Academic literature on the topic 'IOCG(U)'
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Journal articles on the topic "IOCG(U)"
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Sillitoe, Richard H., Georgi Magaranov, Veselin Mladenov, and Robert A. Creaser. "ROSEN, BULGARIA: A NEWLY RECOGNIZED IRON OXIDE-COPPER-GOLD DISTRICT." Economic Geology 115, no. 3 (May 1, 2020): 481–88. http://dx.doi.org/10.5382/econgeo.4731.
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Abstract The Rosen copper veins in southeastern Bulgaria are recognized for the first time as an iron oxide-copper-gold (IOCG) district. The veins are located in the East Srednogorie segment of the Carpathian-Balkan calc-alkaline volcano-plutonic arc and were formed during an end-stage interval of extreme slab rollback and intra-arc rifting, which gave rise farther east to seafloor spreading in the Western Black Sea basin. The resulting submarine volcano-sedimentary rift basin is dominated by intermediate to mafic shoshonitic to ultrapotassic volcanism and subsidiary gabbro to syenite intrusion. The E- to NE-striking veins define a NW-striking alignment along the western contact of the syenite-dominated Rosen pluton, inferred to be part of a large ring dike. More than 40 veins, the most important formerly mined to depths as great as 1,000 m, contain an early, pegmatoidal, calcic-potassic assemblage followed by predominant magnetite (including the mushketovite variety), chlorite, and carbonates but also quartz, chalcopyrite, pyrite, and numerous other metallic minerals, which combine to give an unusual Fe-Cu-Au-Mo-Co-Ni-U-light rare earth element (LREE)-W-Bi-Zn-Pb geochemical signature. The close correlation between Fe, Cu, U, and LREEs is evident even in the flotation tailings. Vein molybdenite was dated during this study at 80.6 ± 0.4 Ma, which is similar to a U-Pb zircon age for monzosyenite from the Rosen pluton. The mineralogic and compositional features of the Rosen district are comparable to those of well-known IOCG deposits worldwide and geometrically similar to the vertically extensive IOCG veins in the Coastal Cordillera province of northern Chile. The subsidiary granitophile signature that accompanies the characteristic siderophile IOCG suite was also recognized recently at the giant Olympic Dam deposit in South Australia and elsewhere. Although no exposed intrusion is definitively implicated in the genesis of the Rosen veins, coexisting gabbro and syenite fluid sources may be hypothesized at depth in or beneath the coeval ring dike.
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Brotodewo, Adrienne, Caroline Tiddy, Diana Zivak, Adrian Fabris, David Giles, Shaun Light, and Ben Forster. "Recognising Mineral Deposits from Cover; A Case Study Using Zircon Chemistry in the Gawler Craton, South Australia." Minerals 11, no. 9 (August 25, 2021): 916. http://dx.doi.org/10.3390/min11090916.
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Detrital zircon grains preserved within clasts and the matrix of a basal diamictite sequence directly overlying the Carrapateena IOCG deposit in the Gawler Craton, South Australia are shown here to preserve U–Pb ages and geochemical signatures that can be related to underlying mineralisation. The zircon geochemical signature is characterised by elevated heavy rare-earth element fractionation values (GdN/YbN ≥ 0.15) and high Eu ratios (Eu/Eu* ≥ 0.6). This geochemical signature has previously been recognised within zircon derived from within the Carrapateena orebody and can be used to distinguish zircon associated with IOCG mineralisation from background zircon preserved within stratigraphically equivalent regionally unaltered and altered samples. The results demonstrate that zircon chemistry is preserved through processes of weathering, erosion, transport, and incorporation into cover sequence materials and, therefore, may be dispersed within the cover sequence, effectively increasing the geochemical footprint of the IOCG mineralisation. The zircon geochemical criteria have potential to be applied to whole-rock geochemical data for the cover sequence diamictite in the Carrapateena area; however, this requires understanding of the presence of minerals that may influence the HREE fractionation (GdN/YbN) and/or Eu/Eu* results (e.g., xenotime, feldspar).
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Courtney-Davies, Liam, Cristiana L. Ciobanu, Simon R. Tapster, Nigel J. Cook, Kathy Ehrig, James L. Crowley, Max R. Verdugo-Ihl, Benjamin P. Wade, and Daniel J. Condon. "OPENING THE MAGMATIC-HYDROTHERMAL WINDOW: HIGH-PRECISION U-Pb GEOCHRONOLOGY OF THE MESOPROTEROZOIC OLYMPIC DAM Cu-U-Au-Ag DEPOSIT, SOUTH AUSTRALIA." Economic Geology 115, no. 8 (August 27, 2020): 1855–70. http://dx.doi.org/10.5382/econgeo.4772.
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Abstract Establishing timescales for iron oxide copper-gold (IOCG) deposit formation and the temporal relationships between ores and the magmatic rocks from which hydrothermal, metal-rich fluids are sourced is often dependent on low-precision data, particularly for deposits that formed during the Proterozoic. Unlike accessory minerals routinely used to track hydrothermal mineralization, iron oxides are dominant components of IOCG systems and are therefore pivotal to understanding deposit evolution. The presence of ubiquitous, magmatic-hydrothermal U-(Pb)-W-Sn-Mo–bearing zoned hematite resolves a range of geochronological issues concerning formation of the ~1.6 Ga Olympic Dam IOCG deposit, South Australia, at up to ~0.05% precision (207Pb/206Pb weighted mean; 2σ) using isotope dilution-thermal ionization mass spectrometry (ID-TIMS). Coupled with chemical abrasion-ID-TIMS zircon dates from host granite and volcanic rocks within and enclosing the ore-body, a confident magmatic-hydrothermal chronology is defined. The youngest zircon date from the granite intrusion hosting Olympic Dam indicates magmatism was occurring up until 1593.28 ± 0.26 Ma. The orebody was principally formed during a major mineralizing event following granite uplift and during cupola collapse, whereby the hematite with the oldest age is recorded in the outer shell of the deposit at 1591.27 ± 0.89 Ma, ~2 m.y. later than the youngest documented magmatic zircon. Hematite dates captured throughout major lithologies, different ore zones, and the ~2-km vertical extent of the deposit support ~2 m.y. of hydrothermal activity. New age constraints on the spatial-temporal evolution of the formation of Olympic Dam are considered with respect to a mantle to crustal continuum model. Cyclical tapping of magma reservoirs to maintain crystal mushes for extended time periods and incremental building of batholiths on the million-year scale prior to main mineralization pulses can explain the ~2-m.y. temporal window temporal window inferred from the data. Despite the challenge of reconciling such an extended window with contemporary models for porphyry deposits (≤1 m.y.), formation of Proterozoic ore deposits has been addressed at high-precision and supports the case that giant IOCG deposits may form over millions of years.
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Courtney-Davies, Ciobanu, Verdugo-Ihl, Slattery, Cook, Dmitrijeva, Keyser, et al. "Zircon at the Nanoscale Records Metasomatic Processes Leading to Large Magmatic–Hydrothermal Ore Systems." Minerals 9, no. 6 (June 16, 2019): 364. http://dx.doi.org/10.3390/min9060364.
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The petrography and geochemistry of zircon offers an exciting opportunity to better understand the genesis of, as well as identify pathfinders for, large magmatic–hydrothermal ore systems. Electron probe microanalysis, laser ablation inductively coupled plasma mass spectrometry, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging, and energy-dispersive X-ray spectrometry STEM mapping/spot analysis were combined to characterize Proterozoic granitic zircon in the eastern Gawler Craton, South Australia. Granites from the ~1.85 Ga Donington Suite and ~1.6 Ga Hiltaba Suite were selected from locations that are either mineralized or not, with the same style of iron-oxide copper gold (IOCG) mineralization. Although Donington Suite granites are host to mineralization in several prospects, only Hiltaba Suite granites are considered “fertile” in that their emplacement at ~1.6 Ga is associated with generation of one of the best metal-endowed IOCG provinces on Earth. Crystal oscillatory zoning with respect to non-formula elements, notably Fe and Cl, are textural and chemical features preserved in zircon, with no evidence for U or Pb accumulation relating to amorphization effects. Bands with Fe and Ca show mottling with respect to chloro–hydroxy–zircon nanoprecipitates. Lattice defects occur along fractures crosscutting such nanoprecipitates indicating fluid infiltration post-mottling. Lattice stretching and screw dislocations leading to expansion of the zircon structure are the only nanoscale structures attributable to self-induced irradiation damage. These features increase in abundance in zircons from granites hosting IOCG mineralization, including from the world-class Olympic Dam Cu–U–Au–Ag deposit. The nano- to micron-scale features documented reflect interaction between magmatic zircon and corrosive Fe–Cl-bearing fluids in an initial metasomatic event that follows magmatic crystallization and immediately precedes deposition of IOCG mineralization. Quantification of α-decay damage that could relate zircon alteration to the first percolation point in zircon gives ~100 Ma, a time interval that cannot be reconciled with the 2–4 Ma period between magmatic crystallization and onset of hydrothermal fluid flow. Crystal oscillatory zoning and nanoprecipitate mottling in zircon intensify with proximity to mineralization and represent a potential pathfinder to locate fertile granites associated with Cu–Au mineralization.
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Xing, Yanlu, Yuan Mei, Barbara Etschmann, Weihua Liu, and Joël Brugger. "Uranium Transport in F-Cl-Bearing Fluids and Hydrothermal Upgrading of U-Cu Ores in IOCG Deposits." Geofluids 2018 (August 28, 2018): 1–22. http://dx.doi.org/10.1155/2018/6835346.
