What was the palaeoenvironment of the Arctic Ocean in Middle Eocene times?A study into the nature and genesis of biosiliceous-rich laminae

High abundances of marine diatoms and freshwater chrysophyte cysts are preserved in mm-scale laminated organic-rich Middle Eocene sediments on the Lomonosov Ridge in the Arctic Ocean. This work aims to elucidate the nature and genesis of the laminations i n terms of biosiliceous components and chemical composition in order to assess the environmental conditions under which they were deposited. Our results will also shed light on the temporal significance of the laminae. By a non-destructive method of analy sis, we will permanently preserve the fine lamina structures allowing the delicate sedimentary fabrics to be analysed in a Scanning Electron Microscope without risk of them falling apart. Secondly, we will analyse fluctuations in diatom and chrysophyte cy st assemblage composition and abundance changes through several Milankovitch cycles identified by XRF analysis. Both aspects to this work will give us insight into the various cyclical mechanisms (?seasonal to longer timescales) in operation at the Lomono sov Ridge in the Middle Eocene. These proposed investigations are internationally collaborative and will provide the first ever truely detailed record of siliceous microfossil changes for the Arctic Ocean at any timescale, thereby significantly advancing our understanding of Middle Eocene palaeonvironments and Arctic Basin history.