Craters, cryovolcanism, and clathrates: Exploring interactions between titan’s ice shell, surface, and atmosphere

Abstract

Titan’s subsurface liquid water ocean and organic-rich surface and atmosphere make it a particularly exciting target of interest for astrobiology. Its dense atmosphere requires a methane replenishment mechanism, potentially linking the interior and atmosphere. Interactions between the interior, surface, and atmosphere manifest in various geologic features, such as modified impact craters and potential cryovolcanic features, indicating that Titan is a dynamic world. This dissertation explores the interactions between Titan’s ice shell, surface, and atmosphere through three distinct projects. Chapter 2 focusses on the formation of Titan’s rampart craters, investigating an endogenic origin through a gas explosion mechanism. This project models the explosive release of gas from liquid methane and nitrogen, and gas sourced from methane clathrate. I find that an explosive origin for rampart craters can reproduce the observed morphologies, estimate the amount of gas released into the atmosphere, and discuss the implications for atmosphere replenishment. Chapter 3 examines the potential for effusive cryovolcanism via a pressure-driven eruption mechanism for transporting subsurface materials to Titan’s surface. I constrain the conditions under which pressure-driven eruption are feasible and the characteristics of the resulting cryolava flows. Chapter 4 investigates the role of a clathrate crust in the topographic relaxation of complex impact craters on Titan. By comparing the simulated crater morphologies to observed craters on Titan, we provide constraints on the thickness of Titan’s clathrate crust. Overall, this dissertation advances our understanding of the dynamic processes shaping Titan’s surface and subsurface, including potential cryovolcanic mechanisms and impact crater formation and evolution.