Abstract

The patterns of a few trace element partition coefficients between coexisting minerals from six sulfide occurrences are presented. The data show that the distribution patterns range from linear through curvi-linear to scattered. It was observed that even within the diagrams showing linear distributions, complexities do exist. Furthermore, it was also evident from the data that some elements partition between a specific mineral pair from one deposit in accord with the dilute distribution law, while other elements do not. These complexities in the distribution patterns cannot be interpreted in terms of the dilute distribution law alone. In the case of a majority of the scattered and curvi-linear distribution patterns, the partition coefficient was observed to be dependent on the element concentrations in either of the phases ("concentration" plots) and/or the presence of other trace elements in the phases ("interaction" plots); indicating non-adherence to Henry's law. However, a consideration of the effect of "induced point imperfections" in crystals on the partition coefficients indicates that the presence of these imperfections may have been the effective cause of the deviation from Henry's law.The presence of similar patterns in the "concentration" and "interaction" plots from different mineral assemblages suggest, to a first approximation, that the patterns are independent of the detailed paragenetic factors characterizing individual deposits. It was also demonstrated that the presence of non-linear distribution patterns do not necessarily mean that the minerals are in "gross disequilibrium." We have proposed criteria which can be used to determine the state or degree of equilibrium in a deposit.

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