Tesi sul tema "Broken Hill"

This thesis uses a translational research approach and combines theoretical, empirical and experiential evidence to explore four key issues that provide further direction to current efforts to reduce lead exposure in Broken Hill, and more generally to improve management of environmental health risks in the community setting. A theoretical review argues for an adaptive response to program development, recognising that the solution to the problem is not straightforward. The review indicated the need for multi-pronged strategies including both population-based approaches and strategies focussing on particular risk groups. Unintended negative consequences must be scanned for and managed so as to ensure a positive benefit : harm ratio is maintained. A qualitative, interview based case study of successful lead exposure reduction programs identified the need for an accurate understanding of sources and pathways of exposure, which may need an iterative approach; effective control of those sources and pathways, adequate funding to undertake the work and active cooperation of relevant stakeholders. A qualitative, interview based case study of the Broken Hill Lead Reference Group found there was broad agreement as to what was required to further reduce lead exposure but that lack of recognition of constraints other organisations faced and overall lack of resources (funding and leadership) within the LRG significantly inhibited collaboration across the group and efforts to reduce lead exposure. Improving collaboration and leadership within this Group is necessary in the long term to reduce lead exposure. A before-after study of changes in participation in blood lead screening found that changing from venous to capillary screening and improving convenience both increased screening, and showed that restructuring services in response to community concern can effectively increase participation. A $13 million, five year program to reduce lead exposure in Broken Hill was established in 2015; considerably more funding is likely to be required.

The Broken Hill deposit, Aggeneys, is a metamorphosed stratiform Cu-Pb-Zn-Ag sulphide deposit situated in the mid-Proterozoic supracrustal sequence of the Bushmanland Subprovince in the Namaqualand Metamorphic Complex. The deposit comprises two superposed orebodies, each consisting mainly of massive sulphide lenses and iron formation which are hosted within a metapelitic schist close to major quartzite horizons. This study is concerned with the tectonically lower orebody (LOB). The iron formation is magnetite-rich and contains varying proportions of (Fe,Mn)-rich silicates (garnet, amphibole, olivine, orthopyroxene, pyroxenoid), quartz and Cu-Pb-Zn-sulphides. These minerals occur in mm- to 5 cm-thick bands and are often traceable over tens of metres. The well preserved banding is considered to represent bedding. Five different varieties of silicate-rich mesobands in the iron formation can be distinguished based on the predominant mineral assemblage: (a) amphibole-olivine-quartz +/- garnet, (b) amphibole-quartz, (c) garnet-apatite-quartz +/- amphibole, (d) garnet-apatite-quartzorthopyroxene, (e) pyroxferroite-quartz +/- amphibole and (f) quartz. These rocks all contain magnetite, and Ba-rich biotite is common but is not always present.

The historiography of Australian racism has principally "blamed" the labour movement for the existence of the White Australia policy and racist responses to the presence of migrant workers. This study argues that the motivations behind ruling class agitation for the White Australia policy have never been satisfactorily analysed. To address this omission, the role of the Returned and Services League of Australia (RSL) in race relations is examined. As an elite-dominated, cross-class organisation with links to every section of society, it is argued that the RSL was a significant agitator for migrant exclusion and white unity in the interwar period. The thesis employs case studies, oral history and qualitative assessment of various written sources, such as newspapers, archival records and secondary material, in order to plot the dynamics of racist ideology in two major mining centres in the interwar period. The results suggest that, although labour organisations were influenced by racist ideas and frequently protested against the presence of migrant workers, it was also true that mining employers had a material interest in sowing racial division in the workplaces they controlled. The study concludes that labour movement responses to migrant labour incorporated a range of different strategies, from demands for racist exclusion to moves towards international solidarity. It also reveals examples of local and migrant workers living, working, playing and striking together in ways that contradict the dominant view of perpetual tension between workers of different nationalities. Lastly, the case studies demonstrate that local employers actively encouraged racial division in the workplace as a bulwark against industrial militancy.

Magister Artium - MA
The rich corpus of postcolonial scholarly engagement on indigenous intermediaries, interpreters, clerks and assistants has a made a strong argument for the active participation of African agents in social scientific knowledge production on Africa. This literature has highlighted the complex and negotiated nature of fieldwork in African anthropology. While this literature has begun to deepen our understanding of the knowledge work of anthropologists and their research assistants, it has not adequately explored the relationship between anthropologists and informants in what one scholar has recently called ‘a triangulation of relationships’ between the anthropologist, the assistant and the informant. This research project proposes to explore these relationships in a detailed case study: that of the British anthropologist Godfrey Wilson (1908–1944), his interpreter Zachariah Mawere, and three primary informants, during three years of pioneering research into the effects of migrant labour at Broken Hill, Northern Rhodesia (Zambia) between 1938 and 1941. Using a close textual reading and detailed analysis of Wilsons Bemba and English fieldnotes held in the Godfrey and Monica Wilson collection at the University of Cape Town’s African Studies Library, the study will apply a micro-historical and biographical approach. It will seek to reconstruct the biographies and anthropological contributions of one interpreter and three central Bemba informants in order to explore the micro-politics of knowledge production in African anthropology.

