Séminaire d’Inès Pereira, LMV

Fingerprinting tectonic and crustal processes using detrital rutile

Much of what is currently known about the early Earth has been recovered from detrital minerals. This is profoundly related to the rather incomplete rock record. Zircon has offered most of the insight, as it contains a multi-isotopic toolkit combining U-Pb, Hf and O and is resistant to weathering processes. Thus, it has been the ideal candidate to retrieve unique information about early Earth processes. However, zircon growth peaks mostly record intermediate to felsic magmatism which, in turn, leads to a certain record bias. This bias can be overcome if combined with detrital rutile. Similarly to zircon, rutile can be widely found in sediments. It grows in a multitude of environments, including a range of P-T metamorphic conditions, from both felsic and mafic protoliths, in magmatic rocks and in hydrothermal systems. In this talk, I will illustrate how we can use detrital rutile to fingerprint different tectonic and crustal processes, and present new coupled U-Pb and Zr-in-rutile geothermometry in a novel attempt to constrain the crustal secular metamorphic evolution.