Ravi Vallis is an ancient
outflow channel
Outflow channels are extremely long, wide swathes of scoured ground on Mars.Carr, M.H. (2006), ''The Surface of Mars''. Cambridge Planetary Science Series, Cambridge University Press. They extend many hundreds of kilometers in length and are typ ...
, the source of which originates from the
Aromatum Chaos depression, and is situated at the eastern end of Xanthe Terra, in the
Margaritifer Sinus quadrangle
The Margaritifer Sinus quadrangle is one of a series of list of quadrangles on Mars, 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Margaritifer Sinus quadrangle is also referred ...
(MC-19) region of
Mars
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
, located at . The Ravi Vallis outflow channel is long, and starts at the northeastern end of the Aromatum Chaos depression. The channel is orientated in an easterly direction, and further down channel, Ravi Vallis divides into two; a larger northern channel, and a smaller southern channel, and is finally truncated by a fault which is located at the western margin of the
Hydraotes Chaos depression. Ravi Vallis was named after the Ravi River, an ancient Indian river.
The Ravi Vallis
outflow channel
Outflow channels are extremely long, wide swathes of scoured ground on Mars.Carr, M.H. (2006), ''The Surface of Mars''. Cambridge Planetary Science Series, Cambridge University Press. They extend many hundreds of kilometers in length and are typ ...
and neighboring deep depression at
Aromatum Chaos, are thought to have been caused by volcano-ice interactions underneath the surface, which pierced an underground
aquifer
An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...
. This released large amounts of water, causing a catastrophic flood event, with an estimated speed of between 10 and 25 m s
−1. The discharge rates from the Ravi Vallis
outflow channel
Outflow channels are extremely long, wide swathes of scoured ground on Mars.Carr, M.H. (2006), ''The Surface of Mars''. Cambridge Planetary Science Series, Cambridge University Press. They extend many hundreds of kilometers in length and are typ ...
are thought to have ranged from a maximum of ~30 × 10
6 m
3 s
−1 after the beginning of the flood event, to below 10 × 10
6 m
3 s
−1 in its later stages. The flood event is thought to have lasted between 2 and 10 weeks, with an estimated minimum total water volume of somewhere in the range of 11,000 to 65,000 km
3.
Intermittent volcanism and related flood events like that which occurred at Ravi Vallis, are known to have occurred in other regions of Mars, such as at
Kasei Valles,
[Keskea, A., C. Hamilton, A. McEwen, I. Daubar. Episodes of fluvial and volcanic activity in Mangala Valles, Mars. Icarus:245, 333-347.] and
Mangala Valles.
Gallery
See also
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Chaotic terrain
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Geology of Mars
The geology of Mars is the scientific study of the surface, crust, and interior of the planet Mars. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is analogous to the field of terrestrial geo ...
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List of areas of chaotic terrain on Mars
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Martian chaotic terrain
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Outburst flood
In geomorphology, an outburst flood—a type of megaflood—is a high-magnitude, low-frequency catastrophic flood involving the sudden release of a large quantity of water. During the last deglaciation, numerous glacial lake outburst floods were ...
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Outflow channels
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Vallis (planetary geology)
''Vallis'' or ''valles'' (plural ''valles'' ) is the Latin word for ''valley''. It is used in planetary geology to name landform features on other planets.
Scientists used ''vallis'' for old river valleys they discovered when they sent the first ...
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Water on Mars
Although very small amounts of liquid water may occur transiently on the surface of Mars, limited to traces of dissolved moisture from the atmosphere and thin films, large quantities of ice are present on and under the surface. Small amounts of ...
References
{{Portal bar, Solar System
Margaritifer Sinus quadrangle
Valleys and canyons on Mars