Canyons on Mars

At www.dailymail.co.uk/sciencetech/article-2647295/Water-didnt-carve-Mars-c… … basically, a group of scientists are saying water did not carve out the canyons on Mars. This idea is in fact relatively recent and we suppose a rump of scientists have not been persuaded and prefer to point a finger at lava flow. There are in fact quite a few volcanoes on Mars – but are they capable of cutting canyons bigger than Earth's Grand Canyon? It's likely the water brigade will be back to hose them down but does it have to be either of these two geological shapers of the landscape. Thunderbolts would say it was something quite different – lightning discharges, for example. Gary Gilligan sent the link and has something like this in mind – an interplanetary electric discharge.