T201 GSA Planetary Geology Division G.K. Gilbert Award Session: Planetary Plumes, Volatiles, and Atmospheres

Tuesday, 17 October 2023
1:30 PM - 5:30 PM
323

ENCELADUS PLUME GRAINS: UV EXPOSURE AGES FOR SURFACE ORGANICS

Paper number: T201-13
Program: Technical Sessions
Time: 4:30 PM – 4:45 PM

Authors

Abstract

The saturnian moon Enceladus presents a remarkable opportunity in our solar system for searching for evidence of life, given its habitable ocean and active plume that deposits organic-bearing ocean material onto the icy surface. Organic ocean material could be sampled by a lander mission on the surface of Enceladus. It is of interest to understand the amount of relatively pristine, unaltered organics present on the surface, given the UV and plasma environment. Here we provide estimates of exposure ages of plume deposits - and the organic material therein - using the UV spectral signature, as observed using the Cassini Ultraviolet Imaging Spectrograph and the Hubble Space Telescope, of Enceladus to understand the penetration depth of solar UV photons into the icy regolith. We investigate the resultant effective exposure ages for various regions on Enceladus, considering the rate of resurfacing by plume fallout. In high plume fallout regions near the south pole, we find that plume grains are buried by fresher grains within years, resulting in low levels of exposure of surface grains to solar UV, which penetrates only ~100 microns. Regions at latitudes south of ~40°S can have exposure ages <100 years, translating to relatively high abundances of pristine organic material preserved in the icy regolith.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-394015

© Copyright 2023 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.