Factors controlling sulfur concentrations in volcanic apatite

Peng, Genyong; Luhr, James F.; McGee, J. J.

doi:10.2138/am-1997-11-1217

Cited by 175 publications

(73 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We measured F, Cl and OH directly using secondary ion mass spectrometry and electron microprobe analysis (see Supplementary Methods). We neglect 4 sulphur, because S diffusion in apatite is inhibited by a coupled substitution 19 (Fig. 3a-c).…”

Section: Volatile Variations In Apatite and Hydrous Glassesmentioning

confidence: 99%

Late-stage volatile saturation as a potential trigger for explosive volcanic eruptions

et al. 2016

View full text Add to dashboard Cite

. (2016) 'Late-stage volatile saturation as a potential trigger for explosive volcanic eruptions.', Nature geoscience., 9 (3). pp. 249-254. Further information on publisher's website:http://dx.doi.org/10.1038/NGEO2639Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Volatile variations in apatite and hydrous glassesThe volatile composition of apatite relates to that of its host liquid by a set of exchange reactions between F, Cl and OH, for example:where exchange coefficients, K, are constant at a given pressure (P) and temperature (T) (ref. 12), f is fugacity, X is mole fraction and superscripts l and Ap denote the liquid and apatite phases, respectively. We measured F, Cl and OH directly using secondary ion mass spectrometry and electron microprobe analysis (see Supplementary Methods). We neglect 4 sulphur, because S diffusion in apatite is inhibited by a coupled substitution 19 , and equilibrium is not maintained on short timescales. Apatite compositions from Astroni 1 show a negative correlation between X F and X OH and a weaker negative correlation between X Cl and X OH (where X F , X Cl and X OH are the mole fractions of F, Cl and OH, respectively;Supplementary Table 1), demonstrating this exchange of components within the crystal volatile site. Some crystals are slightly non-stoichiometric, within the range reported in other studies 20 . We focus on mole fraction ratios as these relate to liquid composition, pressure and temperature through relationships such as equation (1). Data show a positive correlation between X Cl /X OH and X F /X OH ( Fig. 2a), with one low-X Cl , high-X F outlier. In general, X F /X Cl is constant within error, except in the outlier which has high X F /X Cl ( Fig. 2b). Clinopyroxenehosted apatite inclusions extend to higher X halogen /X OH ratios than biotite-hosted apatite inclusions. Both clinopyroxene-and biotite-hosted inclusions extend to higher X halogen /X OH ratios than apatite microphenocrysts that were in contact with melt until eruption. The overall X halogen /X OH trend is apparently linear, suggesting that there was no significant relative change in F or Cl compatibility during apatite crystallization. (Fig. 3a-c). However, matrix glasses have low H 2 O contents relative to both clinopyroxene-and biotite-hosted melt inclusions, typically <1 wt% (Fig. 3d). Modelling fractionation and volatile saturationWe model magma evolution in the Campi Flegrei system using the Rhyolite-MELTS thermodynamic software 23,24, 25,26 Disc...

show abstract

Section: Volatile Variations In Apatite and Hydrous Glassesmentioning

confidence: 99%

Late-stage volatile saturation as a potential trigger for explosive volcanic eruptions

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The elevated SO 3 contents in microphenocrystic apatite indicate that sulfur has been accommodated in magmas dominantly as oxidized species (e.g., Imai et al 1993Imai et al , 1996, whereas the partitioning of SO 3 between apatite and the coexisting melt with respect to f O 2 and temperature has not been quantitatively established (Peng et al, 1997).…”

Section: Chemical Composition Of Microphenocrystic Apatitementioning

confidence: 99%

Metallogenesis of Porphyry Cu Deposits of the Western Luzon Arc, Philippines: K‐Ar ages, SO₃ Contents of Microphenocrystic Apatite and Significance of Intrusive Rocks

Imai

2002

Resource Geology

109

View full text Add to dashboard Cite

K-Ar ages of the following porphyry Cu deposits in the western Luzon arc are determined: Lobo-Boneng (10.5±0.4 Ma), Santo Niño (9.5±0.3 Ma), Black Mountain (2.1±0.1 Ma), Dizon (2.5±0.2 Ma) and Taysan (7.3±0.2 Ma). Microphenocrystic apatite in the late Cenozoic intermediate to silicic intrusions associated with porphyry Cu deposits in the western Luzon arc contains sulfur as SO 3 detectable by electron probe microanalyzer. Sulfur is supposed to have been accommodated dominantly as oxidized species in oxidizing hydrous magmas that generated porphyry Cu deposits. Likewise, such high SO 3 contents in microphenocrystic apatite are common characteristics of the intermediate to silicic magmatism of the western Luzon arc, from tonalitic rocks of the Luzon Central Cordillera of about 15 Ma to an active magmatism at Mount Pinatubo. Thus, the western Luzon arc has been generating porphyry Cu mineralization associated with oxidizing hydrous intermediate to silicic magmatism related to eastward subduction, since Miocene to the present day. Intermediate to silicic rocks since 15 Ma to present-day western Luzon arc generally show high whole-rock Sr/Y ratio ranging from 20 to 184. However, porphyry Cu deposit is not necessarily related to the rocks that show higher Sr/Y ratios compared to the other barren rocks in the western Luzon arc. The characteristics of the intermediate to silicic magma associated with porphyry Cu deposit are not attributed to the composition of the source material of the magma, but to the properties defined by the high activity of oxidized species of sulfur in the fluid phase that is encountered during the generation of intermediate to silicic magmas.

