Using an Eh-pH diagram for the system Cu-Fe-S-O-CO 2 , at 25 degrees C, pressure of 1 atm, and assumed activities of Cu, Fe, S, and CO 2 , the Eh (potential) at any given horizon can be estimated from the mineral phases present. The amount of copper present is inversely proportional to the potential, and calcium is directly proportional. The rates of change in these amounts, when plotted against potential, increase toward the Zechstein (Permian) basin in Poland. When potential is plotted against stratigraphic position, it shows considerable fluctuation; such diagrams are helpful in comparing mineralogy with lithologic characteristics.

First Page Preview

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