• 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 Diversity of Venom: The Importance of Behavior and Venom System Morphology in Understanding Its Ecology and Evolution

      Schendel; Rash; Jenner; Undheim (MDPI AG, 2019-11-14)
      Venoms are one of the most convergent of animal traits known, and encompass a much greater taxonomic and functional diversity than is commonly appreciated. This knowledge gap limits the potential of venom as a model trait in evolutionary biology. Here, we summarize the taxonomic and functional diversity of animal venoms and relate this to what is known about venom system morphology, venom modulation, and venom pharmacology, with the aim of drawing attention to the importance of these largely neglected aspects of venom research. We find that animals have evolved venoms at least 101 independent times and that venoms play at least 11 distinct ecological roles in addition to predation, defense, and feeding. Comparisons of different venom systems suggest that morphology strongly influences how venoms achieve these functions, and hence is an important consideration for understanding the molecular evolution of venoms and their toxins. Our findings also highlight the need for more holistic studies of venom systems and the toxins they contain. Greater knowledge of behavior, morphology, and ecologically relevant toxin pharmacology will improve our understanding of the evolution of venoms and their toxins, and likely facilitate exploration of their potential as sources of molecular tools and therapeutic and agrochemical lead compounds.
    • Eliopoulosite, V7S8, A New Sulfide from the Podiform Chromitite of the Othrys Ophiolite, Greece

      Bindi, L; Zaccarini, F; Bonazzi, P; Grammatikopoulos, T; Tsikouras, B; Stanley, Christopher; Garuti, G (MDPI AG, 2020-03-08)
      The new mineral species, eliopoulosite, V7S8, was discovered in the abandoned chromium mine of Agios Stefanos of the Othrys ophiolite, located in central Greece. The investigated samples consist of massive chromitite hosted in a strongly altered mantle tectonite, and are associated with nickelphosphide, awaruite, tsikourasite, and grammatikopoulosite. Eliopoulosite is brittle and has a metallic luster. In plane-reflected polarized light, it is grayish-brown and shows no internal reflections, bireflectance, and pleochroism. It is weakly anisotropic, with colors varying from light to dark greenish. Reflectance values of mineral in air (Ro, Re’ in %) are: 34.8–35.7 at 470 nm, 38–39 at 546 nm, 40–41.3 at 589 nm, and 42.5–44.2 at 650 nm. Electron-microprobe analyses yielded a mean composition (wt.%) of: S 41.78, V 54.11, Ni 1.71, Fe 1.1, Co 0.67, and Mo 0.66, totali 100.03. On the basis of Σatoms = 15 apfu and taking into account the structural data, the empirical formula of eliopoulosite is (V6.55Ni0.19Fe0.12Co0.07Mo0.04)Σ = 6.97S8.03. The simplified formula is (V, Ni, Fe)7S8 and the ideal formula is V7S8, which corresponds to V 58.16%, S 41.84%, total 100 wt.%. The density, based on the empirical formula and unit-cell volume refined form single-crystal structure XRD data, is 4.545 g·cm−3. The mineral is trigonal, space group P3221, with a = 6.689(3) Å, c = 17.403(6) Å, V = 674.4(5) Å3, Z = 3, and exhibits a twelve-fold superstructure (2a × 2a × 3c) of the NiAs-type subcell with V-atoms octahedrally coordinated by S atoms. The distribution of vacancies is discussed in relation to other pyrrhotite-like compounds. The mineral name is for Dr. Demetrios Eliopoulos (1947–2019), a geoscientist at the Institute of Geology and Mineral Exploration (IGME) of Greece and his widow, Prof. Maria Eliopoulos (nee Economou, 1947), University of Athens, Greece, for their contributions to the knowledge of ore deposits of Greece and to the mineralogical, petrographic, and geochemical studies of ophiolites, including the Othrys complex. The mineral and its name have been approved by the Commission of New Minerals, Nomenclature, and Classification of the International Mineralogical Association (No. 2019-96).
    • Grammatikopoulosite, NiVP, a New Phosphide from the Chromitite of the Othrys Ophiolite, Greece

