Now showing items 1-20 of 457

    • Assessing Thallium Elemental Systematics and Isotope Ratio Variations in Porphyry Ore Systems: A Case Study of the Bingham Canyon District

      Fitzpayne, A; Prytulak, J; Wilkinson, JJ; Cooke, DR; Baker, MJ; Wilkinson, CC (MDPI AG, 2018-11-26)
      The Bingham Canyon porphyry deposit is one of the world’s largest Cu-Mo-Au resources. Elevated concentrations of thallium (Tl) compared to average continental crust have been found in some brecciated and igneous samples in this area, which likely result from mobilization of Tl by relatively low temperature hydrothermal fluids. The Tl-enrichment at Bingham Canyon therefore provides an opportunity to investigate if Tl isotope ratios reflect hydrothermal enrichment and whether there are systematic Tl isotope fractionations that could provide an exploration tool. We present a reconnaissance study of nineteen samples spanning a range of lithologies from the Bingham district which were analysed for their Tl content and Tl isotope ratios, reported as parts per ten thousand (ε205Tl) relative to the NIST SRM997 international standard. The range of ε205Tl reported in this study (−16.4 to +7.2) is the largest observed in a hydrothermal ore deposit to date. Unbrecciated samples collected relatively proximal to the Bingham Canyon porphyry system have ε205Tl of −4.2 to +0.9, similar to observations in a previous study of porphyry deposits. This relatively narrow range suggests that high-temperature (>300 °C) hydrothermal alteration does not result in significant Tl isotope fractionation. However, two samples ~3–4 km away from Bingham Canyon have higher ε205Tl values (+1.3 and +7.2), and samples from more distal (~7 km) disseminated gold deposits at Melco and Barneys Canyon display an even wider range in ε205Tl (−16.4 to +6.0). The observation of large positive and negative excursions in ε205Tl relative to the mantle value (ε205Tl = −2.0 ± 1.0) contrasts with previous investigations of hydrothermal systems. Samples displaying the most extreme positive and negative ε205Tl values also contain elevated concentrations of Tl-Sb-As. Furthermore, with the exception of one sample, all of the Tl isotopic anomalies occur in hydrothermal breccia samples. This suggests that ε205Tl excursions are most extreme during the migration of low-temperature hydrothermal fluids potentially related to sediment-hosted gold mineralization. Future investigation to determine the host phase(s) for Tl in breccias displaying both chalcophile element enrichment and ε205Tl excursions can potentially provide new information about hydrothermal fluid composition and could be used to locate sites for future porphyry exploration.
    • The barnacle Amphibalanus improvisus (Darwin, 1854), and the mitten crab Eriocheir: one invasive species getting off on another!

      Naser, M; Rainbow, P; Clark, P; Yasser, A; Jones, D (Regional Euro-Asian Biological Invasions Centre, 2015-06-16)
    • Hemigrapsus takanoi Asakura and Watanabe, 2005 (Crustacea: Decapoda: Brachyura: Grapsoidea): first records of the brush-clawed shore crab from Great Britain

      Wood, C; Bishop, J; Davies, C; Delduca, E; Hatton, J; Herbert, R; Clark, P (Regional Euro-Asian Biological Invasions Centre, 2015-02-21)
      The brush-clawed shore crab is reported from the River Medway, Kent and the River Colne, Essex, England. These represent the first records of Hemigrapsus takanoi Asakura and Watanabe, 2005 from Great Britain. If H. takanoi becomes established in GB, it may pose a threat to populations of the native shore crab Carcinus maenas.
    • New species of Apostolepis (Serpentes, Dipsadinae, Elapomorphini) from Bolivia, from the Apostolepis borellii group

      Campbell, P; Lema, T (Research & Reviews, 2017-02-28)
      Description of a new species of Apostolepis based on three specimens labelled A. borellii from Bolivia in The Museum of Natural History of London. The new species belongs to the borellii Group which is at present only represented by the species A. borellii. This new species differs from A borelii by the following characters: (a) snout with median stripe (vs. immaculate); (b) supralabial blotch long (vs. short); (c) stripes evident on brown background (vs. having a blackish brown background with almost indistinct stripes) (d) ratio subcaudal by ventral scales low (vs. high) (e) lower sides cream (vs. darkish and dotted). The species area is Mato Grosso Plateau neighbouring the highlands of Bolivia in Cerrado Domain. The species is similar to A. striata and A. serrana from which it differs mainly by having nucho-cervical collars which is absent in the latter species. These species are placed in a specialized group (borellii group) while the phillipsae group is represented by A. phillipsae.
    • UniEuk : Time to Speak a Common Language in Protistology!

