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Astronomical and Earth-system controls on Late Devonian environmental dynamics by Loïc Sablon -
Jeudi 19 novembre 2026 à 15h00 - Auditoire CYCL01 - Bâtiment de Hemptinne - Chemin du Cyclotron, 2 - 1348 Louvain-la-Neuve -
During the Devonian, parts of the ocean repeatedly lost oxygen, with severe consequences for marine life. Rhythms preserved in rocks suggest a link between these crises and slow changes in Earth’s orbit and tilt. This thesis explores how these orbital cycles could have influenced ancient climates and ocean oxygen levels. We use computer models to trace the connections between climate, the continents and the sea. Rainfall affects how rocks break down and how nutrients are carried from land to sea. These nutrients support the growth of marine organisms, whose decay consumes oxygen. To study these interactions over long geological timescales, we develop a faster way to simulate ancient climates. We also investigate how the spread of early land plants changed soils and nutrient delivery, and how changes in underground water storage and land ice could alter sea level. Sea-level changes can reshape shallow seas and their connections to the open ocean, affecting the oxygen available to marine life. The aim is to understand how these linked processes could have contributed to recurring marine crises.
Jury members :
Prof. Michel Crucifix (UCLouvain) (Supervisor)
Prof. Anne-Christine Da Silva (ULiège) (Supervisor)
Prof. Qiuzhen Yin (UCLouvain) (Chairperson)
Prof. Thierry Fichefet (UCLouvain) (Secretary)
Dr. Yannick Donnadieu (CEREGE, Fr.)
Prof. Benjamin J. W. Mills (University of Leeds, U.K.)
Pay attention : the public defense of Loïc Sablon will also take place in the form of a videoconference
