Partial molar volumes of oxide components in silicate liquids |
| |
| Authors: | S A Nelson I S E Carmichael |
| |
| Institution: | (1) Lawrence Berkeley Laboratory and Department of Geology and Geophysics, University of California, 94720 Berkeley, California, USA;(2) Present address: Department of Earth Sciences, Tulane University, 70118 New Orleans, LA, USA |
| |
| Abstract: | Densities of 21 silicate liquids have been determined from 1,000 ° to 1,600 ° C. The compositions studied contain from two to eight oxide components and have the following ranges in composition (mole %): SiO2, 35–79%; TiO2, 4–36%; Al2O3, 5–25%; FeO, 11–41%; MgO, 7–28%; CaO, 7–35%; Na2O, 5–50%; and K2O, 4–20%. The compositions thus cover the upper range observed in magmas for each oxide. Precision for each determination of liquid density is always better than ±1%.Volumes/gfw (gram formula weight) calculated from the density measurements and the chemical compositions of the analyzed liquids have been combined with data on 96 silicate liquids reported in the literature. From this data set we derive, by using multiple linear regression, partial molar volumes of the components SiO2, TiO2, A12O3, FeO, MgO, CaO, Na2O, and K2O at five temperatures. The standard deviation of the multiple regression is 1.8% of the molar volumes, which is considered about equal to the total errors due to compositional and instrumental uncertainties.These derived partial molar volumes have been used to calculate volumes/gfw of natural silicate liquids which are found to agree within 1% of the measured values. No compositional dependence of the partial molar volumes can be detected within the error considered to be typical of the measurements. This is further supported by the close agreement between the calculated volumes of CaMgSi2O6 and Fe2SiO2 liquids derived from the initial slopes of their fusion curves and their heats of fusion, and the volumes obtained by summing the respective partial molar volumes. The experimental data indicate that silicate liquids mix ideally with respect to volume, over the temperature and composition range of this data set. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
