Mardi 10 Janvier à 14h dans la salle des séminaires (1.10) : Vincent Busigny (IPGP)

Titre : « Reconstitution d’environnements et écosystèmes Précambriens par les isotopes du fer : une approche triphasique »

« Deciphering Precambrian environments and ecosystems from Fe isotopes: a triphasic approach »

The evolutions of Earth’s surface and biosphere have always been strongly interconnected, with the one influencing the other. Precambrian environments and ecosystems are recorded in ancient sedimentary rocks deposited in the ocean and can potentially be deciphered from mineralogical and geochemical variations. Iron isotopes are an emerging biogeochemical paleoproxy that can improve our understanding of life and environment co-evolutions. One of the main difficulties of Precambrian studies lies in the interpretation of the biogeochemical signatures recorded in sediments. I will present three different types of parallel and complementary approaches that can be used to overcome this problem: (1) laboratory experiments for calibrating biogeochemical tools, (2) a study of a modern analogue for anoxic and ferruginous Precambrian ocean, providing a view not only on sediments but also on associated water column processes, and (3) a paleo-environmental reconstruction of early Archean ocean from a sedimentary sequence.