Geological and geophysical studies of the upper oceanic crust and corresponding components of ophiolite complexes indicate that significant heterogeneities exist in this region on scales of a few kilometers to a few centimeters. This project is a detailed geological study of major submarine fault scarps at the Hess Deep using ALVIN in order to elucidate the petrological and structural complexities of the upper oceanic crust. The Hess Deep exposes basaltic and plutonic rocks on the face of a major fault scarp with average slope greater than 60 degrees and vertical relief of greater than 2 km. This window into the oceanic crust was created at the Galapagos Ridge propagated westward into normal one million-year-old crust of the east flank of the East Pacific Rise. Because this escarpment is parallel to a seafloor responsible for abyssal hill topography, the most pervasive land form on earth, can be examined for the first time. This study will produce a more realistic view of the lateral and vertical heterogeneity of the East Pacific crust.
