The Pacific phase of IPOD ocean crust drilling was initiated with Leg 54, the region targeted for study by the Ocean Crust Panel being survey area PT-4 (Figure 1) (and Plate 1 [in back pocket]) north of the Siqueiros fracture zone on the western flank of the East Pacific Rise (EPR). The original purpose of this leg was to establish a type section for fast-spreading, nonrifted crust by direct sampling with stratigraphic control. We anticipated that this section would serve, in part, as a standard of comparison for other type sections, such as the Mid-Atlantic Ridge (MAR). [NOT CONTROLLED OCR]