Garnetization as a ground preparation process for copper mineralization: evidence from the Mazraeh skarn deposit, Iran

Somarin, Alireza Karimzadeh

doi:10.1007/s00531-008-0394-0

Cited by 20 publications

(4 citation statements)

References 31 publications

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“…This is generally regarded as “immobile” in the formation of many skarn deposits worldwide (Karimzadeh Somarin, 2004, 2010; Lentz, 2005; Mrozek et al, 2020), but up to 28% was removed during endoskarn formation in the Tonglushan system so it must have been relatively easily transported. It is mobile in neutral and slightly acid solutions but more so in fluids which are: (1) ultra‐acid (Stoffregen, 1987), which are uncommon in skarn systems, as discussed above; and (2) alkali‐rich (Anderson & Burnham, 1983).…”

Section: Discussionmentioning

confidence: 99%

Chemical changes during endoskarn and porphyry‐style alteration and Cu—Fe exoskarn mineralization in the Tonglushan system, eastern China

Zhang,

Williamson,

Ullmann

et al. 2023

Resource Geology

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Element mobility and chemical mass transfer are evaluated in the formation of Cu—Fe exoskarn deposits and endoskarn and minor porphyry‐style alteration in the Tonglushan quartz monzodiorite (QMD) system, eastern China. Endoskarn formation involved the migration of Ca into the QMD from the exoskarnification of carbonates (now marble) xenoliths and wall rocks, addition of Fe and Mn by magmatic‐hydrothermal fluids emanating from the interior of the QMD, and removal of alkali elements due to the replacement of feldspars and mica by prograde skarn minerals. Zirconium, Hf, U, and rare earth elements (REE) were added by hydrothermal fluids which were able to carry these often poorly mobile high field strength elements (HFSE) due to elevated F activity. Additions of Al were likely from Na‐rich fluids that also caused sodic alteration. Several factors favored mineralization within the exoskarns rather than endoskarns and QMD. The endoskarns were relatively oxidizing, as evidenced by a significant addition of Fe3+, which caused Cu to remain in magmatic‐hydrothermal fluids until they entered and precipitated sulphides in the more reducing environment of the exoskarns. Fluid migration from the QMD through the endoskarns and into the exoskarns was favored due to decarbonation of wall rock carbonates and related upwards migration of CO2 to produce a self‐sustaining chimney effect, which drew further fluids towards the carbonates to form, alter and mineralize the exoskarns. The higher porosity and permeability of the endoskarns compared with the QMD further promoted the lateral flow of Cu‐bearing fluids towards the exoskarns and limited porphyry‐style alteration and mineralization within the QMD. This proposed mechanism is only likely to be relevant for porphyry‐type systems developed predominantly within carbonate host rocks. Its significance for exploration models is that relatively poorly mineralized porphyry stocks in this setting may be associated with more substantive exoskarn deposits on their margins.

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Section: Discussionmentioning

confidence: 99%

Chemical changes during endoskarn and porphyry‐style alteration and Cu—Fe exoskarn mineralization in the Tonglushan system, eastern China

Zhang,

Williamson,

Ullmann

et al. 2023

Resource Geology

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“…Skarn minerals record the physicochemical conditions during the ore fluid evolution (e.g.Bin & Barton, ; Jamtveit et al, ; Chapman & Williams, ; Clechenko & Valley, ; Karimzadeh Somarin, ; Stowell et al, ; Xu et al, ). In particular, the chemical compositions of garnet and clinopyroxene can indicate the fluid redox state during the skarn alteration (e.g.Einaudi, ; Zaw & Singoyi, ; Lu et al, ; Markowski et al, ; Maher, ; Oyman, ).…”

Section: Discussionmentioning

confidence: 99%

Mineralogy, Fluid Inclusion, and Hydrogen and Oxygen Isotope Studies of the Intrusion‐Related Yangla Cu Deposit in the Sanjiang Region, SW China: Implications for Metallogenesis and Deposit Type

Huang

et al. 2019

Resource Geology

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The Yangla deposit is an intrusion‐related Cu deposit in the Jinshajiang tectonic belt (eastern Sanjiang region, SW China). Despite extensive studies that have been conducted on this deposit, the relationship between the granitic magma and Cu mineralization is still unclear, and hence, the genesis is debated. To answer this question, we conducted an integrated study of mineralogy, fluid inclusions (FIs), and hydrogen and oxygen (H‐O) isotopes. Three mineralization stages were identified based on the ore textures, alteration zonation, and crosscutting relationships: (i) pre‐ore prograde skarn (stage I), with the garnet and pyroxene dominated by andradite and diopside, respectively; (ii) syn‐ore retrograde alteration (stage II), which is subdivided into the early syn‐ore stage (stage IIa) marked by retrograde hydrated mineral assemblages and significant Fe‐Cu‐Mo‐Pb‐Zn sulfide mineralization, and the late syn‐ore stage (stage IIb) featured by quartz‐calcite veins; and (iii) late supergene mineralization (stage III), which is characterized by secondary azurite and malachite. These results of mineralogy, FIs, and H‐O isotopes indicate that: (i) Cu mineralization has a close temporal, spatial, and genetic relationship with skarn alteration; (ii) the ore fluids were magmatic dominated with late‐stage meteoric water incursion; and (iii) Type‐S (halite‐bearing) and Type‐V (vapor‐rich) FIs coexisted in garnet and clinopyroxene of stage I, indicating that fluid boiling might have occurred during this stage. From stage I to stage IIa, the FI type transformed from Type‐S + Type‐V + Type‐L (liquid‐rich) to Type‐V + Type‐L with the conduct of mineralization and was accompanied by the disappearance of Type‐S, and homogenization temperature and salinity also tended to decrease dramatically, which may be caused by the deposition of skarn minerals. At stage IIa, boiling of the ore fluids still continued due to the change from lithostatic to hydrostatic pressure, which triggered the precipitation of abundant quartz‐Cu‐Mo‐Fe sulfides. Furthermore, fluid mixing between a high‐temperature magmatic fluid and a low‐temperature meteoric water might cause a considerable drop in temperature and the deposition of Cu‐bearing quartz/calcite veins during stage IIb. Hence, we consider the Yangla deposit to be of a skarn type, genetically related to the Mesozoic magmatism in the Sanjiang region.

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“…In hydrothermal deposits, the Al-OH absorption feature of sericite group minerals may point to the hydrothermal and mineralization centre of the mine area [20,21,[63][64][65], but reports on successful SWIR applications on skarn deposit prospecting are fairly limited [20]. As for skarn deposits, garnet can be used as a guide in prospecting Cu skarn deposits [66]. However, garnet could only be observed in TIR, due to the fact that some atomic group vibrations in garnet can be detected in TIR.…”

Section: Relationship Between the Spectra And Mineralisationmentioning

confidence: 99%

Garnet Characteristics Associated with Jiama Porphyry-Skarn Cu Deposit 1# Skarn Orebody, Tibet, Using Thermal Infrared Spectroscopy

et al. 2020

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Field measurements of the thermal infrared (TIR) reflectance from drill hole samples proved to be an effective method to map variations in garnet species associated with hydrothermal alteration zonation of the Jiama porphyry-skarn Cu deposit 1# skarn orebody, Tibetan Plateau, China. The TIR mineral spectral information was combined with electron probe micro-analysis (EPMA) measurements to provide geological insights on effectively determining (a) garnet end components and providing a format for further research on the type and genesis of the deposit; (b) the significance of the characteristic spectrum of garnet to the variation of mineralization environment; (c) the relationship between the characteristic spectrum of garnet and Fe/Al content; (d) the garnet characteristic spectrum to the economic mineralization. The results suggest that garnet characteristics of the thermal infrared spectrum can be used as an indicator for skarn deposit prospecting.

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Garnetization as a ground preparation process for copper mineralization: evidence from the Mazraeh skarn deposit, Iran

Cited by 20 publications

References 31 publications

Chemical changes during endoskarn and porphyry‐style alteration and Cu—Fe exoskarn mineralization in the Tonglushan system, eastern China

Chemical changes during endoskarn and porphyry‐style alteration and Cu—Fe exoskarn mineralization in the Tonglushan system, eastern China

Mineralogy, Fluid Inclusion, and Hydrogen and Oxygen Isotope Studies of the Intrusion‐Related Yangla Cu Deposit in the Sanjiang Region, SW China: Implications for Metallogenesis and Deposit Type

Garnet Characteristics Associated with Jiama Porphyry-Skarn Cu Deposit 1# Skarn Orebody, Tibet, Using Thermal Infrared Spectroscopy

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