Geochemistry of the Late Neoproterozoic Hadb adh Dayheen ring complex, Central Arabian Shield: Implications for the origin of rare-metal-bearing post-orogenic A-type granites

Moghazi, A.M.; Harbi, Hussein M.; Ali, Kamal A.

doi:10.1016/j.jseaes.2011.07.018

Cited by 52 publications

(12 citation statements)

References 110 publications

(129 reference statements)

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“…These rocks 47 typically occur in extensional, intraplate/post-collisional settings (Burt et al, 1982;48 Kovalenko et al, 2007;Taylor, 1992). Ongonites and other strongly fractionated, 49 topaz-bearing rocks are known to be enriched in Li, B, Sn, Zn, W, Mo and U, other 50 than Nb-Ta, to concentrations that can amount to ore deposits (Antipin et al, 2006;51 Burt et al, 1982;Christiansen and Lee, 1986;Haapala, 1997;Syritso et al, 2012;52 Taylor, 1992; Moghazi et al, 2011). Niobium-Ta oxides, such as the columbite-53 tantalite solid solution series and ixiolite, deposited as magmatic accessory phases and 54 in alteration zones around F-rich intrusions, account for most of the current 55 production of these elements worldwide (Melcher et al, 2014).…”

Section: Introduction 16mentioning

confidence: 99%

Crystallisation of magmatic topaz and implications for Nb–Ta–W mineralisation in F-rich silicic melts — The Ary-Bulak ongonite massif

Agangi

Kamenetsky

Hofmann

et al. 2014

Lithos

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Textural, mineralogical and geochemical data on F-rich rhyolite (ongonite) from the Ary-Bulak massif of eastern Transbaikalia help constraining the formation of magmatic topaz. In these rocks, topaz occurs as phenocrysts, thus providing compelling evidence for crystallisation at the orthomagmatic stage. Cathodoluminescence images of topaz and quartz reveal growth textures with multiple truncation events in single grains, indicative of a dynamic system that shifted from saturated to undersaturated conditions with respect to topaz and quartz. Electron microprobe and Raman analyses of topaz indicate near-pure F composition [Al2SiO4F2], with very limited OH replacement. Laser ablation ICP-MS traverses revealed the presence of a large number of trace elements present at sub-ppm to hundreds ppm levels. The chemical zoning of topaz records trace element fluctuations in the coexisting melt. Concentrations of some trace elements (Li, Ga, Nb, Ta and W) are correlated with cathodoluminescence intensity, thus suggesting that some of these elements act as CL activators in topaz. The study of melt inclusions indicates that melts with different F contents were trapped at different stages during formation of quartz and topaz phenocrysts, respectively. Electron microprobe analyses of glass in subhedral quartz-hosted melt inclusions indicate F ≤1.2 wt.%, whereas irregular-shaped melt inclusions hosted in both topaz and quartz have F ≤9 wt.%. Cryolithionite [Na3Li3Al2F12] coexists with glass in irregular inclusions, implying high Li contents in the melt. The very high F contents would have increased the solubility of Nb, Ta and W in the melt, thus allowing progressive concentration of these elements during magma evolution. Crystallisation of Nb-Ta-W-oxides (W-ixiolite and tantalite-columbite) may have been triggered by separation of cryolithionite, which would have caused F and Li depletion and consequent drop in the solubility of these elements.

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Section: Introduction 16mentioning

confidence: 99%

Crystallisation of magmatic topaz and implications for Nb–Ta–W mineralisation in F-rich silicic melts — The Ary-Bulak ongonite massif

Agangi

Kamenetsky

Hofmann

et al. 2014

Lithos

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“…Considering the sharp intrusive contacts between the alkali feldspar granites and host country rocks, as well as the lack of evidence for any metasomatic effects in the rocks, we favour a magmatic origin for the F. The halogens (F or Cl) remain dissolved within the magma, lowering the crystallisation temperature, which cause REEs and high-field-strength elements (HFSE) to form complexes and behave as incompatible elements (Moghazi et al, 2011). Such behaviour can explain the high and variable contents of REE and HFSE in the alkali feldspar granites and their MME.…”

Section: Accepted Manuscriptmentioning

confidence: 90%

New constraints on the Cretaceous geodynamics of paleo-Pacific plate subduction: Insights from the Xiaojiang–Beizhang granitoids, Zhejiang Province, southeast China

