Chromium Cycling in Redox‐Stratified Basins Challenges δ <sup>53</sup> Cr Paleoredox Proxy Applications

Details

Ressource 1Download: Janssen et al., 22.pdf (3104.26 [Ko])
State: Public
Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_57B9F07FA2A5
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Chromium Cycling in Redox‐Stratified Basins Challenges δ <sup>53</sup> Cr Paleoredox Proxy Applications
Journal
Geophysical Research Letters
Author(s)
Janssen David J., Rickli Jörg, Wille Martin, Sepúlveda Steiner Oscar, Vogel Hendrik, Dellwig Olaf, Berg Jasmine S., Bouffard Damien, Lever Mark A., Hassler Christel S., Jaccard Samuel L.
ISSN
0094-8276
1944-8007
Publication state
Published
Issued date
16/11/2022
Peer-reviewed
Oui
Volume
49
Number
21
Language
english
Abstract
Chromium stable isotope composition (δ53Cr) is a promising tracer for redox conditions throughout Earth's history; however, the geochemical controls of δ53Cr have not been assessed in modern redox-stratified basins. We present new chromium (Cr) concentration and δ53Cr data in dissolved, sinking particulate, and sediment samples from the redox-stratified Lake Cadagno (Switzerland), a modern Proterozoic ocean analog. These data demonstrate isotope fractionation during incomplete (non-quantitative) reduction and removal of Cr above the chemocline, driving isotopically light Cr accumulation in euxinic deep waters. Sediment authigenic Cr is isotopically distinct from overlying waters but comparable to average continental crust. New and published data from other redox-stratified basins show analogous patterns. This challenges assumptions from δ53Cr paleoredox applications that quantitative Cr reduction and removal limits isotope fractionation. Instead, fractionation from non-quantitative Cr removal leads to sedimentary records offset from overlying waters and not reflecting high δ53Cr from oxidative continental weathering.
Keywords
chromium, paleoproxy, stable isotopes, euxinia
Pubmed
Web of science
Open Access
Yes
Funding(s)
European Research Council (ERC) / 819139
Create date
30/10/2022 13:27
Last modification date
11/01/2023 6:52
Usage data