Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.
Active Motif, Inc

Site Tools

  • AAAS
  • Subscribe
  • Feedback

Site Search

Search Advanced

Science 16 May 2008:
Vol. 320. no. 5878, pp. 916 - 919
DOI: 10.1126/science.1156563
Prev | Table of Contents | Next

Reports

Metasomatized Lithosphere and the Origin of Alkaline Lavas

Sébastien Pilet,* Michael B. Baker, Edward M. Stolper

Recycled oceanic crust, with or without sediment, is often invoked as a source component of continental and oceanic alkaline magmas to account for their trace-element and isotopic characteristics. Alternatively, these features have been attributed to sources containing veined, metasomatized lithosphere. In melting experiments on natural amphibole-rich veins at 1.5 gigapascals, we found that partial melts of metasomatic veins can reproduce key major- and trace-element features of oceanic and continental alkaline magmas. Moreover, experiments with hornblendite plus lherzolite showed that reaction of melts of amphibole-rich veins with surrounding lherzolite can explain observed compositional trends from nephelinites to alkali olivine basalts. We conclude that melting of metasomatized lithosphere is a viable alternative to models of alkaline basalt formation by melting of recycled oceanic crust with or without sediment.

Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.

* To whom correspondence should be addressed. E-mail: sebastien.pilet{at}unil.ch

Read the Full Text

ADVERTISEMENT
Click Me!

ADVERTISEMENT
Click Me!

To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)