Geomorphic Analyses of Lobate Debris Aprons in Deuteronilus Mensae, Mars

Lobate debris aprons are concentrated in several mid-latitude regions on Mars, including around the Hellas and Agyre basins in the southern highlands and along the northern dichotomy boundary of Tempe Terra/Mareotis Fossae and Deuteronilus Mensae. Debris aprons typically have lobate fronts, surface lineations, and convex-up cross-sectional shapes that suggest glacier-like flow of ice-rich debris. Aprons also have relatively crater-free surfaces, indicating a young age and, perhaps, recent storage of ice on the Martian surface. The Deuteronilus Mensae region (10-50° E, 35-50° N) is an area about 1000 km across with a large population of debris aprons. These features are typically tens of kilometers long and extend from source regions such as isolated mesas, knobs, and valley walls. Geomorphic analyses of the aprons provide insights regarding their overall development, including erosion rates for source units, debris supply to apron masses, and ice content. This information may provide further constraints on the types of source materials, the climatic conditions under which aprons were formed, and the geologic evolution of the dichotomy boundary in Deuteronilus Mensae. We have compiled a series of apron morphometric parameters using Viking Orbiter, Mars Orbital Camera (MOC) and Thermal Emission Imaging System (THEMIS) images and Mars Orbital Laser Altimeter (MOLA) digital elevation data in ESRI ArcView 8.2 Geographic Information Systems software. These parameters, which include area, volume, slope, thickness, relief, and height/length ratio, are being used to characterize the Deuteronilus Mensae apron population and compare it to other apron populations on Mars.