Transfer of volatiles and metals from mafic to felsic magmas in composite magma chambers: An experimental study

Guo, Haihao; Audétat, Andreas

doi:10.1016/j.gca.2016.11.029

Cited by 27 publications

(22 citation statements)

References 64 publications

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“…Importantly, Cu has the stronger affinity to partition into an exsolving magmatic volatile phase as shown by volatile-silicate melt partition coefficients between 10 and 100 (Candela and Holland 1984;Zajacz et al 2008;Guo and Audétat 2017). In contrast, the volatile-silicate melt partition coefficients for Mo is between 0.1 and 4 (Candela and Holland 1984;Guo and Audétat 2017). Consequently, associated magmatic volatiles will characteristically be enriched in Cu compared to Mo.…”

Section: Evidence For Cu Degassing In the Brothers Magmatic Systemmentioning

confidence: 99%

Constraints on the source of Cu in a submarine magmatic-hydrothermal system, Brothers volcano, Kermadec island arc

Keith

Haase

Klemd

et al. 2018

Contrib Mineral Petrol

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Most magmatic-hydrothermal Cu deposits are genetically linked to arc magmas. However, most continental or oceanic arc magmas are barren, and hence new methods have to be developed to distinguish between barren and mineralised arc systems. Source composition, melting conditions, the timing of S saturation and an initial chalcophile element-enrichment represent important parameters that control the potential of a subduction setting to host an economically valuable deposit. Brothers volcano in the Kermadec island arc is one of the best-studied examples of arc-related submarine magmatic-hydrothermal activity. This study, for the first time, compares the chemical and mineralogical composition of the Brothers seafloor massive sulphides and the associated dacitic to rhyolitic lavas that host the hydrothermal system. Incompatible trace element ratios, such as La/Sm and Ce/Pb, indicate that the basaltic melts from L'Esperance volcano may represent a parental analogue to the more evolved Brothers lavas. Copper-rich magmatic sulphides (Cu > 2 wt%) identified in fresh volcanic glass and phenocryst phases, such as clinopyroxene, plagioclase and Fe-Ti oxide suggest that the surrounding lavas that host the Brothers hydrothermal system represent a potential Cu source for the sulphide ores at the seafloor. Thermodynamic calculations reveal that the Brothers melts reached volatile saturation during their evolution. Melt inclusion data and the occurrence of sulphides along vesicle margins indicate that an exsolving volatile phase extracted Cu from the silicate melt and probably contributed it to the overlying hydrothermal system. Hence, the formation of the Cu-rich seafloor massive sulphides (up to 35.6 wt%) is probably due to the contribution of Cu from a bimodal source including wall rock leaching and magmatic degassing, in a mineralisation style that is hybrid between Cyprus-type volcanic-hosted massive sulphide and subaerial epithermal-porphyry deposits.

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Section: Evidence For Cu Degassing In the Brothers Magmatic Systemmentioning

confidence: 99%

Constraints on the source of Cu in a submarine magmatic-hydrothermal system, Brothers volcano, Kermadec island arc

Keith

Haase

Klemd

et al. 2018

Contrib Mineral Petrol

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“…An exsolved volatile phase lowers the bulk density and increases the buoyancy of magmas (Anderson, 1995), influences phase equilibria (Ghiorso and Gualda, 2015;Moore and Carmichael, 1998), as well driving convection (Cardoso and Woods, 1999;Longo et al, 2006) and promoting magma mingling and mixing through overturn (Huppert et al, 1982;Ruprecht et al, 2008). Recent work has shown that the exsolved volatile phase may be mobile in crystal-rich magma (Barth et al, in review;Oppenheimer et al, 2015;Parmigiani et al, 2016), leading to accumulation in the roof zones of magma reservoirs, which may play a role in triggering eruptions, activating hydrothermal systems through volatile injection (Chiodini et al, 2012) and in the generation of porphyries hosting economic concentrations of metals (Guo and Audétat, 2017;Huber et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Exsolved volatiles in magma reservoirs

Edmonds

Woods

2018

Journal of Volcanology and Geothermal Research

120

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Introduction 2. Achieving volatile saturation in magmas 2.1. Volatiles in natural magmatic systems 2.2. Sulfur partitioning into the exsolved volatile phase 3. Consequences of exsolved volatiles in magma reservoirs for rheology and dynamics 3.1. Magma compressibility 3.2. Pressure increase during second boiling 3.3. Effect of compressibility on the mass of magma erupted 4. The role of the exsolved volatile phase in magma mixing and mingling 4.1. Magma mixing and overturn, driven by vesiculation of the lower magma layer 4.2. Vesiculation of underplating magmas and formation of mafic enclaves 5. Exsolved volatile phase generation and transport through crystal-rich magma bodies 5.1. Transport of an exsolved volatile phase in crystal-rich magma 5.2. Implications of our new understanding of the transport of the exsolved volatile phase

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“…Cu and V show more variable behaviours than other elements, including enrichment in these ash and oxidised domains ( Figures 5 and 6). Both are associated with mafic melts, although V is not volatile [Guo and Audétat 2017;Mather et al 2012]. We argue that this enrichment is evidence for the potential interaction of a volatile-rich mafic melt with the silicic melt in the Cordón Caulle system either before or during the eruption.…”

Section: Bismuth Behaviour At Cordón Caullementioning

confidence: 72%

“…Alternatively, the source material for the ash matrices could be Bi-enriched relative to the vein and breccia hosts. Bismuth is a highly volatile element, commonly associated with mafic magmas and found enriched in plumes [Guo and Audétat 2017;Mather et al 2012]. Thus, Bi enrichment could be suggestive of the transfer and incorporation of volatiles from a mafic magma to the silicic magma at depth.…”

Section: Bismuth Behaviour At Cordón Caullementioning

confidence: 99%

“…This suggests an abrupt change in the gas capacity of Tl, which drove rapid Tl resorption into the available silicate melt (the ash particles). Bi enrichment throughout permeable zones could reflect volatile input from more mafic magmas [Guo and Audétat 2017]. It is unresolved whether Bi is adsorbed onto the edges of shards within veins, or is entering the rhyolite melt at depth.…”

Section: Summary: Fracturing Processes At Cordón Caullementioning

confidence: 99%

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Degassing-induced chemical heterogeneity at the 2011-2012 Cordón Caulle eruption

Paisley

Berlo²,

Whattam³

et al. 2019

Volcanica

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The mechanisms of hazardous rhyolitic eruptions such as Cordón Caulle, Chile, in 2011-2012 are controlled by poorly-understood shallow conduit processes. Here we characterise texturally and chemically heterogeneous domains (e.g. ash, breccias and tuffisites) generated via fracturing, gas fluxing and melt relaxation within the conduit, and preserved in glassy, oxidised and devitrified samples. Volatile trace element depletions (e.g. Zn, Pb) in relict degassing pathways record metal scavenging by fluxing gases. Diffusion modelling of preserved trace element concentration gradients (e.g. Li, Rb, Tl) at domain interfaces indicate deep-conduit degassing events were short-lived (~minutes) whereas late-stage venting from discrete locations was prolonged (~hours), corroborating visual observations of the eruption. Later-erupted vent deposits are volatile-depleted with respect to earlier-erupted bombs, indicating progressive syn-eruptive volatile loss. We show that a combination of in situ textural and volatile trace element analyses can provide new constraints on magmatic degassing in shallow systems depleted in H 2 O and CO 2. Résumé Les éruptions dangereuses de type rhyolitiques comme l'éruption du Cordón Caulle, au Chili, en 2011-2012, sont contrôlés par des mécanismes mal compris qui sont localisés dans un conduit peu profond. Dans cette étude, nous caractérisons des domaines où la texture et la chimie sont hétérogènes (par exemple : les cendres, les brèches et les tuffisite). Ces domaines ont été généré par la fracturation, le flux de gaz et la relaxation du liquide dans le conduit et sont conservées dans des échantillons vitreux, oxydés et dévitrifiés. L'appauvrissement des éléments traces et volatiles (par exemple Zn, Pb) enregistré dans les voies de dégazage, témoigne de l'absorption du métal par le flux de gaz. La modélisation des gradients de diffusion des éléments traces conservés (par exemple, Li, Rb, Tl) aux interfaces des domaines, indiquent que des événements de dégazage en conduit profond ont été de courte durée (~minutes) alors que la ventilation tardive de zones plus localisées était de longue durée (~heures). Ces résultats sont en accord avec des observations visuelles de l'éruption. Les dépôts tardifs sont appauvris en volatiles par rapport aux bombes éjectés antérieurement. Cela indique une perte en volatile progressive durant l'éruptive. Nous montrons qu'une association d'analyses in situ des textures et des éléments traces volatiles peut fournir de nouvelles contraintes sur le dégazage magmatique dans des systèmes peu profonds et appauvris en H 2 O et CO 2 .

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Transfer of volatiles and metals from mafic to felsic magmas in composite magma chambers: An experimental study

Cited by 27 publications

References 64 publications

Constraints on the source of Cu in a submarine magmatic-hydrothermal system, Brothers volcano, Kermadec island arc

Constraints on the source of Cu in a submarine magmatic-hydrothermal system, Brothers volcano, Kermadec island arc

Exsolved volatiles in magma reservoirs

Degassing-induced chemical heterogeneity at the 2011-2012 Cordón Caulle eruption

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