      Bindi, L; Zaccarini, F; Ifandi, E; Tsikouras, B; Stanley, Christopher; Garuti, G; Mauro, D (MDPI AG, 2020-01-31)
      Grammatikopoulosite, NiVP, is a new phosphide discovered in the podiform chromitite and hosted in the mantle sequence of the Othrys ophiolite complex, central Greece. The studied samples were collected from the abandoned chromium mine of Agios Stefanos. Grammatikopoulosite forms small crystals (from 5 μm up to about 80 μm) and occurs as isolated grains. It is associated with nickelphosphide, awaruite, tsikourasite, and an undetermined V-sulphide. It is brittle and has a metallic luster. In plane-polarized light, it is creamy-yellow, weakly bireflectant, with measurable but not discernible pleochroism and slight anisotropy with indeterminate rotation tints. Internal reflections were not observed. Reflectance values of mineral in air (R1, R2 in %) are: 48.8–50.30 at 470 nm, 50.5–53.5 at 546 nm, 51.7–55.2 at 589 nm, and 53.2–57.1 at 650 nm. Five spot analyses of grammatikopoulosite give the average composition: P 19.90, S 0.41, Ni 21.81, V 20.85, Co 16.46, Mo 16.39, Fe 3.83, and Si 0.14, total 99.79 wt %. The empirical formula of grammatikopoulosite—based on Σ(V + Ni + Co + Mo + Fe + Si) = 2 apfu, and taking into account the structural results—is (Ni0.57Co0.32Fe0.11)Σ1.00(V0.63Mo0.26Co0.11)Σ1.00(P0.98S0.02)Σ1.00. The simplified formula is (Ni,Co)(V,Mo)P and the ideal formula is NiVP, which corresponds to Ni 41.74%, V 36.23%, P 22.03%, total 100 wt %. The density, calculated on the basis of the empirical formula and single-crystal data, is 7.085 g/cm3. The mineral is orthorhombic, space group Pnma, with a = 5.8893(8), b = 3.5723(4), c = 6.8146(9) Å, V = 143.37(3) Å3, and Z = 4. The mineral and its name have been approved by the Commission of New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2019-090). The mineral honors Tassos Grammatikopoulos, geoscientist at the SGS Canada Inc., for his contribution to the economic mineralogy and mineral deposits of Greece.
    • Multi-Proxy Characterisation of the Storegga Tsunami and Its Impact on the Early Holocene Landscapes of the Southern North Sea

      Gaffney, Vincent; Fitch, S; Bates, M; Ware, RL; Kinnaird, Tim; Gearey, B; Hill, Thomas; Telford, Richard; Batt, C; Stern, Benjamin; et al. (MDPI AG, 2020-07-15)
      Doggerland was a landmass occupying an area currently covered by the North Sea until marine inundation took place during the mid-Holocene, ultimately separating the British landmass from the rest of Europe. The Storegga Event, which triggered a tsunami reflected in sediment deposits in the northern North Sea, northeast coastlines of the British Isles and across the North Atlantic, was a major event during this transgressive phase. The spatial extent of the Storegga tsunami however remains unconfirmed as, to date, no direct evidence for the event has been recovered from the southern North Sea. We present evidence of a tsunami deposit in the southern North Sea at the head of a palaeo-river system that has been identified using seismic survey. The evidence, based on lithostratigraphy, geochemical signatures, macro and microfossils and sedimentary ancient DNA (sedaDNA), supported by optical stimulated luminescence (OSL) and radiocarbon dating, suggests that these deposits were a result of the tsunami. Seismic identification of this stratum and analysis of adjacent cores showed diminished traces of the tsunami which was largely removed by subsequent erosional processes. Our results confirm previous modelling of the impact of the tsunami within this area of the southern North Sea, and also indicate that these effects were temporary, localized, and mitigated by the dense woodland and topography of the area. We conclude that clear physical remnants of the wave in these areas are likely to be restricted to now buried, palaeo-inland basins and incised river valley systems.
    • The Phylogenetics and Biogeography of the Central Asian Hawkmoths, Hyles hippophaes and H. chamyla: Can Mitogenomics and Machine Learning Bring Clarity?

