Doctor of Philosophy
Livio Leonardo Tornabene
Gullies in the mid- and high-latitudes of Mars were first observed in Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images in 1997. Appearing to be geologically young, they quickly became a feature of interest due to the implication of liquid water in their formation based on distinct morphological characteristics including incised channels, many exhibiting features indicative of fluid flow. However, the temperature and pressure conditions on the surface of Mars during its most recent geologic era have not been conducive to sustaining water in the liquid phase for extended periods of time; therefore, a number of “wet” (water-related) and “dry” (driven by CO2 gas or granular flow) gully formation mechanisms have been proposed. The goal of this thesis is to conduct a large-scale study of gullies on Mars in order to determine how they are likely to have formed and evolved. I begin with a comprehensive global inventory of martian gullies to determine how their geographic distribution correlates with the effects of past and present climate conditions based on recent models, as well as thermophysical properties of the surface. Then I move to a regional focus in Utopia Planitia in Mars’ northern mid-latitudes, using gullies as a stratigraphic marker for the relative timing of formation of other mid-latitude landforms found in the region. Lastly, I take a localized approach within Gasa Crater, a particularly active gully site in the southern mid-latitudes, to investigate methods of looking for recent changes in martian gullies.
Harrison, Tanya Nicole, "Martian Gully Formation and Evolution: Studies From the Local to Global Scale" (2016). Electronic Thesis and Dissertation Repository. 3980.