Zinkgruvan is a stratiform Zn-Pb-Ag and Cu sulphide deposit hosted by Paleoproterozoic strata in southern Bergslagen, Sweden. The deposit underwent medium-high grade regional metamorphism during the Svecokarelian orogeny, including partial melting of the host succession. Subordinate zones of semi-massive to massive magnetite and Fe-rich skarns occur in marble stratigraphically below the stratiform Zn-Pb-Ag ore but have so far not been described in detail in the scientific literature. This thesis presents results from detailed geological drill core logging, light optical microscopy (LOM) and scanning electron microscopy (SEM), which have been integrated with results from electron microprobe analysis (FE-EMPA) and whole-rock lithogeochemical analysis to provide a comprehensive description of the magnetite mineralization. Samples from the formerly mined magnetite deposits Västerby, Garpa and Åmme - distal to Zinkgruvan - have also been studied to allow for a comparison. The combined dataset has been used to 1) discuss the genesis of the magnetite mineralizations, including their relationship to base metal sulphide mineralization, and 2) evaluate potential vectors to Zn-Pb-Ag and Cu mineralization based on variations in the magnetite deposits. The semi-massive to massive magnetite, adjacent and associated Fe-rich skarn at Zinkgruvan are located in the stratigraphic upper part of the marble host. Three different varieties of magnetite mineralization can be defined: 1) semi-massive to massive magnetite mineralization in marble, 2) magnetite-bearing veins and 3) retrograde magnetite after olivine. Detailed optical microscopy has revealed a positive spatial correlation between aluminium spinel, apatite, magnetite and graphite. Semi-massive to massive magnetite mineralization at Zinkgruvan is enriched in P2O5, ΣREELa-Lu and Mn relative to a carbonate precursor. A positive correlation exists between P2O5 and ∑REELa-Lu, suggesting apatite and monazite are the primary REE-bearing minerals. The fact that the samples with highest P2O5 and ∑REELa-Lu are all Fe-rich rocks suggest the enrichment of the latter is related to the event which formed the Fe mineralization. Magnetite mineralization from the historic iron mines NW of Zinkgruvan share several key attributes with magnetite mineralization at Zinkgruvan. These include: 1) magnetite is the only iron oxide, 2) lithological and mineralogical similarities, including spatial association with marble, 3) equally high whole-rock Fe content, 4) equally high Mn (1-4 wt.% MnO), 5) equally high Eu anomalies (Eu/Eu* = 1.1- 2.8, avg. 1.75), and 6) local presence of sphalerite mineralization. Bending of the tectonic foliation from c. E-W to NW in the western part of Zinkgruvan suggest these magnetite mineralizations may be located along the same trend as those at Zinkgruvan. The normal calc-silicate mineralogy in Zinkgruvan marble (e.g. diopside, forsterite, phlogopite) can be explained by prograde regional metamorphic reactions between silicates and dolomite or calcite in impure carbonate rocks with a variable content of detrital siliciclastic and volcaniclastic material. However, the stratabound magnetite mineralization and associated Fe-rich skarns cannot be fully accounted for by this model. It is plausible that the Fe-rich skarns can be explained by similar reactions but involving more Fe-rich carbonates (ferrodolomite, ankerite, siderite). In the absence of quartz, siderite is known to thermally decompose into magnetite and graphite at temperatures above 465° C, whereby siderite-rich rocks may have been precursor to the semi-massive to massive magnetite mineralization. A recent genetic model suggests that the ore-forming fluids which formed Zinkgruvan where similar to those which formed McArthur-type SEDEX deposits. The presented results are consistent with this model, since e.g. siderite is a common alteration mineral in alteration envelopes to such deposits. Hence, magnetite mineralization, Zn-Pb-Ag and Cu-ore may all be related to the same pre-metamorphic hydrothermal system. The current genetic model places the magnetite mineralization at Zinkgruvan proximal to a fossil hydrothermal vent zone (the Burkland discontinuity). It is plausible that the magnetite mineralization mined at surface lay along the northern continuation of the Burkland discontinuity. Based on the assumption that the Burkland Cu-mineralization is most proximal and the old iron mines at Åmme are most distal along this structure, variations in whole-rock lithogeochemistry, mineral chemistry and mineralogy have been used to define nine vectors to economic Zn-Pb-Ag and Cu ore as is mined at Zinkgruvan.

The research in this study consisted of two strands. The first consists of noble metal geochemical studies and the second involves base metal supergene processes. The precious metal geochemistry carried out in the scope of this thesis involves palladium and tellurium geochemistry, surface chemistry studies of palladium-bismuth- and tellarium-bearing synthetic minerals, and electrochemical determinations of the inactivity of a variety of primary telluride minerals and alloys. Two new minerals have been found in deposits near Broken Hill, N.S.W. The second section of the research concerns itself with supergene processes in two copper-bearing orebodies. This was carried out by designing a method utilising solution equilibria to predict whether secondary mineral species are precipitating or dissolving in the supergene zones of the Girilambone, N.S.W. and North Mungana, Qld. orebodies. Results found could be used to develop new geochemical prospecting methods in the regions discussed.
Doctor of Philosophy (PhD)

This dissertation examines the evolution of the mining industry in three British dominions during the late nineteenth and early twentieth centuries. Adopting a case study approach, it describes the establishment and growth of mining in Rossland, British Columbia; Broken Hill, New South Wales; and Waihi, New Zealand. Separate chapters trace developments in each area, focussing on the emergence of organised labour, the growth of mining companies and the sophistication of mining operations. These underline the need to consider diverse themes, maintaining that the mining industry's pattern of growth can be understood only by adopting such a broad approach. Following the three case studies, the final chapters of the dissertation offer a comparative analysis of Rossland, Waihi and Broken Hill. The study emphasises the similarities of these three communities, especially the cycle of growth, and identifies a crucial common denominator. Despite differences in climate, in the type and nature of the ore deposit and in the scale of mining activity, all three areas experienced a common trajectory of initial boom followed by subsequent retrenchment. The changing character of the resource base forced this fundamental alteration of productive relations. In each region, the mineral content of the ore declined as the mines went deeper. In addition, with depth the ore tended to become more difficult to treat. Faced with a decline in the value of the product of their mines, companies had to adopt sweeping changes in order to maintain profitable operations. This re-structuring was accomplished in a variety of ways, but the most significant factors, common to Rossland, Broken Hill and Waihi, were the heightened importance of applied science and economies of scale. Both developments underlined the growing importance of the mining engineer and technological innovations, principally in milling and smelting operations. In addition, new non-selective extractive techniques reduced the significance of skilled underground labour. The re-structuring of the industry not only had similar causes but also had a similar effect. The comparative chapter on labour relations, for example, argues that these managerial initiatives were closely associated with militant episodes in each community. While the leading companies in Rossland, Waihi and Broken Hill successfully reduced their working costs, they all faced the same ultimate end. Their long-term success or failure reflected the skill with which they coped with the inevitable depletion of their ore body. The common experience of Rossland, Waihi and Broken Hill demonstrates the importance of placing colonial development within a larger context. Regional historians should make greater use of the comparative approach, rather than continuing to focus on the unique and the particular.
Arts, Faculty of
History, Department of
Graduate

