interfaces. They are able to scavenge high concentrations of iron thanks to the biomineralization of magnetic crystals in their unique organelle, the so-called magnetosome chain. Although their biodiversity has been intensively studied in recent years, their ecology and impact on iron cycling remain largely unexplored. Predation by protozoa was suggested as one of the ecological processes that could be involved in the release of iron back into the ecosystem. Magnetic protozoa have previously been observed in aquatic environments, but their diversity and the fate of particulate iron during grazing are poorly documented. In this study, we report the morphological and molecular characterization of a magnetically responsive MTB-grazing protozoan able to ingest high quantities of MTB. This protozoan is tentatively identified as Uronema marinum, a ciliate known to be a bacteria predator. Using light and electron microscopy, we investigate in detail the vacuoles in which lysis of phagocytized prokaryotes occurs. We carried out high-resolution observations of aligned magnetosome chains and ongoing dissolution of crystals. Particulate iron in the ciliate represented about 0.01% of its total volume. We show the ubiquity of this interaction in other types of environments and describe different grazing strategies. These data contribute to the mounting evidence that interaction between MTB-protozoan might play a significant role in iron turnover in microaerophilic habitats. IMPORTANCE Identifying participants of each biogeochemical cycle is a prerequisite to our understanding of ecosystems functioning. Magnetotactic bacteria (MTB) participate to iron cycling by concentrating large amounts of biomineralized iron minerals into their cells, which impacts their chemical environment at or below the oxic-anoxic transition zone in aquatic habitats. It was shown that some protozoa inhabiting this niche could become magnetic with the ingestion of magnetic crystals biomineralized by grazed MTB. In this study, we show that magnetic MTB-grazers are commonly observed in marine and freshwater sediments and can sometimes accumulate very large amounts of particulate iron. Using magnetic particles from MTB as tracers after their ingestion by the protozoa, different phagocytosis strategies are described. This study paves the way for potential scientific or medical applications using MTB-grazers as magnetosome-hyperaccumulators.
    • The air-abrasive technique: A re-evaluation of its use in fossil preparation

      Graham, M; Allington-Jones, L (Society of Vertebrate Paleontology, 2018-08)
      This paper outlines the history of air-abrasion (also known as airbrasion) as a paleontological preparation technique and evaluates various powders and their properties. It explores the rationale behind the selection of abrasive powders and presents, for the first time, trench-scatter experiments through Scanning Electron Microscope (SEM) photography and three-dimensional (3-D) profiling. This article also offers general practical advice and details the results of an international survey of practising fossil preparators.
    • The air-abrasive technique: a re-evaluation of its use in fossil preparation.

      Graham, M; Allington-Jones, L
      This paper outlines the history of air-abrasion (also known as airbrasion) as a palaeontological preparation technique and evaluates various powders and their properties. It explores the rationale behind the selection of abrasive powders and presents, for the first time, trench-scatter experiments through Scanning Electron Microscope (SEM) photography and three-dimensional (3-D) profiling. This article also offers general practical advice and details the results of an international survey of practising fossil preparators
    • Alkali-rich replacement zones in evolved NYF pegmatites: metasomatic fluids or immiscible melts?

      Muller, A; Spratt, J; Thomas, R; Williamson, BJ; Seltmann, R (International Mineralogical Association, 2018-08-13)
      IMA2018 Abstract submission Pegmatite mineralogy, geochemistry, classification and origins IMA2018-1337 Alkali-rich replacement zones in evolved NYF pegmatites: metasomatic fluids or immiscible melts? Axel Muller* 1, John Spratt2, Rainer Thomas3, Ben J. Williamson4, Reimar Seltmann2 1Natural History Museum, University of Oslo, Oslo, Norway, 2Department of Earth Sciences, Natural History Museum, London, United Kingdom, 3Chemistry and Physics of Earth Materials, German Research Centre for Geoscience GFZ, Potsdam, Germany, 4Camborne School of Mines, University of Exeter, Penryn, United Kingdom What is your preferred presentation method?: Oral or poster presentation : Replacement zones (RZ), which are a common feature of evolved granitic pegmatites, are irregular, commonly alkali-rich zones superimposing, cross-cutting and replacing the primary zonation in almost all consolidated pegmatite bodies. RZ are widely considered to result from late-stage metasomatism even though little is known about the melts and/or fluids involved in their formation. However, the observed textures and mineral paragenesis of RZ cannot be explained by metasomatism in a strict sense. In this study, the nature of the late stage silicate melt forming “cleavelandite” RZ is assessed from textural, mineralogical, chemical and melt inclusion studies of evolved, Proterozoic Niobium-Yttrium-Fluorine (NYF) rare metal pegmatites from Evje–Iveland, southern Norway. These were studied as they are mineralogically simple, compared with RZ in evolved Lithium-Caesium-Tantalum (LCT) pegmatites. Silicate melt inclusions in RZ-forming topaz and “cleavelandite” document high H2O contents of up to18 wt.% of the F-rich silicate melt from which the RZ crystallized. In addition, from mineral compositions (“cleavelandite”, “amazonite”, white mica, garnet, columbite group minerals, topaz, fluorite, and beryl), they must have also been strongly alkaline (Na-dominated) with enrichments in F (at least 4 wt.%), Cs, Rb, Ta, Nb, Mn, Ge, Bi, As, and in some cases also Li compared with host pegmatites. These elements are concentrated in a few RZ-forming minerals resulting in very distinctive mineral-trace element signatures. “Amazonite” is strongly enriched in Cs and Rb and often white mica and beryl in Li and Cs. To acquire these mineral compositions, the overall Li-Cs-Ta-poor Evje-Iveland original pegmatite melt must have undergone extreme internal chemical differentiation resulting in melt/melt immiscibility aiding rheology contrasts and resulting in RZ formation. The resulting RZ-forming H2O-F-rich silicate melt would have shown large differences in viscosity and density, and therefore physical flow/transport properties, to the host pegmatite melt resulting in discordant contacts. The mineralogy and melt inclusion data from the Evje-Iveland pegmatites document a gradient of crystallization temperatures within the investigated pegmatite bodies with highest temperatures at the pegmatite margin (during initial emplacement, ~680°C) and lowest temperatures within the RZ (<500°C). Considering the temperature and pressure conditions of the host rocks gneisses and amphibolites (~650°C, up to 5 kbar) at the time of pegmatite emplacement and the crystallization conditions of the RZ, the Evje- Iveland pegmatites and RZ likely formed over a period of 2.2 million years, assuming an exhumation rate of 1.5 mm per million years and a geothermal gradient of 45°C km-1. Such a long crystallization time contradicts the classical view that pegmatites represent strongly undercooled melts which crystallize relatively fast.
    • All Our Eggs In One Basket: Challenges of High Resolution X-Ray Micro-Computed Tomography of Great Auk Pinguinus impennis Eggshell

      Russell, D; Bernucci, A; Scott-Murray, A; Jackson, D; Ahmed, F; Garbout, A; Birkhead, T (2018-06-13)
    • The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)

      Gao, F; Zhang, Q; Gong, J; Miao, M; Sun, P; Xu, D; Huang, J; Yi, Z; Song, W; Warren, A (2016-07)
    • The alteration history of the Jbilet Winselwan CM carbonaceous chondrite: An analog for C-type asteroid sample return

      King, A; Russell, S; Schofield, P; Humphreys-Williams, E; Strekopytov, S (Wiley, 2018-12-13)
      Jbilet Winselwan is one of the largest CM carbonaceous chondrites available for study. Its light, major, and trace elemental compositions are within the range of other CM chondrites. Chondrules are surrounded by dusty rims and set within a matrix of phyllosilicates, oxides, and sulfides. Calcium‐ and aluminum‐rich inclusions (CAIs) are present at ≤1 vol% and at least one contains melilite. Jbilet Winselwan is a breccia containing diverse lithologies that experienced varying degrees of aqueous alteration. In most lithologies, the chondrules and CAIs are partially altered and the metal abundance is low (<1 vol%), consistent with petrologic subtypes 2.7–2.4 on the Rubin et al. (2007) scale. However, chondrules and CAIs in some lithologies are completely altered suggesting more extensive hydration to petrologic subtypes ≤2.3. Following hydration, some lithologies suffered thermal metamorphism at 400–500 °C. Bulk X‐ray diffraction shows that Jbilet Winselwan consists of a highly disordered and/or very fine‐grained phase (73 vol%), which we infer was originally phyllosilicates prior to dehydration during a thermal metamorphic event(s). Some aliquots of Jbilet Winselwan also show significant depletions in volatile elements such as He and Cd. The heating was probably short‐lived and caused by impacts. Jbilet Winselwan samples a mixture of hydrated and dehydrated materials from a primitive water‐rich asteroid. It may therefore be a good analog for the types of materials that will be encountered by the Hayabusa‐2 and OSIRIS‐REx asteroid sample‐return missions.
    • Amazon plant diversity revealed by a taxonomically verified species list

      Cardoso, D; Särkinen, T; Alexander, S; Amorim, AM; Bittrich, V; Celis, M; Daly, DC; Fiaschi, P; Funk, VA; Giacomin, LL; et al. (2017-10-03)
    • The Anatomy of an Alkalic Porphyry Cu-­‐Au System: Geology and Alteration at Northparkes Mines, NSW, Australia

      Pacey, A; Wilkinson, JJ; Owens, J; Priest, D; Cooke, DR; Millar, IL (Society of Economic Geologists, 2019-05-01)
      The Late Ordovician-Early Silurian (~455-435 Ma) Northparkes system is a group of silica-saturated, alkalic porphyry deposits and prospects which developed within the Macquarie Island Arc. The system is host to a spectacular and diverse range of rocks and alteration-mineralization textures that facilitate a detailed understanding of its evolution, in particular into the nature and controls of porphyry-related propylitic alteration. The first intrusive phase at Northparkes is a pre- to early-mineralization pluton that underlies all the deposits and varies in composition from a biotite quartz monzonite (BQM) to alkali feldspar granite (AFG). Prior to total crystallization, this pluton was intruded by a more primitive quartz monzonite (QMZ) that marks the onset of a fertile fractionation series. Towards its upper levels, the QMZ is porphyritic and locally rich in Cu sulfides. Subsequently, a complex series of syn-mineralization quartz monzonite porphyries (QMP) were emplaced. The QMP intrusions have a distinct pipe-like morphology and are ubiquitously K-feldspar altered with a crystal-crowded porphyritic texture. The textures of the QMPs and common occurrence of porphyry-cemented contact breccias indicate they were forcibly emplaced and of relatively low viscosity. The QMPs are therefore interpreted as crystal-bearing, silicate melt-aqueous fluid slurries that represent the conduits through which deep-seated magmatic-derived ore fluid was discharged into the shallow crust (1-2 km depth). Each deposit is centred on a multiphase cluster of QMP intrusions that drove discrete hydrothermal systems. Initial fluid evolution was similar in all the deposits, with three major alteration facies developed as largely concentric zones around the QMP complexes. The innermost zone is host to Cu sulfide ore and dominated by K-feldspar alteration. This transitions outwards through a shell of magnetite ± biotite alteration, with pyrite and minor chalcopyrite, to an outer halo of propylitic alteration. Generally, epidote, chlorite and pyrite are abundant in the most deposit-proximal propylitic zone, with a decrease in the abundance of pyrite, and then epidote, with increasing distance away from deposit centers. Propylitic alteration, particularly within relatively low permeability rocks, is fracture-controlled and a hierarchy of veins is observed. Veins of chlorite-quartz-pyrite ± calcite ± hematite ± epidote ± chalcopyrite (P1) appear to represent the principal fluid conduits. They are surrounded by pervasive and intense alteration halos with a distinct mineralogical zonation from vein-proximal chlorite-sericite (phengite) ± epidote ± pyrite, through hematite-sericite-chlorite ± epidote, ultimately to a vein-distal hematite-albite ± chlorite ± epidote assemblage. These P1 veins are surrounded by regions in which smaller epidote-chlorite ± calcite ± quartz ± pyrite veins (P2) are abundant, again with zoned alteration envelopes: vein-proximal chlorite-sericite (phengite) ± epidote ± pyrite grades out into an epidote-rich zone, which in turn transitions into vein-distal albite-hematite ± chlorite ± epidote. Areas of weakest propylitic alteration, distant from both P1 and P2 veins, are characterised by small epidote-only veinlets (P3) with albite-hematite halos. Mineralogical transitions across the propylitic zone are therefore repeated in the evolution from P1 to P3 veins, as well as in the halos around these veins. It is the overall vein abundance and overlap of associated alteration halos which controls the intensity and appearance of propylitic alteration in most rocks. Such scale-invariance and spatial relationships strongly suggests the transition from P1 to P3 veins reflects a broadly decreasing outward flux of (magmatic-derived?) fluid that passed through the fracture network and progressively reacted with country rocks. Further support for this hypothesis comes from cross cutting relationships and Rb-Sr dating of epidote (returning an age of 450 ± 11 Ma), which demonstrate the bulk of propylitic alteration was coeval with mineralization and potassic alteration. Late-stage fluid evolution at each deposit was unique. Much of the E48 orebody and locally the GRP314 deposit was overprinted by texturally-destructive, white sericite-albite-quartz-alunite ± chlorite alteration. In the E26 deposit, and in regions of the GRP314 deposit, a series of quartz-anhydrite ± pyrite ± Cu sulfide veins with distinctive, vein-proximal, sericite-dominant alteration halos cut the primary, deposit-concentric alteration facies. The vein-distal mineralogy of these alteration halos is controlled by their distance from deposit centers, changing from K-feldspar ± biotite in deposit-proximal veins to chlorite ± epidote-albite in deposit-distal veins. Late-mineralization QMPs at E26 and GRP314 also appear to be related to the generation of anhydrite-quartz ± sphalerite veins and a set of quartz-calcite-pyrite-sphalerite ± chalcopyrite ± galena veins. Post-mineralization magmatic activity produced relatively primitive and barren monzonite porphyries and younger alkali basalt dikes.
    • Anatomy of Rhinochelys pulchriceps (Protostegidae) and marine adaptation during the early evolution of chelonioids

