HR: 11:50h
AN: P21C-07    [PDF]
TI: Martian polar layered deposits: the latest from the THEMIS investigation.
AU: * Ivanov, A B
EM: anton.ivanov@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, ca 91109
AU: Byrne, S
EM: shane@gps.caltech.edu
AF: California Institute of Technology, 1205 E. California blvd, Pasadena, ca 91125
AB: In this work we present the latest imaging data acquired by the Mars Odyssey THermal EMission Imaging System (THEMIS) and place it into context of the Mars Global Surveyor (MGS) data. This work concentrates on comparison of properties of North and South polar layered deposits (PLD) observed in thermal IR and visible channels of the THEMIS camera. We are primarily interested in major properties of the layers in both ice caps: their continuity, morphology and stratigraphy. These questions can be addressed by THEMIS VIS color images, along with MOC high resolution data and MOLA Digital Elevation Models (DEM). THEMIS Visible Imaging Subsystem (VIS) was used to obtain full coverage of the South Polar Layered Deposits (SPLD) during early spring, when this area is still covered by seasonal frost. This mosaic covers all of the South Polar region poleward of 80S. The staircase structure of the layered deposits is clearly seen. Layers in the North PLD (NPLD) are much smoother and don't exhibit staircase structure. Discontinuities and unconoformities are much more evident in the SPLD rather than in NPLD. MOC high-resolution images taken along the troughs and layers provide excellent context. We will also present initial results on monitoring seasonal changes in "swiss cheese" terrains. The most useful band for polar observations with THEMIS IR camera is band 9 (12.57 micron). Band 10 (14.88 micron) data can be used for atmospheric calibration. High resolution THEMIS IR data allows us to distinguish bulk properties of of layered terrain and ice. While we were not able to distinguish between individual layers, we will present initial observations of temperature trends in the polar layered deposits. Our ultimate goal is to characterize continuity, morphology and stratigraphy of the polar layered terrains and suggest mechanisms and timescales for their formation. Our approach is to use THEMIS VIS images to investigate continuity of the layers in the layered deposits and their stratigraphic relationships using high-resolution MOLA topography. MOC images provide important morphological detail. We will also attempt to detect heating or cooling trends in THEMIS Thermal IR imagery for selected troughs in the PLD and interpret these data in terms of thermophysical properties (e.g. thermal inertia) of the layers.
DE: 5416 Glaciation
DE: 5460 Physical properties of materials
DE: 5462 Polar regions
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting