9301058 Detrick The above-referenced project comprises a seismic refraction/wide angle reflection survey in the vicinity of Hole 504B in the eastern Pacific. One of the priorities of the Ocean Drilling Program (ODP) is to increase knowledge of ocean crustal structure. Core materials and logs from Hole 504B provide a "reference section" for the composition and structure of the upper oceanic crust. ODP drilling has deepened this hole to over two km sub-seafloor depth, in the process documenting the transition between upper extrusive and lower intrusive basalts, as predicted by studies of on-land ophiolite exposures, and ocean seismic refraction and reflection data. The hole currently bottoms in sheeted dikes. The OBS seismic refraction/wide angle reflection experiment will target the transition between seismic layers 2 and 3. This work would aim at resolving the discrepancy between ocean crustal seismic and petrologic knowledge, and will help tie data from the 504B "reference section", ophiolite exposures, and marine seismic refraction and reflection data. ***
