Marte Vallis is a valley in the Amazonis quadrangle of Mars, located at 15 North and 176.5 West. It is 185 km long and was named for the Spanish word for "Mars". It has been identified as an

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 ...

, carved in the geological past by catastrophic release of water from

aquifers 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 ...

beneath the Martian surface. The surface material is thought to have been created out of 'a'ā and pāhoehoe lava flows from the Elysium volcanic province in the west. Marte Vallis is the site of the first discovery of

columnar jointing Columnar jointing is a geological structure where sets of intersecting closely spaced fractures, referred to as Joint (geology), joints, result in the formation of a regular array of polygonal Prism (geometry), prisms, or columns. Columnar join ...

on Mars.Milazzo, M.P., Keszthelyi, L.P., Jaeger, W.L. Rosiek, M., Mattson, S., Verba, C., Beyer, R.A., Geissler, P.E., McEwen, A.S., and the HiRISE Team. (2009) Discovery of columnar jointing on Mars. Geology. 37(2), 171–174
Abstract
/ref> Columnar jointing often forms when basalt lava cools.Bates, R. and J. Jackson (eds.) 1976. Dictionary of Geological Terms. Doubleday, New York. File:Marte Vallis Island.JPG, Streamlined Island in Marte Vallis, as seen by

HiRISE High Resolution Imaging Science Experiment is a camera on board the '' Mars Reconnaissance Orbiter'' which has been orbiting and studying Mars since 2006. The 65 kg (143 lb), US$40 million instrument was built under the direction ...

. The enlarged image gives a good view of dark slope streaks. Island is just to the west of Pettit Crater. Scale bar is 500 meters long. ESP 045120 1905layers.jpg, Layers in old crater rim, in Marte Vallis as seen by HiRISE under HiWish program 45120 1905layers.jpg, Close view of layers from previous image, as seen by HiRISE under HiWish program Some dark slope streaks are visible. Image:Columnar Jointing in Yellowstone.JPG, Columinar Jointing in

Yellowstone National Park Yellowstone National Park is a List of national parks of the United States, national park of the United States located in the northwest corner of Wyoming, with small portions extending into Montana and Idaho. It was established by the 42nd U ...

. Image:Giants-causeway-in-ireland.jpg, Columnar jointing in the basalt of the

Giant's Causeway The Giant's Causeway () is an area of approximately 40,000 interlocking basalt columns, the result of an ancient volcano, volcanic fissure eruption, part of the North Atlantic Igneous Province active in the region during the Paleogene period. ...

Northern Ireland Northern Ireland ( ; ) is a Countries of the United Kingdom, part of the United Kingdom in the north-east of the island of Ireland. It has been #Descriptions, variously described as a country, province or region. Northern Ireland shares Repub ...

References

See also