High Cliffs Surrounding Echus Chasma on Mars

What created this great cliff on Mars? Did giant waterfalls once plummet through its grooves? With a four-kilometer drop, this high cliff surrounding Echus Chasma , near an impressive impact crater, was carved by either water or lava . A leading hypothesis is that Echus Chasma, at 100-kilometers long and 10-kilometers wide, was once one of the largest water sources on Mars . If true, water once held in Echus Chasma likely ran over the Martian surface to carve the impressive Kasei Valles , which extends over 3,000 kilometers to the north. Even if initially carved by water, lava appears to have later flowed in the valley, leaving an extraordinarily smooth floor . Echus Chasma lies north of tremendous Valles Marineris , the largest canyon in the Solar System . The above image was taken by the robotic Mars Express spacecraft currently orbiting Mars.