N Fox

Mitogen‐induced responses in lymphocytes from platypus, the Tasmanian devil and the eastern barred bandicoot

OBJECTIVEnAs the platypus (Ornithorhynchus anatinus), the Tasmanian devil (Sarcophilus harrisi) and the eastern barred bandicoot (Perameles gunni) are currently at risk of serious population decline or extinction from fatal diseases in Tasmania, the goal of the present study was to describe the normal immune response of these species to challenge using the lymphocyte proliferation assay, to give a solid basis for further studies.nnnMETHODSnFor this preliminary study, we performed lymphocyte proliferation assays on peripheral blood mononuclear cells (PBMC) from the three species. We used the common mitogens phytohaemagglutinin (PHA), concanavalin A (ConA), lipopolysaccharide (LPS) and pokeweed mitogen (PWM).nnnRESULTSnAll three species recorded the highest stimulation index (SI) with the T-cell mitogens PHA and ConA. Tasmanian devils and bandicoots had greater responses than platypuses, although variability between individual animals was high.nnnCONCLUSIONnFor the first time, we report the normal cellular response of the platypus, the Tasmanian devil and the eastern barred bandicoot to a range of commonly used mitogens.

Tourmaline-rich features in the Heemskirk and Pieman Heads granites from western Tasmania, Australia: Characteristics, origins, and implications for tin mineralization

Abstract Distinctive magmatic-hydrothermal, tourmaline-rich features have developed in the Heemskirk and Pieman Heads granites from western Tasmania, Australia. They are categorized as tourmaline-rich patches, orbicules, cavities, and veins, based on their distinctive morphologies, sizes, mineral assemblages, and contact relationships with host granites. These textural features occur in discrete layers in the roof zone of granitic sills within the Heemskirk and Pieman Heads granites. Tourmaline patches commonly occur below a tourmaline orbicule-rich granitic sill. Tourmaline-filled cavities have typically developed above the tourmaline-quartz orbicules in the upper layer of the white phase of the Heemskirk Granite. Tourmaline-quartz veins penetrate all exposed levels of the granites, locally cutting tourmaline orbicules and cavities. The tourmalines are mostly schorl (Fe-rich) and foitite, with an average end-member component of schorl45 dravite6 tsilaisite1 uvite0 Fe-uvite3 foitite31 Mg-foitite4 olenite10. Element substitutions of the tourmalines are controlled by FeMg−1, YAlX□(R2+Na)−1, and minor YAlO(R2+OH)−1 (where R2+ = Fe2+ + Mg2+ + Mn2+) exchange vectors. Several trace elements in tourmaline have consistent chemical evolutions grouped from tourmaline patches, through orbicules and cavities, to veins. There is a progressive decrease of most transition and large ion lithophile elements, and a gradual increase of most high-field strength elements. These compositional variations in the different tourmaline-rich features probably relate to element partitioning occurring in these phases due to volatile exsolution and fluxing of aqueous boron-rich fluids that separated from the granitic melts during the emplacement of S-type magmas into the shallow crust (4 to 5.5 km). Tourmalines from the Heemskirk Granite are enriched in Fe, Na, Li, Be, Sn, Ta, Nb, Zr, Hf, Th, and rare earth elements relative to the tourmalines from the Pieman Heads Granite, but depleted in Mg, Mn, Sc, V, Co, Ni, Pb, Sr, and most transition elements. These results imply that bulk compositions of the host granites exert a major control on the chemical variations of tourmalines. The trace element compositions of tourmalines from the Sn-mineralized Heemskirk Granite are different from those of the barren Pieman Heads Granite. Trace element ratios (e.g., Zn/Nb, Co/Nb, Sr/Ta, and Co/La) and Sn concentrations in tourmaline can distinguish the productive Heemskirk Granite from the barren Pieman Heads Granite.

A new test for plant bioaccessibility in sulphidic wastes and soils: A case study from the Wheal Maid historic tailings repository in Cornwall, UK

Currently, bioaccessibility testing at contaminated sites is dominated by techniques designed to assess oral bioaccessibility to humans. Determining the plant bioaccessibility of toxic trace elements is also important. In mining landscapes, sulphides are an important source of potentially toxic elements. Simple tests to evaluate readily leachable metals and metalloids exist but do not extract elements temporarily constrained within the sulphide fraction. Sequential extractions describe the association of trace elements with different geochemical fractions but are time consuming, costly and provide excessive detail. This paper proposes a new test for plant bioaccessibility in sulphidic mine wastes and soils that uses hydrogen peroxide to simulate environmental oxidation. The bioaccessible fraction determined is operationally defined and does not predict actual plant uptake. The test targets a) the portion of an element that is currently available in the pore water for uptake by plant roots and also b) the fraction that is temporarily constrained in sulphide minerals but may become available upon oxidation of the substrate. A case study was conducted at a historic mine waste repository site in Cornwall, U.K. where near total As concentrations were extremely elevated and Cd, Cu, Pb, Sb and Zn were also high. Our test determined that bioaccessible concentrations of As, Cd, Cu and Zn and to a lesser extent Sb and Pb were highest in samples of pyritic grey tailings. This is attributed to sulphide mineral oxidation and, particularly for Cd and Zn, the dissolution of soluble secondary minerals. High As concentrations in the marbled tailings were not bioaccessible. Results from the case study show that this new test provides useful information on the future bioaccessibility of contaminants, allowing for classification of mineralised sulphidic waste materials which otherwise cannot be obtained using established geochemical and mineralogical techniques. Furthermore, the test is rapid, repeatable and cost effective.

Porphyry Au-Cu mineralization controlled by reactivation of an arc-transverse volcanosedimentary subbasin

Located in the accreted remnants of the Ordovician Macquarie Arc (Australia), Cadia East is the largest alkalic porphyry Au-Cu deposit currently known. The deposit is centered on a 2-km-long, northwest-trending volcanosedimentary subbasin, which was identified by mapping variations in the distribution and thickness of faulted sedimentary marker horizons. The normal faults that define the subbasin predate porphyry mineralization and are oriented parallel to a major arc-transverse lineament. Porphyry Au-Cu mineralization was controlled by reactivation of the subbasin during postorogenic extension as the Macquarie Arc was accreted to the Gondwana margin in the early Silurian. Dilation of the northwest-trending subbasin faults facilitated emplacement of alkalic porphyry dikes and associated sheeted quartz-sulfide veins that define the Cadia East orebody. During the middle Silurian, north-trending fault-bound marine basins buried Cadia East, significantly enhancing preservation of the ore system. These north-trending faults were optimally oriented for reactivation during Devonian east-directed compression, leaving the mineralized Cadia East volcanosedimentary subbasin largely intact. We identify the significance of reactivated premineralization structures within an arc-transverse lineament in controlling porphyry Au-Cu mineralization in a postsubduction setting. At Cadia East, the manifestation of such premineralization structures can be observed at regional, district, and deposit scales, and highlights the influence of preexisting crustal architecture on the structural character, geometry, and preservation potential of porphyry deposits throughout the arc life cycle.

Prediction of Metal Mobility from Sulfidic Waste Rocks Using Micro-Analytical Tools, Spray, Tasmania

The Zeehan Pb-Zn field in western Tasmania (Australia) contains over one hundred abandoned and historical mine sites. Combined with a temperate rainforest climate and abundant waste rock material, many sites are affected by acid rock drainage (ARD). The Spray mine, located southwest of the town of Zeehan, was one of the field’s largest historical producers of Pb and Ag. Abandoned in the early 1900s, the site contains numerous adits and waste rock piles which contribute to ARD in the region. The aim of this study was to predict the likely ARD surface water quality, using the major and trace element chemistry of sulfide minerals present within waste materials on site. Major ore sulfides are galena and sphalerite with associated Sb-rich sulfosalt minerals including boulangerite and geocrocite. These minerals contain minor concentrations of Ag, Bi, Cd , In and Sn. Minor arsenopyrite and abundant pyrite (average 7500 ppm As) represent the main repository for As. Siderite is a major gangue mineral, containing slightly elevated In, Pb, Sb and Zn (250–50 ppm). Metals and metalloids (Ag, As, Bi, Cd, Cu, In, Pb, Zn) contained within sulfides and siderite may be mobilized upon mineral dissolution into ARD waters. Consequently, micro-analytical analyses of sulfides and associated gangue minerals can assist in the prediction of aqueous metal and metalloid mobility from sulfidic waste rock piles.

Prediction of Leachate Quality for a Gossan Dump, Angostura, Spain

The Iberian Pyrite Belt (IPB) is one of the largest of the world’s massive sulfide provinces. Since the Chalcolithic era, gossans formed from massive sulfide mineralization have been worked for copper, silver and gold. Consequently many historical mine sites have abandoned dumps of gossanous material. One such example is located at Angostura, a historical copper mine which operated from 1906 to 1931. The aims of this study are to determine the mineralogical hosts of environmentally significant elements (As, Ba, Bi, Co, Cu, Hg, Mo, Sb, Se, Ni, Pb, Zn) in gossanous waste rocks dumped adjacent to the Angostura open cut, using geochemical, optical, SEM-MLA and laser ablation techniques. Our findings demonstrate that the gossan materials are enriched in environmentally significant elements with several hosted by iron oxides and iron-oxyhydroxides. Leaching of these gossan materials was performed using three extractants to represent different conditions which may be experienced in a surficial environment (i.e., deionized water, hydrogen peroxide and sulfuric acid). Results from these experiments indicated that under ambient surface conditions all analyzed elements will not be released from their goethite and hematite hosts. However, under ARD conditions, elements such Co, Cu, Pb and Zn will be mobilized.

Prediction of Metal Mobility from Sulfidic Waste Rocks Using Micro-analytical Tools, Baal Gammon, Northern Australia

Predictions on the behavior of environmentally significant elements at mine sites requires the use of advanced laboratory techniques. The aim of this contribution is to demonstrate the use of electron microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) to gain an understanding of likely element behaviour. Sulfidic boulders sampled from an acid rock drainage (ARD) impacted ephemeral stream adjacent to the historical Baal Gammon workings are dominated by chalcopyrite, arsenopyrite, pyrrhotite and lesser pyrite. Micro-analytical investigations using EMPA and LA-ICPMS reveal that chalcopyrite contains significant quantities of Ag, Cd, Sn, In and Zn either substituted directly into the crystal lattice or occurring as discrete sphalerite and stannite inclusions. Arsenopyrite, comprising more than 50 % of some boulders, is most notably rich in Co, Ni, Sb and Se, but it also contains inclusions of sphalerite, chalcopyrite and stannite. By contrast, pyrrhotite contains relatively few trace elements, but it may be a significant contributor to ARD development. The trace element composition of Fe-oxides in the oxidized rinds of these boulders is likely directly influenced by the mineralogy of the sulfidic boulders on which they precipitate. Although significant quantities of As, Bi, Cu, In, Pb and Zn occur in Fe-oxides at Baal Gammon, these elements may be liberated during acid flushing of the ephemeral stream. Consequently, EMPA and LA-ICPMS represent valuable tools for evaluating the source and potential mobility of environmentally significant elements at mine sites.