This field exploits optical imagery and 3-D topographic model. Geomorphology, morphometry and stratigraphic relationship give information on the type and time of processes that affected the surface, like impact cratering, tectonic, or fluvial. Time information can also be gained with the so-called crater counting technique, or crater size-frequency distribution measurements, coupled with model and chronologies of impact history. In parallel, physical models of geological processes (e.g., viscous flows models), provide an in-depth and complementary understanding of a planet's geology.
PLANETARY visible and near-infrared spectroscopy
This method characterizes the mineralogy of a planetary surface or a sample in the lab by analyzing the light it reflects. Absorption bands of rock-forming minerals, like pyroxene, olivine, phyllosilicates and carbonates can be detected, quantified and mapped across the surface of a planetary object. This tell us about how rocks formed, for example by magmatic processes, volcanism or aqueous alteration.