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Journal articles on the topic "IOGC ore deposit"
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Rodriguez-Mustafa, Maria A., Adam C. Simon, Irene del Real, John F. H. Thompson, Laura D. Bilenker, Fernando Barra, Ilya Bindeman, and David Cadwell. "A Continuum from Iron Oxide Copper-Gold to Iron Oxide-Apatite Deposits: Evidence from Fe and O Stable Isotopes and Trace Element Chemistry of Magnetite." Economic Geology 115, no. 7 (November 1, 2020): 1443–59. http://dx.doi.org/10.5382/econgeo.4752.
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Abstract Iron oxide copper-gold (IOCG) and iron oxide-apatite (IOA) deposits are major sources of Fe, Cu, and Au. Magnetite is the modally dominant and commodity mineral in IOA deposits, whereas magnetite and hematite are predominant in IOCG deposits, with copper sulfides being the primary commodity minerals. It is generally accepted that IOCG deposits formed by hydrothermal processes, but there is a lack of consensus for the source of the ore fluid(s). There are multiple competing hypotheses for the formation of IOA deposits, with models that range from purely magmatic to purely hydrothermal. In the Chilean iron belt, the spatial and temporal association of IOCG and IOA deposits has led to the hypothesis that IOA and IOCG deposits are genetically connected, where S-Cu-Au–poor magnetite-dominated IOA deposits represent the stratigraphically deeper levels of S-Cu-Au–rich magnetite- and hematite-dominated IOCG deposits. Here we report minor element and Fe and O stable isotope abundances for magnetite and H stable isotope abundances for actinolite from the Candelaria IOCG deposit and Quince IOA prospect in the Chilean iron belt. Backscattered electron imaging reveals textures of igneous and magmatic-hydrothermal affinities and the exsolution of Mn-rich ilmenite from magnetite in Quince and deep levels of Candelaria (>500 m below the bottom of the open pit). Trace element concentrations in magnetite systematically increase with depth in both deposits and decrease from core to rim within magnetite grains in shallow samples from Candelaria. These results are consistent with a cooling trend for magnetite growth from deep to shallow levels in both systems. Iron isotope compositions of magnetite range from δ56Fe values of 0.11 ± 0.07 to 0.16 ± 0.05‰ for Quince and between 0.16 ± 0.03 and 0.42 ± 0.04‰ for Candelaria. Oxygen isotope compositions of magnetite range from δ18O values of 2.65 ± 0.07 to 3.33 ± 0.07‰ for Quince and between 1.16 ± 0.07 and 7.80 ± 0.07‰ for Candelaria. For cogenetic actinolite, δD values range from –41.7 ± 2.10 to –39.0 ± 2.10‰ for Quince and from –93.9 ± 2.10 to –54.0 ± 2.10‰ for Candelaria, and δ18O values range between 5.89 ± 0.23 and 6.02 ± 0.23‰ for Quince and between 7.50 ± 0.23 and 7.69 ± 0.23‰ for Candelaria. The paired Fe and O isotope compositions of magnetite and the H isotope signature of actinolite fingerprint a magmatic source reservoir for ore fluids at Candelaria and Quince. Temperature estimates from O isotope thermometry and Fe# of actinolite (Fe# = [molar Fe]/([molar Fe] + [molar Mg])) are consistent with high-temperature mineralization (600°–860°C). The reintegrated composition of primary Ti-rich magnetite is consistent with igneous magnetite and supports magmatic conditions for the formation of magnetite in the Quince prospect and the deep portion of the Candelaria deposit. The trace element variations and zonation in magnetite from shallower levels of Candelaria are consistent with magnetite growth from a cooling magmatic-hydrothermal fluid. The combined chemical and textural data are consistent with a combined igneous and magmatic-hydrothermal origin for Quince and Candelaria, where the deeper portion of Candelaria corresponds to a transitional phase between the shallower IOCG deposit and a deeper IOA system analogous to the Quince IOA prospect, providing evidence for a continuum between both deposit types.
