Olivine-to-liquid partition coefficients for Ni (DNi), calculated from Ni versus MgO abundance variations in komatiite series basalts, compare favorably with experimentally determined values if Ni variations in olivine-controlled basalts can be modeled with an equation that assumes equilibrium between the entire olivine crystal and its coexisting liquid. Thus, Ni abundances in evolved komatiite series basalts can be calculated by using an equilibrium or Nemst crystallization equation and are independent of reasonable choices for the Ni and MgO content of the primary magma. Using published partition coefficients, calculations of Ni and MgO abundances in cumulate olivines in komatiite series basalts suggest that DNi values determined from natural basalt systems are more geologically valid, i.e., produce more reasonable olivine compositions than do DNi values from synthetic basalt systems.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.