Thierry's research interests concern major catastrophes in Earth's history in the broadest sense, including meteorite impacts and episodes of major volcanic eruptions, and their biotic effects. This research integrates paleontology, stratigraphy, sedimentology, clay mineralogy and geochemistry in reconstructing past environmental change associated with or leading up to mass extinctions.
His research covers a wide variety of climatic and oceanographic problems from the Phanerozoic and concentrates on the global aspects of major environmental changes (e.g., Cretaceous-Tertiary boundary mass extinction, Paleocene-Eocene thermal maximum, global oceanic anoxic events, end-Devonian mass extinction). Other preferred topics include environmental geology, paleoclimatology, global change, phosphorus and carbon cycles, feedback loops, evolution of carbonate platforms, large-scale changes in carbonate facies, sequence stratigraphy, continental weathering systems, chemical weathering, soil formation, in Cretaceous, Tertiary and Quaternary deposits.
An extinction event is a sharp decrease in the diversity and abundance of macroscopic life. Major extinctions are generally caused by a combination of phenomena such as e.g. large-scale volcanism, climate and sea level change and meteoritic impacts. During mass extinctions, it has been observed that the middle and even the upper layers of the ocean may become deficient or totally lacking in oxygen, a process known as oceanic anoxic event. Although such events have not happened for millions of years, the geological record shows that they occurred many times in the past and that they played a major role in mass extinctions. Based on a multidisciplinary approach our research is aimed at better understanding the dynamics of mass extinctions, and, in particular, of oceanic anoxic events.