Spatial and temporal variation of Peruvian coastal upwelling during the latest Quaternary

Abstract

Two shelf and upper-slope sites (681 and 686) near present cores of active coastal upwelling on the Peruvian margin were sampled continuously at 7.5 cm intervals down to approximately 25 m below the seafloor (mbsf). Sedimentary structures were subdivided into homogeneous/bioturbated, laminated, and laminated-varved intervals. Diatom analysis and statistical treatment of data revealed almost persistent upwelling over the last 400 000 yr, with slightly increased upwelling during oxygen-isotope Stages 3, 5, 7, and 8 that resulted in anoxic bottom-water conditions and deposition of laminated/undisturbed primary sedimentary structures. -Authors