HR: 0830h
AN: V41C-0309    [PDF]
TI: Molar Volume of Lanthanide-Bearing Silicate Melts
AU: * Courtial, P
EM: courtial@min.uni-muenchen.de
AF: Ludwig-Maximilians-University Department for Earth & Environmental Sciences, Theresienstrasse 41/III, Munich, 80333 Germany
AU: Dingwell, D B
EM: dingwell@min.uni-muenchen.de
AF: Ludwig-Maximilians-University Department for Earth & Environmental Sciences, Theresienstrasse 41/III, Munich, 80333 Germany
AB: The lanthanides are of crucial importance in igneous petrology since they are sensitive indicators of the processes involved in the petrogenesis of magmas. One of the primary goals of igneous petrology is the development of thermodynamic models that can accurately predict the crystal-melt phase equilibria in a magma and produce the observed chemical diversity of igneous rocks. The development of such models requires a reliable thermodynamic database which includes volumetric data available for both major and trace element oxide liquids.\\ Efforts have been made to extend the volumetric database of silicate melts on a variety of multi-component systems for the most naturally abundant oxides. However, experimental data on other significant oxides, such as lanthanides, are lacking. Therefore, in order to fill this gap and to provide a new volumetric dataset, which will allow the available models in the literature to be extended to lanthanide-bearing liquids, the molar volume of lanthanide-bearing silicate melts has been determined through high-temperature density measurements using the Pt-based double-Archimedean method.\\ In this paper, we present density measurements obtained in air for various lanthanide-bearing silicate melts (either Na-disilicate or one-atmosphere anorthite-diopside eutectic containing different amounts of one lanthanide oxide). The present results suggest that the addition of lanthanide leads to an increase in density of the melt. In addition, the melt density at a given lanthanide content increases with increasing atomic number, with the exception of La. This volumetric dataset allows a first estimation of the partial molar volume of each lanthanide oxide liquids (i.e., the partial molar volumes calculated at 1550 K for the investigated lanthanide oxides range from 15 to 23 cm$^{3}$/mol for Tm$_{2}$O$_{3}$ and Pr$_{6}$O$_{11}$, respectively).
DE: 3630 Experimental mineralogy and petrology
DE: 3640 Igneous petrology
DE: 3670 Minor and trace element composition
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting