Carbonatite metasomatism, the key to unlocking the carbonatite-phoscorite-ultramafic rock paradox

Vasyukova, O. V.; Williams‐Jones, Anthony E.

doi:10.1016/j.chemgeo.2022.120888

Chemical Geology

2022

DOI: 10.1016/j.chemgeo.2022.120888

|View full text |Cite

Carbonatite metasomatism, the key to unlocking the carbonatite-phoscorite-ultramafic rock paradox

O. V. Vasyukova

Anthony E. Williams‐Jones

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...

Citation Types

Supporting

Mentioning

Contrasting

Year Published

2022

2024

Publication Types

Select...

Article6

Relationship

Self Cite0

Independent6

Authors

Journals

Cited by 18 publications

(1 citation statement)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A consensus among all experimental studies is that the solubility of silica (SiO 2 ) is low in upper crustal carbonatite melts of below 5 kbar and 1000 °C (mostly much less than 5 wt% SiO 2 ) 1 , 2 , in agreement with most natural melt inclusion studies 3 – 6 . Recently, Berndt and Klemme (B&K hereafter) documented haüyne-hosted melt inclusions from the Laacher See volcano exhibiting carbonatite–silicate liquid immiscibility formed at 720–880 °C and 1–2 kbar, with measured carbonatite melt containing high SiO 2 (~ 15 wt%), and moderately low Na 2 O and K 2 O (combined contents below 8 wt%) 7 .…”

supporting

confidence: 66%

Silica is unlikely to be soluble in upper crustal carbonatite melts

Anenburg

Guzmics²

2023

Nat Commun

View full text Add to dashboard Cite

supporting

confidence: 66%

Silica is unlikely to be soluble in upper crustal carbonatite melts

Anenburg

Guzmics²

2023

Nat Commun

View full text Add to dashboard Cite

Metasomatic ijolite, glimmerite, silicocarbonatite, and antiskarn formation: carbonatite and silicate phase equilibria in the system Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–O2–CO2

Anenburg,

Walters

2024

Contrib Mineral Petrol

View full text Add to dashboard Cite

Silicocarbonatites are carbonatite rocks containing > 20% silicate minerals. Their formation is not well understood due to low silica solubility in carbonatite melts and negligible amounts of silicate minerals on carbonatite melt cotectics at upper crustal conditions. We explore whether silicocarbonatites can be thought of as antiskarns: rocks formed by leaching of SiO2 from siliceous wall rocks by carbonatite melts, and its deposition as solid silicate minerals by reaction with chemical components already present in the carbonatite melt. Solid state thermodynamic modelling at 1–5 kbar and 500–800 °C predicts that calcite–dolomite–magnetite assemblages will transform to dolomite-free silicocarbonatites with an increase in silica contents. In sodic systems, the formation of aegirine and alkali amphiboles suppresses silica activity despite elevated silica contents. Therefore, dolomite remains stable, but Fe3+ is consumed, firstly from magnetite breakdown, and secondly by coupled Fe oxidation and reduction of CO2 to CO, CH4, and graphite, particularly at higher pressures. Despite a net increase in Fe3+/Fe2+, the system evolves to increasingly lower oxygen fugacity. In aluminous systems, nepheline indicates high temperatures whereas alkali feldspars form at lower temperatures. Modelling of potassic systems demonstrates stability of mostly phlogopite-rich biotites, leading to Fe2+ increase in all other carbonate and silicate phases. We find that perthites are expected in high pressures whereas two feldspars are more likely in lower pressures.Aspects of the clinopyroxene natural compositional trend (diopside to hedenbergite to aegirine) of carbonatite systems can be explained by silica contamination. Ferrous clinopyroxenes typically require low alumina and are predicted in potassic or low temperature sodic systems, primarily at mid to high pressures. Silica contamination permits the formation of silicocarbonatite-like assemblages in a way that is not limited by SiO2 solubility in carbonatite melts. Glimmerites and clinopyroxene-rich rocks (such as the ijolite series) that often occur around carbonatite rocks at the contact with silica-oversaturated wall rocks can be explained as the extreme end of silica contamination of carbonatite melts. Therefore, these clinopyroxenites and glimmerites can form solely via metasomatic processes without the presence of a silicate melt.

show abstract

High MREE-HREE solubility in a carbonatite-derived hydrothermal fluid: Evidence from fluorite-hosted fluid inclusions in the Amba Dongar carbonatite complex, India

et al. 2022

View full text Add to dashboard Cite

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

hi@scite.ai

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Carbonatite metasomatism, the key to unlocking the carbonatite-phoscorite-ultramafic rock paradox

Cited by 18 publications

References 29 publications

Silica is unlikely to be soluble in upper crustal carbonatite melts

Silica is unlikely to be soluble in upper crustal carbonatite melts

Metasomatic ijolite, glimmerite, silicocarbonatite, and antiskarn formation: carbonatite and silicate phase equilibria in the system Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–O2–CO2

High MREE-HREE solubility in a carbonatite-derived hydrothermal fluid: Evidence from fluorite-hosted fluid inclusions in the Amba Dongar carbonatite complex, India

Contact Info

Product

Resources

About