Ceraunius Tholus and Uranius Tholus
Ceraunius Tholus (bottom) shows several incised valleys cut into its
flanks which indicate that it was easily eroded and probably consists of ash deposits due
to explosive activity. The lower flanks of the volcano have been buried beneath the
plains material. Ceraunius Tholus is about the size of the Big Island of Hawaii.
Uranius Tholus (Top) also shows similar characteristics to Ceraunius Tholus. A major
impact crater, just above Ceranius Tholus, postdates the plains material and
volcano. However, a prominent delta of probable volcanic material was emplaced
within the impact crater at the mouth of a sinuous channel that extends up the flank of
Cerauius Tholous to the summit crater.