New North Atlantic Palaeo-Temperature Reconstruction from Terrestrial Sedimentary Archives: Implications for the Influence of the Icelandic Plume on O

The Icelandic Plume is the most vigorous mantle convection cell currently within Earth's mantle. The Greenland-Scotland Ridge (GSR) is the hotspot track of the Icelandic Plume and forms one of the most important gateways in the global circulation system. Relatively small (c. 100 m) changes in GSR elevation have a strong influence on oceanic circulation. Pulsing behaviour of the Icelandic Plume has driven 100 m-scale changes in GSR elevation on a million-year timeframe throughout Cenozoic time, resulting in variations in oceanic circulation. North Atlantic palaeo-temperature records are required to ask how these circulation changes influence climate. Surprisingly, there is relatively little high quality palaeo-temperature information in the vicinity of the GSR itself.
The few available North Atlantic palaeo-temperature reconstructions are predominantly based on marine sedimentary archives, for which temperature proxies are well established. Recent advances in organic geochemistry have developed the use of branched glycerol dialkyl glycerol tetraethers (br-GDGTs) in organic-rich terrestrial sediments as a proxy for air temperature. Such new tools open the possibility of significantly increasing the number of North Atlantic Cenozoic palaeo-temperature records by analysing lignite-bearing sedimentary packages.
A pilot study of the thick, Pliocene, lignite-bearing Tjörnes sedimentary succession of northern Iceland shows that original palaeo-temperature information is overprinted, but not destroyed, by burial. Several geographically localised palaeo-temperature calibrations currently exist for br-GDGTs. This project aims to produce a single, widely applicable calibration that accounts for a range of burial conditions by combining lab-based experiments and fieldwork. The new Icelandic Pliocene palaeo-temperature record will then be extended back to the Oligocene using lignites from Northern Ireland, Norway and Greenland, with access aided by project partners.
The new Cenozoic palaeotemperature record will be interpreted in the light of an ongoing Birmingham-based General Circulation Model (GCM) study of the effect of GSR elevation on oceanic circulation. This analysis will work alongside and benefit from anticipated IODP drilling in the North Atlantic south of Iceland. Building a more complete understanding of climate change through the Cenozoic will help better predict how anthropogenic climate change might affect the world in the next century.