Earth’s geodynamic evolution constrained by ¹⁸²W in Archean seawater

authored by

A. Mundl-Petermeier, S. Viehmann, J. Tusch, M. Bau, F. Kurzweil, C. Münker

Abstract

Radiogenic isotope systems are important geochemical tools to unravel geodynamic processes on Earth. Applied to ancient marine chemical sediments such as banded iron formations, the short-lived ¹⁸²Hf-¹⁸²W isotope system can serve as key instrument to decipher Earth’s geodynamic evolution. Here we show high-precision ¹⁸²W isotope data of the 2.7 Ga old banded iron formation from the Temagami Greenstone Belt, NE Canada, that reveal distinct ¹⁸²W differences in alternating Si-rich (7.9 ppm enrichment) and Fe-rich (5.3 ppm enrichment) bands reflecting variable flux of W from continental and hydrothermal mantle sources into ambient seawater, respectively. Greater ¹⁸²W excesses in Si-rich layers relative to associated shales (5.9 ppm enrichment), representing regional upper continental crust composition, suggest that the Si-rich bands record the global rather than the local seawater ¹⁸²W signature. The distinct intra-band differences highlight the potential of ¹⁸²W isotope signatures in banded iron formations to simultaneously track the evolution of crust and upper mantle through deep time.

External Organisation(s)

University of Vienna
University of Cologne
Jacobs University Bremen

Type

Article

Journal

Nature Communications

Volume

13

ISSN

2041-1723

Publication date

12.2022

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Chemistry, General Biochemistry,Genetics and Molecular Biology, General, General Physics and Astronomy

Sustainable Development Goals

SDG 14 - Life Below Water

Electronic version(s)

https://doi.org/10.1038/s41467-022-30423-3 (Access: Open)