The rare earth elements and yttrium (REY) in bioapatite from deep-sea sediments are potential proxies for reconstructing paleoenvironmental conditions. However, the REY enrichment mechanism and the reliability of this tracer remain elusive because of the lack of key information from ambient pore water. Here, we report high-resolution geochemical data for pore water, bottom water, and bioapatite from deep-sea sites in the western Pacific. Our results reveal that the benthic flux of REY from the deep sea is less substantial than from the shallow marine realm, resulting in REY-rich sediment. The depth distribution of REY in pore water is opposite to that of bioapatite, and REY patterns and neodymium isotopic compositions are not uniformly distributed within bioapatite. These results indicate alteration of REY and neodymium isotopic compositions during early diagenesis. Therefore, we infer that REY from bioapatite are not robust recorders of the deep marine environment through Earth’s history.

中文翻译：

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深海沉积物中稀土元素富集分馏的早期成岩控制

来自深海沉积物的生物磷灰石中的稀土元素和钇（REY）是重建古环境条件的潜在代理。然而，由于缺乏来自环境孔隙水的关键信息，REY 富集机制和该示踪剂的可靠性仍然难以捉摸。在这里，我们报告了来自西太平洋深海地点的孔隙水、底水和生物磷灰石的高分辨率地球化学数据。我们的研究结果表明，来自深海的 REY 底栖通量不如来自浅海领域的大，导致富含 REY 的沉积物。REY在孔隙水中的深度分布与生物磷灰石相反，REY模式和钕同位素组成在生物磷灰石内部分布不均匀。这些结果表明在早期成岩过程中 REY 和钕同位素组成发生了变化。因此，我们推断来自生物磷灰石的 REY 并不是地球历史上深海环境的可靠记录器。