Tyrrhenus Mons, formerly Tyrrhena Mons or Tyrrhena Patera, is a large

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

in the

Mare Tyrrhenum quadrangle The Mare Tyrrhenum 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. This quadrangle (geography), quadrangle is also referre ...

of Mars, located at 21.36° south latitude and 253.47° west longitude. The name "Tyrrhena Patera" now refers only to the central depression, a

volcanic crater A volcanic crater is an approximately circular depression in the ground caused by volcanic activity. It is typically a bowl-shaped feature containing one or more vents. During volcanic eruptions, molten magma and volcanic gases rise from an ...

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

. It was named after a classical albedo feature name. Pit chains are found at the summit of Tyrrhenus Mons. They are formed by collapse of material into underground voids. Since they form chains and concentric fractures that are aligned, they are probably caused by extension of the surface. Volcanic processes made the crust pull apart. Voids were formed, then material fell into them, leaving holes. It is one of the oldest volcanoes on Mars. As a consequence of its old age, Tyrrhenus Mons has many radiating gullies on its slope. When it was formed, magma may have gone through frozen ground and then erupted as easily eroded ash, instead of lava flows.Hartmann, W. 2003. A Traveler's Guide to Mars. Workman Publishing. NY NY.

Images

Image:Mare Tyrrhenum map.JPG, Map of

. Image:057Tyrrhena_Patera.png, Tyrrhenus Mons - a major

. Image:Tyrrhena Patera.JPG, Pit crater chains around Tyrrhenus Mons.

References

Mare Tyrrhenum quadrangle Volcanoes of Mars Shield volcanoes {{Mars-stub