Search

The Herberton Mineral Field hosts multiple small-scale, polymetallic Sn-Cu and Sn-Zn deposits. The Baal Gammon and Isabel polymetallic deposits in the Herberton Mineral Field contain early Sn that is overprinted by sulfides. At Baal Gammon, the sulfide overprinting is Cu-In-rich, whereas Isabel is a Zn-Pb-In-rich system. These deposits are hosted in the meta-sedimentary rocks of the Hodgkinson Formation and the porphyry dikes and volcanic rocks of the Kennedy Igneous Association. Primary Sn in these deposits occurs as cassiterite, which was altered to stannite during sulfide mineralization. The sulfide ores from Baal Gammon consist of chalcopyrite, pyrrhotite, and minor sphalerite, and sphalerite, galena, and minor chalcopyrite are observed at Isabel. Chalcopyrite from Baal Gammon contains on average 609 ppm Ag, 1194 ppm In, and 1410 ppm Sn, whereas chalcopyrite from the Isabel deposit contains on average 2302 ppm Ag, 725 ppm In, and 1042 ppm Sn. Sulfur isotope (δ34S) measurements of in-situ chalcopyrite-pyrrhotite mineral pairs show limited variation and low values that are indicative of a magmatic sulfur source with limited interaction with sulfur from connate and meteoric fluids during mineralization. The chalcopyrite and pyrrhotite δ34S values at the Baal Gammon deposit vary between 0.99–1.91‰ and 1.35–2.48‰, respectively. The δ34S values at the Isabel deposit vary between 0.91–1.45‰ for chalcopyrite and 1.12–2.11‰ for pyrrhotite. The trace element composition of major sulfides and sulfur isotopes of chalcopyrite and pyrrhotite combined with thermodynamic modeling indicates that the mineralizing fluids at the Baal Gammon and Isabel deposits have an igneous source, where the metals were transported as metal-chloride complexes at low pH (< 5) and below ~ 300 °C. The source of these sulfide-rich mineralizing fluids is most likely derived from the magmatic activity associated with the emplacement of the Slaughter Yard Creek Volcanics during a period of crustal thinning between 300 and 280 Ma. [ABSTRACT FROM AUTHOR]

The Herberton Mineral Field in Northeast Australia hosts world class magmatic-hydrothermal Sn–W polymetallic deposits that are enriched in In. The Baal Gammon and Isabel deposits from the Herberton Mineral Field contains early tin, as cassiterite, overprinted by sulfide mineralization as chalcopyrite, sphalerite, galena, pyrrhotite, and stannite. We investigated the distribution of In in the sulfide ores from these two deposits, calculated the temperature of formation via sphalerite-stannite geothermometer, and deduced the physicochemical conditions favorable for enriching In in this mineralizing environment. The Baal Gammon deposit is dominated by chalcopyrite, with In contained in chalcopyrite, sphalerite, and stannite. The average In concentrations measured by EPMA in chalcopyrite, sphalerite, and stannite are 0.10, 0.68, and 0.92 wt%, respectively. Chalcopyrite, pyrrhotite, and sphalerite textures indicate that In incorporation occurred during exsolution from an intermediate solid solution of cubanite composition. The Isabel deposit is dominated by sphalerite associated with galena and contains only minor amounts of chalcopyrite. The average concentration of In in sphalerite from the Isabel deposit is 0.11 wt%. The stannite-sphalerite geothermometer indicates mineralization temperatures of ~ 290 °C at the Baal Gammon deposit, and ~ 307 °C at the Isabel deposit. At these temperatures, the physicochemical modeling suggests that stable In chlorine complexes occur in acidic conditions (pH < 3). These results when combined with the Eh–pH phase model of the sulfide assemblage further constrain the redox conditions during mineralization. [ABSTRACT FROM AUTHOR]

In this work, we studied a geochemically unique abandoned tin mining tailings facility in tropical north Queensland, Australia. Tin mining residues from local operations were reprocessed and left without proper remediation, after which native plant species colonised this site over time. The aim of this study was to characterize the mine tailings to understand the geochemistry and predict the potential mobility and bioavailability of major contaminants, arsenic and tin. Major and trace minerals were identified with X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). Acid digestion and sequential extraction procedures were used to quantify elemental concentrations and potential mobility. We found that the highly oxidized tailing cells were dominated by quartz with limited buffering capacity to prevent acid mine drainage formation, consequently creating an acidic environment (pH 4). Arsenic (As) and tin (Sn) were identified as the main contaminants in the tailings with concentrations of up to 2980 μg g−1 and 2910 μg g−1, respectively. Tin was mainly bound to the residual fraction (52% of total Sn) and crystalline Fe-oxide fraction (33% of total Sn), limiting its release and mobility. The bulk of As (~77% of total As) was present in the crystalline Fe-oxide fraction, while ~19% in the amorphous/poorly crystalline Fe-oxide fraction. The bioavailable As fraction was negligible (~1%), and this was confirmed by limited As accumulation in terrestrial and aquatic plants (Cyperaceae sp., Eleocharis equisetina, and Poaceae sp.) sampled at the site. This interdisciplinary study reveals biogeochemical properties of Sn tailings, the fate of As, and how native plants can thrive in this unfavourable environment. This information can potentially guide further phytostabilization efforts at this site. [ABSTRACT FROM AUTHOR]

