Abstract Carbonate zinc (Zn) isotopes have increasingly been used to track changes in seawater Zn isotopic composition. A large body of recent work, in particular studies conducted under the GEOTRACES program, have added significantly to our knowledge of how Zn behaves in the water column. However, our understanding of how water-column Zn isotopic signals become incorporated into carbonate sediments is at a much more nascent stage. To help solve this issue, we have measured the Zn isotopic composition of modern surficial and core-top carbonate sediments and seawater from the Bahamas, Panama, and the Persian Gulf. Whereas modern Bahamian seawater has a δ 66 Zn of 0.14 ± 0.12‰ (2σ), Bahamian carbonates show a large range of δ 66 Zn—from −0.56 to 1.11‰. The δ 66 Zn of carbonate mud is ∼0.3‰ higher than that of the Bahamian seawater, potentially due to Zn isotopic fractionation during precipitation. Carbonate ooids and peloids and certain skeletal and microbial aragonites, including gastropods, green algae, stromatolites and precipitates associated with cyanobacterial (Dichothrix) filaments, have δ 66 Zn indistinguishable, within analytical error, from that of modern seawater. This suggests that these carbonate phases may be promising archives for seawater δ 66 Zn.

中文翻译：

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浅水碳酸盐作为海水锌同位素档案的评价

摘要 碳酸盐锌 (Zn) 同位素越来越多地用于跟踪海水中锌同位素组成的变化。最近的大量工作，特别是在 GEOTRACES 计划下进行的研究，大大增加了我们对 Zn 在水柱中的行为的了解。然而，我们对水柱 Zn 同位素信号如何融入碳酸盐沉积物的理解还处于初级阶段。为了帮助解决这个问题，我们测量了来自巴哈马、巴拿马和波斯湾的现代地表和核心顶部碳酸盐沉积物和海水的锌同位素组成。现代巴哈马海水的 δ 66 Zn 为 0.14 ± 0.12‰ (2σ)，而巴哈马碳酸盐的 δ 66 Zn 范围很广——从 -0.56 到 1.11‰。碳酸盐泥的δ 66 Zn 比巴哈马海水高~0.3‰，可能是由于沉淀过程中的 Zn 同位素分馏。碳酸盐鲕粒和球粒以及某些骨骼和微生物文石，包括腹足类动物、绿藻、叠层石和与蓝藻 (Dichothrix) 细丝相关的沉淀物，其 δ 66 Zn 在分析误差范围内与现代海水的 δ 66 Zn 无法区分。这表明这些碳酸盐相可能是海水 δ 66 Zn 的有希望的档案。