ABSTRACT

Tectonic pit chains are geologic landforms observed on many solar system bodies, and in the outer solar system they are most clearly observed on Enceladus. Pit chains form above a dilational fault or extensional crack underlaying a layer of loose, unconsolidated material (hereafter referred to as regolith). Using an updated map of pit chains, we identify individual pits that we use to measure the thickness of the regolith they form in. We measured regolith thicknesses up to 700 m (mean=250 m, n=116), and constrained the time needed to deposit the observed sequences of regolith using recent models of plume-generated regolith deposition. We interpret the long deposition times needed to match regolith thicknesses to suggest that Enceladus's mass flux from the plume was significantly higher in the past, that the regolith is possibly a low-density/high-porosity material, and/or additional regolith-forming processes (like alternative vent localities) exist, or have existed.

About the Speaker:

Dr. Emily Martin is a Research Geologist in the Center for Earth and Planetary Studies at the National Air and Space Museum. She has spent much of her career reconstructing Enceladus's early tectonic history to provide insight into how Enceladus developed into a geologically active world. Emily's research interests are in planetary surface processes and tectonic deformation of icy bodies of the outer solar system. Emily received her BA in physics from Wheaton College (MA) where she first began exploring the icy satellites. She subsequently obtained her MS from Northwestern University in earth and planetary science and her PhD in geological sciences from the University of Idaho.