Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by ADAM, J. Articles by GREEN, T. Search for Related Content GeoRef GeoRef Citation

The influence of pressure, mineral composition and water on trace element partitioning between clinopyroxene, amphibole and basanitic melts

ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, Department of Earth and Planetary Sciences, Macquarie University, Sydney, N.S.W. 2109, Australia

^* E-mail: john_adam{at}bigpond.com

Trace and minor elements in clinopyroxenes, amphiboles and basanitic melts produced in experiments at 0.5 to 2.0 GPa and 1000 to 1050°C were analysed by LAM-ICP-MS. The analyses reproduce the results of previous electron microprobe analyses by Adam & Green (1994) but also provide data for many new elements. The expanded data set was used to evaluate the trace element partitioning models of Blundy & Wood (1994) and Wood & Blundy (1997). Although the lattice-strain model of Blundy & Wood (1994) could be successfully fitted to our data, the thermodynamic model of Wood & Blundy (1997) does not predict the negative correlations that we found between D_REE and pressure. This is not explained by variations in the amounts of H₂O in our experiments. Instead, we attribute the variations in D_REE to volume-reducing substitutions in octahedral and tetrahedral sites that increase the activities of +3 and +4 ions, and decrease those of +1 ions, in sites of 8-fold coordination as pressure increases. We were able to quantitatively model some of these effects using a combination of simple electrostatics, Pauling bond strengths and bond-valence calculations. Notwithstanding this, it is apparent that pressure, temperature and the properties of the melt phase also influence partition coefficients independently of mineral composition and crystal-chemical effects.

Key-words: trace elements, valence, clinopyroxene, amphibole, basanite, partitioning.

This article has been cited by other articles:

				A. Demeny, R. Casillas, T. W. Vennemann, E. Hegner, G. Nagy, A. Ahijado, J. De La Nuez, P. Sipos, S. Pilet, and J. Milton Plume-related stable isotope compositions and fluid-rock interaction processes in the Basal Complex of La Palma, Canary Islands, Spain Geological Society, London, Special Publications, January 1, 2008; 293(1): 155 - 175. [Abstract] [Full Text] [PDF]

				R. Oberti, F. C. Hawthorne, E. Cannillo, and F. Camara Long-Range Order in Amphiboles Reviews in Mineralogy and Geochemistry, October 1, 2007; 67(1): 125 - 171. [Full Text] [PDF]

				M. Tiepolo, R. Oberti, A. Zanetti, R. Vannucci, and S. F. Foley Trace-Element Partitioning Between Amphibole and Silicate Melt Reviews in Mineralogy and Geochemistry, October 1, 2007; 67(1): 417 - 452. [Full Text] [PDF]

				J. Adam, R. Oberti, F. Camara, and T. H. Green An electron microprobe, LAM-ICP-MS and single-crystal X-ray structure refinement study of the effects of pressure, melt-H2O concentration and fO2 on experimentally produced basaltic amphiboles European Journal of Mineralogy, October 1, 2007; 19(5): 641 - 655. [Abstract] [Full Text] [PDF]