This study reports the discovery of a suite of primary lead bromine-substituted chlorides and bromine-iodine substituted oxy-hydroxychlorides which have subsequently exsolved from a sulfogen melt. The implications are that halogens have substituted into sulfide ores at peak metamorphic conditions, during partial melting and exsolved.They provide a direct view of the chemical evolution of the Broken Hill partially melted ore system and may be used as an indicator of coeval melting. The presence of halogens and low melting point chalcophile elements (LMCEs) in these ores suggest that they were introduced together and are a protolith feature. It appears that halogens in the Broken Hill ore deposit were associated with the ores from the outset. Partial melting, melt residue fractionation, enrichment and subsequent mobilisation is predicted. Lead halide compounds have been found in other styles of mineralisation such as Cannington Pb-Zn-Ag ore deposit in NW Queensland and the magmatic Merensky Reef, Bushveld layered complex, South Africa. The highest halogen concentrations recorded in the Broken Hill ore deposit are also confined to the coarse-textured pegmatitic galena. This suggests, that the galena host and a suite of lead halides, represent a bulk composition or final fractionate of a sulfide melt preserved in the post-metamorphic ore deposit at Broken Hill. The halogens have affectively lowered the melting point of the ores at Broken Hill, allowing exsolution of lead halide exsolution lamellae and halide-bearing compounds. A high halogen solubility in galena at regional metamorphic temperatures of ~800{u00B0}C, is a prerequisite for a lowered eutectic. Observed eutectic intergrowth textures, globular textures and low dihedral angle relationships in the ores provide cogent evidence of melting and likely coexisted with an immiscible silicate melt at Broken Hill. Halogen fractionation and partitioning between silicates and sulfides is modeled. Remobilization of massive sulfide orebodies may result from the process of in situ partial melting and liquidus undercooling. Indeed, the lode pegmatite and sulfide ore lithologies at Broken Hill are considered coeval. Halogens are also recorded in the ores of the regional Thackaringa-type deposits of the Consols and Junction Mine lodes. This style of mineralisation is modelled as melt derived. Geochemical and isotopic links are made between the Broken Hill ore deposit and the Thackaringa-type deposits through mobilisation of (LMCEs) and halogens, via F{u2084} fault conduits. The economic implications for partial melting of both styles of mineralisation are profound. Previous experimental work by Mavrogenes et al. (200I), Frost et at. (2002), Kalinowski (2002), Sparks and Mavrogenes (2005) and Wykes and Mavrogenes (2005) provide evidence that partial melting of sulfides occurred. Experimental work in this thesis demonstrates that the solubility of galena in a lead sulfide-halide melt ' sulfogen melt' increases with temperature at a constant pressure of 5 kbar. The behaviour of PbCI{u2082}-PbI{u2082}-PbBr{u2082}-PbS mixtures under high Pressure Temperature define an identifiable eutectic, cotectic relationships as low as 200{u00B0}C, which are well below peak metamorphism conditions of 800{u00B0}C and 5 kbar at Broken Hill. This demonstrates that it is possible for halogen-bearing ore to partially melt and to persist to temperatures well below peak metamorphic conditions. One single experiment performed herein has determined significant melting point depression of pure galena. A general relationship between temperature increase and dissolution of galena into melt above the solidus is established. Melting the PbCl{u2082}-PbI{u2082}-PbBr{u2082}-PbS mixture experimentally suggests a general increase in grain size and in increase in halogen concentration within coarse-grained pegmatitic galena at Broken Hill. The coarse-grained pegmatitic galena is modeled as a product of fractionated and evolved high temperature melts. Thus sulfide melts will accumulate in areas of highest temperatures. A correlation between morphology, temperature and halogen content is established. The Pressure Temperature conditions which formed solid solutions of lead halide and galena phenocrysts in both natural and experimental systems are equivalent. Therefore metamorphic sulfide melting at Broken Hill is fundamentally and theoretically proven to have taken place.

The Broken Hill Zn-Pb-Ag deposit (Australia) is the largest base metal deposit in the world (Large et al. 2005)1. Despite almost 130 years of mining, core logging is still undertaken qualitatively. Most old core has disappeared. The Western Mineralisation is the subject of this study and it is soon to be exploited in the Rasp Mine. The 77 Western Mineralisation drill cores provided an opportunity to statistically evaluate 3,215 surface and underground samples. In this process, 61,696 data were acquired from magnetic susceptibility measurements and quantitative mineralogical, lithological and textural core logging. These data sets were integrated with assay, specific gravity, collar and survey data. The large data sets2 (93,192) were treated by statistical methods such as univariate and bivariate analyses, compositional data analysis, statistical test, linear multivariate regression, cluster analysis, principal component analysis, variogram analysis and univariate ordinary kriging estimation. Moreover, the previous data set of mineral chemistry was evaluated by correspondence analysis, compositional data analysis and principal component analysis. The statistical results were demonstrated in variety of diagrams such as bar diagrams, core log diagrams, contour plots, correspondence map, map of PC loading and PC score, biplot, 3D biplot and 424 cross-sections of the orebody. It was shown that Bi and Sb are pathfinder elements for the Western Mineralisation and that these elements form a broader halo around sulphide masses whereas Ag, As and Cd form a small halo. Galena-sphalerite rich ores have a higher proportion of magnetic pyrrhotite and magnetic susceptibility can be used to evaluate proximity to sulphide masses. Statistical studies suggest that Broken Hill might not be an isolated deposit and that the "next" Broken Hill may not be identical. Predictor elements for Pb are Fe, Ag and Bi and for Zn are Cd, Sb and Ag. Optimal sampling is on 22m and 10m along and across strike respectively and a 20 × 20 × 10 m polygon is the optimum size for block model analysis. The Western Mineralisation at Broken Hill is zoned from a Pb-Zn-S-Cd rich upper portion to a Cu-Ag-As-Bi rich lower portion. Variations within the Western Mineralisation may be primary features but are more likely to derive from intense tectonism. 1 Harvard (UTS) Style - 6th edition (version 2004) has been used for the purpose of citation and referencing. 2 The data base (Excel Format), additional diagrams and satellite maps of this thesis are provided in supplementary files included on a CD to this thesis.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2011

This item is only available electronically.
Seventeen magnetotelluric survey sites were occupied across the Olary and Broken Hill Domains in the Curnamona Province, Australia. Two dimensional modelling along the magnetotelluric profile identifies the Broken Hill Domain as a zone of high electrical resistivity to a depth of 15km. Gravity modelling along a coincident profile has also shown the Broken Hill Domain to be significantly more dense than its surrounds. Seismic data have provided evidence of numerous faults and shear zones within the Pre-cambrian Broken Hill Domain basement, and is indicative of compression during the Delamarian Orogeny. It is proposed that the majority of crustal fluids were removed from these rocks by granulite facies metamorphism and tectonic compression. The boundary of the Olary Domain appears to be delineated by the Mundi Mundi Fault with an order of magnitude increase in resistivity on the Broken Hill side. The location of the Flinders Conductivity Anomaly was also observed and a number of conducting mechanisms considered, including crustal fluids and graphite films.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2002

In technical geological publications it has been demonstrated that Broken Hill Type deposits and their host provinces are characterised by similarities in their geological settings and ore deposit mineralogy at both local and regional scales. The purpose of this thesis was to examine magnetic characteristics of the globally most significant BHT deposits, and their host provinces, in order to develop a magnetic exploration model for BHT deposits. This involved detailed aeromagnetic interpretation of available datasets with reference to mapped geology. Four significant BHT provinces were studied: Broken Hill Block - Australia Eastern Succession, Mt Isa Block - Australia Bergslagen District - Sweden Aggenys -Gamsberg District - South Africa The study showed that host provinces to BHT deposits share common magnetic characteristics which reflect common geological characteristics. However, significant differences in the aeromagnetic character occur which are related to differences in volume of BHT host stratigraphy, basement stratigraphy and structural style of the host province. BHT deposits naturally divide into two classes, based on the presence or absence of magnetic minerals within the ore. This may result from differing ore-forming environments and/or fluid chemistry. Deposits which contain magnetic minerals within the ore are commonly associated with magnetic anomalies which are amongst the strongest within the host meiasedimentary /metavolcanic sequence. Deposits which do not contain magnetic minerals within the ore itself are associated with a locally anomalous signature when the immediate environs of the ore deposit are considered. The most economically signifcant deposit, Broken Hill (Australia), is of this type, although both types include large tonnage deposits. Thermodynamic modelling was undertaken to test whether the variations of magnetic deposit signatures could be explained by variations in the environment of exhalation. The roles of boiling, cooling and seawater mixing (oxidised and reduced) as precipitation mechanisms were examined. The modelling showed that a single fluid can give rise to a spectrum of iron oxide distribution, depending on whether the dominant precipitation mechanism was boiling, cooling, mixing with oxidised sea water or mixing with reduced sea water. Precursors to metamorphosed BHT ore and gangue minerals were produced by several of these thermodynamic models. It is concluded that the interpreter, when defining the likely spectrum of magnetic responses of a BHT deposit, must consider the likely range of environments of deposition consistent with known geology.

