9314632 Mottl The PIs past participation on NOAA cruises at three hydrothermal sites on basement highs on the eastern flank of JdF (namely, FlankFlux `90,'92) led him to propose a model of how hydrothermal processes operate at flanks of ridges. In the present project, the PI will go back with the ALVIN and make some spatially fine-scale observations, measurements (heat-flow, water column properties etc.), and collect samples in order to evaluate his current model. The PI argues that past work on ridge flank hydrothermal vents at a number of different sites revealed that the hydrothermal processes and their effects are diverse; and therefore, descriptive studies of the kind proposed are necessary in order to determine global impact of ridge flank hydrothermal circulation. The site chosen is "JdF-3" which provides an unique opportunity in having high sedimentation rate combined with high basedment temperature normally, such small diffuse hydrothermal vents would be difficult to locate in unsedimented areas . ***
