Sulfide Breccia in Fossil Mississippi Valley-Type Mud Volcano Mass at Decaturville, Missouri, USA
The fossil sulfide and carbonate breccia of Decaturville, Missouri, is described and the structural position of the breccia mass discussed. The large and the small carbonate rock fragments show remnant textures typical of marine carbonates. The isotopic compositions of the carbonate fragments and the “flow” carbonates of the breccia compare well with those of sedimentary carbonates from the host sequence of Mississippi Valley-type stratiform lead-zinc deposits of southeastern Missouri. Therefore, an involvement of deep-seated (mantle) carbon in the process of breccia formation is not indicated.