The dataset compiles P/Al XRF core-scanning measurements of IODP Site 303-U1308 (3871 mbsl) representing a reoccupation of Deep Sea Drilling Project (DSDP) Site 609. The data were obtained previously following methods described by Hodell et al., 2008 and used in support of reconstructed changes in deep-water oxygen concentration for the past 1.5 Ma using stable carbon isotope measurements of benthic foraminifer: the epibenthic Cibicidoidies wuellerstorfi and the infaunal Globobulimina affinis, obtained from the International Ocean Discovery Program (IODP) Site 339-U1385 along the Iberian Margin (Northeast Atlantic; 2578 mbsl). The P/Al dataset covers the Middle Pleistocene Transition (MPT) and shows a drop beginning with MIS 26 with both the mean and base level lower after 960 ka which is speculated to result from the increased occurrence of suboxic conditions during glacial periods in the North Atlantic.