show abstract

“…The highest SO 3 contents in apatite in each sample are generally > 0.4 wt% from other intrusions. Such elevated SO 3 contents in microphenocrystic apatite indicate that sulfur has been accommodated in the oxidizing magmas dominantly as oxidized species (e.g., Imai et al, 1993Imai et al, , 1996, whereas the partitioning of SO 3 between apatite and coexisting melt with respect to f O 2 and temperature has not been quantitatively established yet (Peng et al, 1997).…”

Section: Apatite Mineral Chemistrymentioning

confidence: 99%

Generation and Evolution of Ore Fluids for Porphyry Cu‐Au Mineralization of the Santo Tomas II (Philex) Deposit, Philippines

Imai¹

2001

Resource Geology

View full text Add to dashboard Cite

Abstract:The Santo Tomas II (Philex) deposit is a porphyry Cu-Au deposit, located in the southern part of the Baguio mineral district, Benguet Province, northern Luzon, Philippines. The Santo Tomas II deposit is associated with an intrusive complex consisting of four rock types that are distinguished based on petrography. They are 1) post-ore clinopyroxene-bearing hornblende andesite porphyry, 2) ore-generating hornblende andesite porphyry, 3) hornblende quartz diorite porphyry and 4) porphyritic hornblende quartz diorite. K-Ar age of hydrothermal biotitization was estimated to be 1.5±0.4 Ma.A number of intrusive bodies having broadly similar petrography and K-Ar age occur in the vicinity of the Santo Tomas II deposit, such as at Clifton, Ligay (Binang), Bumolo (Waterhole) and Philex Main Camp areas. The intrusions at the Santo Tomas II deposit and in the vicinity are characterized by high X Mg (Mg/[Mg+Fe] atomic ratio, about 0.7 or higher) of mafic silicate phenocrysts such as hornblende, and high sulfur contents (> 0.2 wt% as SO 3 ) in accessory microphenocrystic apatite, suggesting a highly oxidizing condition. Sulfur is accommodated dominantly as oxidized species since the crystallization of phenocrysts. Sub-dendritic rim of tremolitic amphibole on hornblende phenocryst in the ore-generating andesite porphyry at the Santo Tomas II deposit suggests interaction of magma and aqueous fluid(s) exsolved due to decompression during intrusion.Dissemination of magnetite is associated with hydrothermal biotitization and is followed by sheeted and stockwork quartz veinlets having silician magnetite and rare titanohematite instead of Cu-Fe sulfides. The silician magnetite-rich quartz veinlet was formed at f O2 near the hematite-magnetite buffer at nearly magmatic temperature, where sulfur dominantly existed as oxidized species such as SO 2 . Chalcopyrite and bornite, which commonly exhibit micrographic texture often accompanying Pd telluride and native gold/Au-rich electrum, are associated with subsequent anhydrite (-quartz) veinlets and stringers. Both intermediate solid solution (iss) and bornite solid solution (bnss) are thought to have coprecipitated primarily at above 500°C based on fluid inclusion microthermometry and sulfur isotope thermometry applied for anhydrite and associated chalcopyrite and bornite. The initial iss is considered to have converted to chalcopyrite partly replacing bnss during cooling. The hypersaline polyphase fluid inclusions abundantly found in the sheeted and stockwork quartz as well as anhydrite veinlets with scarce gaseous inclusions suggest that they have been trapped in the two aqueous fluid immiscible region.The western Luzon arc associated with porphyry Cu mineralization is characterized by oxidized hydrous magmatism and shallow emplacement, and by the source of sulfur enriched in 34 S.

show abstract

Factors controlling sulfur concentrations in volcanic apatite

Cited by 175 publications

References 46 publications

Late-stage volatile saturation as a potential trigger for explosive volcanic eruptions

Late-stage volatile saturation as a potential trigger for explosive volcanic eruptions

Metallogenesis of Porphyry Cu Deposits of the Western Luzon Arc, Philippines: K‐Ar ages, SO₃ Contents of Microphenocrystic Apatite and Significance of Intrusive Rocks

Generation and Evolution of Ore Fluids for Porphyry Cu‐Au Mineralization of the Santo Tomas II (Philex) Deposit, Philippines

Contact Info

Product

Resources

About

Factors controlling sulfur concentrations in volcanic apatite

Cited by 175 publications

References 46 publications

Late-stage volatile saturation as a potential trigger for explosive volcanic eruptions

Late-stage volatile saturation as a potential trigger for explosive volcanic eruptions

Metallogenesis of Porphyry Cu Deposits of the Western Luzon Arc, Philippines: K‐Ar ages, SO3 Contents of Microphenocrystic Apatite and Significance of Intrusive Rocks

Generation and Evolution of Ore Fluids for Porphyry Cu‐Au Mineralization of the Santo Tomas II (Philex) Deposit, Philippines

Contact Info

Product

Resources

About

Metallogenesis of Porphyry Cu Deposits of the Western Luzon Arc, Philippines: K‐Ar ages, SO₃ Contents of Microphenocrystic Apatite and Significance of Intrusive Rocks