The effects of pressure and temperature on the partitioning of Ti, Sr and REE between amphibole, clinopyroxene and basanitic melts

• Published in: Chemical geology Vol. 117; no. 1; pp. 219 - 233
• Main Authors: Adam, J., Green, T.H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.1994
• ISSN: 0009-2541; 1872-6836
• DOI: 10.1016/0009-2541(94)90129-5

An electron microprobe was used to measure partition coefficients ( D-values) for Ti, Sr, La, Sm, Ho and Lu in amphiboles, clinopyroxenes and Sr- and REE-enriched basanitic melts. D-values were found to be negatively correlated with pressure at pressures from 0.5 to 3.0 GPa. This effect is greatest for Ti and smallest for Lu. Changes in D-values accompanying changes in temperature are less apparent than those caused by changes in pressure. Only D Lu for clinopyroxene shows a small but consistent increase as temperature increases from 1050° to 1200°C. D-values for amphibole are not noticeably affected by changes in f O2. In contrast, D-values for clinopyroxene become larger as f O2 increases. The correlations between D-values and pressure may be related to changes in site volumes and electrostatic potentials accompanying shifts in the relative concentrations of Al IV, Al VI and Na +.