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Uranium mineralization is commonly accompanied by enrichment of fluorite and other F-bearing minerals, leading to the hypothesis that fluoride may play a key role in the hydrothermal transport of U. In this paper, we review the thermodynamics of U(IV) and U(VI) complexing in chloride- and fluoride-bearing hydrothermal fluids and perform mineral solubility and reactive transport calculations to assess equilibrium controls on the association of F and U. Calculations of uraninite and U3O8(s) solubility in acidic F-rich (Cl : F = 100 [ppm-based]) hydrothermal fluids at 25–450°C, 600 bar, show that U(IV)-F complexes (reducing conditions) and uranyl-F complexes (oxidizing conditions) predominate at low temperature (T<~200°C), while above ~250°C, chloride complexes predominate in acidic solutions. In the case of uraninite, solubility is predicted to decrease dramatically as U(IV)Cl22+ becomes the predominant U species at T>260°C. In contrast, the solubility of U3O8(s) increases with increasing temperatures. We evaluated the potential of low-temperature fluids to upgrade U and F concentrations in magnetite-chalcopyrite ores. In our model, an oxidized (hematite-rich) granite is the primary source of F and has elevated U concentration. Hydrothermal fluids (15 wt.% NaCl equiv.) equilibrated with this granite at 200°C react with low-grade magnetite-chalcopyrite ores. The results show that extensive alteration by these oxidized fluids is an effective mechanism for forming ore-grade Cu-U mineralization, which is accompanied by the coenrichment of fluorite. Fluorite concentrations are continuously upgraded at the magnetite-hematite transformation boundary and in the hematite ores with increasing fluid : rock (F/R) ratio. Overall, the model indicates that the coenrichment of F and U in IOCG ores reflects mainly the source of the ore-forming fluids, rather than an active role of F in controlling the metal endowment of these deposits. Our calculations also show that the common geochemical features of hematite-dominated IOCG deposits can be related to a two-phase process, whereby a magnetite-hematite-rich orebody (formed via a number of processes/tectonic settings) is enriched in Cu ± U and F during a second stage (low temperature, oxidized) of hydrothermal circulation.
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Reid, Anthony. "The Olympic Cu-Au Province, Gawler Craton: A Review of the Lithospheric Architecture, Geodynamic Setting, Alteration Systems, Cover Successions and Prospectivity." Minerals 9, no. 6 (June 20, 2019): 371. http://dx.doi.org/10.3390/min9060371.
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The Olympic Cu-Au Province is a metallogenic province in South Australia that contains one of the world’s most significant Cu-Au-U resources in the Olympic Dam deposit. The Olympic Cu-Au Province also hosts a range of other iron oxide-copper-gold (IOCG) deposits including Prominent Hill and Carrapateena. This paper reviews the geology of the Olympic Cu-Au Province by investigating the lithospheric architecture, geodynamic setting and alteration systematics. In addition, since the province is almost entirely buried by post-mineral cover, the sedimentary cover sequences are also reviewed. The Olympic Cu-Au Province formed during the early Mesoproterozoic, ca. 1.6 Ga and is co-located with a fundamental lithospheric boundary in the eastern Gawler Craton. This metallogenic event was driven in part by melting of a fertile, metasomatized sub-continental lithospheric mantle during a major regional tectonothermal event. Fluid evolution and multiple fluid mixing resulted in alteration assemblages that range from albite, magnetite and other higher temperature minerals to lower temperature assemblages such as hematite, sericite and chlorite. IOCG mineralisation is associated with both high and low temperature assemblages, however, hematite-rich IOCGs are the most economically significant. Burial by Mesoproterzoic and Neoproterozoic-Cambrian sedimentary successions preserved the Olympic Cu-Au Province from erosion, while also providing a challenge for mineral exploration in the region. Mineral potential modelling identifies regions within the Olympic Cu-Au Province and adjacent Curnamona Province that have high prospects for future IOCG discoveries. Exploration success will rely on improvements in existing potential field and geochemical data, and be bolstered by new 3D magnetotelluric surveys. However, drilling remains the final method for discovery of new mineral resources.
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Rodriguez-Mustafa, Maria A., Adam C. Simon, Laura D. Bilenker, Ilya Bindeman, Ryan Mathur, and Edson L. B. Machado. "The Mina Justa Iron Oxide Copper-Gold (IOCG) Deposit, Peru: Constraints on Metal and Ore Fluid Sources." Economic Geology 117, no. 3 (May 1, 2022): 645–66. http://dx.doi.org/10.5382/econgeo.4875.
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Abstract Iron oxide copper-gold (IOCG) deposits are major sources of Cu, contain abundant Fe oxides, and may contain Au, Ag, Co, rare earth elements (REEs), U, and other metals as economically important byproducts in some deposits. They form by hydrothermal processes, but the source of the metals and ore fluid(s) is still debated. We investigated the geochemistry of magnetite from the hydrothermal unit and manto orebodies at the Mina Justa IOCG deposit in Peru to assess the source of the iron oxides and their relationship with the economic Cu mineralization. We identified three types of magnetite: magnetite with inclusions (type I) is only found in the manto, is the richest in trace elements, and crystallized between 459° and 707°C; type Dark (D) has no visible inclusions and formed at around 543°C; and type Bright (B) has no inclusions, has the highest Fe content, and formed at around 443°C. Temperatures were estimated using the Mg content in magnetite. Magnetite samples from Mina Justa yielded an average δ56Fe ± 2σ value of 0.28 ± 0.05‰ (n = 9), an average δ18O ± 2σ value of 2.19 ± 0.45‰ (n = 9), and Δ’17O values that range between –0.075 and –0.047‰. Sulfide separates yielded δ65Cu values that range from –0.32 to –0.09‰. The trace element compositions and textures of magnetite, along with temperature estimations for magnetite crystallization, are consistent with the manto magnetite belonging to an iron oxide-apatite (IOA) style mineralization that was overprinted by a younger, structurally controlled IOCG event that formed the hydrothermal unit orebody. Altogether, the stable isotopic data fingerprint a magmatic-hydrothermal source for the ore fluids carrying the Fe and Cu at Mina Justa and preclude significant input from meteoric water and basinal brines.
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CHU, Geng, and Xiaoyong YANG. "Geochemical Constraints on the Anqing Ore-cluster Field in Anhui: An IOCG (-U) Mineralization System." Acta Geologica Sinica - English Edition 88, s2 (December 2014): 348–49. http://dx.doi.org/10.1111/1755-6724.12372_1.
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Schlegel, Tobias U., Renee Birchall, Tina D. Shelton, and James R. Austin. "MAPPING THE MINERAL ZONATION AT THE ERNEST HENRY IRON OXIDE COPPER-GOLD DEPOSIT: VECTORING TO Cu-Au MINERALIZATION USING MODAL MINERALOGY." Economic Geology 117, no. 2 (March 1, 2022): 485–94. http://dx.doi.org/10.5382/econgeo.4915.
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Abstract Iron oxide copper-gold (IOCG) deposits form in spatial and genetic relation to hydrothermal iron oxide-alkali-calcic-hydrolytic alteration and thus show a mappable zonation of mineral assemblages toward the orebody. The mineral zonation of a breccia matrix-hosted orebody is efficiently mapped by regularly spaced samples analyzed by the scanning electron microscopy-integrated mineral analyzer technique. The method results in quantitative estimates of the mineralogy and allows the reliable recognition of characteristic alteration as well as mineralization-related mineral assemblages from detailed mineral maps. The Ernest Henry deposit is located in the Cloncurry district of Queensland and is one of Australia’s significant IOCG deposits. It is known for its association of K-feldspar altered clasts with iron oxides and chalcopyrite in the breccia matrix. Our mineral mapping approach shows that the hydrothermal alteration resulted in a characteristic zonation of minerals radiating outward from the pipe-shaped orebody. The mineral zonation is the result of a sequence of sodic alteration followed by potassic alteration, brecciation, and, finally, by hydrolytic (acid) alteration. The hydrolytic alteration primarily affected the breccia matrix and was related to economic mineralization. Alteration halos of individual minerals such as pyrite and apatite extend dozens to hundreds of meters beyond the limits of the orebody into the host rocks. Likewise, the Fe-Mg ratio in hydrothermal chlorites changes systematically with respect to their distance from the orebody. Geochemical data obtained from portable X-ray fluorescence (p-XRF) and petrophysical data acquired from a magnetic susceptibility meter and a gamma-ray spectrometer support the mineralogical data and help to accurately identify mineral halos in rocks surrounding the ore zone. Specifically, the combination of mineralogical data with multielement data such as P, Mn, As, P, and U obtained from p-XRF and positive U anomalies from radiometric measurements has potential to direct an exploration program toward higher Cu-Au grades.
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Ciobanu, Cristiana L., Max R. Verdugo-Ihl, Ashley Slattery, Nigel J. Cook, Kathy Ehrig, Liam Courtney-Davies, and Benjamin P. Wade. "Silician Magnetite: Si–Fe-Nanoprecipitates and Other Mineral Inclusions in Magnetite from the Olympic Dam Deposit, South Australia." Minerals 9, no. 5 (May 20, 2019): 311. http://dx.doi.org/10.3390/min9050311.
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A comprehensive nanoscale study on magnetite from samples from the outer, weakly mineralized shell at Olympic Dam, South Australia, has been undertaken using atom-scale resolution High Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF STEM) imaging and STEM energy-dispersive X-ray spectrometry mapping and spot analysis, supported by STEM simulations. Silician magnetite within these samples is characterized and the significance of nanoscale inclusions in hydrothermal and magmatic magnetite addressed. Silician magnetite, here containing Si–Fe-nanoprecipitates and a diverse range of nanomineral inclusions [(ferro)actinolite, diopside and epidote but also U-, W-(Mo), Y-As- and As-S-nanoparticles] appears typical for these samples. We observe both silician magnetite nanoprecipitates with spinel-type structures and a γ-Fe1.5SiO4 phase with maghemite structure. These are distinct from one another and occur as bleb-like and nm-wide strips along d111 in magnetite, respectively. Overprinting of silician magnetite during transition from K-feldspar to sericite is also expressed as abundant lattice-scale defects (twinning, faults) associated with the transformation of nanoprecipitates with spinel structure into maghemite via Fe-vacancy ordering. Such mineral associations are characteristic of early, alkali-calcic alteration in the iron-oxide copper gold (IOCG) system at Olympic Dam. Magmatic magnetite from granite hosting the deposit is quite distinct from silician magnetite and features nanomineral associations of hercynite-ulvöspinel-ilmenite. Silician magnetite has petrogenetic value in defining stages of ore deposit evolution at Olympic Dam and for IOCG systems elsewhere. The new data also add new perspectives into the definition of silician magnetite and its occurrence in ore deposits.
Dissertations / Theses on the topic "IOCG(U)"
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Kontonikas-Charos, A. "Albitization and REE-U-enrichment in IOCG systems: insights from Moonta-Wallaroo, Yorke Peninsula, South Australia." Thesis, 2013. http://hdl.handle.net/2440/106289.
