10Be/9Be ratios reveal marine authigenic clay formation


As reverse weathering has been shown to impact long-term changes in atmospheric CO2 levels, it is crucial to develop quantitative tools to reconstruct marine authigenic clay formation. We explored the potential of the beryllium (Be) isotope ratio (10Be/9Be) recorded in marine clay-sized sediment to track neoformation of authigenic clays. The power of such proxy relies on the orders-of-magnitude difference in 10Be/9Be ratios between continental Be and Be dissolved in seawater. On riverine and marine sediments collected along a Chilean margin transect we chemically extracted reactive phases and separated the clay-sized sediment fraction. We compare the riverine and marine 10Be/9Be ratio of this fraction. Moreover, we compare the elemental and mineralogical composition and the Nd and Sr-isotopic composition of these samples. 10Be/9Be ratios increase four-fold from riverine to marine sediment. We attribute this increase to the incorporation of Be high in 10Be/9Be from dissolved biogenic opal, which also serves as a Si-source for the precipitation of marine authigenic clays. 10Be/9Be ratios thus sensitively track reverse-weathering reactions forming marine authigenic clays.

DOI https://doi.org/10.1594/PANGAEA.918725
Related Identifier https://doi.org/10.1029/2019GL086061
Related Identifier https://store.pangaea.de/Publications/Bernhardt-etal_2020/Bernhardt_README.pdf
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.918725
Creator Bernhardt, Anne; Oelze, Marcus ORCID logo; Bouchez, Julien; von Blanckenburg, Friedhelm (ORCID: 0000-0002-2964-717X); Mohtadi, Mahyar ORCID logo; Christl, Marcus ORCID logo; Wittmann, Hella ORCID logo
Publisher PANGAEA
Publication Year 2020
Rights Creative Commons Attribution 4.0 International; https://creativecommons.org/licenses/by/4.0/
OpenAccess true
Resource Type Bundled Publication of Datasets; Collection
Format application/zip
Size 4 datasets
Discipline Earth System Research
Spatial Coverage (-74.514W, -37.540S, -73.170E, -36.810N)
Temporal Coverage Begin 2001-04-27T15:39:00Z
Temporal Coverage End 2001-04-28T19:13:00Z