An oceanic composition on early and today's Enceladus
An oceanic composition on early and today's Enceladus
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早期和今天土卫二的海洋成分
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
M. Zolotov
中科院分区：
文献类型：
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作者：
M. Zolotov
在土星的卫星土卫二上的海洋成分是通过计算热液和冻结环境下的热化学平衡来评估的。岩石蚀变的条件受到月球内部成分和热演化的假设和模型以及土卫二羽流成分的限制。结果表明，早期的海洋是碱性的Na+-Cl−-HCO 3 −溶液。下伏蚀变岩由镁层状硅酸盐、磁铁矿、铁和镍硫化物以及碳酸盐组成。随后的海水冻结导致NaCl水合物，Na，K和Ca碳酸盐的沉积，以及无盐冰壳的形成。如果今天的土卫二上存在水相，它可能由低共熔的Na‐Cl‐ HCO 3 −盐水组成，至少局部地使冰壳膨胀，并促进潮汐加热。在土卫二缺乏对Na和Cl的可靠检测，这与盐在冰岩边界的积累是一致的，并意味着通过冰壳中的升华形成了羽流。
The oceanic composition on Saturn's moon Enceladus is evaluated through calculations of thermochemical equilibria at hydrothermal and freezing settings. Conditions of rock alteration are constrained from assumptions and models for the moon's interior composition and thermal evolution, and from the composition of Enceladus' plume. Results show that an early ocean was an alkaline Na+‐Cl−‐HCO3− solution. Underlying altered rocks consisted of Mg‐phyllosilicates, magnetite, Fe and Ni sulfides, and carbonates. Subsequent freezing of oceanic water caused the deposition of a NaCl hydrate, Na, K and Ca carbonates, and the formation of a salt‐free ice shell. If an aqueous phase exists on today's Enceladus, it could consist of eutectic Na‐Cl‐HCO3− brine that at least locally decouples the ice shell and facilitates tidal heating. A lack of firm detection of Na and Cl at Enceladus is consistent with the accumulation of salts at the ice‐rock boundary and implies the plume formation via sublimation in the ice shell.