Noble Gas Depletion On Titan: Clathrate Sequestration During The Open Ocean Phase

A plausible explanation for the absence of primordial argon, krypton, and xenon in Titan’s current atmosphere is that these gases were sequestered in clathrate hydrates during Titan’s “open-ocean” phase.

We examine how clathrate hydrate formation at Titan’s ocean surface in its early history may have contributed to noble gas depletion in the primordial atmosphere. Starting with vapor-liquid equilibrium modeling between water and volatiles, we used a statistical thermodynamic model to determine the clathrate hydrate crust thickness needed to deplete the primordial atmosphere of noble gases.

Our computations suggest that if Titan’s volatile budget was delivered by icy planetesimals with a comet-like composition, its primordial atmosphere should be rich in CO₂ and CH₄, with NH₃ largely retained in water as ions.

We show that at 273.15 K, a clathrate crust tens of kilometers thick would deplete the primordial atmosphere of xenon and krypton. The lack of primordial argon in Titan’s atmosphere may result from the partial de-volatilization of its accreted materials.

Evolution of the composition of Titan’s primordial atmosphere and ocean at equilibrium, as a function of surface temperature. — astro-ph.EP

Alizée Amsler Moulanier, Olivier Mousis, Alexis Bouquet, Ngan H.D. Trinh

Comments: Accepted for publication in A&A. 5 pages, 4 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2505.02701 [astro-ph.EP] (or arXiv:2505.02701v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2505.02701
Focus to learn more
Submission history
From: Alizée Amsler Moulanier
[v1] Mon, 5 May 2025 14:55:03 UTC (226 KB)
https://arxiv.org/abs/2505.02701
Astrobiology,