近日，中国地质调查局邓义楠课题组的最新研究揭示了深海远洋沉积物在海洋锌同位素平衡收支中的关键作用。相关论文于2024年7月30日发表在《地质学》杂志上。

据悉，含Fe-Mn氧化物颗粒的深海浮游沉积物是现代海洋中过渡金属的关键海洋氧汇。然而，人们对浮游带中自生Zn的同位素组成仍然知之甚少，这阻碍了对全球锌同位素收支的理解。

本文分析了采自太平洋的两个深海浮游沉积物柱的Zn同位素组成。结果表明，深海沉积物中自生Zn主要以Fe-Mn(羟基)氧化物为主。深海沉积物中的轻Zn同位素特征(δ⁶⁶Zn：-0.02‰至0.34‰，n=42；根据JMC-Lyon标准，以⁶⁶Zn/⁶⁴Zn比值的千分之偏差计算)，与先前根据铁锰结壳和结核中Zn同位素组成所假设的约1.0‰完全不同。基于这一观测结果(深海沉积物Zn通量=5.3×10⁸mol yr^-1)，研究人员提出了一个新的、平衡的全球Zn同位素收支。

附：英文原文

Title: Balancing the oceanic Zn isotope budget: The key role of deep-sea pelagic sediments

Author: Ganglan Zhang, Yangtao Zhu, Yinan Deng, Jun Cao, Pengcong Wang, Ao Yang, Gaowen He, Bin Zhao, Mingyu Zhao

Issue&Volume: 2024-07-30

Abstract: Oxygenated deep-sea pelagic sediments with Fe-Mnoxide particles represent a key oceanic oxic sink for transition metals in the modern ocean. However, the isotopic composition of authigenic Zn in the pelagic zone remains poorly constrained, which hampers our understanding of the global budget of Zn isotopes. Here, we analyzed the Zn isotopic compositions of two deep-sea pelagic sediment columns collected from the Pacific Ocean. The results show that authigenic Zn in deep-sea sediments is primarily hosted by the Fe-Mn (oxyhydr)oxides. The light Zn isotopic signatures (δ⁶⁶Zn: -0.02‰ to 0.34‰, n= 42; computed as the per mille deviation of the ⁶⁶Zn/⁶⁴Zn ratio from the JMC-Lyon standard) observed in deep-sea sediments are completely different from the previously assumed values of ～1.0‰ based on the Zn isotopic compositions of Fe-Mn crusts and nodules. Based on this observation (Zn flux of deep-sea sediments = 5.3 × 10⁸mol yr^-1), we propose a new, balanced global budget for Zn isotopes.

DOI: 10.1130/G52363.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52363.1/645999/Balancing-the-oceanic-Zn-isotope-budget-The-keyredirectedFrom=fulltext