CHANGES IN SEDIMENT SOURCES SINCE EUROPEAN COLONIZATION IN PORT LEVY, BANKS PENINSULA, NEW ZEALAND

The landscape of Banks Peninsula has changed significantly since Māori and European settlement 800 and 150 years ago, respectively. Previous studies on the region, which examined sedimentation rate changes and tsunami deposits in the sedimentary record, describe broad changes occurring in the landscape, but provide limited insight into changes to the landscape since human settlement. This study explores these changes in landscape by examining sediment source shifts since European colonization in Port Levy. Cores from four sites were retrieved in a cross-section of mudflats spanning multiple subcatchments of Port Levy. Each core contains sediments from pre- and post-European colonization, which was determined through correlation of tsunami deposits with similar deposits in previous studies in the region. Sediment composition was measured with a Portable X-Ray Fluorescence analyzer (PXRF). Wide variation in sediment chemistry between the subcatchments was observed, indicating that changes in source lithologies and sedimentary processes vary within each subcatchment. Furthermore, sediment sources have shifted since European colonization, evidenced by enrichments of Al and Mg. These results point towards the heterogeneous impact of human settlement on landscape, and showcase the ability of the PXRF to measure these impacts.