Calcium isotope evidence for early Archaean carbonates and subduction of oceanic crust - Université Clermont Auvergne Access content directly
Journal Articles Nature Communications Year : 2021

Calcium isotope evidence for early Archaean carbonates and subduction of oceanic crust

Abstract

Continents are unique to Earth and played a role in coevolution of the atmosphere, hydrosphere, and biosphere. Debate exists, however, regarding continent formation and the onset of subduction-driven plate tectonics. We present Ca isotope and trace-element data from modern and ancient (4.0 to 2.8 Ga) granitoids and phase equilibrium models indicating that Ca isotope fractionations are dominantly controlled by geothermal gradients. The results require gradients of 500-750°C/GPa, as found in modern (hot) subduction-zones and consistent with the operation of subduction throughout the Archaean. Two granitoids from the Nuvvuagittuq Supracrustal Belt, Canada, however, cannot be explained through magmatic processes. Their isotopic signatures were likely inherited from carbonate sediments. These samples (> 3.8 Ga) predate the oldest known carbonates preserved in the rock record and confirm that carbonate precipitation in Eoarchaean oceans provided an important sink for atmospheric CO 2. Our results suggest that subduction-driven plate tectonic processes started prior to~3.8 Ga.

Keywords

Domains

Geochemistry
Fichier principal
Vignette du fichier
Antonelli et al., 2021.pdf (2 Mo) Télécharger le fichier
Origin Publisher files allowed on an open archive

Dates and versions

hal-03533770 , version 1 (19-01-2022)

Identifiers

Cite

Michael A Antonelli, Jillian Kendrick, Chris Yakymchuk, Martin Guitreau, Tushar Mittal, et al.. Calcium isotope evidence for early Archaean carbonates and subduction of oceanic crust. Nature Communications, 2021, 12, ⟨10.1038/s41467-021-22748-2⟩. ⟨hal-03533770⟩
44 View
68 Download

Altmetric

Share

Gmail Mastodon Facebook X LinkedIn More