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This item is only available electronically.Iron Oxide Copper Gold (IOCG) deposits are the products of crustal-scale metasomatic alteration, generally considered to be associated with the emplacement of large felsic intrusions. These systems are typified by zoned, broad alteration haloes comprising the products of an early, barren albitization event, and late, ore-hosting potassic/calcic (skarn) alteration associated with mineralization. Yttrium and rare earth elements (REY), and also uranium, are prominent components of most IOCG systems. The REY-signatures of feldspars and accessory apatite, Fe-(Ti)-oxides and other minerals are geochemical tracers of alteration stages within a magmatic-hydrothermal system. This study sets out to identify links between magmatism and initiation of hydrothermal activity, and to test the hypothesis that albitization is a pre-requisite stage for REE-U enrichment in magmatically-derived IOCG systems. The compositions and trace element concentrations in key minerals have been analysed using scanning electron microscopy, electron probe microanalysis and laser-ablation inductively-coupled plasma mass spectrometry in a varied range of magmatic to metasedimentary lithologies from the Moonta-Wallaroo region, an area in which broad regional-scale alkali alteration is recognised. Results confirm a strong link between albitization and REE-U-enrichment. The process of albitization is seen to consume, redistribute and lock-in REY, LILE and HFSE via complex fluid-rock reactions dependent on the pre-existing mineral assemblages and fluid characteristics, providing a holistic model for IOCG-driven alkali metasomatism. The trace element signatures recorded by K-feldspar reflect a transition from magmatic to hydrothermal stages within an evolving IOCG system. Although further constraints on these signatures are required, they could prove invaluable in mineral exploration as they suggest a quantifiable distinction between alteration associated with mineralization, and regional background. This hypothesis requires testing elsewhere in the Olympic Province and in analogous terranes.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010
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Owen, N. D. "Characteristics of K-Fe alteration in relation to IOCG(U) mineralisation in the northern Yorke Peninsula." Thesis, 2015. http://hdl.handle.net/2440/118209.
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This item is only available electronically.The Moonta-Wallaroo area in the Northern Yorke Peninsula (NYP) is inferred to have been associated with the major deformation, metamorphic and magmatic event at ca. 1600-1575 Ma that affected much of eastern Proterozoic Australia. Widespread K-Fe (biotite-magnetite) alteration is genetically linked with the main pyrite ±chalcopyrite mineralising event within the Doora Member of the Wandearah Formation. Zones of high mineralisation were seen to correspond with coarsening grain size of biotite in petrological and hand samples and were supported by geochemical trends between Fe2O3, S and Cu. Later stage hematite bearing phases of alteration resulted in intense alteration and pyrite-chalcopyrite mineralisation locally within carbonate bearing zones. It is suggested that uranium enrichment is also associated with biotite-magnetite alteration but was later stripped from the highly mineralised zones by less pervasive hydrothermal fluids. U-Pb isotope analysis of zircon grains constrain the age of formation of the basement in which mineralisation occurs. The Moonta Porphyry revealed an age of 1752 ±6Ma. Based on its interdigitising relationship with the Moonta Porphyry a maximum age of sedimentation of the Doora Member is proposed at ca. 1752 Ma. The protolithic material of the Harlequin Stone was determined to be similar to that of the Doora Member and was sourced mainly from the ca. 1850 Ma Donington Suite Granitoids. A Pb207/Pb206 age of ca. 1708 Ma suggests a wider age of formation of the Wallaroo Group than previously reported in the literature. Alteration within the Oorlano Metasomatite metasediment samples showed a clear deviation in chemical characteristics from the Doora Member suggesting different styles of alteration in relation to their proximity to the Arthurton and Tickera Granites.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2015
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Cave, B. W. "U-Pb geochronology and trace element analysis of apatite and calcite from Ernest Henry." Thesis, 2017. http://hdl.handle.net/2440/126656.
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This item is only available electronically.Ernest Henry is the largest known IOCG deposit in the Eastern Succession of the Mount Isa inlier, NW Queensland. To improve our understanding of the timing of alteration and mineralisation in the Ernest Henry deposit, we attempt to date apatite from the Interlens (a pre-mineralization structure) and the ore-stage breccia, and calcite from the Interlens, ore-stage breccia and post-mineralization alteration using the in-situ U-Pb LA-ICP-MS method. This also approach provides the opportunity to examine the trace element composition of the minerals, which can be used to identify their sources and constrain metasomatic processes. Coarse-grained apatite from Interlens was dated at 1581 ± 16 Ma, coeval with regional peak metamorphic conditions and D2 deformation of the Isan Orogeny. Finer-grained apatite from the Interlens produced an age of 1557 ± 23 Ma, possibly representing regional D2, D2.5 or D3 deformation, coeval with retrograde metamorphic conditions. Ore-stage apatite produced an age of 1529 ± 39 Ma, coeval with the accepted age for sulphide mineralisation, D3 deformation and the formation of the nearby Mount Margaret Granite. Calcite samples were unable to be dated by this method, as the samples were dominated by common lead. Trace element analysis indicate that apatite from the Interlens and ore-stage assemblage were sourced from magmatic/hydrothermal fluids. Furthermore, metasomatism and coupled dissolution re-precipitation reactions of apatite were induced by a Na and/or Ca rich fluid, possessing varying amounts of Cl and S. Calcite from this study displays similarities with altered granites, and greisen type deposits, likely the result of fluid diffusing through the heavily altered Mount Fort Constantine host rocks. This study also geochemically links calcite from the Ernest Henry and the nearby E1 deposit, suggesting the REE composition of calcite may be used to link hydrothermal systems from various deposits.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2017
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Chalk, H. C. "Mesoproterozoic bimodal magmatism of southern Australia: assessing relative mantle input and implications for IOCG mineralisation prospectivity." Thesis, 2014. http://hdl.handle.net/2440/109703.
