Iani Chaos, Margaritifer
The source of the outflow channel
Ares Vallis lies in an area of jumbled and broken slabs of rock.
This area, called Iani Chaos, probably formed when the groundwater
(or ice) aquifer failed and catastrophically released water onto
the surface. The rock was undermined and collapsed into broken
massifs. This image is 146 kilometers across. Nearly all tributaries
flowing into Ares Vallis, as well as other outflow channels emptying
into the Chryse Basin, originate in areas of chaos located near
the eastern and northern ends of Valles Marineris. Several flood
events may have occurred in each channel. The trigger for these
events is unknown. Mars Pathfinder landed successfully at the
mouth of Ares
Vallis in July 1997.
Imaging from the Viking 1 Orbiter and Lunar and Planetary Institute