Geophysical Measurement and Monitoring of Planetary Rock Glacier Surface Processes

Abstract

Buried glaciers with varying fractions of debris and ice (henceforth referred to as rock glaciers) are found in mountainous regions with transitional climates on both Earth and Mars. On both worlds, there are questions as to the thickness, composition, and evolutionary history of these types of landforms. A surface feature that is ubiquitous to rock glaciers across planetary settings is the transverse ridge and furrow morphology. Two endmember hypotheses exist for the formation mechanisms behind this morphology: climatic and compressional processes. This work uses in situ geophysical field data from terrestrial rock glaciers to evaluate the formation processes governing the ridge and furrow morphologies and to determine diagnostic characteristics for each type of ridge in order to infer the origins of the ridges observed on the analogous features on Mars. By determining these formation mechanisms and developing criteria for identifying climatic ridges, a climate record can be reconstructed by mapping the surface morphology of martian rock glacier populations. First, we review the prior work that this thesis builds on. Next, we present a novel method for using two ground-penetrating radar antenna configurations to measure rock glacier thickness, internal structure, and composition, all essential parameters for reconstructing an ice emplacement history. We then demonstrate the advancement of a photogrammetric change detection method for monitoring rock glacier surface motion using repeated imaging campaigns across drone, airborne, and satellite platforms. This section provides a snapshot into the three-dimensional change of rock glacier surfaces due to both ice flow and surface melt. The surface motion and internal structure measurements are then combined to determine the formation mechanisms for ridges on the terrestrial sites, providing criteria for ridge classification. The thesis concludes by applying these ridge formation criteria to four regions on Mars with dense rock glacier populations.