Collaborative Research: Crustal Structure and Evolution of the Newfoundland-Iberia Non-Volcanic Rift: A Seismic Study of the Newfoundland Conjugate Margin

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OCE 98-15999HolbrookeThe recommended project is a marine geophysical field program on the Newfoundland margin, which was conjugate to the Iberia margin during the initial opening of the Atlantic ocean. The project will provide geophysical site survey data in support of JOIDES ODP Proposals 504 and 504-Full 2. It will utilize the R/V Ewing's large, tuned airgun array and 6 krn streamer together with an extensive ocean-bottom seismometer array to seismically profile three transects that extend from known continental crust to known oceanic crust. The program will be conducted jointly with Canadian and Danish Lithosphere Centre scientists. Together with other geophysical and drilling data from the Iberian margin, it will provide a critical dataset for testing models of continental rifting, breakup, and initiation of seafloor spreading in a "non-volcanic" rifted environment. Specifically, it will: 1) characterize the nature of the crust transitional between oceanic and continental crust in the region; 2) provide a comparison with the Iberian margin, thereby allowing testing of models of pure-shear vs. simple-shear during rifting; and 3) determine the amount of igneous material intruded and extruded during rifting, providing comparative data with other "volcanic" rifted margins, such as the East Greenland margin.***