Efficient extraction of past seawater Pb and Nd isotope signatures from Southern Ocean sediments

Huang, Huang; Gutjahr, Marcus; Kuhn, Gerhard; Hathorne, Ed C; Eisenhauer, Anton

doi:10.1002/essoar.10503414.2

Cited by 3 publications

(4 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We collected trace metal samples from the RR1804 cruise using the ship's regular CTD rosette and Niskin bottles, which is not a standard TMC sampling technique. But previous studies have shown that ship's regular sampling system can be clean for some trace metals, such as Mn, Cd, and Nd (Janssen et al 2014; Huang et al 2021; Zhang et al 2021). In order to assess the cleanliness of the ship's regular sampling system, we compared the RR1804 concentrations with those of RR1805—when a TMC sampling technique was used.…”

Section: Resultsmentioning

confidence: 99%

Biogeochemical cycling of Cd, Mn, and Ce in the Eastern Tropical North Pacific oxygen‐deficient zone

Bian

Yang

Bolster

et al. 2022

Limnology & Oceanography

View full text Add to dashboard Cite

Oxygen‐deficient zones (ODZs) play an important role in the distribution and cycling of trace metals in the ocean, as important sources of metals including Fe and Mn, and also as possible sinks of chalcophile elements such as Cd. The Eastern Tropical North Pacific (ETNP) ODZ is one of the three largest ODZs worldwide. Here, we present results from two sectional surveys through the ETNP ODZ conducted in 2018, providing high‐resolution concentrations of several metals, along with complimentary measurements of nutrients and iodine speciation. We show that samples obtained from the ship's regular rosette are clean for Cd, Mn, Ni, and light rare earth elements, while uncontaminated Fe, Zn, Cu, and Pb samples cannot be obtained without a special trace‐metal clean sampling system. Our results did not show evidence of Cd sulfide precipitation, even within the most oxygen‐depleted water mass. High Mn and Ce concentrations and high Ce anomalies were observed in low‐oxygen seawater. These maxima were most pronounced in the upper water column below the oxycline, coincident with the secondary nitrite maxima and the lowest oxygen concentrations, in what is generally considered the most microbially active part of the water column. High Mn and Ce features were also coincident with maxima in excess iodine, a tracer of shelf sediment sources. Mn and Ce maxima were most prominent within the 13°C water mass, spanning a density horizon that enhances isopycnal transport from the shelf sediments, resulting in transport of Mn and Ce at least 2500 km offshore.

show abstract

Section: Resultsmentioning

confidence: 99%

Biogeochemical cycling of Cd, Mn, and Ce in the Eastern Tropical North Pacific oxygen‐deficient zone

Bian

Yang

Bolster

et al. 2022

Limnology & Oceanography

View full text Add to dashboard Cite

show abstract

“…Additionally, the risk of contamination is minimized by the use of a weak leaching solution 34 . A future analysis of core ODP 1094 using the recently developed protocol of a very short leaching method 38 could lead to further insights. Nevertheless, contamination of the record of ODP 1094 evoked from volcanic material is possible due to the vicinity to the volcanically active Bouvet region 39 .…”

Section: Discussion Nd Signature Of the Two Deeper Cores Mainly Refl...mentioning

confidence: 99%

Large-scale Pacific-sourced intrusion into the glacial South Atlantic

Hallmaier

Rückert

Link

et al. 2022

Preprint

View full text Add to dashboard Cite

The deep Southern Ocean (SO) circulation plays a key role in the storage and release of CO2 in Earth’s climate system. Uptake and release of CO2 strongly depend on the redistribution of well and poorly ventilated water masses. Here, we present new neodymium isotope data (εNd) from three sediment cores from the Atlantic sector of the SO to assess the distribution of water masses during the past 150 ka. ODP 1094 (2807 m) reveals a tremendous Holocene εNd-variability (-0.25 to -6.07), which most likely reflects local influences. PS 1768-8 (3299 m) and ODP 1093 (3624 m), show far more unradiogenic interglacial εNd-signatures, which are similar to the present-day Antarctic Bottom Water (AABW) (εNd~-8). During peak glacial periods, radiogenic εNd-values of ~-2.5 to -3.5 are recorded. This confirms a predominance of glacial Pacific-sourced deep water at depths of 3.3-3.6 km in the South Atlantic, with proportions close to 100% and lacking AABW. We advocate for the presence of Pacific Deep Water even during interglacials and further hypothesize that a possible intrusion due to a warming climate could accelerate climate warming. The persistent occurrence of such a highly radiogenic water mass substantially changes the view regarding the selection of the Southern Hemisphere εNd-endmember for the Atlantic Ocean and reinforces the major importance of carbon storage in the Glacial SO.

show abstract

“…However, the applicability of a given leaching method varies according to the target geochemical tracers. Hence, modifications have been performed for specific tracers and different sample types based on these basic methods (Filgueiras et al 2002), such as for Fe (Poulton and Canfield 2005), Mn (Lenstra et al 2021), Zn (Fujiyoshi et al 1994), Nd (Wilson et al 2013) and Pb (Huang et al 2021). To date, sequential leaching methods have only been sparsely applied and only partly developed to extract Li from different phases within silicate solids.…”

mentioning

confidence: 99%

“…2013) and Pb (Huang et al . 2021). To date, sequential leaching methods have only been sparsely applied and only partly developed to extract Li from different phases within silicate solids.…”

mentioning

confidence: 99%

Experimental Investigation of Oxide Leaching Methods for Li Isotopes

Liu

Strandmann

Tarbuck

et al. 2022

Geostandard Geoanalytic Res

View full text Add to dashboard Cite

To examine the applicability of different leaching methods used to extract secondary oxides from silicate solids for lithium isotope (δ7Li) measurement, this study has conducted leaching experiments on five different types of silicate solids, including a fresh basalt, two weathered basalts, a Yellow River sediment (loess‐dominated) and a shale. Four factors were assessed in the experiments: the concentration of the leaching reagent hydroxylamine hydrochloride (HH), the leaching temperature (20 °C vs 95 °C), the leaching time and the reagent/solid ratio. Based on elemental concentrations and Li isotopes, 0.04 mol l−1 hydroxylamine hydrochloride (HH) in 25% v/v acetic acid at room temperature for 1 h with 40 ml g−1 reagent/solid ratio is recommended. At high temperatures, low δ7Li and high magnesium/iron ratios indicate that minerals other than secondary oxides are dissolved. With increased leaching time, there is no evidence for Li isotopic fractionation at room temperature. However, longer leaching time or increased reagent/solid ratios may increase the risk of leaching from non‐oxide phases. Meanwhile, results suggest that low concentrations of HH are not sufficient to target the secondary oxides evenly, while high concentrations of HH can leach out more non‐oxides. We also examined the optimal oxide leaching method within a full sequential leaching procedure (i.e., exchangeable, carbonate, oxide, clay and residual phases). Elemental concentrations show that no elements exist exclusively in oxides, so it is essential to analyse multi‐elemental concentrations to verify that the leaching has accessed this phase in a given sample. Comparing secondary oxides with their corresponding solutions, we estimate the isotopic fractionation (Δ7Lioxide‐solution) is −16.8‰ to −27.7‰.

show abstract

Efficient extraction of past seawater Pb and Nd isotope signatures from Southern Ocean sediments

Cited by 3 publications

References 29 publications

Biogeochemical cycling of Cd, Mn, and Ce in the Eastern Tropical North Pacific oxygen‐deficient zone

Biogeochemical cycling of Cd, Mn, and Ce in the Eastern Tropical North Pacific oxygen‐deficient zone

Large-scale Pacific-sourced intrusion into the glacial South Atlantic

Experimental Investigation of Oxide Leaching Methods for Li Isotopes

Contact Info

Product

Resources

About