P31C-2076
Forming Enceladus’ Near-Surface CO2 Units
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Dennis Matson1, Ashley Gerard Davies2, Torrence V Johnson2, Jean Philippe Combe3, Thomas B McCord3 and Jani Radebaugh4, (1)Retired, Washington, DC, United States, (2)Jet Propulsion Laboratory, Pasadena, CA, United States, (3)Bear Fight Institute, Winthrop, WA, United States, (4)Brigham Young University, Provo, UT, United States
Abstract:
Enceladus has CO2 surface deposits in its South Polar Region that have been mapped by J.-P. Combe et al. (2015; see their abstract at this meeting). Assuming that these units are CO2 frost, we show how they can be formed by CO2 from a subsurface ocean. We use an ocean-water circulation model [1] that shows how pressure gradients drive water to the surface from a relatively gas-rich, subsurface ocean. The model calculates the temperatures, pressures, exsolution, and flow rates throughout the circulation system. We now examine the formation of CO2 gas pockets in the ice close to the surface; the movement of CO2 to the surface; and the subsequent venting of CO2, when at least some of the CO2 freezes to form frost. If the heat flow at these locations is known (cf. [2]), then the depths of the corresponding gas pockets (at ~0 o C) can be calculated. References: [1] Matson et al. (2012) Icarus, 221, 53-62. [2] Howett et al. (2011) J. Geophys. Res. 116, E03003. Acknowledgements: AGD thanks the NASA OPR Program for support.