      Evers, SW; Benson, RBJ; Barrett, PM (PeerJ Inc., 2019-05-01)
      Knowledge of the early evolution of sea turtles (Chelonioidea) has been limited by conflicting phylogenetic hypotheses resulting from sparse taxon sampling and a superficial understanding of the morphology of key taxa. This limits our understanding of evolutionary adaptation to marine life in turtles, and in amniotes more broadly. One problematic group are the protostegids, Early–Late Cretaceous marine turtles that have been hypothesised to be either stem-cryptodires, stem-chelonioids, or crown-chelonioids. Different phylogenetic hypotheses for protostegids suggest different answers to key questions, including (1) the number of transitions to marine life in turtles, (2) the age of the chelonioid crown-group, and (3) patterns of skeletal evolution during marine adaptation. We present a detailed anatomical study of one of the earliest protostegids, Rhinochelys pulchriceps from the early Late Cretaceous of Europe, using high-resolution mCT. We synonymise all previously named European species and document the variation seen among them. A phylogeny of turtles with increased chelonioid taxon sampling and revised postcranial characters is provided, recovering protostegids as stem-chelonioids. Our results imply a mid Early Cretaceous origin of total-group chelonioids and an early Late Cretaceous age for crown-chelonioids, which may inform molecular clock analyses in future. Specialisations of the chelonioid flipper evolved in a stepwise-fashion, with innovations clustered into pulses at the origin of total-group chelonioids, and subsequently among dermochelyids, crown-cheloniids, and gigantic protostegids from the Late Cretaceous.
    • Ancestral origins and invasion pathways in a globally invasive bird correlate with climate and influences from bird trade

      Jackson, H; Strubbe, D; Tollington, S; Prys-Jones, R; Matthysen, E; Groombridge, JJ (2015-08)
    • Ancient hydrothermal seafloor deposits in Eridania basin on Mars

      Michalski, JR; Dobrea, EZN; Niles, PB; Cuadros, J (2017-07-10)