Univerity of Colorado Astrobiology Seminar

Subsurface Radar Mapping of Mars

Presented by : Nathaniel Putzig (SwRI)

DATE: Wednesday, November 17
TIME: 2:00 PM
LOCATION: LASP Conference Room D142, Duane Physics Building, University of Colorado-Boulder


Because water is so critical to life processes, Astrobiology has a shared interest with the Mars Exploration Program in a goal of better understanding the distribution, state, and history of water at and below the surface of Mars. Until recently, the presence and nature of water in the Martian subsurface could only be inferred from surface imagery, temperature and neutron-spectrometer observations, and numerical modeling. That situation has changed with the advent of radar sounders in orbit at Mars, which are clearly delineating the extent and nature of glacial ices, both in the polar regions and at mid-latitudes. The strength of returned radar signals from the base of these deposits indicates that they are nearly pure water ice, with only minor admixtures of lithic materials or relatively thin lag deposits. Within the north polar cap, subsurface layers are sufficiently well illuminated by the radar to map subunits throughout the entire stack of icy materials, allowing a reconstruction of the deposits at earlier times in their history. Correlation of layering patterns with insolation cycles modeled from well-understood variations in obliquity points to a 4.2-Ma age for the north polar layered deposits. Beneath the layers, the radar reveals a dramatically flat-lying substrate,requiring unexpectedly low heat flow that has important implications for the deep interior.