In situ major and trace element analysis of amphiboles in quartz monzodiorite porphyry from the Tonglvshan Cu–Fe (Au) deposit, Hubei Province, China: insights into magma evolution and related mineralization

Duan, Deng-Fei; Jiang, Shao‐Yong

doi:10.1007/s00410-017-1355-z

Cited by 24 publications

(4 citation statements)

References 32 publications

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“…The fO 2 condition of the rhyolitic melt, determined using the amphibole oxygen barometer (Ridolfi et al, ), is >ΔNNO (Figure b), which indicates a relatively oxidized magma (Figure d). The high fO 2 condition of the rhyolitic magma favors sulfate (SO 4 2− ) and not sulfide (S 2− ), thereby limiting the removal of chalcophile elements and promoting the enrichment of chalcophile elements in the melt (Carroll & Rutherford, ; Duan & Jiang, ; Richards, ).…”

Section: Discussionmentioning

confidence: 99%

Amphibole perspective to unravel the rhyolite as a potential fertile source for the Yonaguni Knoll IV hydrothermal system in the southwestern Okinawa Trough

Chen

Zeng

et al. 2019

Geological Journal

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Yonaguni Knoll IV is an active seafloor hydrothermal system containing massive Zn-Pb sulfides located in the southwestern OkinawaTrough. Previous research has suggested that the metal elements Zn and Pb were dominantly derived from the local volcanic rocks via water-rock interactions. However, it is not known whether or why the volcanic rocks are rich in these metals. Here, we performed a detailed in situ analysis of the major and trace elements in amphiboles in the rhyolite from the hydrothermal field to decipher the physical-chemical conditions of the silicic magma, including temperature (T), pressure (P), oxygen fugacity (fO 2 ), volatile contents (Cl, H 2 O) and metal contents (Pb, Zn), and investigate the behavior of the metals (Zn and Pb) during melt evolution. Our results show that the amphiboles are euhedral calcic magnesiohornblende and are in equilibrium with the hydrous and oxidized host rhyolitic melt characterized by high H 2 O melt (~5.8-6.5 wt.%), fO 2 (NNO +0.1 to +0.6) and SiO 2 melt (~71.73-72.62 wt.%) values at 761-797°C and 102-137 MPa, corresponding to an approximate depth of 3.9-5.2 km. In addition, the rare earth element (REE) patterns of the melt reconstructed from the amphiboles are analogous to those of cold-wetoxidized rhyolites. Thus, the amphiboles crystallized in a cold-wet-oxidized shallow silicic magma chamber. The high oxygen fugacity is inferred to have favored sulfur and metal enrichment in the melt. The most abundant metal in the amphiboles is Zn (237-294 ppm), and the concentrations of Pb are much lower (0.86-3.32 ppm), suggesting that Zn preferentially entered the amphibole and that Pb was retained in the melt. The Cl content of the amphiboles ranges from 0.11 to 0.25 wt.%, and accordingly, the Cl melt content estimated from the amphiboles varies from 0.15 to 0.28 wt. %. The low (Cl/H 2 O) melt ratios, which are <0.05 (i.e.,~0.02-0.04), suggest that the melt exsolved an H 2 O-rich vapor rather than a hydrosaline fluid with insufficient Cl to transport metals (e.g., Pb and Zn) into the vapor phase during degassing both in the magma chamber and during ascent. The lack of exsolved hydrosaline fluid and the high oxidation conditions resulted in the metal elements Pb and Zn remaining dissolved in the rhyolitic melt and/or partitioning into crystalline minerals upon eruption. Thus, the large volumes of rhyolitic magma that intruded into the upper crust of the Yonaguni Knoll IV hydrothermal field are a potential fertile source of these elements via leaching by heated seawater.

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Section: Discussionmentioning

confidence: 99%

Amphibole perspective to unravel the rhyolite as a potential fertile source for the Yonaguni Knoll IV hydrothermal system in the southwestern Okinawa Trough

Chen

Zeng

et al. 2019

Geological Journal

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“…The mineralogy of the porphyry is dominated by plagioclase (50%–55%), quartz (10%–15%), hornblende (10%–15%), K‐feldspar (5%–10%), with lesser biotite (<2%), most of which occurs as both phenocryst and groundmass phases (Zhang et al, 2018; Zhang et al, 2021). Accessory minerals, which make up around 3%–4% of the samples, are mainly apatite, magnetite and titanite (Duan & Jiang, 2017). The QMD has undergone varying degrees of potassic and sodic alteration, carbonatization and endoskarn formation (Shu et al, 1992; Zhao et al, 2012).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…phases (Zhang et al, 2018;Zhang et al, 2021). Accessory minerals, which make up around 3%-4% of the samples, are mainly apatite, magnetite and titanite (Duan & Jiang, 2017). The QMD has undergone varying degrees of potassic and sodic alteration, carbonatization and endoskarn formation (Shu et al, 1992;Zhao et al, 2012).…”

Section: Igneous Precursors and Endoskarnsmentioning

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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“…DOI: https://doi.org/10.2138/am-2021-7951. http://www.minsocam.org/(Zhou et al 2020a;Duan et al 2017), and ΔNNO +0.9 to ΔNNO +2.1, respectively. Thus,…”

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confidence: 99%

The efficiency of copper extraction from magma bodies: Implications for mineralization potential and fluid-silicate melt partitioning of copper

Zhou,

Wang,

Wyman

et al. 2022

American Mineralogist

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In situ major and trace element analysis of amphiboles in quartz monzodiorite porphyry from the Tonglvshan Cu–Fe (Au) deposit, Hubei Province, China: insights into magma evolution and related mineralization

Cited by 24 publications

References 32 publications

Amphibole perspective to unravel the rhyolite as a potential fertile source for the Yonaguni Knoll IV hydrothermal system in the southwestern Okinawa Trough

Amphibole perspective to unravel the rhyolite as a potential fertile source for the Yonaguni Knoll IV hydrothermal system in the southwestern Okinawa Trough

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

The efficiency of copper extraction from magma bodies: Implications for mineralization potential and fluid-silicate melt partitioning of copper

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