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This item is only available electronically.Mesoproterozoic magmatism of the Gawler Craton and the Curnamona Province demonstrates regions of variable mantle input characteristics. Zircons from Hiltaba Suite granitoids and Gawler Range Volcanics, Gawler Craton, return εHf(T) values ranging from +7.1 to -0.4, +2.0 to -7.4, and +0.2 to -5.3 from the western, central, and eastern Gawler Craton respectively. Ninnerie Supersuite granitoids and Benagerie Volcanic Suite, Curnamona Province, return εHf(T) values ranging from +2.5 to -3.8. Mantle input modelling of the central/eastern Gawler Craton and the Curnamona Province returns similar mantle input fraction values ranging from 0.1 to 0.6, averaging 0.3, and 0.1 to 0.6, averaging 0.3, respectively. Hiltaba Suite magmatism of the western Gawler Craton is compositionally more juvenile than the central and eastern regions. The western Gawler Craton mantle input fractions range from 0.2 to 0.9 averaging 0.5, more elevated than the central/eastern regions of the Gawler Craton and the Curnamona province. The Benagerie Ridge region of the Curnamona Province displays similar bimodal ca. 1590 Ma magmatism, εHf(T) values, mantle input characteristics, crustal preservation (exhumation) and regional iron oxide copper-gold alteration as the highly prospective Olympic IOCG Province, Gawler Craton.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2014
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Courtney-Davies, Liam. "Geochronology of Iron Oxides and Development of Matrix-Matched Reference Material for Routine U-Pb Dating." Thesis, 2019. http://hdl.handle.net/2440/123663.
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Iron oxides, hematite and magnetite, are common minerals throughout rocks and ores of all types and ages. The discovery of U-bearing hematite at Olympic Dam, the largest iron oxide copper-gold (IOCG) deposit in the Gawler Craton (South Australia) prompted development of this mineral as a new U-Pb geochronometer. Unlike accessory minerals routinely used to track hydrothermal mineralisation, iron oxides are dominant components of Precambrian IOCG systems and therefore geochronology of iron oxides is pivotal to understand deposit evolution. Iron oxide minerals are studied in terms of U-Pb systematics and reliability for dating Olympic Dam and surrounding IOCG prospects formed at ~1.6 Ga. The temporal window between crystallisation of magmatic zircon and hydrothermal Fe-oxides is investigated to define the onset and lifespan of mineralisation and assess magma fertility. A matrix-matched reference material for routine microbeam geochronology is synthesised and tested for U/Pb isotope homogeneity by ID-TIMS. The U-Pb systematics of hematite are complex, exhibiting U-Th-Pb concentration and ratio heterogeneity at the nano- to micron-scales. Nevertheless, using a multi-instrument approach, high- precision data is routinely obtained. Reconnaissance SEM imaging in BSE mode and LA-ICP-MS isotope mapping allows pinpointing of U/Pb-homogeneous, inclusion-free grain domains. Dating of such domains via LA-ICP-MS using both mixed-(U/Pb)-solution and zircon reference materials produced successful results and a steppingstone to investigate at higher resolution and precision. The first application of both SHRIMP and ID-TIMS to hematite dating confirmed the robust U-Pb system in natural hematite, yielding 207Pb/206Pb (ID-TIMS) precision of up to ~0.05%. Coupled with (CA-)ID-TIMS analysis of magmatic zircon, hematite sampled throughout the Olympic Dam deposit provides a well constrained magmatic-hydrothermal timeline of events. The granite intrusion hosting Olympic Dam was emplaced rapidly at 1593.28 ± 0.28 Ma. The orebody was formed during a major mineralising event following granite uplift and during cupola collapse over a period of ~2 Ma, whereby the earliest hydrothermal activity is recorded in the early, deep ‘outer shell’ of the deposit at 1591.27 ± 0.89 Ma. Findings discredit a shallow origin for the deposit based on irreconcilable differences between the depth of granite emplacement and timeframes of uplift and fluid exsolution. Recognition of U-bearing hematite with a comparable W-Mo-Sn-bearing signature and age as Olympic Dam hematite within other IOCG systems, Wirrda Well and Acropolis, links the fluid forming the wider Olympic Cu-Au Province to a common source and time period. LA-ICP-MS U-Pb dating of U-bearing, silician magnetite from Fe-rich lithologies in the outer shell at Olympic Dan yields an age of 1761 ± 19 Ma, distinct from any other ages found within the deposit. The age is likely linked to ca. 1750 Ma intrusive/extrusive magmatism reported across the Gawler Craton. This shows the presence of older ore protoliths within Olympic Dam and represents the first successful application of U-Pb dating to magnetite. Magmatic zircon studied down to the nanoscale from two granite suites in the Gawler Craton shows crystal zoning with respect to ‘non-formulae’ elements such as Fe, Ca, and Cl, and also chloro-hydroxy-zircon nanoprecipitates when associated with IOCG mineralisation. This is indicative of early Fe-Cl-metasomatism prior to metamictisation, a diagnostic tool for assessing ‘fertility’ of granitic magmas. In contrast, metamict zircon from high-grade bornite ores shows patchy amorphisation throughout domains with pervasive enrichment in U-, Y- and non-formula elements. Hydrated ferric oxide doped with U-Pb solutions was converted to Fe-oxide and assessed by SEM imaging, XRD and LA-ICP-MS indicating the presence of homogenous U-Pb domains in cm-sized chips of hematite. Micro-sampled domains were measured by ID-TIMS confirming U-Pb isotope homogeneity at high precision. Hematite is a remarkably robust U-Pb geochronometer for dating hydrothermal ore deposits. Dissemination of the synthesized reference material to the wider community will allow routine LA-ICP-MS dating.Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering & Advanced Materials, 2020
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Owen, Nicholas Daniel. "The mineralogical deportment of radionuclides in South Australian Ca-Au-(U) ores." Thesis, 2019. http://hdl.handle.net/2440/123640.