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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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Kostin, Aleksey. "A new mineral assemblage from the diorite complex in the Fe-Oxide-Cu-Au ores of the Kis-Kuel deposit (Eastern Yakutia, Russia)." IOP Conference Series: Earth and Environmental Science 906, no. 1 (November 1, 2021): 012007. http://dx.doi.org/10.1088/1755-1315/906/1/012007.
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Abstract This research continues our investigations of the iron-oxide copper-gold deposits in the Western Verkhoyansk region, where recent years efforts of the IGABM SB RAS led to the discovery of a new gold Kiskuel deposit. The Kis-Kuel intrusion-related IOCG deposit in Eastern Yakutia (Russia) with a wide range of mineral styles has a direct genetic link with a cooling intrusion during its formation. The IOCG worldwide and the Kis-Kuel deposit have common features for this style - the abundance of iron oxides and low of sulfides. Magmatic contribution to the Kis-Kuel deposit is significant. Intrusive rocks range from diorite to granodiorite in composition. The Kiskuel deposit hosted in diorites and granodiorites; xenoliths confirming deep mineralization represented by pyrrhotite (main), pyrite, chalcopyrite, and clinosafflorite (Co, Fe, Ni)As2, chromite, pentlandite. Clinosafflorite localized at the contact of pyrrhotite and chalcopyrite and at the contact of pyrrhotite and biotite. Chalcopyrite is found in intergrowth with pyrrhotite, were it forms bands and lenses. Parallel to the biotite cleavage, the thinnest layers of chalcopyrite are common. Clinosafflorite is rare and discovered in hydrothermal cobalt-nickel ores of the Bou-Azzer (Morocco), Cobalt (Canada), Glassberg (Germany), Silver Mine (England) and several others. Mineralization of rich mica processes occur in connection with the chromite, pentlandite, chalcopyrite, pyrite, and pyrrhotite; a common feature of the mineralized dark-colored rock is phlogopite abundance, ilmenite, potassium feldspar, calcite, rarely quartz; clinoenstatite metasomaticaly replaced with phlogopite and dolomite. This new evidence supports a magmatic-hydrothermal model for the formation of IOCG deposit in the Kis-Kuel, where iron-oxide mineralization sourced from intermediate magmas. The deep complex predominantly composed of chromite, ilmenite, magnetite, pentlandite, and clinocafflorite; less of galena and sphalerite. Many diverse mineraization systems from Kis-Kuel classified together as iron oxide copper-gold (IOCG) deposits. The obtained data suggest deep ore-bearing structure of the Kis-Kuel ore-magmatic cluster with the potential for discovering of a new mineral ores style. All of this help in developing a new robust prospecting model.
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Lotfi, Mohammad, Mansoureh Shirnavard Shirazi, Nima Nezafati, and Arash Gourabjeripour. "MINERALOGY AND GEOCHEMISTRY STUDY OF REE MINERALS IN HOST ROCKS IN IIC IRON DEPOSIT, BAFGH MINERAL AREA, CENTRAL IRAN." Geosaberes 11 (January 8, 2020): 51. http://dx.doi.org/10.26895/geosaberes.v11i0.909.
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The IIC deposit area to the east of the Bafq region exposes rocks that comprise the part of the Central Iran continental terrane. The IIC deposit iron orebodies are magmatic-related hydrothermal deposits that, when considered collectively display a vertical zonation from high-temperature, magmatic ± hydrothermal deposits emplaced at moderate depths (~1–2 km) to magnetite-dominant IOCG deposits emplaced at an even shallower subvolcanic level. The shallowest parts of these systems include near-surface, iron oxide-only replacement deposits, surficial epithermal sediment-hosted replacement deposits, and synsedimentary (exhalative) ironstone deposits. Alteration associated with the IOCG mineralizing system within the host volcanic, plutonic, and sedimentary rocks dominantly produced potassic with lesser amounts of calcic- and sodic-rich mineral assemblages. Our data suggest that hydrothermal magmatic fluids contributed to formation of the primary sodic and calcic alterations. The aim of this study is to delineate and recognize the different iron mineralized zones, based on surface and subsurface study. However, the data do not discriminate between a magmatic-hydrothermal source fluids resolved from Fe-rich immiscible liquid or Fe-rich silicate magma. Iron ores, occurring as massive-type and vein-type bodies are chemically different. Minor pyrite occurs as a late phase in the iron ores. The REE patterns of the mineralized metasomatites show LREE enrichment and strong Eu negative anomalies. The strong negative Eu anomaly probably indicates near-surface fractionation of alkali rhyolites involving feldspars. Field observations, ore mineral and alteration assemblages, coupled with lithogeochemical data suggest that an evolving fluid from magmatic dominated to surficial brine-rich fluid has contributed to the formation of the IIC deposit.
