SESSION SUMMARY: GLOBAL VENT PROCESSES 



Stephen R. Hammond 



NOAA VENTS Program 



Pacific Marine Environmental Laboratory 



Marine Resources Research Division 



Hatfield Marine Science Center 



Newport, OR 97365 



On October 22, 1987, as part of NOAA's Office of Undersea 

 Research (OUR), an Undersea Science Symposium was convened to 

 report on the status and results of diverse investigations 

 having as a broad, common goal, gaining an understanding of the 

 distribution, causes, and the physical, chemical and biological 

 effects of submarine venting. A number of the presentations also 

 address the application of technology rapidly being developed 

 with enhanced capabilities for carrying out these studies in what 

 are, in many instances, unusually harsh undersea environments. 



During the past decade, there has been a dramatic increase 

 in the number of scientific investigations focused on venting, 

 and associated, processes. This is happening, in part, because 

 of the growing recognition that submarine venting, rather than 

 simply resulting in localized geological, geochemical, or 

 biological anomalies, is instead a worldwide, fundamental, and 

 quantitatively important means for transferring heat and/or mass 

 from the earth's mantle to the earth's crust, hydrosphere, and 

 perhaps even to the atmosphere. These processes are now known to 

 have been responsible for the generation of economically 

 significant deposits of continental metal ores; they provide a 

 unique environment for the evolution of extensive animal 

 communities which appear to be completely independent of a 

 photosynthetic link with the earth's surface and all other known 

 earth life forms. These same processes appear to govern the 

 budgets of some of the important hydrothermal activity preserved 

 in the geological record and have been linked with long-term 

 climate changes. 



Initially, it was the discovery of hydrothermal venting - 

 which can now be reliably predicted to occur throughout the 

 global ocean along the worldwide seafloor spreading-center system 

 - that sparked international interest in venting processes. Now, 

 not only is ridgecrest research flourishing, but the papers 

 included in this Symposium also illustrate that the geographic 

 and scientific scope of venting research has been extended to 

 include other important geological environments, e.g., active 

 submarine volcanoes and subaerial hot springs associated with 

 mantle hotspots and the subducting edges of crustal plates. 

 NOAA's Office of Undersea Research is providing a means for 

 carrying out this important research by providing critical 



