PhD in Earth and Planetary Science - The role of ice on the formation of martian valley networks

Thousands of valley networks incise the Martian southern hemispheric highlands, and stand as a reflect of an ancient past characterized by active hydrology and surface liquid water. After a peak of valley network formation around ~3.8 Byr ago (Gya), surface water presence and active hydrology steadily decreased in activity throughout Mars’ history, until reaching Mars’ present state of a desertic, global cryosphere. Whereas surface liquid water activity is a robust interpretation of the conditions on early Mars (4-3.5 Gya), the role of ice in the formation of these valleys is much less understood. Indeed, the surface conditions at the time of valley network formation and generally throughout Mars’ history have fluctuated between subfreezing and melting, suggesting that ice may have played a significant – yet largely overlooked – role in valley network formation. Such a role likely included permafrost and ground ice melt, snowmelt, and glacial melt, with potential geographic variations such as those related to latitude distribution and elevation.

The objective of this project is to characterize the role of ice on the formation of valley networks on Mars, spanning both ancient valleys (>3.5 Gya) to comparatively much younger valleys (~100 Mya) through geomorphological observations of Martian valleys complimented with terrestrial analogue observations. This objective can be broken down into three: (1) Characterization of distinctive morphologies associated with permafrost and ground ice melt, to snowmelt, and to glacial melt leading to channel and valley development, (2) mapping martian valleys located in a focus study region on the north – northeast of Hellas basin, a known region of ice accumulation on Mars, (3) identifying the presence/absence of distinctive landforms and morphologies related to permafrost, snow, and glacial ice melt within the valley networks, noting their distribution and age dates to put the findings in the larger perspective of Mars’ long-term climate change.

The project will involve geomorphological mapping using ArcGIS/QGIS. For Mars, we will utilize remote sensing datasets including image and derived topography from the cameras HiRISE, CTX, and CaSSIS, for which the student will have direct access and the possibility to acquire data through the participation of Nicolas Mangold on HiRISE and CaSSIS, and Anna Grau Galofre on CaSSIS. For Earth, available data includes the high resolution, open source ArcticDEM and daily Planet Scope satellite image data (3m/px), accessible via the ASU affiliation of Anna Grau Galofre, complimented with field data from Axel Heiberg and Devon Island (Canadian Arctic Archipelago) including high-resolution topography (LiDAR) and aerial imagery (see Figure). The project will also include a degree of physical comprehension of the processes leading to valley network development, including quantitative landscape evolution, snow and ice melt, and thermal erosion, captured using numerical models on python or MATLAB. A field component is possible but not envisaged a priori.