scholarly journals Monazite as an Exploration Tool for Iron Oxide-Copper-Gold Mineralisation in the Gawler Craton, South Australia

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 809
Author(s):  
Caroline Tiddy ◽  
Diana Zivak ◽  
June Hill ◽  
David Giles ◽  
Jim Hodgkison ◽  
...  
Keyword(s):  
Iron Oxide ◽  
South Australia ◽  
Intermediate Composition ◽  
Iocg Deposits ◽  
Basement Rocks ◽  
Copper Gold ◽  
Exploration Tool

The chemistry of hydrothermal monazite from the Carrapateena and Prominent Hill iron oxide-copper-gold (IOCG) deposits in the IOCG-rich Gawler Craton, South Australia, is used here to define geochemical criteria for IOCG exploration in the Gawler Craton as follows: Monazite associated with IOCG mineralisation: La + Ce > 63 wt% (where La > 22.5 wt% and Ce > 37 wt%), Y and/or Th < 1 wt% and Nd < 12.5 wt%; Intermediate composition monazite (between background and ore-related compositions): 45 wt% < La + Ce < 63 wt%, Y and/or Th < 1 wt%. Intermediate monazite compositions preserving Nd > 12.5 wt% are considered indicative of Carrapateena-style mineralisation; Background compositions: La + Ce < 45 wt% or Y or Th > 1 wt%. Mineralisation-related monazite compositions are recognised within monazite hosted within cover sequence materials that directly overly IOCG mineralisation at Carrapateena. Similar observations have been made at Prominent Hill. Recognition of these signatures within cover sequence materials demonstrates that the geochemical signatures can survive processes of weathering, erosion, transport and redeposition into younger cover sequence materials that overlie older, mineralised basement rocks. The monazite geochemical signatures therefore have the potential to be dispersed within the cover sequence, effectively increasing the geochemical footprint of mineralisation.

scholarly journals Paleoproterozoic Iron Oxide Apatite (IOA) and Iron Oxide-Copper-Gold (IOCG) mineralization in the East Arm Basin, Northwest Territories, Canada

2020 ◽  
Vol 57 (1) ◽  
pp. 167-183
Author(s):  
E.G. Potter ◽  
L. Corriveau ◽  
B.A. Kjarsgaard
Keyword(s):  
Iron Oxide ◽  
Direct Relationship ◽  
Regional Analysis ◽  
Volcanic Rocks ◽  
Intermediate Composition ◽  
Iocg Deposits ◽  
Copper Gold ◽  
Great Bear Magmatic Zone ◽  
Host Rocks ◽  
Fault Breccia

The Paleoproterozoic East Arm Basin of Canada hosts polymetallic vein, iron oxide–apatite (IOA), and potential iron oxide–copper–gold (IOCG) mineral occurrences, mainly associated with a belt of ca. 1.87 Ga intermediate-composition sills termed the Compton intrusions. Advances in our knowledge of the East Arm Basin and of IOA and IOCG deposits within the broader context of iron oxide and alkali-calcic alteration systems enables a new regional analysis of this mineralization and facilitates comparison of these mineral occurrences and host rocks to the nearby Great Bear magmatic zone IOCG districts. The Compton intrusions and co-magmatic Pearson Formation volcanic rocks are comparable in age and composition to intrusive plus volcanic rocks of the Great Bear magmatic zone that host IOA–IOCG mineralization. Taking into account fault displacements, emplacement of Compton intrusions and Pearson Formation volcanic rocks are also consistent with the architecture of modern arcs, supporting a direct relationship with the Great Bear subduction zone. Trace element patterns of uraninite contained in IOA occurrences of the East Arm Basin are also similar to the patterns of uraninite from the Great Bear magmatic zone occurrences, consistent with both regions having experienced similar iron oxide and alkali-calcic alteration and mineralization. Our new results indicate that exploration for IOA, IOCG, and affiliated deposits in the East Arm Basin should focus on delineating increased potassic-iron alteration types and fault/breccia zones associated with these systems through field mapping and application of geochemical, radiometric, magnetic, and gravity surveys.

scholarly journals Evidence of multiple halogen sources in scapolites from iron oxide-copper-gold (IOCG) deposits and regional Na Cl metasomatic alteration, Norrbotten County, Sweden

2017 ◽  
Vol 451 ◽  
pp. 90-103 ◽  
Author(s):  
Nelson F. Bernal ◽  
Sarah A. Gleeson ◽  
Martin P. Smith ◽  
Jaime D. Barnes ◽  
Yuanming Pan
Keyword(s):  
Iron Oxide ◽  
Metasomatic Alteration ◽  
Iocg Deposits ◽  
Copper Gold

MAPPING THE MINERAL ZONATION AT THE ERNEST HENRY IRON OXIDE COPPER-GOLD DEPOSIT: VECTORING TO Cu-Au MINERALIZATION USING MODAL MINERALOGY

2022 ◽  
Vol 117 (2) ◽  
pp. 485-494
Author(s):  
Tobias U. Schlegel ◽  
Renee Birchall ◽  
Tina D. Shelton ◽  
James R. Austin
Keyword(s):  
Iron Oxide ◽  
Gamma Ray ◽  
Geochemical Data ◽  
Iocg Deposits ◽  
Mineral Mapping ◽  
Gamma Ray Spectrometer ◽  
Mineral Assemblages ◽  
Copper Gold ◽  
Host Rocks ◽  
Acid Alteration

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.

Hematite geochemistry and geochronology resolve genetic and temporal links among iron-oxide copper gold systems, Olympic Dam district, South Australia

2019 ◽  
Vol 335 ◽  
pp. 105480 ◽  
Author(s):  
Liam Courtney-Davies ◽  
Cristiana.L. Ciobanu ◽  
Max R. Verdugo-Ihl ◽  
Marija Dmitrijeva ◽  
Nigel J. Cook ◽  
...  
Keyword(s):  
Iron Oxide ◽  
South Australia ◽  
Copper Gold ◽  
Olympic Dam

ROSEN, BULGARIA: A NEWLY RECOGNIZED IRON OXIDE-COPPER-GOLD DISTRICT

2020 ◽  
Vol 115 (3) ◽  
pp. 481-488
Author(s):  
Richard H. Sillitoe ◽  
Georgi Magaranov ◽  
Veselin Mladenov ◽  
Robert A. Creaser
Keyword(s):  
Iron Oxide ◽  
South Australia ◽  
Close Correlation ◽  
Submarine Volcano ◽  
Zircon Age ◽  
Ring Dike ◽  
Slab Rollback ◽  
Copper Gold ◽  
End Stage ◽  
First Time

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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