HR: 1330h
AN: P22A-0063    [PDF]
TI: Understanding Rocky Surfaces on Mars: Observations from TES and THEMIS
AU: * Nowicki, S A
EM: snowicki@asu.edu
AF: Arizona State University, Mars Space Flight Facility Box 6305, Tempe, AZ 85287
AU: Christensen, P R
AF: Arizona State University, Mars Space Flight Facility Box 6305, Tempe, AZ 85287
AB: The TES and THEMIS experiments have provided complementary data for interpreting the physical characteristics of surfaces on Mars. Thermal inertia and rock abundance values derived from TES data have been used to make interpretations of surface materials and characteristics while THEMIS data provide high-resolution morphology and temperature which can serve to test and develop the interpretations from the TES investigation. A global view of rock abundance on Mars is presented here followed by an analysis of the physical characteristics of surfaces on both a regional and high-resolution scale. The overall goal of this investigation is to identify the processes which may be responsible for exposing or generating rocks, and estimate the scales at which these processes may have been at work. A rock is defined as a surface material that has a thermal inertia of 1250 J/m2-s1/2-K (30 cal/cm2-s1/2-K) or greater. A surface with a high rock abundance value could be exposed bedrock, blocky debris, indurated materials or a combination. The TES rock abundance data were binned at 8 pixels/degree to produce a global map of percent aerial coverage of rocks on the surface of Mars. This new rock map is visually similar to global thermal inertia maps, but differences between the datasets suggest that there are complicated processes generating and exposing rocks on the surface. A number of regions with interesting thermophysical characteristics are being investigated to determine the relationships between thermal inertia, rock abundance and morphology. We are focusing on understanding regions with anomalous rock abundance/thermal inertia characteristics, including the southeastern slope of Arsia Mons, the northern scarp of Olympus Mons, Solis Planum, Ares Vallis, and Isidis rim. On a global scale, the TES rock abundance and thermal inertia values suggest that where a thick layer of dust is not completely mantling the surface, that the high thermal inertia material is not homogeneous and is composed of a mixture of coarse particulate (sand, gravel) and rock. Even in regions covered in dunes, some of the surface that surrounds and underlies the sand can have a higher thermal inertia than saltating material. There are a few places on Mars where the thermal inertia and rock abundance suggest that there have been processes at work to produce or expose unique materials that either have not formed elsewhere on Mars or have been removed.
DE: 5415 Erosion and weathering
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting