Paleoclimate reconstructions

The accumulation of microscopic organisms over thousands to millions of years can lead to massive deposits, like the one here in Etretat (France), which can be used to study past environments.

Microfossils, in particular those formed by phytoplanktonic organisms, make up an important component of the sediments found on the seafloor. The specific and geochemical composition of these microfossils is known to vary significantly with a range of environmental parameters, which makes these microscopic objects precious archives for the study of past environments. During my PhD, I showed that a group of these microfossils, called coccoliths, could be used to reconstruct past changes in atmospheric CO₂. A preliminary application of this CO₂ proxy to the Mid-Pleistocene Transition—a pivotal period in Earth's geological history—was explored during my PhD, and is available online here for any French enthusiasts!