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Anand, Abhishek, Sahendra Singh, Arindam Gantait, Amit Srivastava, Girish Kumar Mayachar, and Manoj Kumar. "Geological Constraints on the Genesis of Jagpura Au-Cu Deposit NW India: Implications from Magnetite-Apatite Mineral Chemistry, Fluid Inclusion and Sulfur Isotope Study." Minerals 12, no. 11 (October 24, 2022): 1345. http://dx.doi.org/10.3390/min12111345.
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The Jagpura Au-Cu deposit is situated within the Aravalli craton in the northwestern part of India. In the present work, petrography, mineral chemistry, fluid inclusion and sulfur isotopic compositions were used to study the Jagpura Au-Cu deposit. The ore mineral association of the deposit is arsenopyrite, loellingite, chalcopyrite, pyrrhotite and pyrite, along with native gold, magnetite and apatite. The gold fineness ranges from 914–937‰ (avg. 927‰). The presence of Au-Bi-Te phases, pyrite (>1 Co/Ni ratio), magnetite (≥1 Ni/Cr ratio, <1 Co/Ni ratio) and apatite (>1 F/Cl ratio) suggest the hydrothermal origin Au-Cu mineralization. A fluid inclusion study indicates the different episodes of fluid immiscibility with the homogenization temperatures varying between 120–258 °C and salinities range within the 8.86–28.15 wt% NaCl eq. The sulfur isotopic composition of sulfides varies from 8.98 to 14.58‰ (avg. 11.16‰). It is inferred that the variation in the sulfur isotopic compositions of sulfides is due to the cooling and dilution of the metalliferous fluid of mixed origin, derived from the basement meta-sedimentary rocks and the high saline basinal fluid. The iron oxide-copper-gold-apatite associations, structural control of mineralization, pervasive hydrothermal alteration, fluid salinity and sulfur isotope compositions indicate that the Jagpura Au-Cu deposit is similar to the iron oxide-copper-gold (IOCG)-iron oxide-apatite (IOA)types of deposits. Based on the ore geochemistry and the trace elements systematic of magnetite, the deposit is further classified as an IOCG-IOA type: IOCG-Co (reduced) subtype.
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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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Gauthier, Michel, and Francis Chartrand. "Metallogeny of the Grenville Province revisited." Canadian Journal of Earth Sciences 42, no. 10 (October 1, 2005): 1719–34. http://dx.doi.org/10.1139/e05-051.
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Four new petrogenetic and metallogenic models are proposed herein to explain the formation of important mineral deposits in the Grenville Province, providing a framework from which to reappraise Grenvillian mineral potential. Recognition of a high-pressure metamorphic belt within the Grenville Province suggests a potential for eclogite-hosted rutile deposits, an important and much-sought commodity. A recently developed Norwegian model proposes that anorthosite genesis occurred through lower crust underplating and coeval partial melting, rather than by plume magmatism. Applied to the Grenville Province, the new petrogenetic model may provide insight into the widespread occurrence of platinum group element (PGE) poor nickel showings and the distribution of chromite, Ti-rich, and low-Ti iron-oxide deposits within the Grenville and adjacent terranes. A new type of sedimentaryexhalative (SEDEX) mineralization formed by oxidized brines has been defined following the discovery of new deposits in Australia. Applied to the Grenville Province, it provides a possible explanation for two long-recognized features of marble-hosted zinc deposits: (i) the presence of meta-siderite beds occurring as distal haloes around SEDEX zinc deposits, and (ii) the mutually exclusive division of these SEDEX deposits into massive sulphide and nonsulphide groups. The discovery of the giant Olympic Dam iron-oxide coppergold (IOCG) deposit in Australia renewed the interest in magmatic low-Ti iron-oxide deposits in the Grenville Province that have been known and mined since early colonial times. Subsequent exploration in the northeastern part of the Grenville Province revealed the presence of breccia-hosted CuAuU rare-earth element (REE)-bearing iron-oxide mineralization. This deposit and other low-Ti iron-oxide deposits in the southwestern Grenville Province have a previously undocumented close spatial and temporal association with Ti-rich iron-oxide deposits. These examples demonstrate how new petrogenetic, tectonic, and ore deposit models developed in unmetamorphosed rocks can be successfully adapted to high-grade terranes, where they stimulate mineral exploration in these challenging conditions. Furthermore, by tracking the formation of ore deposits in the lower crust, the existence of unsuspected metallogenic associations in the higher crust, such as the low-Ti and high-Ti iron-oxide association observed in the Grenville Province, may be revealed.
