摘要
In this paper, the charateristics of topography and chemical compositions of rocks in Mare Imbrium were extracted using combination of CE-1 LAM data, CCD data and Clementine UVVIS data. Then mare basaltic units were defined, and surface ages of the defined basaltic units were evaluated using the Crater Size-Defrequency Distribution measurements. Relationships among topography, chemical compositions and surface ages of mare basaltic units in Mare Imbrium indicate that the younger in surface ages of the basaltic units, the more enrichment in Titanium and Iron, exactly from low Titanium, low Iron in Late Imbrium to high Titanium, high Iron in Eratosthenian. It is the relationship between filling process and coverage that results in topographic changes and distribution of the surface ages of basaltic units. Therefore, a mode of multi-staged with northward stepwise almost in every stage and gradual minishing scales was suggested.