The origin of paleochemical signatures in North Pacific pelagic clays: Partitioning experiments

Three techniques for partitioning sediment chemical composition into source end-members, normative partitioning, multivariate Q-mode factor analysis, and linear programming, were used to determine the origin of chemical variation in a pelagic clay core, LL44-GPC3, from the central North Pacific. All partitioning models indicated that the downcore elemental distributions reflect the changing relative influence of detrital, hydrothermal, and hydrogenous sediment components. Two models suggested that biogenic sediment components influenced the sediment as well. The down core distributions of these end-members were very similar in all models, although the chemical compositions of the end-members varied slightly. There was no indication that the compositions of the end-members changed significantly over the 70 m.y. of clay sedimentation represented in the core. The changes in relative importance of the end-members downcore cannot be explained solely by changes in the position of the core site along its backtrack path and therefore suggest that there have been changes in the relative importance of different sediment sources to the North Pacific during the Cenozoic.