The iron isotope composition of iron-bearing carbonates is commonly used to obtain insights into ancient environmental conditions. However, it is often challenging to target only Fe‑carbonates (e.g. siderite and ankerite) from samples containing a variety of other Fe-bearing minerals, such as observed in Precambrian iron formations. Chemical extraction (i.e. leaching) methods of Fe‑carbonates could be an alternative to in-situ measurements and/or micro-drilling techniques applied to isotopic studies. Yet, only a few studies have looked at the effects of leaching carbonates (e.g. partial and/or total dissolution) on their Fe isotope composition. Here, we tested several leaching protocols, using 5 to 20% acetic acid (HAc) and 0.4 M HCl, on a siderite standard and three natural samples, including an iron formation, Fe-rich and Fe-poor carbonates. We showed that carbonate mineralogy has a strong control on how much of each mineral phase was being dissolved, and that variations in HAc concentration from 5% to 20% are less likely to change how much siderite dissolves (e.g. ∼30% dissolution) under a 12 h period at room temperature. Importantly, the Fe isotope composition of partially dissolved siderite had indistinguishable values within error from the whole-rock composition (i.e. complete dissolution) as shown with HAc and HCl attacks. Carbonates from the three natural samples were almost completely dissolved under the same protocol with 5 to 20% HAc, while 0.4 M HCl attacks dissolved additional mineralogical phases, which might contribute to the Fe leachate. Moreover, the iron isotope composition of carbonate leachates was preserved without generating anomalous results. Hence, weak chemical leaches represent a reliable tool to study Fe isotopic composition of carbonate to understand how the Fe cycle was operating throughout Earth's history.

含铁碳酸盐的铁同位素组成通常用于深入了解古代环境条件。然而，从含有多种其他含铁矿物的样品（例如在前寒武纪铁地层中观察到的）中仅针对铁碳酸盐（例如菱铁矿和铁陨石）通常具有挑战性。碳酸铁的化学提取（即浸出）方法可以替代原位测量和/或应用于同位素研究的微钻孔技术。然而，只有少数研究关注浸出碳酸盐（例如部分和/或全部溶解）对其铁同位素组成的影响。在这里，我们测试了几种浸出方案，使用 5 到 20% 乙酸 (HAc) 和 0.4 M HCl，对菱铁矿标准和三个天然样品，包括铁形成、富铁和贫铁碳酸盐。我们表明，碳酸盐矿物学对每种矿物相的溶解量有很强的控制作用，并且 HAc 浓度从 5% 到 20% 的变化不太可能改变菱铁矿的溶解量（例如~30% 溶解）。室温下12小时。重要的是，部分溶解菱铁矿的 Fe 同位素组成与整个岩石组成（即完全溶解）在误差范围内具有无法区分的值，如 HAc 和 HCl 攻击所示。在相同的方案下，使用 5% 至 20% HAc 的三个天然样品中的碳酸盐几乎完全溶解，而 0.4 M HCl 侵蚀溶解了额外的矿物相，这可能有助于铁浸出液。此外，碳酸盐渗滤液的铁同位素组成得到保存，没有产生异常结果。因此，