Description du projet
Que nous apprennent les vieux océans sur les débuts de l’évolution sur notre planète?
Les océans agissent comme une interface entre l’atmosphère, les continents et le manteau profond de la Terre à travers les processus de surface, l’érosion et l’hydrothermalisme. L’objectif du projet GOforISOBIF, financé par l’UE, consiste à étudier la composition de l’eau de mer initiale enregistrée dans les formations de fer rubanées précambriennes pour fournir un aperçu unique des processus ayant influencé les principaux réservoirs de la Terre au début de l’histoire de notre planète. À l’aide d’outils géochimiques nouveaux et innovants, le projet se concentrera sur trois questions de premier ordre: 1) l’origine, la composition et la taille des premiers continents; 2) la détection de bouffées d’oxygène dans les premiers océans avant la Grande Oxydation (GO); 3) la relation entre l’activité hydrothermale et la géodynamique mondiale du manteau terrestre.
Objectif
Since the beginning of Earth’s history, the oceans acted as an interface between the atmosphere, the continents, and the mantle via atmospheric exchange, weathering, sedimentation, and submarine volcanism. Such interactions make the composition of early seawater a unique recorder of the processes that have affected the Earth’s major reservoirs. Yet, this record has not been explored in details. Here, I propose to investigate the geochemistry of the first oceans that is recorded in Precambrian banded iron formations (BIFs) to address first-order questions related to the early evolution of our planet.
The proposed project combines well-established radiogenic isotopic systems with novel and highly promising stable isotope tracers that will be developed as part of the project. These geochemical proxies will be measured on a unique collection of BIF samples deposited from ~3.8 to 0.7 Ga ago with the following objectives: (1) determine the origin, composition, and size of the first continents, (2) detect whiffs of oxygen in the early oceans in various depositional settings before and after the Great Oxidation Event (GOE), (3) identify the periods of intense hydrothermal activity through Earth’s history and link them to global mantle geodynamics.
The proposed project will promote the application of state-of-the-art isotopic measurements, with an emphasis on further methodological development to set-up new isotope proxies. This innovative approach is needed to test previously suggested hypotheses, develop new ideas, and to tackle the challenging questions of the early Earth evolution from a different angle.
Champ scientifique
- natural sciencesearth and related environmental sciencesgeochemistry
- natural sciencesearth and related environmental sciencesgeologysedimentology
- natural scienceschemical scienceselectrochemistryelectrolysis
- natural sciencesearth and related environmental sciencesgeologyvolcanology
- natural sciencesphysical sciencesastronomyplanetary sciencesplanets
Mots‑clés
Programme(s)
Thème(s)
Régime de financement
ERC-STG - Starting GrantInstitution d’accueil
75794 Paris
France