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Gao, Yu, Yujie Hao, and Siyu Lu. "Genesis of the Weizigou Au Deposit, Heilongjiang Province, NE China: Constraints from LA-ICP-MS Trace Element Analysis of Magnetite, Pyrite and Pyrrhotite, Pyrite Re-Os Dating and S-Pb Isotopes." Minerals 11, no. 12 (December 7, 2021): 1380. http://dx.doi.org/10.3390/min11121380.
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The Weizigou Au deposit in Heilongjiang Province, NE China, located in the southern Jiamusi Massif, shows similarities to IOCG deposits. To determine the mineralization age, sources of ore-forming materials and genetic type, pyrite Re-Os dating, S-Pb isotopic analysis, in situ sulfur analysis and LA-ICP-MS analysis of trace elements in magnetite, pyrite and pyrrhotite were conducted. Four pyrite samples yielded a Re-Os isochron age of 197 ± 11 Ma, implying the occurrence a metallogenic event in the Early Jurassic. The δ34S values of sulfides display a relatively narrow range from 4.70‰ to 12.83‰ (mainly 9.90‰ to 12.83‰), which may be accounted for the extensively exposed granitic gneiss and meta-gabbro, with δ34S values of 7.44‰ to 8.44‰ and 4.37‰ to 10.54‰, respectively. Sulfide lead isotopic compositions have 206Pb/204Pb = 18.605–20.136, 207Pb/204Pb = 15.637–15.710 and 208Pb/204Pb = 38.534–39.129, indicating that the lead was derived from a mixed source. Magnetite has the characteristics of a lower Ti content and higher Zn content, indicating that it should be of hydrothermal origin, which may be related to IOCG-type mineralization. Pyrite and pyrrhotite have a Co/Ni ratio greater than 1 and a lower As content, indicating that they are of magmatic hydrothermal origin. Integrating the above analysis results, we inferred that the Weizigou Au deposit experienced the IOCG-type mineralization in the Middle-Late Permian, associated with magmatic-hydrothermal mineralization in the Early Jurassic.
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Groves, David I., Liang Zhang, and M. Santosh. "Subduction, mantle metasomatism, and gold: A dynamic and genetic conjunction." GSA Bulletin 132, no. 7-8 (November 4, 2019): 1419–26. http://dx.doi.org/10.1130/b35379.1.