Liu

Zhong

et al. 2018

Lithos

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The relationship between the evolution of Cretaceous magmatism along the southeastern margin of Eurasia and subduction of the paleo-Pacific plate remains controversial. Here we investigate the petrogenesis of the Xiaojiang-Beizhang ferroan and magnesian granitoids, melanocratic microgranular enclaves (MME) that are found within the granitoids, and an associated mafic dyke exposed in southeast China to

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“…Second, post‐magmatic re‐equilibration and metasomatism may lead to redistribution of some major elements as well as HFSEs and REEs (Moghazi, Harbi, & Ali, ). Geochemically, the high SiO 2 and low Na 2 O contents of the altered granites are likely due to silicification and sericitization, respectively (Zhu et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…REEs (Moghazi, Harbi, & Ali, 2011). Geochemically, the high SiO 2 and low Na 2 O contents of the altered granites are likely due to silicification and sericitization, respectively (Zhu et al, 2008).…”

Section: Nature Of Fluid Alteration and Metasomatismmentioning

confidence: 99%

Mesozoic multi‐stage W–Sn polymetallic mineralization in the Nanling Range, South China: An example from the Dengfuxian–Xitian ore field

Sun

Algeo

et al. 2018

Geological Journal

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The Dengfuxian and Xitian ore fields, located in the central Nanling Range of South China, are characterized by multi‐stage W–Sn polymetallic mineralization. In this study, whole‐rock and zircon compositions in altered granites from four typical deposits in these ore fields (i.e., Dalong Pb–Zn, Xiangdong W, Gaolong fluorite, and Shaiheling Sn–Pb–Zn) were studied to constrain their fluid chemistry and mineralization history. Compared to unaltered granites at Dengfuxian and Xitian, these fluid‐altered granites are characterized by more variable SiO2 (64.2–78.4%) and lower TiO2 (0.02–0.12%), CaO (0.25–1.2%), and Na2O (0.31–2.6%) concentrations, lower ΣREE (87–156 ppm), and higher Zr/Hf (11.1–31.6) and Y/Ho (31.1–53.4) ratios, suggesting intense F‐rich fluid metasomatism. Zircon cathodoluminescence (CL), transmitted light and back‐scattered electron (BSE) imaging, laser ablation multi‐collector inductively coupled plasma mass spectrometry (LA‐MC‐ICP‐MS) trace‐element analysis, U–Pb dating, and Hf isotopes revealed a sequence of three W–Sn polymetallic mineralization stages: a Triassic stage (~220 Ma), a Jurassic stage (~150 Ma), and a Cretaceous stage (~80 Ma). The Triassic episode was associated with a highly fractionated granitic magma derived from the lower crust and contaminated by basement rocks; the magmatic fluid was affected by a high 176Hf/177Hf component from the ~770‐Ma basement and probably precipitated under high F and high fO2 conditions. The Jurassic episode was related to mantle–crust interaction and resulted in large‐scale W–Sn mineralization at decreased fO2. The Cretaceous episode was marked by Sn mineralization in a lithospheric extensional setting. We infer that basement rocks were the major source of metals for the world‐class W–Sn ore deposits in the Nanling Range of South China. This study also demonstrates that whole‐rock geochemistry of hydrothermally altered granites in combination with Lu–Hf isotopic, U–Pb dating, and trace element analyses of magmatic and hydrothermal zircons can be a useful approach to recognition of multi‐stage magmatic and mineralization processes.

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Geochemistry of the Late Neoproterozoic Hadb adh Dayheen ring complex, Central Arabian Shield: Implications for the origin of rare-metal-bearing post-orogenic A-type granites

Cited by 52 publications

References 110 publications

Crystallisation of magmatic topaz and implications for Nb–Ta–W mineralisation in F-rich silicic melts — The Ary-Bulak ongonite massif

Crystallisation of magmatic topaz and implications for Nb–Ta–W mineralisation in F-rich silicic melts — The Ary-Bulak ongonite massif

New constraints on the Cretaceous geodynamics of paleo-Pacific plate subduction: Insights from the Xiaojiang–Beizhang granitoids, Zhejiang Province, southeast China

Mesozoic multi‐stage W–Sn polymetallic mineralization in the Nanling Range, South China: An example from the Dengfuxian–Xitian ore field

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