Objective is to make a comprehensive study of low temperature hydrothermal convection occurring in young mid- ocean ridge flanks where sediment cover is thin and incomplete. The field program will involve a transponder navigated heat flow survey in three sediment ponds of different ages on the flanks of the Mid-Atlantic Ridge, as well as pore pressure measurements to determine flow rates and in situ hydrologic properties of the sediment. Heat flow measurements will be made in a profile along and across each pond, with additional measurements in the neighborhood of anomalies. Piston cores will be taken for the determination of physical properties and will be preserved for future work on pore water chemistry. The data will be interpreted in terms of fluid flow models. %%% Hydrothermal circulation in the oceanic crust has a profound impact on the heat budget of the earth and on chemical exchange between the crust and the ocean. Little is known about the low temperature hydrothermal regime of incompletely covered sediment ponds that occur on the flanks of mid-ocean ridges. This field program will be the first detailed look at this important thermal regime in the oceanic crust.
