Efficient Extraction of Past Seawater Pb and Nd Isotope Signatures From Southern Ocean Sediments
Efficient Extraction of Past Seawater Pb and Nd Isotope Signatures From Southern Ocean Sediments
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从南大洋沉积物中有效提取过去海水中的 Pb 和 Nd 同位素特征
DOI：
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发表时间：
2020
影响因子：
3.5
通讯作者：
A. Eisenhauer
中科院分区：
文献类型：
--
作者：
Huang Huang;M. Gutjahr;G. Kuhn;E. Hathorne;A. Eisenhauer
从海洋沉积物自生相中提取的放射性铅（Pb）和钕（Nd）同位素组成是重建过去海洋环流和水团混合的敏感示踪剂。由于替代档案的稀缺性，从散装沉积物中的水成铁锰氢氧化物的化学还原浸出是恢复过去的海水Pb和Nd同位素特征在南大洋最实用的方法。然而，如果在化学提取过程中从非水成沉积物组分中释放出大量的Pb和Nd，则沥滤信号可能会受到影响。在这里，我们开发了一个非常短的10-s的浸出方法，提取可靠的海水Pb和Nd同位素信号，从沉积物中的大西洋部门的南大洋。研究了先前推荐的MgCl 2预洗的效果、浸提溶液中螯合配体的作用和浸提时间长度。结果表明，与常用的30分钟浸出方法相比，沉积物暴露于还原浸出的10秒时间提取了充足且更可靠的水成Pb和Nd。我们改进的浸出方法的鲁棒性进行了验证，通过直接比较铅和钕同位素的签名与实际的海水，孔隙水，和相应的沉积物沥滤物从三个站在南极Filchner-Rønne冰架前面。我们的研究结果还表明，在对比以前研究的西南极大陆架上的网站，底部海水钕浓度是通过底栖通量在南部威德尔海大陆架地区升高较少。
Radiogenic lead (Pb) and neodymium (Nd) isotope compositions extracted from authigenic phases in marine sediments are sensitive tracers to reconstruct past ocean circulation and water mass mixing. Chemical reductive leaching of hydrogenetic ferromanganese oxyhydroxides from bulk sediments is the most practical way to recover past seawater Pb and Nd isotope signatures in the Southern Ocean, due to the scarcity of alternative archives. However, the leached signal could be compromised if substantial quantities of Pb and Nd were released from non‐hydrogenetic sediment fractions during chemical extraction. Here we developed a very short 10‐s leaching method to extract reliable seawater Pb and Nd isotope signals from sediments in the Atlantic sector of Southern Ocean. The effect of a previously recommended MgCl2 pre‐wash, the role of chelate ligands in the leaching solution and length of leaching time were investigated. The results show that 10‐s exposure time of sediments to reductive leaching extracted sufficient and more reliable hydrogenetic Pb and Nd compared with the commonly used 30‐min leaching approaches. The robustness of our improved leaching method was validated via direct comparison of Pb and Nd isotope signatures with actual seawater, porewater, and corresponding sediment leachates from three stations in front of the Antarctic Filchner‐Rønne Ice Shelf. Our findings also indicate that in contrast previously studied sites on the West Antarctic continental shelf, the bottom seawater Nd concentration is less elevated through benthic fluxes in the area of the southern Weddell Sea shelf.
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影响因子：
5
作者：
S. Kraft;M. Frank;E. Hathorne;S. Weldeab
通讯作者：
S. Kraft;M. Frank;E. Hathorne;S. Weldeab
影响因子：
5.3
作者：
T. Stichel;M. Frank;J. Rickli;B. Haley
通讯作者：
T. Stichel;M. Frank;J. Rickli;B. Haley
南大西洋 GEOTRACES GA10 剖面水柱中溶解和可浸出颗粒 Pb 的分布
DOI：
10.1016/j.dsr.2019.05.001
发表时间：
2019
期刊：
Oceanographic Research Papers
影响因子：
--
作者：
Schlosser C
通讯作者：
Schlosser C
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影响因子：
4
作者：
Crocket K
通讯作者：
Crocket K
自末次盛冰期以来大西洋西北深海水团的起源
影响因子：
3.5
作者：
Pöppelmeier;M. Gutjahr;P. Blaser;L. D. Keigwin;J. Lippold
通讯作者：
J. Lippold