• Are vent communities controlled by such factors as nutrients, heat, or symbiosis and, if 



so, how? How do vent communities colonize in new areas? How do such communities 

 adapt to unique chemical surroundings, high-temperature, and high-pressure 

 environments? What is the physiology and productivity of vent organisms? 



The major elements of this initiative are: 



• Improved capabilities in multichannel seismics (MCS) and their expanded use in selected 



areas with experiments focused on determining the thermo-mechanical properties of the 

 oceanic lithosphere under varying conditions of age and stress/strain. ODP crustal 

 drilling and downhole experiments for direct physical measurements will augment this 

 work. 



• Increase in number of field programs with modern detailed survey capabilities to 



determine history and scale of crustal accretion. Development of integrated geological, 

 chemical, and biological studies using research submersibles for representative sites - 

 e.g., high- and low-temperature, seamounts, sedimented and unsedimented sites. 



• Development of in situ instrumentation for long-term monitoring of hydrothermal vents 



and crustal accretion - e.g., flow meters, chemical and thermal sensors, strain gauges, 

 seismometers. ODP drilling on the rise crest region will provide depth control from 

 downhole instruments. 



• Long-term integrated biological program to understand the unique properties of vent 



organisms with emphasis on chemolithotrophic bacteria, symbiont hosts, substrates 

 used for energy, and physiological adaptions. This will define community structure, life 

 history strategies, and evolution of biological communities. 



Incremental funding will provide essential upgrading of existing capabilities, expanded and 

 integrated use of new, multichannel seismic, side-scan sonar, Seabeam and submersible 

 systems, and development and implementation of a long term ridge crest/hydrothermal vent 

 monitoring program. Ship and facility operational costs are included. 



Tectonics and Structure of Submerged Continental Margins 



Continental margins not only form the boundary between the two major physiographic provinces 

 on our planet, but also, in many cases, are past or present boundaries of the lithospheric plates 

 that make up the earth's surface. A much deeper understanding of the structure, tectonics, and 

 dynamic evolution of these fundamental geological features is within our grasp. It can be 

 realized with extensive application of multichannel seismic tools, with development of 

 new and more powerful techniques to use these tools, with long coring capabilities, and with 

 ocean drilling at carefully selected margin sites, ultimately using a riser capability. 



Some of the major questions to be addressed are: 



• What geologic units underly active and passive continental margins? What are the 

 dominant tectonic, geochemical, and thermal processes involved in creating 

 ocean-continental boundaries? 



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