Abstract A key process in the early solar system that significantly affects the further evolution and transport of highly volatile elements throughout the solar system hydrothermal parent body alteration. To determine whether hydrothermal alteration in outer solar system parent bodies occurred more or less simultaneously or due to a sequence of multiple different events, we investigated low-temperature hydrothermally altered CM and CI chondrites along with volatile-rich CM-like clasts and C1 clasts with abundant mineral phases that contain volatiles. In this respect, C1 clasts are particularly important as they closely resemble the CI chondrites but originate from isotopically different parent bodies. Specifically, we applied the SIMS-based Mn/Cr in situ dating technique to carbonates, a common hydrothermally formed phase in low-temperature hydrothermally altered meteorites. The Mn/Cr ages of dolomites in CI chondrites and C1 clasts as well as calcites in CM chondrites and CM-like clasts reveal that nearly all carbonates in low-temperature hydrothermally altered clasts and chondrites were formed within a brief period between 2-6 Ma after CAI formation. Given this sharp separation, and that hardly any material contains carbonates formed later than ∼6 Ma after CAI formation, hydrothermal alteration likely occurred near-contemporaneously among different parent bodies in the outer solar system. Further, the timing of hydrothermal alteration matches peak heating of 26Al decay that ceased at ∼5 Ma after CAI formation. Hereby, these results are consistent with a model in which the carbonates in low-temperature hydrothermally altered parent bodies precipitated from the fluid produced by melting ice. The results also show that other potential heating events (e.g., impacts) only negligibly contributed to creating environments where fluid-mediated dissolution and precipitation of carbonates was possible. Additionally, the isotopic (H, O, Cr, and S) differences between C1 clasts and CI chondrites are most likely not caused by differences in timing of hydrothermal aqueous alteration and, thus, are best explained by spatially different isotopic reservoirs.

中文翻译：

---

外太阳系中短暂的 26Al 引起的热液蚀变事件：碳酸盐锰/铬年龄的限制

摘要 太阳系早期的一个关键过程，它显着影响了整个太阳系热液母体蚀变过程中高挥发性元素的进一步演化和传输。为了确定外太阳系母体中的热液蚀变是否或多或少同时发生或由于一系列不同的事件，我们研究了低温热液蚀变的 CM 和 CI 球粒陨石以及富含挥发物的类 CM 碎屑和 C1 碎屑含有挥发物的丰富矿物相。在这方面，C1 碎屑特别重要，因为它们与 CI 球粒陨石非常相似，但起源于同位素不同的母体。具体来说，我们将基于 SIMS 的 Mn/Cr 原位测年技术应用于碳酸盐，低温热液蚀变陨石中常见的热液形成相。CI 球粒陨石和 C1 碎屑中的白云岩以及 CM 球粒陨石和类 CM 碎屑中的方解石的 Mn/Cr 年龄表明，低温热液蚀变碎屑和球粒陨石中的碳酸盐几乎都是在 2-6 Ma 的短暂时间内形成的CAI形成后。鉴于这种明显的分离，并且几乎没有任何物质包含在 CAI 形成后约 6 Ma 之后形成的碳酸盐，因此热液蚀变很可能在太阳系外的不同母体之间几乎同时发生。此外，热液蚀变的时间与 CAI 形成后 5 Ma 停止的 26Al 衰变的峰值加热相匹配。特此，这些结果与低温热液蚀变母体中的碳酸盐从冰融化产生的流体中沉淀出来的模型一致。结果还表明，其他潜在的加热事件（例如，撞击）对创造可能发生流体介导的碳酸盐溶解和沉淀的环境的贡献微乎其微。此外，C1 碎屑和 CI 球粒陨石之间的同位素（H、O、Cr 和 S）差异很可能不是由热液水蚀变时间的差异引起的，因此，最好用空间不同的同位素储层来解释。影响）对创造可能发生流体介导的碳酸盐溶解和沉淀的环境的贡献微乎其微。此外，C1 碎屑和 CI 球粒陨石之间的同位素（H、O、Cr 和 S）差异很可能不是由热液水蚀变时间的差异引起的，因此，最好用空间不同的同位素储层来解释。影响）对创造可能发生流体介导的碳酸盐溶解和沉淀的环境的贡献微乎其微。此外，C1 碎屑和 CI 球粒陨石之间的同位素（H、O、Cr 和 S）差异很可能不是由热液水蚀变时间的差异引起的，因此，最好用空间不同的同位素储层来解释。