HR: 1340h
AN: P13A-0980    [Abstracts]
TI: Evidence for Ancient Equatorial Ice Sheets on Mars?
AU: * Kite, E S
EM: ek265@cam.ac.uk
AF: Department of Earth Sciences, Cambridge University, Downing Street, Cambridge, ENG CB2 3EQ United Kingdom
AB: During August 2004, a survey of available high-resolution MOLA gridded topography and THEMIS VIS imagery in the Equatorial Transition Zone of Mars was carried out. Other data sets, paticurlarly THEMIS IR and MOC NA, were exploited to study areas of interest. Although ~100 metres-per-pixel THEMIS daytime IR coverage is almost complete at the equator, ~18 metres-per-pixel THEMIS VIS coverage was patchy at the time of the survey, and repeat observations are lacking. Therefore, the THEMIS VIS survey could only capture a subset of the geomorphology of the Equatorial Transition Zone. Nevertheless, a suite of features were catalogued: some may be of relevance to the problem of the genesis and postdepositional history of the Medusae Fossae Formation. At the THEMIS scale, the features include eskers, subparallel hummocky ridge packages, ridge-bounded hummocky terrain, metre-scale layering, small-scale chaos terrain / outflow channel landsystems, dissected terrain, rim and central mound crater-interior deposits, polygonally fractured and channelized mesa tops, "wirebrush," "eggbox/bullseye," outcrops of a pasty lithology, and apparent cwms and aretes. At MOLA scale (as noted by other workers) they include rampart craters and trough-and-lobe landscapes. One possible framework for an initial synthesis of these early results will be adumbrated, exploiting recent progress in numerical modelling of the Martian water cycle at high obliquity, and the chaotic diffusion of Mars' obliquity over geological time. Finally, the relationship of these initial results to those of other workers will be described, and some future research directions will be sketched out.
DE: 9699 General or miscellaneous
DE: 5416 Glaciation
DE: 6225 Mars
DE: 3344 Paleoclimatology
DE: 1620 Climate dynamics (3309)
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting