Geochemical signatures of copper redistribution in IOCG-type mineralisation, Gawler Craton, South Australia

Uvarova, Yulia; Pearce, Mark A.; Liu, Weihua; Cleverley, James S.; Hough, R. M.

doi:10.1007/s00126-017-0749-1

Cited by 8 publications

(4 citation statements)

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“…The electrical conductors observed across the craton (e.g., Figures , , and ) are interpreted as zones of fluid flow along shear zones probably during the Paleoproterozoic to Mesoproterozoic, which decreased the resistivity through aqua‐carbonic fluid entrapment (Heinson et al, ; Thiel & Heinson, ) or sulfide precipitation (Heinson et al, ). The significant domain boundaries within Gawler Craton (Figures b and ) appear to have acted as agents for energy and fluid flux between different geochemical reservoirs across the craton basement along secondary structures (Bastrakov et al, ; Direen & Lyons, ; Fraser et al, ; Haynes et al, ; Kontonikas‐Charos et al, , ; Uvarova et al, ) including shallow levels in the overlying sedimentary basins and basement (Cherry et al, ; Reid & Fabris, ). This is evident from the regional alteration and chemical footprint observed in both northern and southern sectors of the IOCG province (Kontonikas‐Charos et al, , ) and similarities in timing and composition of the hydrothermal alterations between the IOCG and CGG provinces (Bastrakov et al, ; Fraser et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…There is little consensus about the source of hydrothermal fluids associated with the IOCG Province, with genetic models proposing a crustal source (Cherry et al, 2017;McPhie, Kamenetsky, Allen, et al, 2011;McPhie, Kamenetsky, Chambefort, et al, 2011;McPhie et al, 2016), mantle/magmatic source (Creaser & Cooper, 1993;Ciobanu et al, 2013;Heinson et al, 2018;Johnson & McCulloch, 1995;Kirchenbaur et al, 2016;Kontonikas-Charos et al, 2017;McPhie, Kamenetsky, Allen, et al, 2011;Schlegel et al, 2016), and mixing of fluids from different sources Haynes et al, 1995;Huston et al, 2016;Skirrow et al, 2007Skirrow et al, , 2018Uvarova et al, 2017). The formation of the CGG deposits is not clear, as they record characteristics of both orogenic gold and intrusion-related systems (Fraser et al, 2007).…”

Section: Geologic Settingmentioning

confidence: 99%

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Proxies for Basement Structure and Its Implications for Mesoproterozoic Metallogenic Provinces in the Gawler Craton

et al. 2019

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The link between mineral resources and crustal‐rooted structures has been proposed for many of the world's most significant mineral provinces. Here we utilize a new approach by interpreting potential field data, including satellite gravity data, and high‐resolution continental‐scale magnetotelluric data, constrained with aeromagnetic, and seismic tomography and reflection data, to determine the distribution of crustal‐scale faults in the Archean to Proterozoic Gawler Craton (South Australia). The eastern flank of the craton hosts the supergiant Olympic Dam iron oxide‐copper‐gold (IOCG) deposit within a larger Olympic IOCG province. The central part of the craton contains gold‐only deposits, which define the Central Gawler Gold province. Both of these provinces are part of a Mesoproterozoic mineral system with an extensive hydrothermal alteration footprint, which formed during complicated tectonic mode switches. We show that both types of mineralization are located in proximity to crustal‐scale structures that appear to connect deep crustal fragments, which likely record the amalgamation of the Archean nucleus of the craton during the Neoarchean with subsequent reworking during the Mesoproterozoic. Many of these structures do not have a surface expression but coincide with gradients in magnetism, gravity, and electric resistivity anomalies, the latter data set suggesting they acted as fluid pathways extending to the lower crust. The results indicate that the first‐order controls on the distribution of IOCG and Central Gawler Gold metallogenic provinces are inherited from earlier tectonic events, which formed major crustal boundaries and related structures that are prone to reworking during later tectonism.

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Section: Discussionmentioning

confidence: 99%

Section: Geologic Settingmentioning

confidence: 99%

Proxies for Basement Structure and Its Implications for Mesoproterozoic Metallogenic Provinces in the Gawler Craton

et al. 2019

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“…Magnetite and hematite are the main iron ore in IOCG deposits [27,33,39,40]. Fe-Cu sulfides are not abundant in an IOCG system in comparison to iron oxide minerals [88,92]. In terms of paragenetic sequence, hematite formed at a late stage after magnetite [38].…”

Section: Metallogenesis Of Ore Types (Ore Characterization and Ore Ge...mentioning

confidence: 99%

Au-Cu Resources in Some Mines from Antiquity in the South Gabal Um Monqul and Gabal Al Kharaza Prospects, North Eastern Desert, Egypt

Atef,

Surour,

Madani

et al. 2023

Geosciences

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Since Antiquity, sustainable resources of gold and copper have been mined at two prominent prospects in the north Eastern Desert of Egypt, namely the south Gabel Um Monqul (SGUM) and Gabal Al Kharaza (GKZ). Mineralization is hosted by Neoproterozoic shield rocks represented by dacite and monzo- to syenogranite at the SGUM prospect whereas they are diorite, granodiorite, and quartz feldspar porphyry at the GKZ prospect. These hosts have been emplaced in an island arc environment from calc-alkaline magmas with a peraluminous to metaluminous signature. They are hydrothermally altered including albitization, sericitization, silicification, epidotization, and chloritization. The Au and Cu mineralizations are confined to shear zones that lately filled with auriferous quartz veins adjacent to mineralized alteration zones. In the GKZ prospect, the old trenches trend mainly in a NW–SE direction whereas it is NE–SW and NW–SE in the SGUM prospect. Evidence of shearing ranges from megascopic conjugate fractures and shear planes in the outcrops to microscopic sheared and crumbled Au-Cu ore assemblages dominated by Fe-Cu sulfides, specularite, and barite. Microscopic investigation suggests that the formation of specularite is due to the shearing of early existing magnetite. The ore textures and paragenetic sequence indicate that pyrite in the alteration zones is oxidized, leading to the liberation of gold up to 3.3 g/t. The formulae of the analyzed electrum lie in the range Au74.5-76.8 Ag22.2-24.5. Integration of the field, geochemistry, and mineral chemistry data, combined with the gold fire assay data prove the presence of sustainable amounts of disseminated Au and Cu, not only in the mineralized quartz veins, but also in the alteration zones. Data materialized in our paper show similarities in the style of mineralization at the SGUM and the GKZ prospects with iron oxide-copper-gold (IOCG) deposits elsewhere in the Arabian-Nubian Shield (ANS) and other world examples.

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“…In large regions of the Olympic Cu-Au Province magnetite-rich alteration is overprinted by hematite-rich alteration assemblages [20,25,130,133]. Oxygen isotope studies from the Olympic Dam deposit implicate mixing of low temperature, meteoric fluids and higher temperature magmatic waters [134,135].…”

Section: Alteration Mineralogy and Mineral Assemblagesmentioning

confidence: 99%

The Olympic Cu-Au Province, Gawler Craton: A Review of the Lithospheric Architecture, Geodynamic Setting, Alteration Systems, Cover Successions and Prospectivity

Reid

2019

Minerals

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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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Geochemical signatures of copper redistribution in IOCG-type mineralisation, Gawler Craton, South Australia

Cited by 8 publications

References 35 publications

Proxies for Basement Structure and Its Implications for Mesoproterozoic Metallogenic Provinces in the Gawler Craton

Proxies for Basement Structure and Its Implications for Mesoproterozoic Metallogenic Provinces in the Gawler Craton

Au-Cu Resources in Some Mines from Antiquity in the South Gabal Um Monqul and Gabal Al Kharaza Prospects, North Eastern Desert, Egypt

The Olympic Cu-Au Province, Gawler Craton: A Review of the Lithospheric Architecture, Geodynamic Setting, Alteration Systems, Cover Successions and Prospectivity

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