Terrestrial environmental change across the onset of the PETM and the associated impact on biomarker proxies: a cautionary tale

This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint.


Download Preprint


Gordon Neil Inglis, Alex Farnsworth, Margaret Collinson, Matthew Carmichael, B. David. A. Naafs, Dan Lunt, Paul J Valdes, Richard D. Pancost


The Paleocene-Eocene Thermal Maximum (PETM; ~ 56 million years ago (Ma) is the most severe carbon cycle perturbation event of the Cenozoic. Although the PETM is associated with warming in both the surface (~up to 8°C) and deep ocean (~up to 5°C), there are relatively few terrestrial temperature estimates from the onset of this interval. The associated response of the hydrological cycle during the PETM is also poorly constrained. Here, we use biomarker proxies (informed by models) to reconstruct temperature and hydrological change within the Cobham Lignite (UK) during the latest Paleocene and early PETM. Previous work at this site indicates warm terrestrial temperatures during the very latest Paleocene (ca. 22 to 26°C). However, biomarker temperature proxies imply cooling during the onset of the PETM (ca. 5 to 11°C cooling), inconsistent with other local, regional and global evidence. This coincides with an increase in pH (ca. 2 pH units with pH values > 7), enhanced waterlogging, a major reduction in fires and the development of areas of open water within a peatland environment. This profound change in hydrology and environment biases biomarker temperature proxies, including the branched GDGT paleothermometer. This serves as a cautionary tale on the danger of attempting to interpret biomarker proxy records without a wider understanding of their environmental context.




Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics


peat, hydrology, organic geochemistry, biomarkers, wetland, lignite, GDGTs


Published: 2019-04-29 05:59


CC BY Attribution 4.0 International

Add a Comment

You must log in to post a comment.


There are no comments or no comments have been made public for this article.