| In this thesis, the evolution of landforms in Gorgonum and Atlantis basins on Mars is investigated using the geomorphologic approach of landform identification and mapping, and a new dating method (chronologic surface method). Correlations among processes and mechanisms of control that formed the hierarchically structured landforms are analyzed and used to define the evolution of surface morphologies. High-resolution satellite images and a digital elevation model (DEM) are used to describe associations of depositional and erosional structures at a regional scale. Morphometric assemblages of landforms are mapped using local relief as a principal variable and DEM analysis in a GIS environment as the principal tool. Ages of different landforms are investigated using craters' morphometrical characteristics referring to their depth, diameter and the area extent within the landforms on which they are superposed.;Three stages of evolution are described for Gorgonum and Atlantis basins, corresponding to the action of major controlling processes and mechanisms at a planetary scale: major impact cratering (3.48+/-0.163 Gy ago), volcanism and associated tectonism in Tharsis that flexed and fractured the Martian lithosphere toward its periphery (1.21+/-0.056--1.05+/-0.049 Gy ago), and climate change that characterizes the present dry and cold Mars (347-336+/-15 My ago). An intense epoch of fluvial and lacustrine resurfacing took place 714+/-33--607+/-12 My ago which corresponds to the ages derived for the hydrated mineral iddingsite (679+/-66 My ago) in Martian meteorites.;Key words. Mars, landform hierarchy, regional scale analysis, morphologic mapping, chronologic surface method, age determination, Martian meteorite age constraints. |