This article explores nomadic site occupation as a form of planetary colonization involving both human and non-human agents. Conventional understandings of temporary occupation are often humancentric with little attention paid to the disruption of extant site ecologies and processes. The latter are particularly pressing concerns in nomadic settlements located in precarious landscapes. Taking the latter as its focus, this article engages the earth as an agent resisting its own colonization in the Australian-licensed squatter settlement known colloquially as Tin City. Located within the largest mobile sand dune structure in New South Wales, Tin City is an assemblage of several self-built fishing shacks accommodating a nomadic population. Its occupants engage in a daily battle against the shifting sands that threaten to subsume their temporary homes. Located in an area of significant indigenous heritage, the Tin City settlement has become a tourist attraction shrouded in local lore. Current discourses about it and its architectures generally focus on its unusual aesthetics, its contested sociopolitical histories and its ecology, with some discussion on the impacts of European colonization on the sand dune's dynamic geomorphology. To concentrate on the latter, the article develops and deploys the posthumanist conceptualization of the earth posited by Iranian philosopher Reza Negarestani in his ficto-critical text Cyclonopedia: Complicity with Anonymous Materials. Negarestani ascribes the earth with sentient and agentic capacity, whilst the nomads who traverse its surfaces become the penultimate planetary colonizers. Tin City's occupation thus becomes a story of colonization and resistance narrated by the earth itself, and a reminder that the production and consumption of architectural forms does not need to be confined to that which is conventionally human. [ABSTRACT FROM AUTHOR]

Object use by cetaceans has been associated with complex cognitive processes, social relations, play and tool use. A comparative approach of how cetacean species use objects will increase our understanding of this behavior. This study reports on observations of object use by a small group of provisioned wild Australian humpback dolphins (Sousa sahulensis) in Tin Can Bay, Australia. Preliminary data were collated from attendance records, interviews and photographs and classified by dolphin, object type and possible motive. Up to 29 separate occasions of object carrying behavior over seven years were documented, characteristics of which are summarized. A variety of objects biological (n = 6), artificial (n = 5) and live (n = 4) were carried or used by three male dolphins in intraspecific and interspecific interactions. Interactions were operationally defined and categorized as play (n = 4), show (n = 17), or give (n = 10). Object play was more frequent with the juvenile male. Object carrying or showing was associated with the adult males and may be related to male social behavior similar to that seen in Amazon River dolphins (Inia geoffrensis). Relinquishment of objects may be unique to interactions with people as seen during provisioning situations with bottlenose dolphins (Tursiops sp.). The behavior presented in the current study indicates further variations of object use within the species, as objects were not associated with probable foraging as has been observed elsewhere in the wild. [ABSTRACT FROM AUTHOR]

[Display omitted] • The geological setting of indium-rich deposits (Baal Gammon and Isabel) of the Herberton Mineral Field, northeast Queensland, Australia is presented. • New geochronological data from the granite supersuites that occur in the Herberton Mineral Field are reported. • Tectonic synthesis of the Herberton Mineral Field shows that tin mineralization occurred during compression, while sulfides and indium mineralization occurred during crustal extension. Base metal mineralization at the Baal Gammon and Isabel deposits of the Herberton Mineral Field (HMF) is hosted in metamorphosed greywacke beds in the Hodgkinson Formation, which were intruded by granite, porphyry dykes and overlain by volcanic rocks of the Kennedy Igneous Association during the Carboniferous and Permian. The tin mineralization at the Baal Gammon deposit is hosted by a silicified, chlorite-altered, quartz-feldspar porphyry (UNA Porphyry). The tin mineralization at the Isabel deposit is in polymetallic veins hosting disseminated cassiterite. Polymetallic sulfides (Cu-Zn) and indium (In) mineralization at both deposits overprint the tin mineralization. Chalcopyrite, sphalerite, and stannite host indium in the polymetallic sulfide assemblage at both deposits. Based on overprinting relationships, the timing of tin mineralization is related to the magmatic activity at ca. 320 Ma, whereas the sulfide and indium mineralization are most likely associated with the emplacement of porphyry dykes at ca. 290 Ma. The overall magmatic activity in the HMF spreads between ca. 365 and 280 Ma, with peaks at ca. 337, 322, 305, and 285 Ma. The change from tin mineralization at ca. 320 Ma to sulfide and indium mineralization at ca. 290 Ma indicates a transition from a compressive to an extensional tectonic regime. [ABSTRACT FROM AUTHOR]

Initial εNd isotope data for the four granites related to the Ardlethan Sn deposit in the Wagga Sn belt of the central Lachlan fold belt of eastern Australia range from -11.6 to +2.1, increasing with increasing fractionation. The four granites beneath the Renison tin mine in western Tasmania range from -6.1 to -3.9. The data clearly establish the presence of light rare earths of mantle origin in the fractionated granites associated with the Ardlethan porphyry Sn deposits and hint at the same relationship for the Renison granites, though in this case the mineralizing pluton is probably yet to be discovered. Sulfur and carbon isotope data from the Ardlethan and Renison ores, and from similar deposits in Tasmania, suggest that mantle volatiles played a significant role in the genesis of Sn granites and deposits. Mantle input may have occurred either by mixing of crustal and mantle melts or metasomatism by mantle-derived fluids. [ABSTRACT FROM AUTHOR]

A dental health programme which employed group self prophylaxis by school children aged 5-9 years is described. The group used 10 per cent SnF2-ZrSiO4 paste and was supervised within the school by an auxiliary of parents under the direction of a dentist. There was a 36 per cent reduction in DMFT increment at the end of two years in the children aged 7-9 years.