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Abstract Global gold deposit classes are enigmatic in relation to first-order tectonic scale, leading to controversial genetic models and exploration strategies. Traditionally, hydrothermal gold deposits that formed through transport and deposition from auriferous ore fluids are grouped into specific deposit types such as porphyry, skarn, high- and low-sulfidation–type epithermal, gold-rich volcanogenic massive sulfide (VMS), Carlin-type, orogenic, and iron-oxide copper-gold (IOCG), and intrusion-related gold deposits (IRGDs). District-scale mineral system approaches propose interrelated groups such as porphyry Cu-Au, skarn Cu-Au-Ag, and high-sulfidation Au-Ag. In this study, the temporal evolution of subduction-related processes in convergent margins was evaluated to propose a continuum of genetic models that unify the various types of gold deposits. At the tectonic scale of mineral systems, all hydrothermal gold deposits are interrelated in that they formed progressively during the evolution of direct or indirect subduction-related processes along convergent margins. Porphyry-related systems formed initially from magmatic-hydrothermal fluids related to melting of fertile mantle to initiate calc-alkaline to high-K felsic magmatism in volcanic arcs directly related to subduction. Formation of gold-rich VMS systems was related to hydrothermal circulation driven by magmatic activity during rifting of oceanic arcs. Orogenic gold deposits formed largely through fluids derived from devolatilization of the downgoing slab and overlying sediment wedge during late transpression in the orogenic cycle. Carlin-type deposits, IRGDs, and some continental-arc porphyry systems formed during the early stages of orogenic collapse via fluids directly or indirectly related to hybrid magmatism from melting of lithosphere that was metasomatized and gold-fertilized by earlier fluid release from subduction zones near margins of continental blocks. The IOCGs were formed during postorogenic asthenosphere upwelling beneath such subduction-related metasomatized and fertilized lithospheric blocks via fluid release and explosive emplacement of volatile-rich melts. Thus, importantly, subduction is clearly recognized as the key unifying dynamic factor in gold metallogenesis, with subduction-related fluids or melts providing the critical ore components for a wide variety of gold-rich deposit types.
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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 "IOGC ore deposit"
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Wanhainen, Christina. "On the origin and evolution of the palaeoproterozoic Aitik Cu-Au-Ag deposit, northern Sweden : a porphyry copper-gold ore, modified by multistage metamorphic-deformational, magmatic-hydrothermal, and IOCG-mineralizing events." Doctoral thesis, Luleå, 2005. http://epubl.luth.se/1402-1544/2005/36.
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Thomas, B. J. "Trace elements in magnetite and hematite for improving pathfinder element selection of the Hillside copper mineralisation, Yorke Peninsula." Thesis, 2010. http://hdl.handle.net/2440/106278.
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This item is only available electronically.The Hillside deposit is located in the southern part of the Olympic Province on the Gawler Craton, South Australia. This area has a history of IOCG-U style deposits, including the world class Olympic Dam deposit. Several other deposits and prospects have also been identified within this Olympic Dam domain. The Hillside deposit was discovered in the 1800s but recent work by Rex Minerals has expanded the mineralisation zone and have categorised this deposit as part of the IOCG-U family. A prominent characteristic of the Hillside IOCG mineralisation is the conversion of magnetite to hematite which in previous works on IOCG-U deposits was shown to be related to the mineralisation process. Two main mineralizing episodes can be distinguished, an earlier one was extremely Fe rich and allowed the formation of magnetite and pyrite. The second stage of mineralisation involved the injection of copper mineralizing fluids concurrent with the widespread replacement of magnetite by hematite. Analysis of the iron oxides was carried out using optical methods as well as trace element and rare earth element analysis by Electron Probe Micro Analysis and Laser Ablation ICP MS. The trace elements were used to identify compositional signature variations between the different iron oxide minerals. The rare earth element analysis showed a distinct overall enrichment in the hematite samples compared to the magnetite. The trace element analysis showed that several elements are distributed differently between the two oxides and sulphides. These elements include Cr, Zn, V, Ti, Ni, Pb and Co which show anomalies in both the oxides and sulphides. A variation between what elements are enriched is dependent on the mineral they are found within. This is suggested to reflect changes in composition of the mineralising fluid from the early magnetite-pyrite to the late hematite-chalcopyrite stage. The sulphides showed that chalcopyrite was enriched in several trace elements compared to pyrite. Sulphur isotope data were derived for pyrite and chalcopyrite also to characterise the source of the fluids. There was no systematic difference between chalcopyrite and pyrite. The data did show negative values between -2.6 δ34S and -6.6 δ34S which indicates that the source of the sulphur is most likely magmatic. This study gives an indication into the change in conditions that caused the replacement of magnetite by hematite and therefore the changes that caused mineralisation. An element signature was also collected to identify the difference between the iron oxides that will help in future works on this deposit.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010
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Skirrow, Roger. "The genesis of gold-copper-bismuth deposits, Tennant Creek, Northern Territory." Phd thesis, 1993. http://hdl.handle.net/1885/7562.
