Abstract
Traditional carbonate sedimentary archives have proven challenging to exploit for Zn and Cu isotopes, due to the high concentrations of trace metals in potential contaminants (e.g., Fe-Mn coatings) and their low concentrations in carbonate. Here, we present the first dataset of δ66ZnJMC-Lyon and δ65CuSRM 976 values for cold-water corals and address their potential as a seawater archive. Extensive cleaning experiments carried out on two corals with well-developed Fe-Mn rich coatings demonstrate that thorough physical and chemical cleaning can effectively remove detrital and authigenic contaminants. Next, we present metal/Ca ratios and δ66Zn and δ65Cu values for a geographically diverse sample set of Holocene age cold-water corals. Comparing cold-water coral δ66Zn values to estimated ambient seawater δ66Zn values (where Δ66Zncoral-sw = δ66Zncoral – δ66Znseawater), we find Δ66Zncoral-sw = +0.03 ± 0.17‰ (1SD, n = 20). Hence, to a first order, cold-water corals record seawater Zn isotope compositions without fractionation. The average Holocene coral Cu isotope composition is +0.59 ± 0.23‰ (1SD, n = 15), similar to the mean of published deep seawater δ65Cu values at +0.66 ± 0.09‰, but with considerable variability. Finally, δ66Zn and δ65Cu data are presented for a small subset of four glacial-age corals. These values overlap with the respective Holocene coral datasets, hinting at limited glacial-interglacial changes in oceanic Zn and Cu cycling.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.