This project seeks support to quantify and codify measurements of structural, igneous, and metamorphic/alteration features observed in core materials and logs of Ocean Drilling Program Hole 504B. At just over 2 kilometers sub-seafloor depth, 504B is the deepest borehole in ocean crust, and the only one that samples the pillow basalt/sheeted dike transition. This borehole has been successfully deepened through six (6) DSDP and ODP legs. PI began the task of detailed description of structural and petrologic features on the most recent, Leg 140. His initial work shows that significant trends and/or cycles in such features as vein abundance and secondary minerals may exist. PI now wishes to extend this work through examination and description of core materials from the previous five (5) drilling legs. The goals of this research are to provide a standard and more detailed descriptive log of this important ocean crustal reference section, and to determine what overall trends and cycles in structural and petrologic features exist down hole. This information, in turn, will provide insights to processes of ocean crust formation, as well as processes of secondary hydrothermal alteration of ocean crust.