Occurrence of enargite and wulfenite in ore deposits of northern Arkansas

One of the several contrasting features between zinc and lead deposits of the Mississippi Valley type and those of the Cordilleran type is the mineralogic simplicity of the Mississippi Valley ores. Because the usual ore and gangue minerals are few in kind and are those that can conceivably be carried in solution by circulating ground waters, special theories of origin that have prevailed for the Mississippi Valley deposits have carried more weight than might be the case if the ores were chemically and mineralogically more complex. In summarizing the characters of the Mississippi Valley type, Lindgren 2 points out that the elements gold, antimony, arsenic and molybdenum are almost wholly absent. In view of this long recognized dearth of certain elements, it is believed that the discovery of two of them in typical Mississippi Valley lead and zinc ores of northern Arkansas may be of some interest.