EXPERIMENTAL EVALUATION OF LIQUID IMMISCIBILITY IN A PORTION OF THE SYSTEM Fe-Ni-Cu-S USING HIGH GRAVITATIONAL ACCELERATION

摘要

Experimental results reported by Ballhaus et al. (2001) suggest there may be some natural sulfide liquid compositions in equilibrium with primitive mafic magmas that encounter a field of immiscibility at superliq-uidus conditions. In this communication, we present results of static and high acceleration experiments done using one of the bulk compositions for which immiscibility is reported (their MS-11), as well as mixtures of the alleged conjugate melts. At all conditions investigated, melts quenched to a homogeneous distribution of quench phases, with no evidence for compositional separation over the length scale of the sample. These results indicate that the MS-11 composition produced a homogeneous liquid during the experiment, and therefore we could not verify the two-phase field reported by Ballhaus et al. (2001). We suggest caution when evoking sulfide liquid immiscibility as a differentiation mechanism during magmatic sulfide evolution.