Experimental aqueous dispersion of elements around sulfides

The dispersion of elements in rocks around sulfide deposits has been simulated in laboratory tanks at normal temperatures and pressures as part of an investigation to determine the causes of anomalous geochemical patterns in rocks associated with volcanic-sedimentary sulfide deposits. The same broad characteristics found in field examples--Zn generally concentrated in the footwall, Pb concentrated in the hanging wall, and a relative deficiency of Na and Cu around the sulfide---also developed in the laboratory simulations. While the mechanisms of dispersion are not well understood, they are probably influenced by electrochemical control of sulfide dissolution, the pH and Eh of the electrolyte, and electrical potential gradients around the sulfide body. A generalized electrochemical model is proposed as the possible fundamental controlling mechanism.