This award will support a marine geological and geophysical study of the geological history of the far northwestern Pacific. Field work will include the collection of seismic reflection, gravity and magnetic data from the area near the confluence of the Aleutian and Kamchatka Trenches and the northern end of the Emperor Seamount chain. The main objectives of the research project are to: 1) describe the early history of the Emperor hot- spot trail and the lithospheric response to volcanism; 2) reconstruct the plate tectonic history of this part of the Pacific; and 3) to determine the distribution of Mesozoic sediments in the region. Understanding the evolution and sediment distribution will be critical in identifying candidate sites for ocean drilling. Additionally, scientists from Woods Hole Oceanographic Institution will examine cored sediments to determine the paleoceanographic history of the area. The principal investigator is highly qualified to undertake this study. Field work will be done on a 35 day cruise of the R.V. Washington operated by Scripps Institution.