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What Were the Valles Marineris on Mars Formed By?

Often called the "Grand Canyon of Mars," the Valles Marineris is Mars' largest canyon network. It is 10 times longer, 6 to 7 times deeper and 20 times wider than Earth's Grand Canyon. A series of dramatic tectonic events created this impressive landform.

Tectonic Activity
- The original depressions formed as large areas of the Martian surface collapsed, due to some underlying instability. These depressions filled with layers of detritus, likely from the formation of lakes that were fed by a network of rivers branching off the main canyon.
Faulting
- Extensive faulting formed multiple grabens, which are depressed blocks of crust bordered by faults and areas of uplift. Additional faults broke down resistant areas between depressions, creating and connecting canyons. The sediment deposits spilled out as a result of the shifting and uplift.
Landslides
- Enormous landslides resulting from the shifting and faulting dumped new material into the canyon. This dark-colored material is currently drifting across the canyon floor, forming dunes, which are subsequently destroyed and re-formed at the whim of the wind.

Astronomy