Controls on Skarn Mineralization and Alteration at the Cadia Deposits, New South Wales, Australia

Forster, David B.; Seccombe, P. K.; Phillips, David

doi:10.2113/gsecongeo.99.4.761

Cited by 33 publications

(12 citation statements)

References 34 publications

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“…The skarn deposits in the area share features with the typical skarn-porphyry Cu deposits as Cadia in Australia, Gossan in Philippines (Meinert et al, 2003;Forster et al, 2004), Caicayén Hill in Argentina (Franchini et al, 2000).…”

Section: Genetical Types and Modelmentioning

confidence: 86%

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Geology, Ar-Ar Age and Mineral Assemblage of Eocene Skarn Cu-Au±Mo Deposits in the Southeastern Gangdese Arc, Southern Tibet: Implications for Deep Exploration

Qin

Ding

et al. 2006

Resource Geology

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. Medium‐ and large‐scaled skarn Cu‐Au±Mo deposits, e.g. Kelu, Liebu, Chongmuda and Chenba among others, are distributed in Shannan area of the Gangdese Cu‐Au metallogenic belt. Intrusions‐related skarn copper mineralization belongs to high K and calc‐alkaline rock series, located in late collision volcano‐magmatic arc and formed between 20 to 30 Ma. Copper mineralization occurs at exocontact zone of the lower Cretaceous Bima Group carbonate and other calcareous‐bearing sedimentary rocks with intrusions. At present, three main mineralization types are identified, including skarn type, hydrothermal vein type and porphyry type. Mineralizing associations are Cu‐Mo, Cu‐Au and Cu. In ore districts, those mineralization types form an entire porphyry‐skarn Cu‐Au±Mo ore‐forming system. Alterations of the exocontact are mainly skarnization and hornfelsization, while the alterations of the endocontact are mainly sericitization, silicification, and chloritization of intrusion. In the study area, the endoskarn is not well developed. Copper mineralization occurs mainly in the exocontact in the form of stratoid, lenticular and pockety ore body. Veined mineralization can be seen in marblized and hornfelsed siltstone, being away from the contact zone. In the endocontact, the mineralization is mainly veinlet‐like and disseminated. In Shannan area, skarnization can be divided into early skarnization stage and late hydrous silicate stage. The early skarnization stage is featured by mainly andradite and grossular skarn, containing minor diopside, hedenbergite, magnetite and some copper minerals; and the late hydrous silicate stage is of replacement of garnet skarn by chlorite, epidote, quartz and calcite together with sulfides precipitation. The latter is the main stage of copper mineralization. Bornite is the dominant ore mineral associated with minor chalcopyrite and pyrite; and gold as well as silver are distributed in bornite and wittichenite. Results of microthermometry study of fluid inclusions in quartz of late hydrous silicate stage from different deposits show intermediate temperature and low to intermediate‐salinity features for all samples. The dominant inclusion type is composed of two phases, being about 4 to 15 % vapor and 85 to 96 % liquid at room temperature. Homogenization temperatures range from 232 to 335d̀C. Salinities have been recorded between 4.2 and 15.5 wt% NaCl equivalent. Boiling fluid inclusions are not identified and it indicates that metal deposition mainly resulted from water‐rock reactions. The results of sulfur isotope analysis indicate that the sulfur isotope values (δ34S 1.29–1.68 %o) of the samples collected from skarns are similar with that from the endocontact (δ34S 1–1.75 %o). Both of them have very close sulfur isotope values (near δ34S 0 %o), which indicate the sulfur of both the skarn type and the porphyry type mineralization was from deep sources. Ages determined on biotite from ore‐bearing intermediate porphyries by Ar‐Ar methods range from 23.77±0.29 to 29.88±0.56 Ma, showing tha...

