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 DLu 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 fO2. In contrast, D-values for clinopyroxene become larger as fO2 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 AlIV, AlVI and Na+.