Porphyry copper enrichment linked to excess aluminium in plagioclase

Williamson, Ben J.; Herrington, Richard; Morris, Antony

doi:10.1038/ngeo2651

Cited by 87 publications

(61 citation statements)

References 19 publications

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“…Williamson et al . () recently proposed that the chemistry of plagioclase could be a guide to the prospectivity of calc‐alkaline magmatic suites for PCD. This paper aims to test the plagioclase discriminator proposed by Williamson et al .…”

Section: Introductionsupporting

confidence: 63%

Testing the Plagioclase Discriminator on the GEOROC Database to Identify Porphyry‐Fertile Magmatic Systems in Japan

et al. 2018

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Despite showing favorable geology, there are no known porphyry‐type deposits in Japan. This, therefore, provides an ideal porphyry‐“barren” case area on which to test the recently developed plagioclase‐based discriminator for porphyry‐“fertile” calc‐alkaline systems. The discriminator was applied to plagioclase data for Japan in the online GEOROC database for convergent margin settings. Of the 3933 data points available, and considered reliable, 91% fall in the “barren” field, which compares with 73% for equivalent data worldwide. “Fertile” signatures in certain parts of Kyushu and central Honshu should be further investigated, as well as areas where there are magnetite‐series magmatic systems with elevated whole‐rock Sr/Y but for which there are currently little or no plagioclase data (SW‐, N‐central‐, and NE‐Honshu). Why the Japanese arcs appear to show anomalously poor potential for porphyry deposits compared with other arcs worldwide, including Western Luzon, is as yet unclear but possibly relates to tectonic factors or the nature of the magmatic source or because melt PH2O in many of the magmatic systems was too low, as suggested from low average excess Al in plagioclase.

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Section: Introductionsupporting

confidence: 63%

Testing the Plagioclase Discriminator on the GEOROC Database to Identify Porphyry‐Fertile Magmatic Systems in Japan

et al. 2018

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“…Based on the pulsed hydrothermal process suggested here, together with cyclic mineralization processes constrained by recent high-precision U-Pb and Re-Os dating, titanium diffusion modeling, and concentric excess aluminum in plagioclase (Mercer et al, 2015;Spencer et al, 2015;Tapster et al, 2016;Williamson et al, 2016;Li et al, 2017a), we propose that a pulsed magmatic-hydrothermal process is common in the formation of porphyry deposits. Such a process is most likely controlled by periodic fluid release during gradual cooling of the source pluton at depth (Chelle-Michou et al, 2017), although a decline in the amount of melt and fluid associated with multiple recharging events is a competitive alternative mechanism.…”

Section: Pulsed Magmatic-hydrothermal Processmentioning

confidence: 99%

“…To explain the pulsed release of magmatic fluid, as observed at Qulong, two mechanisms are proposed, namely multiple fluid release events from the gradual cooling of a single magmatic reservoir (Chelle-Michou et al, 2017) and multiple fluid-melt recharging events feeding the source pluton (Kamenov et al, 2005;Williamson et al, 2016). For a gradually cooling magmatic reservoir, numerical modeling suggests that the fluids are released episodically, with most (50-75 wt.%) of the fluid being released during the first pulse (ChelleMichou et al, 2017), which is our favored explanation as supported by the observations at Qulong that ~60% of the metals are deposited in the first pulse.…”

Section: Pulsed Magmatic-hydrothermal Processmentioning

confidence: 99%

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Pulsed magmatic fluid release for the formation of porphyry deposits: Tracing fluid evolution in absolute time from the Tibetan Qulong Cu-Mo deposit

Yang

Selby

et al. 2017

Geology

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The magmatic-hydrothermal evolution of porphyry-style mineralization in the shallow crust that is linked to magmatic processes at depth has been extensively studied using bulksample isotopic analysis combined with relative timing constraints. However, a lack of evaluation of the fluid evolution process against an absolute time frame limits further understanding of the ore-forming process. Here, we quantify the fluid evolution process within an absolute time frame for the first time by integrating new in situ oxygen isotope data from the Qulong porphyry Cu-Mo deposit (Tibet) with existing fluid inclusion data and high-precision Re-Os dates of co-precipitated hydrothermal quartz and molybdenite, respectively. We demonstrate that vein quartz records primary oxygen isotopic compositions and reached oxygen isotope equilibrium with ore-forming fluids, and therefore is an archive of the isotopic composition and source of the ore-forming fluids. The δ

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“…Recent interest in the potential application of plagioclase as a fertility indicator has come from the recognition that it appears to be unusually enriched in Alabove normal stoichiometric levels -in fertile porphyry systems (Williamson et al, 2016;see Fig. 8).…”

Section: Plagioclasementioning

confidence: 99%

Porphyry indicator minerals and their mineral chemistry as vectoring and fertility tools

Wilkinson¹,

Cooke²,

Baker³

et al. 2017

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Porphyry copper enrichment linked to excess aluminium in plagioclase

Cited by 87 publications

References 19 publications

Testing the Plagioclase Discriminator on the GEOROC Database to Identify Porphyry‐Fertile Magmatic Systems in Japan

Testing the Plagioclase Discriminator on the GEOROC Database to Identify Porphyry‐Fertile Magmatic Systems in Japan

Pulsed magmatic fluid release for the formation of porphyry deposits: Tracing fluid evolution in absolute time from the Tibetan Qulong Cu-Mo deposit

Porphyry indicator minerals and their mineral chemistry as vectoring and fertility tools

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