      Patzold, Franziska; Marabuto, Eduardo; Daneck, Hana; O’Neill, Mark A; Kitching, I; Hundsdoerfer, Anna K (MDPI AG, 2021-05-17)
      The western Palaearctic species of the hawkmoth genus Hyles (Lepidoptera: Sphingidae) have long been the subject of molecular phylogenetic research. However, much less attention has been paid to the taxa inhabiting the central and eastern Palaearctic, particularly Central Asia, where almost 50% of the species diversity of the genus occurs. Yet, many taxonomic conundrums hinder a proper assessment of the true diversity in these moths. One still unresolved group of species includes Hyles hippophaes and Hyles chamyla. Despite a largely overlapping morphology and ecology, a plethora of infraspecific taxa display some unique divergent characters over a wide geographical area. In this study, we undertook a taxonomic assessment of each population and resolved this species complex using an integrative approach. A combination of new computational techniques (DAISY-II) in comparative morphology and recent advances in DNA extraction methods and sequencing of museum specimens (WISC) alongside more traditional genetic approaches allowed testing of the three main phenotypes—bienerti, chamyla and apocyni—in terms of their morphological, mitochondrial and biogeographical integrity, and to elucidate their evolutionary relationships. Our results support the existence of two closely related species, Hyles chamyla and H. hippophaes, but the former species H. apocyni (here discussed as the ecological form apocyni of H. chamyla) is best regarded as a hybrid between H. chamyla and H. h. bienerti. The results indicate that the evolutionary relationship between H. chamyla and H. hippophaes is one of admixture in the context of ongoing ecological differentiation, which has led to shared morphological characters and a blurring of the species boundaries. These results clarify the evolutionary relationships of this species complex and open future research lines, including the analysis of nuclear markers and denser sampling, particularly of H. hippophaes and H. vespertilio in western Europe.
    • Tsikourasite, Mo3Ni2P1+x (x < 0.25), a New Phosphide from the Chromitite of the Othrys Ophiolite, Greece

      Zaccarini, F; BINDI, LUCA; Ifandi, Elena; Grammatikopoulos, Tassos; Stanley, Christopher; Garuti, G; Mauro, Daniela (MDPI AG, 2019-04-24)
      Tsikourasite, Mo3Ni2P1+x (x < 0.25), is a new phosphide discovered in a mantle-hosted podiform chromitite collected in the abandoned mine of Agios Stefanos (Othrys ophiolite), Central Greece. It forms tiny grains (from a few μm up to about 80 μm) and occurs as isolated grains or associated with other known minerals such as nickelphosphide and awaruite, and with undetermined minerals such as Ni-allabogdanite or Ni-barringerite and a V-sulphide. Tsikourasite is brittle and has a metallic luster. In plane-polarized light, tsikourasite is white yellow and it shows no bireflectance, anisotropism or pleochroism. Internal reflections were not observed, Reflectance values of tsikourasite in air (Rin %) are: 55.7 at 470 nm, 56.8 at 546 nm, 57.5 at 589 nm and 58.5 at 650 nm. Five spot analyses of tsikourasite give the average composition: P 7.97, S 0.67, V 14.13, Fe 14.37, Co 7.59, Ni 23.9, and Mo 44.16, total 99.60 wt%, corresponding to the empirical formula (Mo1.778V1.071Fe0.082Co0.069)Σ3.000(Ni1.572Co0.428)Σ2.000(P0.981S0.079)Σ1.060, on the basisof Σ(Mo +V + Fe + Co + Ni) = 5 apfu and taking into account the structural results. The simplified formula is Mo3Ni2P1+x (x < 0.25). The density, which was calculated based on the empirical formula and single-crystal data, is 9.182 g/cm3. The mineral is cubic, space group F-43m, with a = 10.8215(5) Å and Z = 16. Although tsikourasite is similar in composition to those of monipite (MoNiP), polekhovskyite (MoNiP2), and the synthetic compound MoNiP2, all these phases are hexagonal and not cubic like tsikourasite. It exhibits the same structure as the cubic Mo3Ni2P1.18 compound [space group F-43m, a = 10.846(2) Å] synthesized at 1350 °C. The mineral and its name have been approved by the Commission of New Minerals, Nomenclature and Classification of the International Mineralogical Association (No. 2018-156). The mineral honors Professor Basilios Tsikouras of the Universiti Brunei Darussalam.