Sfaleryt jako termometr geologiczny
Abstract
SPHALERITE AS GEOLOGICAL THERMOMETER
Summary
The present author discusses the Kullerud's geothermometric method. The amount of isomorphic admixture of Fe in sphalerite, that crystallizes in an equilibrium with pyrite and pyrrothite or with pyrite, is the function of the temperature of the formation of solid fIuid (Zn, Fe/S). This function, thought previously to be rectilinear, is in the light of the recent studies not defined univocally. In consequence of this the hitherto existing determinations made by means of Kullerud's method are to be accepted critically. Too analysis of the changes in the parameters of elementar cells of sphalerites in the deposit allows us to evaluate the variations of physic-chemical conditions during the formation of these minerals. Such an analysis has been made for the Silesian- Cracow Zn-Pb deposits. The analysis has demonstrated that no variations are found in the lattice constants ao of sphalerites on a regional scale, and this proves that these minerals crystallized under fairly stable conditions. The paper presents the results of the determinations of the parameter ao, the iron content and the crystallization temperature, made for sphalerites found in the area of Poland.
Summary
The present author discusses the Kullerud's geothermometric method. The amount of isomorphic admixture of Fe in sphalerite, that crystallizes in an equilibrium with pyrite and pyrrothite or with pyrite, is the function of the temperature of the formation of solid fIuid (Zn, Fe/S). This function, thought previously to be rectilinear, is in the light of the recent studies not defined univocally. In consequence of this the hitherto existing determinations made by means of Kullerud's method are to be accepted critically. Too analysis of the changes in the parameters of elementar cells of sphalerites in the deposit allows us to evaluate the variations of physic-chemical conditions during the formation of these minerals. Such an analysis has been made for the Silesian- Cracow Zn-Pb deposits. The analysis has demonstrated that no variations are found in the lattice constants ao of sphalerites on a regional scale, and this proves that these minerals crystallized under fairly stable conditions. The paper presents the results of the determinations of the parameter ao, the iron content and the crystallization temperature, made for sphalerites found in the area of Poland.