H2O-δD-FeIII relations of dehydrogenation and dehydration processes in magmatic amphiboles
Article first published online: 8 FEB 2006
Copyright © 2006 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 20, Issue 5, pages 919–925, 15 March 2006
How to Cite
Demény, A., Vennemann, T. W., Harangi, S., Homonnay, Z. and Fórizs, I. (2006), H2O-δD-FeIII relations of dehydrogenation and dehydration processes in magmatic amphiboles. Rapid Commun. Mass Spectrom., 20: 919–925. doi: 10.1002/rcm.2380
- Issue published online: 8 FEB 2006
- Article first published online: 8 FEB 2006
- Manuscript Revised: 6 JAN 2006
- Manuscript Accepted: 6 JAN 2006
- Manuscript Received: 25 NOV 2005
- Hungarian Scientific Research Fund. Grant Number: OTKA T 029078
- Bolyai János Research Scholarship
Stable isotope compositions of a suite of magmatic amphiboles from alkaline basalts and andesitic rocks were examined to constrain the effects of degassing processes on the hydrogen isotope compositions. The Fe3+ (as Fe3+/Fetotal) and H2O contents, as well as the H isotope compositions of the amphiboles, differ markedly (27–58%, 0.5–2.2 wt%, −107 to −15‰, respectively) but indicate systematic variations. The observed trends can be explained either as dehydrogenation or dehydration processes, both of which are coupled to oxidation processes, the latter most probably related to O2− substitution within amphiboles. The dehydrogenation-dehydration models can be used to assess the primary compositions of the magmas. As an important example, δD values of amphiboles of Martian meteorites are discussed in a similar context. Copyright © 2006 John Wiley & Sons, Ltd.