Hebes Chasma

Hebes Chasma is an enclosed, almost 8&amp;#160;km-deep trough stretching 315&amp;#160;km in an east&ndash;west direction and 125&amp;#160;km from north to south at its widest point. It sits about 300&amp;#160;km north of the vast Valles Marineris canyon. A flat-topped mesa is located in the centre of Hebes Chasma, which was likely shaped by the action 