Pyrite and carbonate minerals are found in large quantities on an inland moor in western Jutland, Denmark. However, they tend to be well separated. An analysis of the groundwater entering the moor revealed samples of high alkalinity, as well as samples containing a high content of sulfates and ferrous solutions, indicating sources of different origin. Subsequent interaction with local conditions of sediment accumulation resulted in a distinctly segregated mineral precipitation. Generally a high amount of pyrite was found in the marginal zone of inland moors, whereas carbonate minerals accumulated in the central part of the moors.