Secondary minerals, formed at low temperature, are the product of the oxidation of primary sulphide ore bodies. The formation and mineralogy of oxidized zones, which phases are stable and which are not, and how toxic heavy metals become incorporated into the crystal structures of the constituent minerals have implications for the heavy metal mobility in the environment and in the disposal of heavy metal and the remediation of contaminated sites This thesis presents an inverstigation of the the crystal chemistry of a suite of Cd, Pb, Zn, Cu, Se and As oxysalt minerals from Broken Hill, NSW; the new mineral species plimerite, nyholmite, liversidgeite and edwardsite, as well as gartrellite, munakataite, osakaite and cadmian serpierite. Crystal structures were studied using single-crystal X-ray diffraction data, in conjunction with the results from electron microprobe analysis, powder X-ray diffraction, infrared absorption spectroscopy, Raman spectroscopy and Mössbauer spectroscopy. The crystal structures are classified according to the mode of polymerization of strongly bonded coordination polyhedra: chains, sheets or frameworks. The chemical compositions of the minerals and their stabilities are discussed in terms of a combinination of hierarchical ordering, bond-valence theory and the valence-matching principle. For the first time in natural minerals, extensive solid solutions involving cadmium have been observed. Solid solutions between Cd and Zn (in nyholmite), Cd and Ca (in serpierite), and Cd and (Pb+Ca) (in sampleite-lavendulan-zdenekite and conichalciteduftite) are examined. The minerals examined in this study have implications for the mobility of heavy metals in the environment and in remediation of heavy metal contaminated sites.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2010

Broken Hill Type lead-zinc-silver deposits (BHT) are a sought after style of mineralisation because of their simple metallurgy and high metal grades. The purpose of this research project is to gain a deeper understanding of the complex BHT style of mineralisation through a comprehensive re-examination of the structure and stratigraphy of the 300 million tonne, multiply deformed and metamorphosed, type example, located at Broken Hill, in far western New South Wales, Australia. This study used the techniques of structural analysis of high-grade gneiss terrains and exploited 119 years of geological data collected during the mining exploitation and exploration of the Broken Hill (BH) mining field. The gneissic sulphide-silicatecarbonate rocks of the BH ore environment lend themselves well to such structural studies because of their mineralogical diversity, coarse grain-size and because of the presence of distinctive and persistent marker units. The result is a deposit-scale stratigraphic and structural model of this complex mineralised system, which allows an unparalleled view of the 'anatomy' of this giant deposit. The Palaeoproterozoic BH mineralised system is a stratified complex that contains at least nine separate economically significant mineralised horizons, known as 3 Lens (lowest); 2 Lens; 1 Lens Lower; 1 Lens Upper (southern 1 Lens); A Lode Lower (Southern A Lode); A Lode Upper and B Lode. It is hosted within a sequence of metasedimentary and metavolcanic rocks, and coeval intrusives, known as the Willyama Supergroup, a multiply deformed upper amphibolite to granulite fades gneiss terrane. The deposit lies at the southwestem end of a lens of quartzofeldspathic and mafic rocks on the boundary between the Thackaringa and Broken Hill Groups. The quartzofeldspathic and mafic rocks are interpreted to be a metamorphosed volcanic complex. A distinctive Mine Sequence hosts the orebodies and their distal equivalents and has been identified over a 25-kilometre strike length. It is a continuous sequence from the basal Footwall Quartzofeldspathic Gneiss to the Hangingwall Quartzofeldspathic Gneiss (interpreted to be an intrusive), but has considerable stratigraphic complexity. It can be subdivided into a Footwall Succession, Lode Sequence (host to the mineralisation) and a Hangingwall Succession. The Lode Sequence can be further subdivided into several lode rock units and associated metasediments in the southwestem and central parts of the field, including the '4.5' Horizon; the Upper Potosi Type quartzofeldspathic Gneiss; the B Lode Horizon and the Gamet Quartzite Horizon. In the near-ore position, the Footwall Succession is represented by the 'underwall zone', which is distinguished by a marked thinning of key horizons and interbedded elastic metasediments. Manganiferous garnet-rich rocks of various types and textures are associated with the main orebodies, as are calc-silicate-rich horizons, magnetite-bearing metasediments, thin "banded iron formation", and mineralised psammite. The orebodies and their wall rocks have been affected by two major periods of regional metamorphism (Ml and M2). Ml coincided with the Olarian Orogeny and two protracted deformational events; D2 and D3, which commenced at or immediately prior to the peak of metamorphism. D2 took place at the culmination of Ml and D3 as it waned. Most deformation of the mineralised system took place during D2 and the first phase of D3 (D3A). Dl is only represented in the Mine Sequence by a pervasive Sl schistosity and by pegmatite dykes and melt segregations. M2 coincided with the Delamerian Orogeny and D4. Only a single phase of granulite to upper amphibolite grade regional metamorphism is recognised in the BH area. High grade, south verging, asymmetric F2 folds comprise all of the significant macroscopic folds in the Mine Sequence and cause much of the present orebody 'geometry. They are parasitic to, and lie within the north limb of, a major regional F2 antiform; the Airport Antiform. The intensity of F2 folding is greater in the northeastem end of the field and is associated with a pervasive galena-defined S2 axial plane foliation in 3 Lens and 2 Lens. Folding and transposition equally affected both ore and adjoining wall rocks. SO banding and syndepositional stratigraphic variations within the orebodies are folded around F2 axes and modified by syn-D2 mobilised sulphides. F2 folds also deform a well-defined layering in 2 Lens, B Lode and A Lode Lower. All significant fluid phase sulphide mobilisation, and most mechanical sulphide mobilisation, took place within the orebodies during D2 and D3A. There is continuity from D2 folding to early retrograde (granulite to upper amphibolite grade) D3A ductile shearing and attenuation. D3A shearing extensively modified the folded geometry of the mineralised system, dislocating and attenuating F2 folds and producing a series of deposit-wide, anastomosing shear arrays in which narrow (<15m), but intense D3A shears traverse the Lode Sequence at acute angles. D3A shears have a north block up, sinistral sense of movement, with horizontal displacements of up to 350 metres and the effects of shearing were particularly focussed in F2 fold limbs, and synformal keels that contained large masses of metasediment-hosted ore. D3A shears contain locallised occurrences of mesoscopic F3 folds with a well-defined sillimanite biotite axial plane fabric (S3), and planes of intense transposition. Each successive stage of D3 is characterised by progressively lower grade metamorphic mineral assemblages in ore and wall rocks, and the styles of deformation reflect decreasing ductility. The differing styles of deformation are interpreted to reflect stages in the waning of Ml. D3B shearing is characterised by a lower amphibolite to greenschist grade mineralogy, and is recognised as belts of quartz-muscovite-biotite schist that are mainly focussed in areas strongly deformed during D3A. The effects of D3B are not evenly distributed in the mining field and the northeastem part of the deposit has been particularly influenced by these structures. M2 affected the orebodies during the Delamerian Orogeny and locally exceeded greenschist grade. M2 was associated with a fourth period of deformation (D4). Within the orebodies, it caused the re-activation of Olarian D3A-D3B shears and produced a generation of brittle fault systems. Transgressive dolerite dykes intruded the ore system in three main belts. There were at least two distinct phases in D4, an earlier, relatively high-grade phase, D4A, which reached lower amphibolite grade in places and with locally higher grades in faults associated with hydrothermal activity, and a subsequent D4B phase, which was possibly a distinct reactivation event. D4A was associated with locallised ductile deformation, in the form of F4 folds, and caused the major reversal in F2 plunges in the central mining field. F4 folds are closely associated with complex fault zones, such as the British Fault System, and refold the main orebodies. Mechanical sulphide mobilisation dismembered dolerite dykes within 2L and 3L. Hydrothermal activity along D4 faults produced alteration within mineralisation, including sulphide mobilisation and impregnation on the margins of the dykes. D4 had particularly widespread effects in the northeastem part of the mines area, being mainly manifested as brittle-ductile to brittle deformation that is most commonly represented by the development of the extensive fault, joint and fracture systems. D4 faults, dykes, folds and quartz-siderite galena veins overprint Olarian structures within the orebodies. The elongate geometry, and the stratigraphy of the BH mineralised system predate all of the deformation that has affected the region and it preserves syn-depositional textures, internal stratification and layered gangue mineral distributions that predate Dl pegmatite intrusion. The stratigraphy of the mineralised complex is tectonically modified but the succession can still be readily discerned and the stratified orebodies and their associated 'lode rocks' are concordant with the surrounding stratigraphy. Structural fabrics have been formed in the ores and in their wall rocks during D2 to D4 and each of these events has affected Dl pegmatite intruded into the mineralisation and host sequence. F2 folds traverse the Lode Sequence stratigraphy, including the Gamet Quartzite Horizon and five orebodies retain a trend that is 20° clockwise of the F2 hinge orientation. D3 shear zones have subsequently accentuated the elongate form of the system. The effects of D3 shears have not been profound however, and they are confined to relatively narrow and discrete planes. There has not been any large or medium scale tectonic mobilisation of syngenetic mineralisation into structural sites during D2 and the ore has not been moved on a mass scale by deformation. The high aspect ratio of the mineralised system is interpreted to be a primary feature and the orebodies are still largely in their site of deposition, relative to the surrounding stratigraphy. The orebodies and most lode rocks were in place, as a series of strongly elongated, lenticular bodies of sulphide-silicate-calcite mineralisation and manganiferous rocks prior to deformation and metamorphism. The relationships between the stratigraphy of the mineralised system and the structures that have modified its geometry show that the BH orebodies are a part of the sedimentary succession in which they lie, and have been deformed and metamorphosed along with the other rocks with which they are interlayered. Empirical exploration models for BHT style mineralisation have been developed, based on the findings of this comprehensive reexamination.

