E. Ocean Drilling Program 



I. Core Program 



The Ocean Drilling Program (ODP) is an international research program organized to explore 

 the structure and history of the earth beneath the ocean basins. The focus of ODP is to provide 

 core samples from the ocean basins, facilities for the study of these samples, and to provide 

 downhole measurements (logging) and experiments to determine in situ conditions within the 

 earth's crust. 



The major scientific themes addressed by ocean drilling, identified in the first Conference on 

 Scientific Ocean Drilling (COSOD) report, include: 



• Processes of magma generation and crustal construction at ridges. What is the character 

 and composition of the deep portion of the oceanic crust? 



• Configuration, chemistry, and dynamics of hydrothermal systems. What are the 



dimensions and characteristics of hydrothermal systems at ridge crests versus those on 

 ridge flanks? How does overlying sediment cover, or the lack of it, affect these 

 hydrothermal systems? 



• Early rifting history of passive continental margins. What is the shallow and deep 

 structure of stretched and normal faulted margins versus those characterized by excessive 

 volcanism? 



• Dynamics of forearc evolution. What are relative motion, deformation, and pore water 

 characteristics of sediments at accreting and erosional margins? 



• Structure and volcanic history of island arcs. What are space and time relationships of 

 forearc subduction, accretion, and erosion; and of backarc spreading, compression, and 

 volcanism? 



• Response of marine sedimentation to fluctuations in sea level. Which stratigraphic 

 sequences and intervenin unconformities represent fluctuations of sea level, and which 

 represent vertical tectonic motion? What is the response of deep-sea sedimentation to 

 fluctuations of sea level? 



• Sedimentation in oxygen-deficient oceans. What are the ocean circulation, paleoclimate, 



and potential hydrocarbon characteristics associated with black shale deposits? 



• Global mass balancing of sediments. What are best estimates of the world sediment mass 



and composition balances in space and time? 



• History of ocean circulation. How do patterns of ocean circulation respond to changing 

 ocean boundaries, e.g., changing ocean size, the extent of shallow continental seas, and the 

 opening and closing of oceanic passages? 



52 