Full textAbstract:
Iron-oxide copper gold (IOCG)-uranium deposits represent South Australia’s primary resource base for copper production. The presence of daughter radionuclides (RN) from the 238U decay series within the ores necessitates a detailed understanding of their mineralogical deportment as a pre-requisite for attempts to remove or reduce RN concentrations. Research presented in this thesis contributes towards this knowledge by identifying and characterising potential RN-carriers, migration of radiogenic lead via geological processes, and provides evidence for RN sorption during processing. Novel approaches to RN reduction are proposed based on mineralogical-geochemical results. Evidence for migration of Pb within the deposit and during processing is relevant for any assessment of RN deportment, especially since the Pb-chalcogenides galena, clausthalite (PbSe) and altaite (PbTe) are often hosted within Cu-(Fe)-sulphides. Lead isotope values measured in-situ by laser ablation inductively coupled plasma mass spectrometry suggest an overwhelmingly radiogenic origin for Pb and thus extensive decoupling of radiogenic Pb from parent U- and Th-minerals. Calculated 207Pb/206Pb ratios suggest Pb mobilisation during an event that postdates the initial Mesoproterozoic Fe-Cu-Au-U mineralisation event, an interpretation consistent with other studies in the Olympic Cu-Au province which indicate cycles of replacement-remobilization-recrystallization. A nanoscale study of the most common of the three Pb-chalcogenide minerals, clausthalite, by high-angle annular dark field scanning transmission electron microscopy, proved highly instructive for identifying mechanisms of remobilization and overprinting. Characteristic symplectite textures involving clausthalite and host Cu-(Fe)-sulphides are indicative of formation via reaction between Se that pre-existed in solid solution within Cu-(Fe)-sulphides and migrating Pb. Observed superstructuring of clausthalite nanoparticles within chalcopyrite provides a direct link between solid solution and symplectite formation. Sr-Ca-REE-bearing aluminium-phosphate-sulphates (APS) of the alunite supergroup are a minor component of the Olympic Dam orebody. They appear paragenetically late, often replacing earlier REE-minerals. Characterisation of these compositionally zoned phases allowed them to be defined as minerals that span the compositional fields of woodhouseite and svanbergite, and also a REE- and phosphate-dominant group displaying solid solution towards florencite. A nanoscale secondary ion mass spectrometry study of RN distributions in APS minerals in acid-leached copper concentrate revealed that APS minerals readily sorb products of 238U decay, notably 226Ra and 210Pb, whereas U remains in solution. Many APS phases, particularly those that are Pb-bearing, are stable over a wide range of pH and Eh conditions and at temperatures up to 450 °C. As such, synthetic APS phases represent viable candidates not only for the removal of radionuclides from metallurgical streams, but also for their safe storage and isolation from surrounding environments. Ca-Sr-dominant phases display preferential enrichment by Pb (notably 210Pb) during flotation. 210Pb uptake then increases during subsequent acid leaching. Mixed Ca- and Sr-bearing APS phases were synthesised by modifying existing recipes to test the role of compositional variability of APS phases on the sorption rate of Pb from dilute Pb(NO3)2 solution. Lead incorporation by the synthetic APS phases was confirmed, whereby Pb replaces Ca, but not Sr, within the APS crystal structure. Extended X-ray absorption fine structure analysis of the resulting solids reveals the nature of Pb sorption by the synthesized material. The data showed that the dynamic incorporation of Pb by APS phases occurred overwhelmingly at pH 3.5, thus verifying that uptake of Pb by synthetic APS phases may represent a robust mechanism to achieve both reduction and immobilisation of 210Pb within metallurgical processing streams.Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering & Advanced Materials, 2020
Conference papers on the topic "IOCG(U)"
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Zygo, W., D. T. Kieu, and H. D. Van. "U-238 in IOCG Sin Quyen deposit, North Vietnam." In EAGE-GSM 2nd Asia Pacific Meeting on Near Surface Geoscience and Engineering. European Association of Geoscientists & Engineers, 2019. http://dx.doi.org/10.3997/2214-4609.201900449.
