A prolonged eruptive history can be inferred from the stratigraphic relationships evident on this volcano. The lower flanks of the volcano have been buried beneath the plains material, as was the case with both Ulysses (slide #11) and Biblis (slide #12) Paterae, but a major impact crater postdates both the volcano and the plains in the upper portion of the frame. However, a prominent delta of probable volcanic material was emplaced within the impact crater (see arrow) at the mouth of a sinuous channel that extends up the flank of the volcano to the summit crater. A smaller sinuous channel on the western (left) flank of the volcano also appears to have a subtle delta of material that may overlay the plains.
24 N, 97 W; Viking
Orbiter frame 516A24, shading corrected version.