September 19 – Seminar "Moving beyond the age-depth paradigm in deep sea paleoclimate archives using single foram 14C dating"

by Bryan Lougheed, Uppsala University

Date: Tuesday 19 September 2017
Time: 12.15–13.00
Place: William-Olssonsalen in the Geoscience building

Abstract

Late-glacial paleoclimate reconstructions from deep-sea sediment archives provide valuable insight into past rapid changes in ocean chemistry, but only a small proportion of the ocean floor is suitable for such reconstructions using the existing state-of-the-art. We employ ultra-small radiocarbon (14C) dating on single microscopic foraminifera to demonstrate that the longstanding age-depth method conceals large age uncertainty caused by post-depositional sediment mixing. To overcome these problems, we use dual 14C and stable isotope (δ18O and δ13C) analysis on single microscopic foraminifera to produce a paleoclimate time series independent of the age-depth paradigm. This new method will address large geographical gaps in late-glacial benthic paleoceanographic reconstructions by opening up vast areas of previously disregarded deep-sea archives, leading to improved understanding of the interaction between oceans and climate.

 

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