Analysis of modern and ancient sediment from the Peru margin indicates that surface productivity on the margin has been persistently high during the Quaternary with relatively higher rates of production during interglacial stages. The oxygen minimum zone has continually intersected the sediment water interface on the Peru margin at depths of approximately 200 to 600m and, in general, has moved in relation to sea level change (i.e., moving landward during times of rising sea level). Sediment ages are determined through oxygen isotope stratigraphy and organic carbon weight percent. The organic carbon content of modern sediment from the Peru margin is principally controlled by surface primary productivity and is the main proxy used to interpret productivity in ancient sediments from ODP Leg 112 drilling cores. Benthic foraminifera populations from modern sediments reveal four principle assemblages that distinguish four environments: middle shelf, low oxygen; midshelf/upper slope, oxygen minimum; lower slope, dysaerobic; and deep, relatively well oxygenated. The presence of these assemblages in ODP core sediments reveal the environments of deposition.