Only two hydrothermal systems -- TAG and Snakepit -- are known to be active on the slow-spreading Mid-Atlantic Ridge. Dr. Thompson participated on a large diving program to both sites last winter; the present award provides he and his colleagues Drs. Humphris and Tivey with funds to analyze and interpret the samples collected on both this most recent expedition and ones from earlier sampling programs. Objectives are to: 1) map the vent sites in detail; 2) determine the nature, origin and time/space processes of mineralization; 3) compare the evolution of the two sites using both observations and models; 4) determine chemical exchanges that occur during supergene alterations; 5) estimate the significance of these deposits to global geochemical budgets and cycles; and 6) assess the economic significance of the sulfide deposits.
