Age and Crystallization Duration of Alpine Fissure Monazite-(Ce) and Correlation with Tectonically-Driven Hydrothermal Dissolution-(Re)Precipitation Events

Diplôme Thèse Age and Crystallization Duration of Alpine Fissure Monazite-(Ce) and Correlation with Tectonically-Driven Hydrothermal Dissolution-(Re)Precipitation Events eng 2020-09-05 author Ricchi Emmanuelle 716833 director Gnos Edwin 704533 director Schaltegger Urs 0000-0003-4404-8607 134356 10.13097/archive-ouverte/unige:144384 urn:nbn:ch:unige-1443846 Sc. 5503 This study investigates deformation along the retrograde path of the Alps through in-situ Th-Pb dating of hydrothermal (or fissure) monazite-(Ce). Fissure monazite-(Ce) crystals are found in alpine-type fissures and crystallizes at relatively low temperatures (∼200 - 400 ̊C). The Th-Pb isotopic system of fissure monazite-(Ce) can only be disturbed by dissolution-(re)precipitation events due to chemical disequilibrium with the hydrothermal fluids, commonly induced by tectonic activity. Fissure monazite-(Ce) ages (i) corroborate existing chronological data, (ii) were completed with structural information in order to constrain tectonic movements associated with monazite-(Ce) crystallization, (iii) were used to attribute fluid inclusion data to different episodes of fissure formation. The combined data show that across the Alps monazite-(Ce) crystallization occurred episodically over 85 Ma. The oldest ages of ∼90 Ma were found in the Eastern Alps whereas younger ages, down to ∼5 Ma, were recorded towards the Central and Western Alps. Hydrothermal monazite-(Ce) Alpine fissures Th-Pb dating Tectonic activity Alpine orogen Dewey 550 42 Département des sciences de la Terre 154 false 16b412ae-88c9-40be-b4ca-2724bf7e0040 Thesis Public ricci3.pdf 435119476 application/pdf Private 2021-11-04 7aef8b97-a9e8-4f4a-83b4-31bdc0c5d34e Agreement Private Ricchi-Emmanuelle_Contrat_diffusion.pdf 486812 application/pdf 56c3c49b-ec75-48d0-8141-7e6ae3e7e19c Publication mode Private RicciE_Mode-de-publication.pdf 84535 application/pdf openAccess Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département des sciences de la Terre

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Age and Crystallization Duration of Alpine Fissure Monazite-(Ce) and Correlation with Tectonically-Driven Hydrothermal Dissolution-(Re)Precipitation Events				2020	360	53

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Ricchi, Emmanuelle