Evidence for mantle metasomatism by hydrous silicic melts derived from subducted oceanic crust

Gaelle Prouteau, Bruno Scaillet (), Michel Pichavant and René Maury
Additional contact information
Gaelle Prouteau: UMR 6538, UBO
Bruno Scaillet: UMR G113, ISTO
Michel Pichavant: UMR G113, ISTO
René Maury: UMR 6538, UBO

Nature, 2001, vol. 410, issue 6825, 197-200

Abstract: Abstract The low concentrations of niobium, tantalum and titanium observed in island-arc basalts are thought to result from modification of the sub-arc mantle by a metasomatic agent, deficient in these elements, that originates from within the subducted oceanic crust1. Whether this agent is an hydrous fluid2 or a silica-rich melt3 has been discussed using mainly a trace-element approach4 and related to variable thermal regimes of subduction zones5. Melting of basalt in the absence of fluid both requires high temperatures and yields melt compositions unlike those found in most modern or Mesozoic island arcs6,7. Thus, metasomatism by fluids has been thought to be the most common situation. Here, however, we show that the melting of basalt under both H2O-added and low-temperature conditions can yield extremely alkali-rich silicic liquids, the alkali content of which increases with pressure. These liquids are deficient in titanium and in the elements niobium and tantalum and are virtually identical to glasses preserved in mantle xenoliths found in subduction zones6 and to veins found in exhumed metamorphic terranes of fossil convergent zones7. We also found that the interaction between such liquids and mantle olivine produces modal mineralogies that are identical to those observed in metasomatized Alpine-type peridotites8. We therefore suggest that mantle metasomatism by slab-derived melt is a more common process than previously thought.

Date: 2001
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/35065583 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:410:y:2001:i:6825:d:10.1038_35065583

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/35065583

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().