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The Au-Cu-Bi- deposits of the Proterozoic Tennant Creek Inlier share geological and geochemical characteristics that indicate strong links in their genesis, yet the diversity in alteration assemblages, metal ratios and zonation patterns reflect variations in ore forming processes that previously have not been explained in detail.
The West Peko deposit is representative of Cu-rich, pyrrhotite-bearing mineralisation with intermediate gold grades, in magnetite+ hematite-rich syntectonic ‘ironstones’. By contrast, the high grade Eldorado Au deposit contains minor sulfides and very low Cu grades, similar to several of the larger gold producers in the field (e.g. Juno, White Devil, Nobles Nob), and is also hematite-rich. Au, Chalcopyrite and Bi-sulfosalts were introduced into pre-existing ironside during progressive shearing, either late in the first regional deformation event (D1) or during a second phase of deformation. The occurrence of some Au zones outside ironstones suggests the ore fluids in part followed different flow paths to hose of the ironside-forming fluids.
Three chemically and isotopically distinct fluids have been characterised. (i) Ironstone-forming fluids at West Peko and Eldorado were Ca-Na-Cl (-Fe?) brines containing 12-20 weight % total dissolved salts, and reached temperatures of 350-400°C during magnetite deposition. Oxygen and hydrogen isotope compositions of minerals formed at the ironside stage are consistent with an origin of ironstones from formation or metamorphic waters.
(ii) The inferred Au-Bi+Cu transport fluid in he Cu- and sulphide-rich West Peko deposit was of low to moderate salinity (3-10 eq. wt. % Na Cl), ~300-350°C and N2 + CH4 – rich. Newly represented phase equilibria among the Fe-silicates stilpnomelane and minnesotaite, chlorite, biotite, sulfides, oxides and carbonates as well as fluid inclusion vapour compositions indicate that the Au-Bi+Cu transport fluid was relatively reducing with near-neutral pH and total dissolved sulphur contents of 0.001m to 0.01m. In the Eldorado Deeps Au- and hematite-rich deposit the Au-transporting fluid also may have been of low-moderate salinity, with Au deposition occurring at ~300°C. The reducing Au-Bi+Cu transport fluid at West Peko resembles primary magmatic or metamorphic water in oxygen and hydrogen isotopic composition. Carbon isotope ratios of Au-sulfide stage carbonates at West Peko point to involvement f organic carbon, probably sourced outside the host Warramunga Formation.
(iii) A regionally distributed, oxidising Ca-Na-Cl brine with 20-35 weight percent total dissolved salts, was present prior to, after and probably during ore deposition. Mixing with lower salinity reducing Au-Bi+Cu transport fluid is inferred at West Peko and us suggested to have caused effervescence of N2+CH4 by ‘salting out’, relatively late in the Au depositional stage.
An hypothesis of metal transport and deposition is proposed for the Tennant Creek deposits in which gold, copper and bismuth were transported in a reducing fluid and were deposited in the Cu- and sulphide-rich deposits dominantly by oxidation, desulfidation and initial pH increase as the reducing fluid reacted with magnetite+hematite ironstone. Mass transfer modelling indicates that relatively small amounts of ironstone are required to precipitate Au + Bi-sulfides, such as Eldorado, the oxidising brine may have played a significant role in ore deposition either by mixing with a reducing Au-Cu-Bi-transporting fluid, or by producing hematite oxidant additional to any already present in the ironstones. The greater extent of oxidation of the ore fluid in such deposits may have generally prevented saturation of copper minerals, resulting in low Cu grades.
Gold is inferred to have been transported dominantly as uncharged bisulfide complexes, although biselenide complexes were potentially important. New thermodynamic data estimated for bismuth complexes are consistent with bismuth transport as uncharged S-H-O-bearing species in the Tenant Creek ore fluids. The existence of high grade Au-Bi deposits outside ironstones is predicted by chemical modelling of mixing between reducing and oxidising fluids, located where structures allowed focused flow of both fluids.
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Chen, Huayong. "THE MARCONA - MINA JUSTA DISTRICT, SOUTH-CENTRAL PERÚ: IMPLICATIONS FOR THE GENESIS AND DEFINITION OF THE IRON OXIDE-COPPER (-GOLD) ORE DEPOSIT CLAN." Thesis, 2008. http://hdl.handle.net/1974/1206.
