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

verfasst von

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.

Externe Organisation(en)

Universität Wien
Universität zu Köln
Constructor University Bremen

Typ

Artikel

Journal

Nature Communications

Band

13

ISSN

2041-1723

Publikationsdatum

12.2022

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Chemie (insg.), Biochemie, Genetik und Molekularbiologie (insg.), Allgemein, Physik und Astronomie (insg.)

Ziele für nachhaltige Entwicklung

SDG 14 – Lebensraum Wasser

Elektronische Version(en)

https://doi.org/10.1038/s41467-022-30423-3 (Zugang: Offen)