Lead contamination is one of an extensive list of chronic environmental hazards which are being faced by an increasing number of communities worldwide. The potential biophysical effects of young children's exposure to relatively low levels of lead are widely recognised. In response to this awareness, policies and programs are being designed and implemented with the aim of reducing potential lead exposure. In addition to their significance for children's biophysical health, the success of these policies also have implications for the well-being of the children, families, and communities involved. This thesis argues that an understanding of the ways in which communities respond to environmental lead contamination is important for the development and implementation of appropriate interventions. This thesis examines community responses to chronic environmental lead contamination in Broken Hill, Australia, a community which is also dealing with mining industry retrenchments. It examines the nature of cognitive and behavioural coping responses, and the resulting effects on the health and well-being of the community and community members. It also examines how responses to the retrenchments interact with the community responses to lead contamination in a cumulative manner, and how mediating factors interact with the community response process. In order to shed light on this complex process, this interdisciplinary study draws together environmental stress and coping, social impact assessment, public health, and community responses to environmental contamination theory. Fieldwork conducted over nine months during six visits included the use of participant observation and in-depth interviews with parents with young children, retrenched workers and their families, and other Broken Hill residents. Interviews were also held with representatives of organisations. The research method proved to be useful for meeting the research aim, and for respecting research participants and the sensitive nature of the research topic. After becoming aware of the lead contamination, community members responded with cognitive minimisation of the lead contamination threat, containment of the threat to the family level, predominant use of private rather than public responses, and individual rather than collective coping strategies. The lead contamination, mediated by this coping process, had the effect of increasing stress and stigma for parents and families of young children most directly affected, reducing stress and stigma for other community members, increasing cooperation between local organisations, and weakening of community social networks. This process was mediated by the characteristics of the contaminant, characteristics of individuals, aspects of the social setting, and responses of organisations. The nature of the lead contamination, and individual residents' perceptions of its controllability interacted with the community response process. The aspects of the social setting which affected the community response process are cultural assumptions, beliefs and values, stigma, relationships between the mining company and the community, social support and undermining, social influence, and economic factors. Responses of organisations, including intervention programs, were also important. Responses to the mining retrenchments interacted within the community response process. A model of community responses to chronic environmental lead contamination in Broken Hill is developed. This thesis argues that health policy needs to focus on positive health and well-being, and should be guided by three principles- a focus on the community rather than individual and family levels, the aim of supporting parents, and communication. Such a reoriented approach will support the efforts of communities and community members to cope with chronic environmental lead contamination in an effective and equitable manner.

Creative Work: The novel Blessed Kiss Blessed Kiss is set in a Roman Catholic seaside parish in Adelaide in 1960-61. Patrick and Margaret Carlow’s marriage is under strain because of Patrick’s secret affair with Fay Netley, a shop assistant he met in a Broken Hill pharmacy while on one of his outback sales trips as a commercial traveller. As the affair deepens and Fay moves to Adelaide to be closer to him, Patrick’s marriage starts to unravel as Margaret worries that something is very wrong. While his parents are preoccupied with their own problems, their nine year old son Michael comes ever more closely under the eye of their parish priest, Father James Quinlan, and in the end Margaret must choose between acting on her suspicions regarding her parish priest, and her faith itself, to save her son. Exegesis: The Author Is The Book The exegesis examines the creative work Blessed Kiss in the light of the history and identity of its author, and progresses to a critique of Roland Barthes’ essay “The Death of the Author”, rejecting the notion of inauthenticity in favour of the work embodying the author.
Thesis (Ph.D.) -- University of Adelaide, School of Humanities, 2011

The Cannington Ag-Pb-Zn deposit is located in the southeastern area of the Palaeo- to Mesoproterozoic Mount Ise lnlier, northwest Queensland. The orebody is totally concealed beneath 10- 60m of flat-lying, semi-lithified Cretaceous to Recent sediments of the Eromanga Basin. The deposit constitutes an economic resource of 43.8 million tonnes (Mt) at 11.6% Pb, 4.4% Zn and 538g/t Ag, and currently the mine is the world's largest Pb and Ag producer. The deposit has been classified as a classic Broken Hill-type (BHT) Pb-Zn deposit based on remarkably similar geochemical, mineralogical and host rock affinities to the giant -280Mt Broken Hill deposit in New South Wales, Australia; the holotype of the BHT classification. Conjecture over the genesis of the Cannington deposit has arisen because of two disparate lines of thought. Metamorphogenic models assume that ore textures, mineralogies and chemistries are a record of the primary ore formation process, whereas syngenetic models consider that the same characteristics have been extensively modified by post-depositional deformation and metamorphism. As a result, premetamorphic and metamorphic-metasomatic models have been proposed. This thesis contributes to this debate by integrating geological, paragenetic, geochemical and isotopic constraints to identify the most plausible genetic model. Cannington is hosted by migmatitic gneiss with intercalated pegmatites, amphibolites, minor quartzites and rare Fe-Mn silicate (± sulphide) units. Various lines of evidence indicate that the gneiss represents metamorphosed, immature, siliciclastic sediments that were deposited during the early stages of intracontinental rifting ca. 1675 Ma. The migmatitic gneiss grades into a 250m-wide sillimanite-garnet schist and garnetiferous quartzite ore envelope that is interpreted to be a metamorphosed hydrothermal alteration halo genetically related to ore formation. Gahnite-bearing schists are a less common, but important component of the envelope. The host succession was subjected to polydeformation and high-P/low-T metamorphism related to dominantly west-vergent folding and thrusting during the lsan Orogeny between ca. 1600-1480 Ma. Using a combination of mineral equilibria and cation exchange thermobarometers, M1-M2 metamorphism is characterised by an anti-clockwise P-T-t path, with peak metamorphic conditions (Mi) of -730-750°C and 5-6kbar; consistent with upper amphibolite to transitional granulite facies conditions. It was during MI that substantial anatectic partial melting of the host metasedimentary succession occurred ca. 1580 Ma. This was followed by a retrograde M2 event that involved the ingress of metamorphically-derived, acidic fluids and the development of characteristic secondary sillimanite shear fabrics (S2). Third generation recumbent folding and thrusting resulted in the development of the Cannington Synform and Footwall Shear; an interpreted fold-thrust pair. The Cannington Synform controls the gross geometry of the deposit, resulting in repetition of ore lenses in the structural hanging wall and footwall. The Footwall Shear truncated ore lenses in the lower, attenuated limb of the Cannington Synform. A fourth generation of deformation (D4) appears to be related to a transient thermal perturbation (M3) initiated by the intrusion of voluminous granitic melts of the Williams-Naraku Batholith ca. 1520 Ma. D4 has a moderate effect on the geometry of the deposit, and is manifested by an open, upright synform. D5 represents a change in deformation style to a brittle regime. Two generations of subvertical faults overprint the orebody and locally offset ore lenses by up to 50m. The youngest of these generations comprises a conjugate fault set. Mineralised rocks can be divided into graphitic, Fe-Mn silicate and siliceous types, based on differing mineralogies, metal zonation and Fe, Mn, Pb and Zn concentrations. Textures are extremely variable depending on the ore type, and include: i) laterally continuous, millimetre to centimetre-scale compositional banding; ii) granoblastic sulphide-silicate textures with spheroidal sulphide inclusions in silicate minerals; iii) durchbewegt textures; iv) anastonnosing mylonitic zones in fluorite-magnetite-rich ores, and; v) quartz-sulphide breccias. The paragenesis of the deposit has been divided into three principal stages based on mineralogical assemblages and temporal relationships to deformation and metamorphic events recorded in the host metasediments and proximal garnetiferous alteration halo. Stage /: peak metamorphic assemblages comprise anhydrous minerals in sulphide-bearing graphitic, olivine and hedenbergite ores; Stage Ha: retrograde syn- to post-D2 metasomatism associated with anhydrous alteration assemblages (hedenbergite-garnet-quartz-pyroxferroite) and silicification; Stage Ilb: amphibole veining and alteration, and minor sulphide deposition; and Stage Ilc: syn- to post-M3 pyrosmalite-magnetite alteration associated with abundant secondary sulphides, sulphosalts and antimonides; Stage ///: syn to post-D5 quartz-carbonate-chlorite alteration, temporally and spatially associated with two generations of subvertical faulting. The Stage Ila hedenbergite-garnet-quartz metasomatism and silicification produced a range of protolith-dependent metasomatic ore types such as siliceous Pb-Zn-Ag and siliceous Zn ore breccias. Overall, syn- to post-D2 metasomatism resulted in reworking and zone-refining of the deposit via localised solution-associated remobilisation of sulphides. Granoblastic sulphide-silicate textures and spheroidal sulphide inclusions in Stage I olivines and magnetite are consistent with the presence of sulphides prior to peak metamorphism. The presence of pseudomorphic bow-tie textures and relic inclusion trials (Si) in garnet porphyroblasts in graphitic ores, indicate that the timing for ore formation can be traced back through prograde metamorphism to pre- Ism Orogeny times. This is supported by cation exchange thermometric estimations that record the prograde evolution of the ores. Compared to migmatitic gneiss, sillimanite-garnet and gahnite-bearing schists have higher K/Na ratios and anomalous Mn, Pb and Zn concentrations. The most significant mass changes associated with alteration of gneissic protolith to sillimanite-garnet and gahnite-bearing schist involved mass gains in K, Mn, Pb, Zn and Rb, and losses in Si, Fe, Mg, Na, Sr and Ba, with average, absolute net mass gains of 0.8g/100g and 5.9g/100g respectively. On the basis of immobile elements (Ti, Zr, Al) graphitic ores contain a pelitic detrital component. Mass balance calculations between an average pelitic gneiss precursor composition and graphitic ores indicate absolute net mass gains between 25.0g/100g for samples that contain the highest proportion of pelitic detritus, to >1000g/100g that contain the least. Such large net mass changes can be explained by the presence of hydrothermal components in the ores, in addition to pelitic detritus. Chondrite-normalised REE signatures are characterised by LREE-enrichment and strong positive Eu anomalies, similar to hydrothermal fluids and chemical sediments proximal to mid-ocean ridge hot springs. Calculated hydrothermal REE signatures are characterised by strong positive Eu anomalies when normalised to the local host gneiss. The data are consistent with the interpretation that graphitic ores are metamorphosed chemogenic sediments. 613C signatures of graphite in graphitic ores range between -27%. to -25%., consistent with a biogenic origin. The preservation of carbon is best accounted for by an anoxic environment if a synsedimentary origin is assumed. The data do not support a retrograde metasomatic model for ore formation. Paragenetically constrained Pb isotope signatures were determined on various ore types, and host rocks. Stage I and II galenas plot as a distinct linear cluster oriented along the machine fractionation trend, but within the limits of the precision ellipse. Most of the data plot just below the average crustal growth curve, and compared to other Proterozoic sediment-hosted Pb-Zn deposits in northern Australia (e.g. McArthur River and Mount lsa), have more primitive p values similar to other BHT deposits, such as Pegmont (30km west of Cannington) and Broken Hill in New South Wales. A strong correlation between Pb isotope signatures from Stage I and II galenas indicates that syn- to post-D3 metasomatic fluids sourced Pb from pre-existing Stage I ores and that significant exotic Pb was not introduced. Stage III galena and amazonite in lode pegmatites inherited their Pb isotopic signatures from pre-existing galena, as well as from radiogenic Pb in gneissic and garnetiferous rocks. The Pb isotope data also reveals that Stage I Pb was not sourced from the nearby granites, or the host metasediments. The available evidence suggests a more primitive, exotic source that is not exposed in the region. Development of a terrain-specific Pb isotope model for the Mount Isa region suggests that mineralisation was deposited at -1675 Ma. This age coincides with maximum depositional ages of ca. 1680 Ma (zircon U-Pb SHRIMP date). It provides further evidence that the orebody formed in a synsedimentary environment. Ore textures, thermobarometric estimates, 813C, Pb isotope systematics and geochemical affiliations, combined with U-Pb zircon ages, provide firm evidence for a synsedimentary timing for ore formation. This is further supported by the fine-scale laterally continuous and compositionally diverse banding in graphitic ores that are interpreted to represent chemogenic sediments with a variable detrital pelitic component. Precursor authigenic hydrothermal assemblages are likely to have been dominated by variable proportions of Fe-Mn carbonates (manganoan siderite and ankerite), fluorapatite, fluorite, magnetite, Fe-Mn chlorites (chamosite, greenalite) and clays, quartz, biogenic matter (kerogens) galena, sphalerite, pyrrhotite, antimonides, arsenopyrite and minor chalcopyrite. These assemblages are consistent with a reduced, anoxic environment where EH2S»ESO42" was maintained during ore deposition in an otherwise oxidised basin. Metal solubility data and interpreted precursor mineralogies suggest that the weakly acidic to neutral (pH -5.5), hypersaline (-15-25 wt% equiv. NaCI), hot (250-300°C) ore-forming fluid contained low ES (10-3-104m) high ECO2 (-1m), Emetals»ZS. In consideration of these aspects and the chemogenic nature of graphitic ores, a fluid of this composition would, upon discharge into oxidised seawater, form a dense brine pool in topographic depressions on the seafloor. A brine pool model provides the best explanation for the existence and long-term maintenance of an anoxic, reduced environment that was insulated from the surrounding oxidised seawater. It also provides an explanation for the lack of barite and/or anhydrite in the ores. Pb isotopes suggest that metals were sourced from exotic rocks that are presently unexposed. This aspect leaves scope for a speculative model involving the generation of hydrothermal fluids via partial melting and concomitant metasomatism of mantle derived mafic melts related to underplating in the middle to lower crust during intracontinental rifting. This implies that deep-seated extensional structures facilitated the rapid advection of ore-forming fluid to the ocean floor.