      Berney, C; Ciuprina, A; Bender, S; Brodie, J; Edgcomb, V; Kim, E; Rajan, J; Parfrey, LW; Adl, S; Audic, S; Bass, D; Caron, DA; Cochrane, G; Czech, L; Dunthorn, M; Geisen, S; Glöckner, FO; Mahé, F; Quast, C; Kaye, JZ; Simpson, AGB; Stamatakis, A; del Campo, J; Yilmaz, P; de Vargas, C (Wiley, 2017-03-24)
      Universal taxonomic frameworks have been critical tools to structure the fields of botany, zoology, mycology, and bacteriology as well as their large research communities. Animals, plants, and fungi have relatively solid, stable morpho‐taxonomies built over the last three centuries, while bacteria have been classified for the last three decades under a coherent molecular taxonomic framework. By contrast, no such common language exists for microbial eukaryotes, even though environmental ‘‐omics’ surveys suggest that protists make up most of the organismal and genetic complexity of our planet's ecosystems! With the current deluge of eukaryotic meta‐omics data, we urgently need to build up a universal eukaryotic taxonomy bridging the protist ‐omics age to the fragile, centuries‐old body of classical knowledge that has effectively linked protist taxa to morphological, physiological, and ecological information. UniEuk is an open, inclusive, community‐based and expert‐driven international initiative to build a flexible, adaptive universal taxonomic framework for eukaryotes. It unites three complementary modules, EukRef, EukBank, and EukMap, which use phylogenetic markers, environmental metabarcoding surveys, and expert knowledge to inform the taxonomic framework. The UniEuk taxonomy is directly implemented in the European Nucleotide Archive at EMBL‐EBI, ensuring its broad use and long‐term preservation as a reference taxonomy for eukaryotes.
    • SEM-microphotogrammetry, a new take on an old method for generating high-resolution 3D models from SEM images

      BALL, AD; JOB, PA; WALKER, AEL (Wiley, 2017-03-22)
      The method we present here uses a scanning electron microscope programmed via macros to automatically capture dozens of images at suitable angles to generate accurate, detailed three‐dimensional (3D) surface models with micron‐scale resolution. We demonstrate that it is possible to use these Scanning Electron Microscope (SEM) images in conjunction with commercially available software originally developed for photogrammetry reconstructions from Digital Single Lens Reflex (DSLR) cameras and to reconstruct 3D models of the specimen. These 3D models can then be exported as polygon meshes and eventually 3D printed. This technique offers the potential to obtain data suitable to reconstruct very tiny features (e.g. diatoms, butterfly scales and mineral fabrics) at nanometre resolution. Ultimately, we foresee this as being a useful tool for better understanding spatial relationships at very high resolution. However, our motivation is also to use it to produce 3D models to be used in public outreach events and exhibitions, especially for the blind or partially sighted.
    • Microbial-tubeworm associations in a 440 million year old hydrothermal vent community

      Georgieva, M; Little, CTS; Bailey, RJ; Ball, AD; Glover, AG (Royal Society, The, 2018-11-14)
    • The use of anthropogenic marine debris as a nesting material by brown boobies (Sula leucogaster)

      Grant, ML; Lavers, JL; Stuckenbrock, S; Sharp, PB; Bond, AL (Elsevier, 2018-10-11)
      Marine debris is pervasive worldwide, and affects biota negatively. We compared the characteristics of debris incorporated within brown booby (Sula leucogaster) nests throughout their pantropical distribution by assessing the type, colour and mass of debris items within nests and in beach transects at 18 sites, to determine if nests are indicators of the amount of debris in local marine environments. Debris was present in 14.4% of nests surveyed, with the proportion of nests with debris varying among sites (range: 0–100%). There was minimal overlap between the type or colour of debris found in nests and on adjacent beaches at individual sites. This suggests that brown boobies do not select debris uniformly across their distribution. We propose that the nests of brown boobies can be used as a sentinel of marine debris pollution of their local environment.
    • Episodic and Declining Fluvial Processes in Southwest Melas Chasma, Valles Marineris, Mars

      Davis, J; Grindrod, P; Fawdon, P; Williams, R; Gupta, S; Balme, M
    • Occurrence of Schistosoma bovis on Pemba Island, Zanzibar: implications for urogenital schistosomiasis transmission monitoring

      Pennance, T; Ame, SM; Amour, AK; Suleiman, KR; Allan, F; Rollinson, D; Webster, BL (2018-11)
    • Urogenital schistosomiasis transmission on Unguja Island, Zanzibar: characterisation of persistent hot-spots

      Pennance, T; Person, B; Muhsin, MA; Khamis, AN; Muhsin, J; Khamis, IS; Mohammed, KA; Kabole, F; Rollinson, D; Knopp, S (2016-12)
    • Introgressed Animal Schistosomes Schistosoma curassoni and S. bovis Naturally Infecting Humans

      Léger, E; Garba, A; Hamidou, AA; Webster, BL; Pennance, T; Rollinson, D; Webster, JP (2016-12)
    • 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