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Neymark, Leonid A., Chris Holm-Denoma, A. J. Pietruszka, C. J. Meighan, and Richard J. Moscati. "IN SITU LA-ICPMS U-PB GEOCHRONOLOGY OF APATITE FROM IOA AND IOCG DEPOSITS, ST. FRANCOIS MOUNTAINS, SOUTHEAST MISSOURI, USA." In GSA Annual Meeting in Denver, Colorado, USA - 2016. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016am-279719.
Full textReports on the topic "IOCG(U)"
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Gandhi, S. S. World Fe Oxide +/- Cu-Au-U (IOCG) deposit database. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2015. http://dx.doi.org/10.4095/296424.
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Corriveau, L. Iron-oxide and alkali-calcic alteration ore systems and their polymetallic IOA, IOCG, skarn, albitite-hosted U±Au±Co, and affiliated deposits: a short course series. Part 1: introduction. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2017. http://dx.doi.org/10.4095/300241.
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Corriveau, L., J. F. Montreuil, O. Blein, E. Potter, M. Ansari, J. Craven, R. Enkin, et al. Metasomatic iron and alkali calcic (MIAC) system frameworks: a TGI-6 task force to help de-risk exploration for IOCG, IOA and affiliated primary critical metal deposits. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/329093.
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Australia's and China's resources (e.g. Olympic Dam Cu-U-Au-Ag and Bayan Obo REE deposits) highlight how discovery and mining of iron oxide copper-gold (IOCG), iron oxide±apatite (IOA) and affiliated primary critical metal deposits in metasomatic iron and alkali-calcic (MIAC) mineral systems can secure a long-term supply of critical metals for Canada and its partners. In Canada, MIAC systems comprise a wide range of undeveloped primary critical metal deposits (e.g. NWT NICO Au-Co-Bi-Cu and Québec HREE-rich Josette deposits). Underexplored settings are parts of metallogenic belts that extend into Australia and the USA. Some settings, such as the Camsell River district explored by the Dene First Nations in the NWT, have infrastructures and 100s of km of historic drill cores. Yet vocabularies for mapping MIAC systems are scanty. Ability to identify metasomatic vectors to ore is fledging. Deposit models based on host rock types, structural controls or metal associations underpin the identification of MIAC-affinities, assessment of systems' full mineral potential and development of robust mineral exploration strategies. This workshop presentation reviews public geoscience research and tools developed by the Targeted Geoscience Initiative to establish the MIAC frameworks of prospective Canadian settings and global mining districts and help de-risk exploration for IOCG, IOA and affiliated primary critical metal deposits. The knowledge also supports fundamental research, environmental baseline assessment and societal decisions. It fulfills objectives of the Canadian Mineral and Metal Plan and the Critical Mineral Mapping Initiative among others. The GSC-led MIAC research team comprises members of the academic, private and public sectors from Canada, Australia, Europe, USA, China and Dene First Nations. The team's novel alteration mapping protocols, geological, mineralogical, geochemical and geophysical framework tools, and holistic mineral systems and petrophysics models mitigate and solve some of the exploration and geosciences challenges posed by the intricacies of MIAC systems. The group pioneers the use of discriminant alteration diagrams and barcodes, the assembly of a vocab for mapping and core logging, and the provision of field short courses, atlas, photo collections and system-scale field, geochemical, rock physical properties and geophysical datasets are in progress to synthesize shared signatures of Canadian settings and global MIAC mining districts. Research on a metamorphosed MIAC system and metamorphic phase equilibria modelling of alteration facies will provide a foundation for framework mapping and exploration of high-grade metamorphic terranes where surface and near surface resources are still to be discovered and mined as are those of non-metamorphosed MIAC systems.
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Corriveau, L. Les systèmes minéralisateurs à oxydes de fer et altération à éléments alcalins (±calciques) et leurs gîtes IOA, IOCG, skarns, U±Au±Co (au sein d'albitites) et affiliés: une série de cours intensifs. Partie 1 : introduction. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2017. http://dx.doi.org/10.4095/300242.
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Corriveau, L., E. G. Potter, J. F. Montreuil, O. Blein, K. Ehrig, and A. F. De Toni. Iron-oxide and alkali-calcic alteration ore systems and their polymetallic IOA, IOCG, skarn, albitite-hosted U±Au±Co, and affiliated deposits: a short course series. Part 2: overview of deposit types, distribution, ages, settings, alteration facies, and ore deposit models. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2018. http://dx.doi.org/10.4095/306560.
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Corriveau, L., E. G. Potter, J. F. Montreuil, O. Blein, K. Ehrig, and A. F. De Toni. Les systèmes minéralisateurs à oxydes de fer et altération à éléments alcalins (±calciques), et leurs gîtes IOA, IOCG, skarns, U±Au±Co (au sein d'albitites) et affiliés : une série de cours intensifs. Partie 2 : Aperçu général des types de gîtes, distribution, âges, contextes, exemples, faciès d'altération et modèles métallogéniques. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2018. http://dx.doi.org/10.4095/308269.
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