REFINING THE USE OF GLYCEROL DIALKYL GLYCEROL TETRAETHERS (GDGTS) AS PALEOCLIMATE PROXIES IN EASTERN AND WESTERN CANADA.

Glycerol dialkyl glycerol tetraethers are a class of lipid biomarkers that in recent decades have been shown to serve as paleoclimate indicators in lake sediment. New research and recent methodological advances have shown that the 5’ methyl branched tetraether index (MBT^5’­­_Me ), among other indices, correlates well with synoptic temperatures, including months above freezing and mean summer temperature. However, the use of the MBT^5’­­_Me as a paleoclimate marker requires the development of calibration estimates for the areas under investigation. Efforts are underway to generate global, regional, and lake-specific temperature calibrations for the MBT^5’_Me index, but to date only two have been generated for Canadian regions. The Arctic, where climate warming is particularly pronounced and relatively understudied, remains particularly under-represented in these global GDGT-temperature calibrations.  This study analyzed two lake sediment transects in Canada, one using lacustrine surface sediment from lakes in Western Canada running parallel to the Rocky Mountains, and the other in Eastern Canada from southern to northern Quebec to create two separate temperature calibrations for use in Canadian ecozones. Preliminary modelling of the transects demonstrate that the MBT^5’_Me index is inversely correlated with latitude, and principal component analyses indicate lipid structure trends consistent with previous studies, showing promising results for its use as a paleoclimate indicator in lake sediments from these regions.

Presentation Preference: Standard Oral (12 Minutes)

Primary Presenter: Adriana Raats, University of Ottawa (adriana.raats.11@gmail.com)

Authors:

Adriana Raats, University of Ottawa  (adriana.raats.11@gmail.com)

Pablo Martinez-Sosa, Geological Survey of Denmark and Greenland  (pamar@geus.dk)

Linda Kimpe, University of Ottawa  (linda.kimpe@uottawa.ca)

Arnaud Huguet, Instutut Pierre Simone Laplace, Sorbonne Université  (arnaud.huguet@sorbonne-universite.fr)

Jules Blais, University of Ottawa  (jules.blais@uottawa.ca)