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Section: Genetical Types and Modelmentioning

confidence: 86%

“…The early skarnization stage is featured by mainly andradite and grossular skarn, containing minor diopside, hedenbergite, magnetite and some copper minerals (Figs. 11-12A, B); indicating that garnet-forming fluids carried the ore metals, as in the Cadia skarn CuAu deposit (Forster et al, 2004).…”

Section: Alterationsmentioning

confidence: 98%

Geology, Ar-Ar Age and Mineral Assemblage of Eocene Skarn Cu-Au±Mo Deposits in the Southeastern Gangdese Arc, Southern Tibet: Implications for Deep Exploration

Qin

Ding

et al. 2006

Resource Geology

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“…Associated phases are actinolite, tourmaline, apatite, chlorite, albite, and calcite. It is noteworthy that scapolite is a common mineral in Fe-Cu and Au skarns (Pan 1998), particularly those related to shoshonitic series igneous rocks (e.g., Forster et al 2004;Soloviev 2011). Based on the presence of this magma type in the region, more attention should paid to the Neogene post-collisional magmatism of the Ouixane area, because all of the geochemical ingredients are present there to suggest potential of the area for hosting undiscovered porphyry and Fe-Cu and Au skarn deposits.…”

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confidence: 99%

Skarn to Porphyry-Epithermal Transition in the Ouixane Fe District, Northeast Morocco: Interplay of Meteoric Water and Magmatic-Hydrothermal Fluids

Bouabdellah

Jabrane²,

Margoum

et al. 2016

Mineral Resource Reviews

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The Ouixane Fe skarn district in the northeastern Alpine Rifan belt is the highest grade iron district in Morocco with past production of 65 Mt of ore at >50 % Fe and estimated remaining reserves of 30 Mt grading 58 % Fe. Overall, the district consists of three major deposits, distributed in a 6 Â 6 km zone along the northeastern part of the Beni Bou Ifrour Massif. Mineralization occurs either within the 7.58 ± 0.03 Ma Ouixane post-collisional, hornblende-biotite quartz-diorite porphyry and related dike swarms, or more importantly at contacts of the porphyry with a *1,500-m-thick sequence of Upper Jurassic-Lower Cretaceous turbiditic and volcaniclastic sedimentary rocks. Igneous rocks have high-K, calc-alkaline to shoshonitic affinities and REE patterns that are consistent with emplacement in a typical arc setting. Concordance between the age of mineralization, which is thought to have occurred at 7.04 ± 0.47 Ma, and the 7.58 ± 0.03 Ma crystallization age of the Ouixane quartz-diorite porphyry constitutes strong evidence for a genetic relationship between Ouixane magnetite skarn mineralization and Late Neogene magmatism. Structural controls were important in focusing fluids and localizing the emplacement of late mineralizing phases. The ore zones have undergone strong post-ore displacement along steeply dipping, predominantly thrust

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“…The age of mineralisation at Cowal is remarkably close to that at Northparkes and Cadia (mainly 440 -435 Ma: Bastrakov 1998;Lickfold et al 2003Lickfold et al , 2007Forster et al 2004;Crawford et al 2007) for a zero porphyry trachyte dyke that transects mineralisation at E37 in the Northparkes leases). This may imply that the structurally controlled vein-type mineralisation at Cowal E42 is linked to undiscovered ca 440 Ma monzonite-type intrusive rocks such as those demonstrably related to the porphyrystyle mineralisation at Northparkes and Cadia, or that deformation at this time as part of the Benambran Orogeny created the veins.…”

Section: Geochronology Of Cowal Igneous Complex Intrusive Rocksmentioning

confidence: 53%

Geochemistry and age of magmatic rocks in the unexposed Narromine, Cowal and Fairholme Igneous Complexes in the Ordovician Macquarie Arc, New South Wales

Crawford

Cooke

2007

Australian Journal of Earth Sciences

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Controls on Skarn Mineralization and Alteration at the Cadia Deposits, New South Wales, Australia

Cited by 33 publications

References 34 publications

Geology, Ar-Ar Age and Mineral Assemblage of Eocene Skarn Cu-Au±Mo Deposits in the Southeastern Gangdese Arc, Southern Tibet: Implications for Deep Exploration

Geology, Ar-Ar Age and Mineral Assemblage of Eocene Skarn Cu-Au±Mo Deposits in the Southeastern Gangdese Arc, Southern Tibet: Implications for Deep Exploration

Skarn to Porphyry-Epithermal Transition in the Ouixane Fe District, Northeast Morocco: Interplay of Meteoric Water and Magmatic-Hydrothermal Fluids

Geochemistry and age of magmatic rocks in the unexposed Narromine, Cowal and Fairholme Igneous Complexes in the Ordovician Macquarie Arc, New South Wales

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