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
Abstract:
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.
http://lasp.colorado.edu/life/seminars.html