This award will support a study of fluids in deep sea drill holes. Specifically, the project will take advantage of a French research project to place instruments in a hole which was drilled ten years ago. Using the French submersible Nautile a series of instruments will be positioned over hole 396 on the Mid-Atlantic Ridge and then lowered up to several hundred meters into the hole. Under this award Dr. Gieskes of Scripps Institution will interface a water sampling capability into the French re-entry system. Analysis of the recovered samples will be used to examine fluid flow in the crust, alteration of crustal rocks by formation waters and the possibility that seawater may have been flowing into the hole. The data will add substantially to our understanding of hydrothermal processes in crustal rocks.