Ravi Vallis is an ancient
outflow channel, 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 (MC-19) region of
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...
, 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 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, permeable rock, rock fractures, or unconsolidated materials ( gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characte ...
. 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 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
The Kasei Valles are a giant system of canyons in Mare Acidalium and Lunae Palus quadrangles on Mars, centered at 24.6° north latitude and 65.0° west longitude. They are long and were named for the word for "Mars" in Japanese. This is one ...
,
[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
In astrogeology, chaos terrain, or chaotic terrain, is a planetary surface area where features such as ridges, cracks, and plains appear jumbled and enmeshed with one another. Chaos terrain is a notable feature of the planets Mars and Mercury, ...
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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 g ...
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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
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Outflow channels
Outflow channels are extremely long, wide swathes of scoured ground on Mars. They extend many hundreds of kilometers in length and are typically greater than one kilometer in width. They are thought to have been carved by huge outburst floods.
...
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Vallis (planetary geology)
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Water on Mars
Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere. What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae, may be grains of ...
References
Margaritifer Sinus quadrangle
Valleys and canyons on Mars
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