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The Marcona district of littoral south-central Perú represents the largest concentration of iron oxide-copper-gold deposits in the Central Andes. Hydrothermal activity occurred episodically from 177 to 95 Ma and was controlled by NE-striking faults.
At Marcona, emplacement of massive magnetite orebodies with subordinate, overprinted magnetite-sulphide assemblages coincided with a 156-162 Ma episode of eruption of andesitic magma in the Jurassic arc, but mineralization is hosted largely by underlying, Lower Paleozoic metaclastic rocks. The magnetite orebodies exhibit smoothly curving, abrupt contacts, dike-like to tubular apophyses and intricate, amoeboid interfingering with dacite porphyry intrusions, interpreted as evidence for the commingling of hydrous Fe oxidic and silicic melts. An evolution from magnetite - biotite - calcic amphibole ± phlogopite assemblages, which are inferred to have crystallized from an Fe-oxide melt, to magnetite - phlogopite - calcic amphibole - sulphide assemblages coincided with quenching from above 700°C to below 450°C and with the exsolution of aqueous fluids with magmatic stable isotopic compositions. Subsequent, subeconomic chalcopyrite - pyrite - calcite ± pyrrhotite ± sphalerite assemblages were deposited from cooler fluids with similar δ34S, δ18O and δ13C values, but higher δD, which may record the involvement of both seawater and meteoric water.
The much younger (95-110 Ma), entirely hydrothermal, Mina Justa Cu (-Ag) deposit is hosted by Middle Jurassic andesites intruded, on a district scale, by small dioritic stocks at the faulted SW margin of an Aptian-Albian shallow-marine volcano-sedimentary basin. Intense albite-actinolite alteration (ca. 157 Ma) and K-Fe metasomatism (ca. 142 Ma) long preceded the deposition of magnetite-pyrite assemblages from 500-600°C fluids with a magmatic isotopic signature. In contrast, ensuing chalcopyrite - bornite - digenite - chalcocite - hematite - calcite mineralization was entirely the product of non - magmatic, probably evaporite-sourced, brines.
Marcona and Mina Justa therefore represent contrasted ore deposit types and may bear minimal genetic relationships. The former shares similarities with other Kiruna-type magnetite (-apatite) deposits. In contrast, the latter is a hydrothermal system recording the incursion of fluids plausibly expelled from the adjacent Cañete basin. Non-magmatic fluids are inferred to be a prerequisite for economic Cu mineralization in the Cu-rich IOCG deposits in the Central Andes and elsewhere.Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2008-05-13 14:39:21.43
Conference papers on the topic "IOGC ore deposit"
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Luvsannyam, Oyunjargal, Ken-ichiro Hayashi, and Teruyuki Maruoka. "GEOLOGICAL, GEOCHEMICAL AND ORE GENETIC STUDY OF CHANDMANI UUL IRON OXIDE COPPER GOLD (IOCG) DEPOSIT IN DORNOGOBI PROVINCE, SOUTHEASTERN MONGOLIA." In GSA Annual Meeting in Phoenix, Arizona, USA - 2019. Geological Society of America, 2019. http://dx.doi.org/10.1130/abs/2019am-332847.
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DelGaudio, Stephen, John M. Hanchar, and Fernando Tornos. "TIMING AND RELATIONS OF MAGNETITE AND COPPER ORE MINERALIZATION IN IOCG AND MTAP DEPOSITS: COASTAL CORDILLERA, COPIAPO REGION CHILE,." In GSA Annual Meeting in Seattle, Washington, USA - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017am-303175.
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Fritis Pérez, Eduardo Esteban, Maria Emilia Schutesky Della Giustina, and Jérémie Garnier. "MULTIPLES SOURCES FOR THE GENESIS OF CU-AU DEPOSITS FROM CARAJÁS MINERAL IOCG SYSTEM, BRAZIL: TRACE ELEMENT AND SM-ND ISOTOPIC EVIDENCE FROM HYPOGENE ORES." In GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-358221.
Full textReports on the topic "IOGC ore deposit"
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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., 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. 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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