Early Earth Dynamics: Pt-Re-Os isotopic constraints on Hadean-Early Archean mantle evolution

Objectif

This project aims to directly constrain the melting history and composition of the mantle of the Earth
for the first 750 Ma of its history. So far, our limited knowledge hinges on isolated detrital zircons from
Archean crustal rocks. They indicate crustal extraction as early as 4.4 Ga with peaks at 4.0 and 4.3 Ga but
reveal conflicting models for the composition of the Hadean mantle. Both the timing and extent of these
early crust formation events and the composition of the Hadean mantle have crucial implications for our
understanding of the Early Earth’s chemical evolution and dynamics as well as crustal growth and thermal
cooling models. Sulfides (BMS) and platinum group minerals (PGM) may hold the key to these fundamental
issues, as they are robust time capsules able to preserve the melting record of their mantle source over
several billion years.
I propose to perform state-of-the-art in-situ Pt-Re-Os isotopic measurements on an extensive
collection of micrometric BMS and PGM from Archean cratonic peridotites and chromite deposits, and
paleoplacers in Archean sedimentary basins. For the first time, < 20 μm minerals will be investigated for Pt-
Re-Os. The challenging but high-resolution micro-drilling technique will be developed for in-situ sampling
of the PGM and BMS with subsequent high-precision 187Os-186Os isotopic measurements by NTIMS. This
highly innovative project will be the first to constrain Hadean Earth history from the perspective of the
Earth’s mantle. By opening a new window towards high-precision geochemical exploration for micrometric
minerals, this project will have long-term implications for the understanding of the micro to nano-scale
heterogeneity of isotopic signatures in the Earth’s mantle and in extra-terrestrial materials.

Champ scientifique

Régime de financement

ERC-SG - ERC Starting Grant

Coordinateur

RHEINISCHE FRIEDRICH-WILHELMS-UNIVERSITAT BONN

Adresse

Regina pacis weg 3
53113 Bonn
Allemagne

Région

Nordrhein-Westfalen Köln Bonn, Kreisfreie Stadt

Type d’activité

Higher or Secondary Education Establishments

Contact administratif

Daniela Sprinkmeier (Mrs.)

Chercheur principal

Ambre Luguet (Dr.)

Liens

Contacter l’organisation Site web

Contribution de l’UE

€ 1 306 742,80

Bénéficiaires (1)