High resolution scanning of South Pacific lake sediment: relative benefits offered by state-of-the-art micro-XRF and SEM systems

A methodological evaluation for the efficient investigation of laminated core material collected from the South Pacific islands is presented that is expected to be of broad interest to the core scanning community. Efficient identification of laminae, their number, chemistry and mineralogy provide crucial information in inferring sediment accumulation rates and environmental and climate change. The material investigated was collected as part of NERC grant NE/N006674/1 - The legacy of cyclone Pam: a unique opportunity to build a long term record of cyclone activity in the western tropical Pacific (PIs David Sear, Pete Langdon and Ian Croudace). The project is part of a multi-party study involving the PIs, 3 PhD students and collaborating specialists. Analytical data obtained from measurements of a 10 cm section of resin impregnated lake sediment from Lake Te Roto (Atiu Island, Cook Islands) will be discussed. Investigation of the sediment block was made using Itrax, Bruker M4+ micro-XRF and Leo SEM systems. The benefits of using the different approaches are evaluated with the purpose of establishing a preferred approach that would be applied to detailed investigation of all or selected core material collected from two field campaigns. The analytical timeline including an efficiency budget (sample preparation, analysis) as well as the robustness and comparability of analytical outputs (textural, density and elemental variations) will be presented