Masters Research - Master of Philosophy (MPhil)
Background: Elevated blood lead levels (PbB) have been shown to reduce mental function in children. Broken Hill has been an important lead/zinc mining town for more than 100 years. The mine is in the middle of the town, the sire is arid and often with little ground cover. Approximately 400 children are born each year in Broken Hill. Fatal lead poisoning of dogs is common. Aim: To monitor blood lead levels in preschool children and identify risk factors for elevated PbB in the community as part of a program to manage PbB in young children. Methods: The work consists of a cross sectional study of 864 children in 1992, a case control study of 300 children conducted in 1992 and a cross sectional study of 478 children conducted in 1993. The work also uses data from a prevalence study of 899 children conducted in 1991. The children were recruited as volunteers with over 70% of children in the older age groups participating over the study period. Venous blood was collected from the children, soil and other environmental samples taken, and questionnaires completed. Results: The geometric mean PbB was 16.3μg/dl in 1991 but decreased steadily to 12.7μg/dl in 1993. The percentage of children with PbB>25μg/dl decreased from 21.0% to 9.6% and the percentage with PbB>10μg/dl decreased from 84.5% in 1991 to 68.5% in 1993. Risk factors for elevated PbB included soil lead level where the child lived, amount of dirt eaten, frequency of playing in dirt and sandpit, frequency of vacuuming, frequency of changing vacuum filter, hand washing, time spent playing outside, percentage of the yard that was bare dirt and frequency of hand washing. Soil lead levels were elevated but were similar to or lower than those in other mining communities. Unlike other mining sites (PbB is often not elevated), the lead species in Broken Hill are highly bioavailable and the particles are often finely divided. Conclusions: PbB in preschool children was elevated in 1991 and declined significantly over the next two years. The number of children with very high PbB has been halved. The results of the work were used to manage individual cases, produce pamphlets, media releases and a video for Broken Hill parents, influence NSW government, local government and industry practices, and to lobby for funds to continue the management of the situation. The decline in PbB has continued after the completion of this work with the establishment of the Broken Hill Environmental Lead Centre. Awareness of lead and its management in the environment of young children in Broken Hill is now more commonly accepted as standard practice for both parents and also government/industry.

