Noctis Labyrinthus, "the labyrinth of the night", is a region of Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

 between the Valles Marineris

Valles Marineris

Valles Marineris is a system of canyons that runs along the Martian surface east of the Tharsis region...

 and the Tharsis

Tharsis

The Tharsis region on Mars is a vast volcanic plateau centered near the equator in Mars’ western hemisphere. The region is home to the largest volcanoes in the Solar System, including the three enormous shield volcanoes Arsia Mons, Pavonis Mons, and Ascraeus Mons, which are collectively known as...

 upland. It is located in the Phoenicis Lacus quadrangle

Phoenicis Lacus quadrangle

The Phoenicis Lacus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey Astrogeology Research Program. The Phoenicis Lacus quadrangle is also referred to as MC-17 ....

. The region is notable for its maze-like system of deep, steep-walled valleys. The valleys and canyons of this region formed by faulting and many show classic features of graben

Graben

In geology, a graben is a depressed block of land bordered by parallel faults. Graben is German for ditch. Graben is used for both the singular and plural....

s, with the upland plain surface preserved on the valley floor. In some places the valley floors are rougher, disturbed by landslide

Landslide

A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...

s, and there are places where the land appears to have sunk down into pit-like formations. It is thought that this faulting was triggered by volcanic activity in the Tharsis region. Research, described in December 2009, found a variety of minerals--including clays, sulfates, and hydrated silicas in some of the layers.