TY - JOUR
T1 - An oceanic composition on early and today's Enceladus
AU - Zolotov, Mikhail
PY - 2007/12/16
Y1 - 2007/12/16
N2 - 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- HCO-3 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-HCO-3 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.
AB - 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- HCO-3 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-HCO-3 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.
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U2 - 10.1029/2007GL031234
DO - 10.1029/2007GL031234
M3 - Article
AN - SCOPUS:39049093666
SN - 0094-8276
VL - 34
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 23
M1 - L23203
ER -