The aim of this thesis is to determine the relative contribution of lateral, as opposed to vertical, dispersion of the geochemical signals of basement-hosted mineralisation in prospective geological provinces that are mantled by transported cover. The study focuses on three areas within and on the margins of, the highly-mineralised Broken Hill Block and the Barrier Ranges in western New South Wales. Fowlers Creek overlies low-grade metasedimentary bedrock with no known mineralisation on the eastern margins of the Barrier Ranges. Stream sediments show a downstream decreasing trend in concentrations in both Pb and Zn with values decreasing by 50% over 7 km of creek. Lead and Ag values were less important along Fowlers Creek in terms of biogeochemical results, with concentrations at background levels Pb 0.27 ppm and Ag 3.04 ppb. Rather, elements of interest along Fowlers Creek included; Cs, Y, U, Co and Ni. These elements peaked at 2 distinct points along the creek, by an order of magnitude above background, at points where the local geology interrupts the flow of the stream base aquifer (SBA). Pine Creek cross-cuts the partially exposed Pinnacles Pb-Zn-Ag mine. Stream sediment samples contain elevated concentrations of Pb, Zn and Ag (Pb 4.5x and Ag 3.5x background values observed along Fowlers and Umberumberka Creeks) for at least 4.5 km downstream of mineralisation. River red gum (RRG) leaves from trees within the creek provided the clearest delineation of the underlying mineralisation. Lead and Ag concentrations steadily increase toward mineralisation and reach concentrations 2.5 orders of magnitude above background immediately above mineralisation. Leaf samples collected after a severe El Niño event where the previous year’s rainfall was 188 mm, had Pb and Ag concentrations 5 -10 times greater than samples from the same trees collected after a La Niña event where the previous year’s rainfall was 605 mm. These results demonstrate that changes in available water plays on the SBA and the significant role it plays in diluting the resulting metal concentration within the trees and the importance of temporal variation. Umberumberka Creek is underlain by high-grade metamorphic rocks with numerous small mineral occurrences. Umberumberka Creek discharges at the western margin of the Broken Hill Block as an alluvial fan system which extends at least 10 km onto the Mundi Mundi Plain. This area is underlain by prospective bedrock but is buried by up to 150 m of transported sediments. On the plains, stream sediment results reflected a catchment average that was carried 10 km onto the plains before values decreased. Silver results on the plains had a mean value of 30 ppb and are comparable to soil survey results obtained by an exploration company over an area of Pb-Ag-Zn mineralisation identified beneath 150+ m of cover, situated on the fan floodout boundaries of Umberumberka Creek. The biogeochemical results for Umberumberka Creek fall within the same range of values as Fowlers creek, suggesting that these values are the natural background range for RRG. Results from both the stream sediments and the RRG suggest that the soil survey results obtained on the plains most likely reflect lateral dispersion from the Broken Hill Block rather than a vertical signal from below. For the Broken Hill Block lateral dispersion is kilometric (at least 10 km) in creeks and distributive depositional systems. The signal is diluted due to catchment averaging but can still be elevated above background thus obscuring potential vertically transported signal from bedrock. The RRG provide a mechanism to see vertically down to the basement at depths of 10s of meters (Pine Creek and to an extent along Fowlers Creek) but don’t give a signal when the depth to the source is 100s of meters. For the exploration industry to be successful in areas of thick transported cover it becomes ever more important to step back from there anomalies and see where they sit within the bigger landscape picture and temporally within the exploration program
Thesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2017

The research in this study consisted of two strands. The first consists of noble metal geochemical studies and the second involves base metal supergene processes. The precious metal geochemistry carried out in the scope of this thesis involves palladium and tellurium geochemistry, surface chemistry studies of palladium-bismuth- and tellarium-bearing synthetic minerals, and electrochemical determinations of the inactivity of a variety of primary telluride minerals and alloys. Two new minerals have been found in deposits near Broken Hill, N.S.W. The second section of the research concerns itself with supergene processes in two copper-bearing orebodies. This was carried out by designing a method utilising solution equilibria to predict whether secondary mineral species are precipitating or dissolving in the supergene zones of the Girilambone, N.S.W. and North Mungana, Qld. orebodies. Results found could be used to develop new geochemical prospecting methods in the regions discussed.

Fe-rich tholeiites intruded the lower Etheridge Group of the Georgetown Inlier of north Queensland during the late-Palaeoproterozoic (ca. 1680-1640 Ma), during a prolonged period of rift-related sedimentation associated with extension in the Georgetown basin. The tholeiites comprise two lithologically distinct units: the extrusive Dead Horse Metabasalt (DHM), a conformable 1000m-thick series of fine- to coarse-grained basalts and pillow lavas; and the intrusive Cobbold Metadolerite (CMD), a multitude of sills and lesser dykes that range from a few metres to over 500 m in thickness. U-Pb LA-ICPMS dating of igneous zircons indicate the tholeiites were intruded in at least two pulses. The first coincided with the extrusion of the DHM and associated CMD sills at ca. 1670 Ma, while a younger pulse occurred during the deposition of the overlying Lane Creek Formation at ca. 1640 Ma. The DHM and CMD are co-magmatic, and have compositions typical of relatively evolved, low-K, Fe-rich continental tholeiites and tholeiites generated in plume-triggered volcanic passive margins leading up to continental breakup. Immobile major and trace element patterns suggest that the tholeiites were derived from partial melting of the convecting depleted upper mantle depleted mantle melt, and melts evolved along a trend of increasing Fe-enrichment to strongly Fe-enriched (21.11 wt% total Fe as Fe\(_2\)O\(_3\)) ferro-tholeiites. Initial ε\(_{Nd}\) values range between +2.6 and +5.3 (average +4.0), confirming a depleted mantle source for the tholeiites. T\(_{DM}\) ages range between 1.85 Ga and 3.39 Ga (average 2.5 Ga). Several samples show slight LILE- and LREE-enrichment and have low initial ε\(_{Nd}\) values (+2.6-2.9) consistent with limited crustal contamination involving local host sedimentary rocks of the lower Etheridge Group. Between ca. 1600 and 1500 Ma, the lower Etheridge Group was deformed and metamorphosed by at least two regionally significant orogenic events. The first event (D\(_1\)) was the most intense, producing a pervasive foliation and metamorphism (M\(_1\)) that varied in intensity from upper amphibolite facies in the east, through to lower greenschist facies in the south-west. Metasediments in the south of the inlier record P-T conditions of up to 650°C and 7.5 kbar for M\(_1\). D\(_1\) was followed by a period of retrogressive metamorphism that lasted until ca. 1550 Ma, when voluminous granitoids of the Forsayth Batholith were intruded into the lower Etheridge Group. High-temperature, low-pressure metamorphism (M\(_2\)) was associated with this event. Initial P-T conditions for M\(_2\) are inferred from a retrogressive mineral assemblage that returned conditions of 550°C and 3 kbar. EMPA monazite dating returned a possible ca. 1585 Ma age for M\(_1\) and a ca. 1550-1530 Ma age for M\(_2\). A younger monazite population (ca. 1500 Ma) suggests either M\(_2\) continued for a further 30-50 million years, or an additional weak thermal event affected the Etheridge Group at this time. The DHM and CMD are broadly correlated temporally and geochemically to basic gneisses of the Broken Hill Group in the Willyama Inlier, and amphibolites of the Soldiers Cap Group in the Mt Isa Eastern Succession. In particular, immobile trace element ratios and REE patterns between these tholeiitic suites are virtually indistinguishable. The crystallisation ages of the DHM and CMD, as determined by U-Pb LA-ICPMS zircon dating also closely resembles established ages for the Broken Hill (ca. 1685 Ma) and Mt Isa Eastern Succession (ca. 1670 Ma) tholeiitic rocks. This relationship is of regional significance, as it suggests the terranes were spatially associated during the Palaeoproterozoic, and places the Georgetown Inlier within the Proterozoic framework of northern Australia, and likely a part of the North Australian Craton in the Palaeoproterozoic.

"Two independent geochronological techniques specifically targeting post-kinematic or late-stage growth of kyanite, staurolite and late-stage garnet in the southern Curnamona Province has found that these minerals grew during the Delamerian Orogeny (~530-500 Ma). Prograde metamorphism during the Delamerian Orogeny attained kyanite-staurolite-garnet grade (amphibolite-facies). Previous interpretations of an anticlockwise P-T path for the Olarian Orogeny need revising, as these interpretations have been shown in this study to be based on textural relationships spanning ~1100 million years. This highlights the importance of in situ geochronological techniques in defining robust P-T-t paths for a region." --p. 121 of source document.
Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2006.