The Elysium Fossae are a group of large troughs in the

Elysium quadrangle The Elysium quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Elysium quadrangle is also referred to as MC-15 (Mars Chart-15). The name Elysium r ...

of Mars at 24.8° north latitude and 213.7° west longitude. They are about 1,175 km long and are named after a classical albedo feature name.

Troughs

Large troughs (long narrow depressions) are called fossae in the geographical language used for Mars. Troughs are created when the crust is stretched until it breaks. The stretching can be due to the large weight of a nearby volcano. Fossae/pit craters are common near volcanoes in the Tharsis and Elysium system of volcanoes. A trough often has two breaks with a middle section moving down, leaving steep cliffs along the sides; such a trough is called a graben. Lake George, in northern

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, is a lake that sits in a graben. ESP 045741 2080troughs.jpg, Troughs showing layers and dark slope streaks, as seen by HiRISE under HiWish program

Layers

The Elysium Fossae contain layers, also called strata. Many places on Mars show rocks arranged in layers. Sometimes the layers are of different colors. Light-toned rocks on Mars have been associated with hydrated minerals like sulfates. The

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'' examined such layers close-up with several instruments. Some layers are probably made up of fine particles because they seem to break up into find dust. Other layers break up into large boulders so they are probably much harder. Basalt, a volcanic rock, is thought to in the layers that form boulders. Basalt has been identified on Mars in many places. Instruments on orbiting spacecraft have detected clay (also called phyllosilicates) in some layers. Scientists are excited about finding hydrated minerals such as sulfates and clays on Mars because they are usually formed in the presence of water. Places that contain clays and/or other hydrated minerals would be good places to look for evidence of life. Rock can form layers in a variety of ways. Volcanoes, wind, or water can produce layers. Image:Elysium Fossae.JPG, Elysium Fossae, 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 o ...

. Click on image to see layers.

Troughs

Layers

References

See also